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Month: October 2024

  • 9th Class Biology Chapter 6: Enzymes

    9th Class Chapter 6: Enzymes Short and Simple Question & Answer

    Our experienced staff has prepared the class 9 biology notes for Punjab Board Biologyclass 9 biology notes 2024 especially for class 9 science students. These areclass 9 biology notes for class 9 biology guess paper and Important Question 2024. This is one of the best ways to get good marks in the exam. Many students practice 2024 Biologyclass 9 biology notes by FAIZ UL ISLAM and get good marks in the exam.

    Q.1. What do you mean by metabolism? Also write its importance and types?

    Ans: Metabolism: “It is the set of biochemical reactions that occur in living things in order to maintain life”, The term metabolism is derived from a Greek word meaning “change”.
    First time Ibn-e-Nafees gave the concept of metabolism. According to his concept “the body and its parts are always undergoing change.
    Importance of metabolism: Metabolism helps organisms to grow, reproduce maintain their structures, respond to their environments.
    and Types of metabolism: There are two types of metabolism:Anabolism: In this type of metabolism larger molecules are produced. Energy is used in anabolism.Catabolism: In this type of metabolism larger molecules are broken down. Energy is released in catabolism. Note: Energy is transferred in biochemical reactions (metabolism).

    Q.2. Define enzymes, substrate and products?

    Ans: Enzymes: “Enzymes are proteins that speed up biochemical reactions and are not changed during the reaction”. They are also called biocatalysts. They also lower the activation energy.
    In 1878, German physiologist Winhelm Kuhne first used the term enzyme.
    Substrate: “These are the molecules at which enzyme acts”.
    Products: “Enzyme converts substrate into different molecules called products”.

    Q.3. What is the importance of enzymes ir metabolism?

    Ans: Enzymes are biocatalysts. They speed up and regulate metabolic pathways. Enzymes convert chemicals from one form to the other during metabolism. Almost all processes in a cell need enzymes.

    Q.4. Explain classification of enzymes?

    Ans: Enzymes are classified into two types on the basis of the site where they work.Intracellular enzymes: “These enzymes work inside the cells where they are formed”. For example enzymes of glycolysis are present in @ytoplasm.Extracellular enzymes: “These enzymes work in cavities outside the cells”. For example pepsin enzyme works in the stomach cavity.

    Q.5. Define activation energy? Explain how enzymes lower activation energy through a diagram?

    Ans: Activation energy: “It is minimum amount of energy required to start a reaction”.
    Importance of activation energy:
    a) It breaks chemical bonds and starts a chemical reaction.
    b) It acts as a barrier to the beginning of reaction.
    c) Enzymes lower such barriers by decreasing the requirement of activation energy.
    d) Thus a reaction proceeds fast in presence of enzymes.
    Methods of lowering the activation energy: Enzymes lower the activation
    energy in many ways. They do this:
    a) By changing the shape of substrate (and reduce the need of energy for this change).
    b) By disturbing the charge distribution on substrates. b c) By bringing substrates in proper direction to react.

    Q.6. Describe characteristics of enzymes?

    Ans: Characteristics of enzymes:Chemical nature Almost all enzymes are proteins. They are made of amino acids.
    (Enzymes are globular proteins which are made of long chains of amino acids. These chains fold and
    form a three dimensional molecule) 2. Speed up the reaction: Enzymes increase the rates of reaction millions times than the reactionswithout enzymes. Enzymes are not consumed in the reactions.Specificity: Enzymes are very specific for a reaction and their substrates. 4. Active site: It is a small portion of enzyme molecule which is involved in catalysis. It identifies and binds substrate and then carries out reaction.Regulation of enzyme activity: Enzyme production can be increased or decreased by a cell according to needs. Enzyme activity can also be regulated by inhibitors and activators.
    a) Inhibitors: These are the small molecules which decrease the rate of reaction controlled by an enzyme. For example some drugs and poisons.
    b) Activators: These are inorganic ions which increase the rate of reaction controlled by an
    enzyme. For example rate of reaction of salivary amylase enzyme increases in presence of
    chloride ions 6. Cofactors: The non-protein molecules or ions which are essential for activity of many enzymes are called cofactors.
    Types of cofactors: Cofactors have two types.
    a) Inorganic cofactors: In these carbon atoms are not essential. For example metal ions. b) Organic cofactors: In these carbon atoms are essential. For example flavin and heme.
    Types of organic cofactors: There are two types of organic cofactors.
    i) Prosthetic groups: If organic cofactors are tightly bound to enzyme, they are called prosthetic groups.
    ii) Coenzymes: If organic cofactors are loosely attached with enzyme, they are called
    coenzymes. They transport chemical groups from one enzyme to another. Vitamins like
    riboflavin, thiamine and folic acid are important coenzymes. 7. Metabolic pathways: Many enzymes work together in a specific order and form metabolic pathways. In this pathway, one enzyme takes the product of another enzyme as a substrate. After the reaction, the product is then passed to the next enzyme.

    Q.7. Describe different uses of enzymes in industries?

    Ans: Enzymes are mostly used in different industries for fast chemical reactions.
    i) Food industry: Enzymes that break starch into simple sugars are used in the production of white bread, buns etc.
    ii) Brewing industry: Enzymes break starch and proteins. The products are used by yeast for fermentation (to produce alcohol).
    iii) Paper industry: Enzymes break starch to lower its viscosity that helps in making paper.
    iv) Biological detergent: Protease enzymes are used for the removal of protein stains from clothes. Amylase enzymes are used for removal of starch stains in dish washing.
    Q.8. Describe different factors affecting the rate of enzyme action?

    Ans: Temperature, substrate concentration and pH are the factors that can affect the rate of
    enzyme action. 1) Temperature: An increase in temperature increases the rate of enzyme action but
    up to a certain limit.
    Optimum temperature: It is a specific temperature at which enzyme works with
    maximum rate. The optimum temperature for the many human enzymes is 37°C.
    Denaturation of enzyme: At very high temperature globular structure of enzyme is lost. It is called denaturation of enzyme. After this rate of enzyme action is rapidly decreased and may be blocked completely.
    (Temperature provides activation energy and kinetic energy in a reaction. So reactions are accelerated.)
    2) Substrate concentration:
    If enzymes are available, increase in substrate concentration increases the rate of reaction.
    If enzymes are kept constant and substrates are increased, a point is reached when further increase in substrate does not increase the rate of reaction.
    Saturation of active sites: It is a state when all active sites of enzymes are occupied and no free
    active sites are available for substrate. pH: (-ve log of H ions concentration)
    Optimum pH: It is a narrow range of pH when enzymes work with maximum rate. Enzyme activity is decreased or blocked with a small change in optimum pH.
    Change in pH can affect the ionization of the amino acids at the active site.
    Every enzyme has its specific optimum pll value.
    Pepsin enzyme works in stomach. It is active in acidic medium (low pH).
    Trypsin enzyme works in small intestine. It is active in alkaline medium (high pH).

    Q.9. Describe the mechanism of enzyme action?

    Ans: Mechanism of enzyme action:
    When enzyme attaches with substrate, a temporary enzyme-substrate (ES) complex is formed.
    Enzyme catalyzes the reaction and substrate is changed into product.
    After this ES complex breaks and enzyme and product are released. E+P
    E+S
    ES complex
    Models of mechanism of enzyme action:
    1) Lock and key model: In 1894, a German chemist Emil Fischer proposed this model.
    According to this model, both enzyme and substrate have specific shapes that fit exactly into one another. It explains enzyme specificity.
    2) Induced-fit model: In 1958, an American biologist Daniel Koshland proposed this model.
    According to this model, active site is not a rigid structure. It is molded into Fig: Induced fit model the required shape to perform its function. Induced fit model is more acceptable than “lock and key”
    model.

    Q.10. Write a note on specificity of enzymes?

    Ans: Specificity of enzymes:
    There are over 2000 known enzymes Each enzyme is involved only in one specific reaction.
    They are also substrate specific.
    Specificity of enzymes is determined by the shapes of their active sites.
    Active sites have specific shapes that fit with specific substrates.
    Example:
    a) Protease enzyme breaks peptide bonds in proteins. It does not work on starch.
    b) Amylase enzyme breaks starch into glucose. c) Lipase enzyme acts only on lipids. It digests them into fatty acids and glycerol.

    Q.12. In a range of 0-35°C, the rate of reaction of un enzyme is proportional to temperature, Above 35°C and below 0°C, enzyme activity slows down and eventually stops. Explain why?

    Ans. Above 35°C globular structure of enzyme is lost. This is known as denaturation of of enzyme. It results in a rapid decrease in rate of enzyme action and it may be blocked. Below optimum temperature (0°C) the reacting molecules move slowly so reaction slow down

    Q.13. What is the difference between catalyst and biocatalyst?

    Ans: Catalyst: It is a substance which speeds up chemical reaction and is not used itself during the reaction.
    Biocatalyst: It is a substance which speeds up chemical reaction in a living cell and is not used itself
    during the reaction.

    Q.14. Is there any relationship between lock and key model and induced fit model?

    Ans: Induced fit model is a modified form of lock and key model.

    Q.15. All biocatalysts are protein in nature or not?

    Ans: All biocatalysts are not protein in nature some RNA molecules also catalyze reactions.

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  • 9th Class Biology Chapter 7: Bioenergetics

    9th Class Chapter 7: Bioenergetics Short and Simple Question & Answer

    Our experienced staff has prepared the class 9 biology notes for Punjab Board Biologyclass 9 biology notes 2024 especially for class 9 science students. These areclass 9 biology notes for class 9 biology guess paper and Important Question 2024. This is one of the best ways to get good marks in the exam. Many students practice 2024 Biologyclass 9 biology notes by FAIZ UL ISLAM and get good marks in the exam.

    Q.1. Explain cell works as open system?

    Ans: A cell works as open system. It means that substances are entering and leaving the cell all the times. Substances that are entered into cell are converted into products through metabolism. Cell uses these products and also transports them to other cells.

    Q.2. Explain different forms of energy in living organisms?

    Ans: Energy is used in breakdown of substances and also in formation of products inside the cell.
    Forms of energy: In living organisms, energy exists in two forms:Kinetic energy (K.E): It is involved in doing work.Potential energy (P.E): It is stored for future use.P.E is stored in chemical bonds and is released as kinetic energy when these bonds brea

    Q.3 Define bioenergetics? Explain energy transformation in organisms?

    Ans: Bioenergetics: It is the study of energy relationships and energy transformations in living organisms.
    Energy transformation in organisms: a. Organisms obtain energy by metabolizing the food.
    b. Food contains potential energy in its bonds.
    c. Large amount of kinetic energy is released after breakdown of these bonds.
    d. Some K.E is stored in ATP molecules as potential energy. Remaining K.E is released as heat.
    e. P.E of ATP is changed into K.E to carry out life activities.

    Q.4. What is meant by oxidation-reduction reaction (redox reaction)? How it acts as energy source

    Ans: In these reactions electrons are exchanged between atoms
    Oxidation: Loss of electrons is called oxidation.
    Reduction: Gain of electrons is called reduction.
    Oxidation-reduction reaction (redox reaction): It is a reaction in which oxidation and reduction occur simultaneously. arrangement in atoms. For example:
    Electrons as energy source: Electrons can be an energy source. It depends upon their location and
    a) When electrons are present in oxygen, they are not good energy source due to stable connection with oxygen atom.
    b) When electrons are removed from oxygen and attached to carbon or hydrogen atom, then they relçase energy aridiinove back to oxygen atom.
    Role of hydrogen in living organisms redox reaction involves the loss and gain of hydrogen atom (contains one proton and one electron).
    Oxidation: Loss of hydrogen atom is called oxidation. It actually involves loss of an electron.
    Reduction. Gain of hydrogen atom is called reduction. It actually involves gain of an electron.
    Significance of redox reactions: Redox reactions are the direct source of energy for all life processes like movement, growth and reproduction etc.

    Q.5. Why ATP? Interpret that ATP is the major energy currency of all cells?

    Ans ATP: Adenosine triphosphate (ATP) is the major energy currency of all cells. ATP was discovered by Karl Lohmann in 1929.
    Fritz Lipmann in 1941 proposed that ATP is the main energy transfer molecule in the cell. Uses of ATP: It is the main energy source for many cellular functions like:
    a) Synthesis of DNA, RNA, and proteins
    d) Active transport
    e) Exocytosis and endocytosis.
    ATP molecule
    b) Movement
    c) Transmission of nerve impulses
    Structure of ATP: ATP molecule has three subunits:
    . Adenine: It is a double-ringed nitrogenous base. a
    b. Ribose: It is a five-carbon suge
    c. Phosphate groups: Three phosphate groups in a linear chain.
    ATP as energy currency/source: The covalent bond connecting two phosphate groups is indicated by
    the “tilde” (~). It is a high energy bond. The energy in this bond is released when one phosphate (Pi) isBIOENERGETICS,
    separated from ATP. When one phosphate bond breaks, then 7.3 kcal (7,300 calories) energy is released and ADP (adenosine diphosphate) is formed.
    ATP+H₂O
    ADP+ Pl+ energy (7.3 kcal/mole)
    In some cases, ADP is further broken down to AMP (adenosine monophosphate) and Pi as follows:
    ADP+H₂O
    AMP+Pi+ energy (7.3 kcal/mole)
    A cell can form ATP by recombining ADP with Pi by using 7.3 kcal of energy per mole. This energy is obtained from the oxidation of foodstuff.
    ➤ ATP is generated by energy-releasing processes.
    ➤ ATP is broken down by energy-consuming processes.

    Q.6. Write a note on photosynthesis in plants?

    Ans: Photosynthesis: It is sa process in which plants prepare glucose (food) from carbon dioxide the presence of sunlight and chlorophyll, with oxygen as a by-product.
    and water in 1 SGD
    6CO₂ + 12H₂O
    chloropby!! light energy
    Importance of photosynthesis:
    a. Photosynthesis is an anabolic process.
    b. It is an important component of bioenergetics.
    c. All life depends on photosynthesis.
    C6H12O6 + 602 + 6H₂O
    d. It occurs in plants, some protists (algae), and some bacteria.
    Q.7 Ans: Water and carbon dioxide are the raw materials of photosynthesis.
    . Write a note on intake of water and carbon dioxide in plants during photosynthesis?
    Intake of water: (through osmosis)
    Water in soil is absorbed by roots and root hairs through o
    This water is transported to leaves through xylem tissues
    Intake of CO2: (through diffusion)
    Air enters into the leaf through stomata.
    Then this air reaches into the air spaces present around mesophyll cells.
    Here CO₂ present in the air is absorbed in water, (around mesophyll cells) and then it diffuses into
    mesophyll cells.
    ➤ Stomata cover 1-2% of the leaf surface but large amount of air is passed through them.

    Q.8.Summarize two major phases of mechanism of photosynthesis?

    Ans: Mechanism of photosynthesis: Photosynthesis occurs in two phases which are called light reactions
    and dark reactions.
    Light Reactions
    Light energy is needed in these reactions.
    Lightenergy is used to make high-energy
    molecules ATP and NADPH).
    They occtir on thylakoid of chloroplast.

    Q.9 Describe the mechanism of light reactions? Light Reactions: The summary of light reactions is as follows:

    Ans: Dark Reactions Light reactions.
    energy is not needed in these
    Carbon dioxide is reduced into glucose by
    using energy of ATP and NADPH.
    They occur in stroma of chloroplast.
    a) When chlorophyll molecules absorb light, their energy level increases and their electrons are
    emitted.
    b) Electrons move through electron transport chain and form ATP.
    c) Light breaks water molecule (photolysis) and oxygen is released.
    d) The hydrogen atoms of water give electrons to chlorophyll and become ions (H’).
    e) The electrons of chlorophyll and the hydrogen ions reduce NADP into NADPH.
    Z-scheme: The whole series of light reactions is called Z- scheme due to its Z-shaped flow chart.
    Photolysis: Breakdown of compounds (water) in presence of light.

    Q.10. Describe the mechanism of dark reactions (Calvin cycle)?

    Ans: Malvin Calvin and his colleagues at the University of California discovered the details of dark reactions (Calvin cycle). The summary of dark reactions is as follows:
    a) CO₂ molecules combine with 3-carbon compounds and form 2 temporary 6-carbon compounds.
    b) Each 6-C compound divides into two 3- carbon compounds. ) c
    3-C compounds are reduced to 3-carbon carbohydrates in presence of ATP and NADPH.
    d) 3-carbon carbohydrates are used to make glucose and also to regenerate Fig: Dark Reaction (Calvin cycle) the original 5-carbon compounds (by using AΤΡ).
    Q.11. Describe the role of chlorophyll and light in photosynthesis?

    Ans: Role of light:
    Sunlight energy is absorbed by chlorophyll.
    It is converted into chemical energy to carry out photosynthesis.
    Only 1% of light is absorbed while the rest is reflected or transmitted.
    Light of different wavelengths (colors) are absorbed by different pigments. Blue and red lights carry out more photosynthesis.
    Role of chlorophyll:
    Pigments: These are the substances that absorb visible light. Different pigments absorb light of different wavelengths (colours).
    Photosystems: These are the clusters of photosynthetic pigments in thylakoid.
    Chlorophyll-a is the main photosynthetic pigment.
    Chlorophyll-b and carotenoids are called accessory pigments.
    Chlorophylls absorb mainly blue and red lights.
    Some wavelengths which are not absorbed by chlorophyll-a are absorbed by accessory pigments and
    vice-versa. Accessory pigments: These pigments help chlorophyll-a for absorption of light of different wavelength.

    Q.12. What is meant by limiting factor? Described limiting factors in photosynthesis?

    Ans: Limiting factor: It is an environmental factor whose absence of deficiency can decrease the rate of a metabolic reaction.
    Limiting factors in photosynthesis: Main limiting factors in photosynthesis are:
    a) Light intensity
    b) Temperature
    c) Concentration of CO2
    a) Effect of light: Rate of photosynthesis decreases as the light intensity decreases and increases as
    d) Availability of water
    light intensity increases. But at very high light intensity rate of photosynthesis becomes constant. Effect of temperature: Rate of photosynthesis decreases as the temperature decreases and increases
    b) as temperature increases but up to a limit. If light intensity is low then temperature has little effects on photosynthesis.
    c) Effect of CO2: Rate of photosynthesis increases with increase of CO₂ concentration. Very high concentration of CO2 causes closing of stomata and the rate of photosynthesis decreases.
    d) Effect of water: Free availability of water increases the rate of photosynthesis.

    Q.13. Define respiration and cellular respiration? How does respiration resemble with burning process

    Ans: Respiration: It is a process in which energy is produced in form of ATP by breakdown of C-H bonds of food in presence of oxygen.
    Cellular respiration: It is the cellular energy yielding process.
    Resemblance with burning process: The process of respiration is same to the burning process. When we burn a fuel, it uses oxygen and yields energy in the form of light and heat. In burning process oxygen is used to break the C-H bonds present in fuel molecules.

    Q.14. Explain different types of cellular respiration?

    Ans: Cellular respiration has two types:
    1) Aerobic respiration:
    a) Aerobic respiration occurs in presence of oxygen.
    2) Anaerobic respiration
    b) In it glucose is complete oxidized and large amount of energy is released.
    c) In the first phase glucose molecule (6C) is broken down into two molecules of pyruvic acid (3C).
    d) In the second phase, pyruvic acid molecules are completely oxidized into CO₂ and water and energy is released. The overall reaction is as follows.
    C6H12O6 + 602
    2) Anaerobic respiration (Fermentation):
    600₂ + 12120 + Energy
    a) Anaerobic respiration occurs in absence of oxygen.
    b) In it glucose is incomplete oxidized and less amount of energy is released.
    c) In the first phase glucose molecule (6C) is broken down into two molecules of pyruvi d) In the second phase, pyruvic acid molecule (C3H4O3) iş incompletely oxidized into ethyl alcohol
    ic acid (3C). or lactic acid.

    Q.15. Explain different types of anaerobic respiration (Fermentation)?

    Ans: Anaerobic respiration is classified as alcoholic fermentation and lactic acid fermentation.

    Alcoholic fermentation:
    a) It occurs in bacteria, yeast etc.
    b) In this pyruvic acid is broken down into alcohol (C2H5OH)) and CO2.
    Pyruvic Acid Lactic acid fermentation:
    Ethyl Alcohol + Carbon Dioxide
    a) It occurs in skeletal muscles of humans and other animals during hard physical exercises.
    b) It also occurs in bacteria present in milk.
    c) In this pyruvic acid molecule is converted into lactic acid (C3H6O3).
    Pyruvic Acid

    Q.16. Give the importance of fermentation?

    Ans: Importance of Fermentation:
    Lactic Acid There was no supply of O₂, at the time of evolution of life on Earth. So early organisms respired anaerobically and got energy for their life activities. 2. Free oxygen is available today. But still some bacteria and some fungi get energy from anaerobic respiration and are called anaerobes. Humans provide energy to their skeletal muscle cells during hard work through anaerobic respiration
    (Oxygen availability is not so much).

    Q.17. Explain the mechanism of respiration?

    Ans: Mechanism of respiration: Aerobic respiration is a continuous process. It is divided into three main
    Stages:1- Glycolysis
    1 . Glycolysis:
    2- Krebs cycle
    3- Electron transport chain (ETC)
    a) In glycolysis, glucose (6C) molecule is broken into two molecules of pyruvic acid (3C).
    b) It occurs in cytoplasm.
    c) It does not require oxygen. So it occurs in both respirations i.e. aerobic and anaerobic.

    Krebs cycle:
    a) In Krebs cycle, pyruvic acid molecules are completely oxidized and ATP, NADH and FADH2 are also formed.
    b) Before entering in Krebs cycle, pyruvic acid is changed into a 2-carbon compound called acetyl- CoA.
    c) This cycle was discovered by Sir Hans Krebs so it is called Krebs cycle.BIOENERGETICS, Class 9th

    Electron transport chain (ETC).
    a) It is the final step of cellular respiration.
    b) It is the transfer of electron on an electron transport chain.
    c) In this NADH and FADH₂ release electrons and hydrogen ions.
    d) These electrons are taken up by electron carriers. When electrons move through the series of electron carriers they lose energy, which is used to form ATP.
    e) At the end, electrons and hydrogen ions combine with molecular oxygen and form water.
    Krebs cycle
    Glycolysis
    Glucose
    Coenzymu
    NACH
    ADP FAD NAD
    COATP + NADH + FADH
    NADH+FADH
    H₂O ATP NAD+ [FAD

    Q.18. Write a note on energy budget of respiration?

    Ans: Energy budget of respiration: (Difference in ATP production b/w aerobic and anaerobic respiration)
    During aerobic respiration oxidation of one glucose molecule produces 36 ATP molecules.
    During anaerobic respiration oxidation of one glucose molecule produces only 2 ATP molecules. Because Krebs cycle and ETC are not present in it.
    ATP production during respiration:
    1) In glycolysis, NADH gives 02 ATP molecules. While 01 ATP molecule is spent during
    the transportation of NADH across mitochondria.
    2) In ETC, each NADH gives 03 ATP molecules.
    3) Each FADH₂ gives 02 ATP molecules.
    During glycolysis ATP formation = 2 ATP (during both aerobic and anaerobic respiration) During glycolysis 2 NADH-4 ATP (during aerobic respiration)
    During pyruvic acid oxidation 2 NADH = 6 ATP (during aerobic respiration)
    During Krebs cycle= 6 NADH 18 ATP (during aerobic respiration) During Krebs cycle 2 FADH24ATP (during aerobic respiration) During ETC, ATP formation 2 ATP (during aerobic respiration)

    Q.19. Differentiate between aerobic and anaerobic respiration?

    Ans: Aerobic Respiration
    It occurs in presence of oxygen.
    36 ATP molecules are formed in it.
    Its final products are CO2 and H2O.
    Anacrobic Respiration
    It occurs in absence of oxygen.
    2 ATP molecules are formed in it.
    Its final products are lactic acid or CO2 and ethanol.
    In this glycolysis occurs in cytoplasm while
    It occurs in cytoplasm.
    Krebs cycle and ETC occur in mitochondria.
    It is main energy source for most organisms.
    It is source of energy for anaerobic
    organisms, some aerobic organisms and also
    source of many products e.g. cheese etc.

    Q.20. Differentiate between respiration and photosynthesis?

    Ans: Photosynthesis
    It is an anabolic process.
    It is a catabolic process.
    It uses light energy and stores it in the form of
    It converts bond energy into chemical energy of ATP.
    bond energy.
    Respiration

    It occurs in all organisms.
    It occurs in some bacteria, all algae and plants.
    It occurs in cytoplasm and mitochondria.
    It occurs in chloroplast.
    It occurs all the time.
    It occurs in day time only.

    Q.21. Why is it said that all life forms are dependent on photosynthesis?

    Ans: Autotrophs prepare their food by photosynthesis. All other organisms need this food for energy source. So we can say that all life forms depend on photosynthesis.

    Q.22 What structures and phenomena are involved in the intake of carbon dioxide and water by plants?

    Ans: Intake of water takes place by roots, root hairs through osmosis. Intake of CO2 takes place by stomata through diffusion.

    Q.23. In what ways the respiratory energy is used in the body of organisms?

    Ans: It is used for growth, movement and reproduction etc.

    Q.24. What is NAD?

    Ans: Nicotinamide adenine dinucleotide (NAD) is a coenzyme.
    Its oxidized form is called NAD. Its reduced form is called NADH. It is formed by combining one electron and hydrogen to NAD. One form of NAD contains phosphate and called NADP

    Q.25. What is FAD?

    Ans: Flavin adenine dinucleotide (FAD) is a coenzyme. It gets 2 hydrogen atoms and reduces to FADH2.

    Q.26. Which common fuel is used by a cell?

    Ans: The most common fuel used by cell to get energy by cellular respiration is glucose.

    Q.27. Differentiate between palisade mesophyll and spongy mesophyll?

    Ans: Palisade mesophyll: It is the upper layer of mesophyll where photosynthesis occurs.
    Spongy mesophyll: It is the lower layer of mesophyll which contains many air spaces.

    Q.28. There is more chloroplasts in palisade mesophyll than in spongy mesophyll. Why?

    Ans: Because palisade cells are on upper surface so they get and absorb more light.

    Q.29 . Give difference of numbers of stomata of terrestrial and aquatic plants?

    Ans: Terrestrifil plantsthave more stomata in lower epidermis and aquatic plants have more stomata in upper epidermis,
    Q.30. Define mesophyll, variegated leaf, Acetyl CoA, Coenzyme A and starch?

    Ans: Mesophyll: It is the inner tissue of leaf whose cells are green because they contain chloroplasts. Variegated leaf: It is a leaf with alternating green and white patches. For example, leaf of Geranium.
    Acetyl CoA: It is used in oxidation of pyruvic acid. It is formed by combination of acetate with coenzyme-A.Coenzyme-A: It is an organic co-factor which is loosely attach with enzyme. Starch: It is a type of carbohydrate. Plants convert glucose into starch for storage.

    Q.31. What is the ultimate source of hydrogen for this reduction?

    Ans: Water In dark reaction, 3-carbon compounds are reduced to form carbohydrates.

    Q.32. How does transport of water and salts take place in non-vascular plants?

    Ans: In these plants water and salts reach the mesophyll cells of leaves by diffusion and osmosis.

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    9th Biologyclass notes 2024 PDF Download

    Since you are a 9th grade student, biology is an important and compulsory subject for you. Biology is a theoretical subject, so it is considered a difficult subject. No need to worry about the exam as we have downloaded the best class 9 biology guesses to score high in the exam. Our best guess consists of important short questions and long questions frequently asked in all Punjab boards in previous exams. We believe that any student can easily score well in class 9 Biology exam. At the request of students, our team prepared this document. You can better understand the nature of the paper by using our class 9 Biologyclass 9 biology notes. By using theseclass 9 biology notes PDF, you will understand what types of questions can be asked and how to conduct yourclass 9 biology notes. To develop this estimate, I referred to all previous exams and past papers over the last ten years, along with notes from Biology 9.

  • 9th Class Biology Chapter 8: Nutrition

    9th Class Chapter 8: Nutrition Short and Simple Question & Answer

    Our experienced staff has prepared the class 9 biology notes for Punjab Board Biologyclass 9 biology notes 2024 especially for class 9 science students. These areclass 9 biology notes for class 9 biology guess paper and Important Question 2024. This is one of the best ways to get good marks in the exam. Many students practice 2024 Biologyclass 9 biology notes by FAIZ UL ISLAM and get good marks in the exam.

    Q.1. Define Nutrition and Nutrients?

    Ans: Nutrition refers to the process by which organisms acquire and utilize food for energy, growth, and maintenance. Nutrients are substances essential for sustaining life and proper bodily function, including carbohydrates, proteins, fats, vitamins, and minerals.

    Q.2. Describe types of organisms on the basis of nutrition?

    Ans: Organisms are categorized based on their nutritional intake: autotrophs (produce their own food, like plants), heterotrophs (rely on external sources for food, like animals), and mixotrophs (capable of both autotrophic and heterotrophic nutrition, like certain bacteria).

    Q.3. How do plants get their food? Explain briefly?

    Ans: Plants primarily use photosynthesis to create their food. They absorb water and minerals from the soil and carbon dioxide from the air. Through photosynthesis, using sunlight, they convert these substances into glucose (food) and oxygen.

    Q.4. Define macronutrients and micronutrients. Explain mineral requirements of plants in detail?

    Ans: Macronutrients are nutrients required in larger quantities by plants, such as nitrogen, phosphorus, and potassium. Micronutrients are needed in smaller amounts, like iron, manganese, and zinc. Plants require minerals for various functions like growth, enzyme activity, and maintaining cellular structure.

    Q.5. What is the role of nitrogen and magnesium in plant growth?

    Ans: Nitrogen is crucial for plant growth as it aids in chlorophyll production, which is vital for photosynthesis. Magnesium is an essential component of chlorophyll, contributing to the green pigment in plants and playing a key role in photosynthesis.

    Q.6. How are inorganic and organic fertilizers important in agriculture?

    Ans: Inorganic fertilizers provide specific nutrients to plants in readily available forms. Organic fertilizers, derived from natural sources, improve soil structure and nutrient retention over time. Both types are essential in maintaining soil fertility and ensuring optimal plant growth in agriculture.

    Q.7. Discuss the hazards of the environment related to fertilizer use?

    Ans: Fertilizer use can lead to water pollution, soil degradation, air pollution, eutrophication, and biodiversity loss, affecting aquatic life, soil quality, air quality, and ecosystems.

    Q.8. Describe the sources, energy values, and functions of carbohydrates, proteins, and fats in detail?

    Ans: Carbohydrates (from grains, fruits) provide energy; proteins (from meat, beans) build tissues; fats (from oils, nuts) store energy, insulate, and aid in nutrient absorption.

    Q.9. What are minerals? Discuss their roles in the human body.

    Ans: Minerals are essential nutrients (like calcium, iron) crucial for body functions: bone health, oxygen transport, nerve signaling, and enzyme reactions.

    Q.12. Why are water and dietary fibers considered important in our diets?

    Ans: Water hydrates, aids digestion, and regulates body temperature. Dietary fibers (from fruits, vegetables) aid digestion, prevent constipation, and lower cholesterol.

    Q.13. What is a balanced diet? How would you relate it to age, sex, and activity?

    Ans: A balanced diet contains essential nutrients in appropriate proportions. Requirements vary based on age, sex, and activity level; e.g., athletes need more protein.

    Q.14. Define malnutrition. Describe its importance and forms?

    Ans: Malnutrition is a condition due to inadequate or excessive nutrient intake. Its importance lies in affecting growth, immunity, and overall health. Forms include undernutrition, overnutrition, and micronutrient deficiencies.

    Q.15. Describe effects of Malnutrition?

    Ans: Malnutrition can lead to stunted growth, weakened immunity, cognitive impairments, organ damage, and increased susceptibility to diseases.

    Q.16. Describe famine as the major cause of malnutrition?

    Ans: Famine, caused by food shortages, leads to widespread hunger and undernutrition in populations, resulting in malnutrition-related health issues.

    Q.17. Describe digestion and its phases?

    Ans: Digestion is the breakdown of food into absorbable nutrients. Phases include mechanical (chewing) and chemical (enzymatic breakdown) digestion in the mouth, stomach, and intestines.

    Q.18. Explain various parts of the digestive system and the process of digestion and absorption in detail?

    Ans: The digestive system comprises the mouth, esophagus, stomach, intestines, and associated organs. Digestion involves enzymes breaking down food into nutrients, which are then absorbed through the intestines into the bloodstream for use by the body.

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    We know you are looking for Class 9 Biologyclass 9 biology notes 2024 for Punjab Boards.class 9 biology notes play a critical role in every student’s life becauseclass 9 biology notes provide allclass 9 biology notes which have more chances in final exams. It is difficult to find the best and more accurateclass 9 biology notes from class 9 biology of the student. Likewise, if you are dealing with this problem, you don’t need to worry about it.

    We have uploaded important biology questions for class 9 to help you prepare for the exam. Our biology notes for Class 9 are equally useful for all Punjab Boards. Including BISE Lahore, BISE Jammu Kashmir, BISE Gujranwala, BISE Sahiwal, BISE Sargodha, BISE DG Khan, BISE Faisalabad BISE Multan.class 9 biology notes with mating scheme.

    9th Biologyclass notes 2024 PDF Download

    Since you are a 9th grade student, biology is an important and compulsory subject for you. Biology is a theoretical subject, so it is considered a difficult subject. No need to worry about the exam as we have downloaded the best class 9 biology guesses to score high in the exam. Our best guess consists of important short questions and long questions frequently asked in all Punjab boards in previous exams. We believe that any student can easily score well in class 9 Biology exam. At the request of students, our team prepared this document. You can better understand the nature of the paper by using our class 9 Biologyclass 9 biology notes. By using theseclass 9 biology notes PDF, you will understand what types of questions can be asked and how to conduct yourclass 9 biology notes. To develop this estimate, I referred to all previous exams and past papers over the last ten years, along with notes from Biology 9.

  • 9th Class Biology Chapter 9: Transport

    9th Class Chapter 9: Transport Short and Simple Question & Answer

    Our experienced staff has prepared the class 9 biology notes for Punjab Board Biologyclass 9 biology notes 2024 especially for class 9 science students. These areclass 9 biology notes for class 9 biology guess paper and Important Question 2024. This is one of the best ways to get good marks in the exam. Many students practice 2024 Biologyclass 9 biology notes by FAIZ UL ISLAM and get good marks in the exam.

    Q1: Why the cells are regarded as units of life?

    Ans: Cells are the primary sites for metabolic processes. That is why they are regarded as the “units of life.

    Q2: Why materials are transported to and from cells?

    Ans: Complex metabolic reactions occur in living organisms. In order to run their metabolism.
    cells need some materials from the environment and also need to place some materials into the environment. For this purpose, materials are transported to and from cells.

    Q3: What is the limitation of phenomenon of diffusion for transport?

    Ans: One method for the movement of molecule is diffusion but it alone cannot fulfill the needs. It takes much time for materials in solution to diffuse even a few inches.

    Q4: Why diffusion can work efficiently in unicellular and simple multicellular organisms?

    Ans: Diffusion can work only in unicellular and simple multicellular organisms because every corner of their body is in close and direct contact with the environment.

    Q5: Why diffusion cannot work efficiently in complex multicellular organisms?

    Ans: In complex multicellular bodies, cells are far apart from the environment and such bodies need a comprehensive system for the transport of materials.

    Q6: What are the functions of roots in plants?

    Ans: Functions of Roots:
    In addition to anchor the plant, roots perform two other vital functions. First; they absorb water and salts from soil. Second; they provide conducting tissues for distributing these substances to the tissues of stem.

    Q7: What is the difference between xylem and phloem tissues?

    Ans: XYLEM TISSUE
    Xylem tissue is responsible for the transport of water and dissolved substances from roots to aerial parts.
    It consists of vessel elements and tracheids.
    Phloem tissue is responsible for the conduction of dissolved organic matter (food) between different parts of plant body.
    It consists of sieve tube cells and companion cells.

    Q8: Discuss role of root hairs in plants for water and ion uptake.

    Ans: Root hairs provide large surface area for absorption. They grow out into spaces between soil particles where they are in direct contact with water. The cytoplasm of root hairs has higher concentration of salts than soil water, so water moves by osmosis into toot hairs. Salts also enter root hairs by diffusion or active transport.

    Q9: Define Transpiration?

    Ans: Transpiration: Transpiration is the loss of water from plant surface through evaporation. This loss may occur through stomata in leaves, through the cuticle present on leaf epidermis, and through special openings called lenticels present in the stems of some plants.

    Q10: Define stomatal transpiration?

    Ans: Most of the transpiration occurs through stomata and is called stomatal transpiration. The mesophyll cells of leaf provide large surface area for the evaporation of water.

    Q11: How air movement affects rate of transpiration?

    Ans: Effects of Air Movement: Wind (air in motion) carries away the evaporated water from leaves and it causes an increase in the rate of transpiration from the surfaces of mesophyll. When air is still, the rate of transpiration is reduced.

    Q12: Which factors affect the rate of transpiration?

    Ans: Following are some important factors affecting the rate of transpiration:
    Temperature,Air humidity,Air movement,Leaf surface area.

    Q13: Why transpiration is known as necessary evil?

    Ans: Transpiration is called a necessary evil. It means that transpiration is a potentially harmful process but is unavoidable too.
    Transpiration may be a harmful process in the sense that during the conditions of drought, loss of water form plant results in serious desiccation, wilting and often death. On the other. hand, transpiration is necessary too. It creates a pulling force called transpirational pull which is principally responsible for the conduction of water and salts.

    Q14: What is cohesion tension theory?

    Ans: According to cohesion tension theory, the force which carries water (and dissolved materials) upward through the xylem is transpirational pull. Transpiration creates a pressure difference that pulls water and salts up from roots.

    Q15: Define Transpiration pull?

    Ans: “When one water molecule moves up in the xylem of the leaf, it creates a pulling force that continues all the way to root. This pulling force created by the transpiration of water is called transpirational pull”.
    It also causes water move transversely (from root epidermis to cortex and pericycle).

    Q16: What is the effect of water stress in plants?

    Ans: There is strong evidence that even mild water stress results in reduced growth rate in plants.

    Q17: What are reasons for creation of transpirational pull?

    Ans: Following are the reasons for the creation of transpirational pull.
    Water is held in a tube (xylem) that has small diameter.
    Water molecules adhere to the walls of xylem tube (adhesion).
    Water molecules cohere to cach other (cohesion).

    Q18: llow food is transported in different parts of plants?

    Ans: Transport of food is through pressure-flow mechanism. In pressure-flow mechanism, food is moved from sources to sinks.

    Q19: What is difference between sources and sinks?

    Ans: Sources:
    Sources include the exporting organs, typically a mature leaf or storage organ.
    Sinks:
    Sinks are the areas of active metabolism or storage e.g. roots, tubers, developing fruits and leaves, and growing regions.
    A storage organ is capable of storing food and exporting the stored materials.
    Example:
    Root of beet is a sink in first growing season, but becomes source in next growing season, when sugars are utilized in the growth of new shoots.

    Q20: Discuss direction of transport of food and salts in plants?

    Ans: One way street:
    Xylem is a one way street from roots to leaves for water and salts.
    Two way Street:
    Phloem is a two way street for food. The direction of the movement of food is decided by supply and demand in sources and sinks.

    Q21: Give an example that plants need a lot of water?

    Ans: Plants need a lot of water. Young Brassica plants take up an amount of water equal to their shoot weight in about 5 hours. If that applied to us, we would have to drink 3 gallons of water an hour to stay alive.

    Q22: Which systems perform transport in humans?

    Ans: Transport of different materials in human body is performed by two systems.
    Blood circulatory system (Cardiovascular System)
    Lymphatic System
    The two systems are well coordinated and associated with each other.

    Q23: What is a closed circulatory system?

    Ans: Definition:
    It is a type of circulatory system in which the blood always remains in the blood vessels.
    Examples:
    Humans and other vertebrates.

    Q24: What is an open circulatory system?

    Ans: Definition:
    It is a type of circulatory system in which blood does not remain in the blood vessels.
    Example:
    Invertebrates like arthropods. See ilm

    Q25: What are the main components of human blood circulatory system?

    Ans: The main components of human blood circulatory system are:
    Blood,Heart,Blood vessels

    Q26: How is plasma separated from blood?

    Ans: Blood is taken from an artery and an anti-coagulant (a chemical that inhibits blood clotting) is mixed in it. After about 5 minutes, plasma separates from blood cells, which settle down.

    Q27: What do you know about blood?

    Ans: Blood:
    Blood is a specialized body fluid (a connective tissue) that is composed of a liquid called blood plasma and blood cells. The weight of blood in our body is about 1/12th of our body. The average adult body has about 5 litres of blood.

    Q28: Describe composition of plasma?

    Ans: Composition of Plasma:
    Plasma is primarily water in which proteins, salts, metabolites and wastes are dissolved. Water constitutes about 90-92% of plasma and 8-10% are dissolved substances. Salts make
    up 0.9% of plasma, by weight. Proteins make 7-9% by weight of plasma. The important proteins present in plasma are antibodies, fibrinogen, albumin etc. Plasma also contains the digested food, nitrogenous wastes and hormones. Respiratory gases i.e. CO₂ and O₂ are present in the plasma.

    Q29: Tell the number of RBCs in human blood?

    Ans: Males:
    A cubic millimeter of blood contains 5 to 5.5 million of RBCs in males,
    Females:
    A cubic millimeter of blood contains 4 to 4.5 million of RBCs in females.

    Q30: What are the two different types of WBCs?

    Ans: Types of WBCs:
    There are two main types of WBCS:
    (i) Granulocytes have granular cytoplasm. These include neutrophils, eosinophils and basophils.
    (ii) Agranulocytes have clear cytoplasm and include monocytes and B and T lymphocytes.

    Q31: What are Thrombocytes? Describe their function?

    Ans: They are not cells, but are fragments of large cells of bone marrow, called megakaryocytes. They do not have any nucleus and any pigment.
    Number:
    One cubic millimeter of blood contains 250,000 platelets.
    Lifespan:
    The average life span of a blood platelet is about 7 to 8 days. Platelets help in blood clotting. The clot serves as a temporary seal at the damaged area.

    Q32: Illow pus is formed?

    Ans: White blood cells die in the process of killing the germs. These dead cells accumulate and make the white substance called pus seen at the infection site.

    Q33: What happens in dengue fever?

    Ans: In dengue fever, there is a sharp decrease in the number of platelets in blood. Because of this, patients bleed from the nose, gums and under the skin.

    Q34: What is leukaemia?

    Ans: It is also called as blood cancer. Leukaemia is the production of great number of immature and abnormal white blood cells.
    Causes:
    This is caused by a cancerous mutation (change in gene) in bone marrow or lymph tissue
    cells. The mutation results in uncontrolled production of defective white blood cells
    (leukocytes).

    Q35: Write a short note on Thalassaemia?

    Ans: It is also called Cooley’s anaemia on the name of Thomas B. Cooley, an American physician. It is a genetic problem due to mutations in the gene of haemoglobin. The mutation results in the production of defective haemoglobin and the patient cannot transport oxygen properly.

    Q36: What is the incidence of thalassaemia in the world?

    Ans: There are about 60-80 million people in the world who carry thalassaemia. India, Pakistan, and Iran are seeing a large increase in thalassaemia patients. Pakistan alone has 250,000 such patients. These patients require blood transfusions for life-time.

    Q37: On what date International Thalassaemia day is celebrated? What is its aim?

    Ans: The world celebrates the International Thalassaemia Day on 8th of May. This day is dedicated to raise public awareness about thalassaemia and to highlight the importance of the care for thalassaemia patients.

    Q38: What is an antigen?

    Ans: “A substance which stimulates the production of an antibody when introduced into the body, i.e. it can stimulate an immune response is called an antigen.”

    Q39: What is the basis of blood group systems?

    Ans: Blood group systems are a classification of blood based products on the presence or absence ee ilm. of antigens on the surface of red blood cells.

    Q40: How many human blood groups systems have been studied till to date?

    Ans: A total of 29 human blood group systems are now recognized by the International Society of Blood Transfusion (ISBT).

    Q41: How many blood groups are there in ABO blood group system?

    Ans: ABO Blood System:
    In this system, there are four different blood groups which are distinct from each other on the basis of specific antigens (antigen A and B) present on the surface or RBCs.
    Blood Group A:
    A person having antigen A has blood group A.
    Blood Group B:
    A person having antigen B has blood group B.
    Blood Group AB:
    A person having both antigens has blood group AB.
    Blood Group O:
    A person having none of the A and B antigens has blood group O.

    Q42: Define blood transfusion?

    Ans: “Blood transfusion is the process of transferring blood or blood-based products from one
    person into the circulatory system of another”
    Blood transfusions can be life-saving in some situations, such as massive blood loss due to injury, or can be used to replace blood lost during surgery.

    Q43: Why the blood of donor should be checked before transfusion?

    Ans: A number of infectious diseases such as AIDS, Hepatitis B and C etc. can pass from the affected donor to the recipient. Before transfusion, the blood of donor is checked for germs etc.

    Q44: What is universal donor?

    Ans: Universal Donor:
    O blood group individuals are called universal donors, because they can donate blood to the recipients of every other blood groups.

    Q45: Who discovered Rh blood group system and also discuss its basis of classification.

    Ans: Discovery:
    In 1930’s Karl Landsteiner discovered the Rh-blood group system.
    Types of blood groups:
    In this system, there are two blood groups i.e. Rh-positive and Rh-negative. These blood groups are distinct from each other on the basis of antigens called Rh factors.

    Q46: Differentiate between pericardium and pericardial fluid?

    Ans: PERICARDIUM
    Heart is enclosed in a sac known as pericardium.
    It helps in protection of heart muscles.
    PERICARDIAL FLUID
    Pericardial fluid is a fluid present between pericardium and heart walls.
    It reduces friction between pericardium and heart, during heart contractions.

    Q47: Why heart is felt to be present on left side of our body?

    Ans: The heart is usually felt to be on the left side because the left chamber of the heart i.e. left ventricle is stronger and has a thicker wall. It pumps blood to all body parts.

    Q49: What is the mass and size of heart in normal adults?

    Ans: In normal adults, the mass of the heart is about 250-350 grams, and its size is equal to a clenched fist.

    Q50: How can we say that heart works as double pump?

    Ans: Human heart works as a double pump. It receives deoxygenated (with less oxygen) blood from body and pumps it to lungs. At the same time, it receives oxygenated (with more oxygen) blood from lungs and pumps it to all body. Inside heart chambers, the deoxygenated and oxygenated bloods are kept separated.

    Q51: Why the walls of the left ventricle are the thickest one?

    Ans: The walls of the left ventricle are the thickest one. These are about a half inch thick. They have enough force to push blood into the body. This gives an evidence that the structures of the parts of heart are adaptive to their function.

    52.Name and explain the valves present in

    Ans: Valves:
    The opening between right atrium and right ventricle is guarded by a valve known as tricuspid valve (because it has 3 flaps).
    At the base of pulmonary trunk, pulmonary semilunar valve is present in which prevents the backflow of blood from pulmonary trunk to right ventricle.
    The opening between left atrium and left ventricle is guarded by a valve known as bicuspid valve (because it has two flaps).
    Aortic semilunar valves

    Q53: Define pulmonary circulation?

    Ans: The pathway one which deoxygenated blood is carried from heart to lungs and in return oxygenated blood is carried from lungs to heart is called pulmonary circulation or circuit.

    Q54: What is systemic circulation?

    Ans: Systemic Circulation:
    “The pathway on which oxygenated blood is carried from heart to body tissues and in return deoxygenated blood is carried from body tissues to heart is called systemic circulation or circuit”.

    Q55: Justify that there is low blood pressure in pulmonary circulation?

    Ans: The blood in pulmonary circulation is at lower pressure than the blood in systemic circulation. It gives sufficient time to blood for gaseous exchange in lungs.

    Q56: What is meant by cardiac cycle? / Define heartbeat?

    Ans: “The relaxation of heart chambers fills them with blood and contractions of chambers propels blood out of them. The alternating relaxation and contractions make up the cardiac cycle and one complete cardiac cycle makes one heartbeat”.
    Duration:
    The total duration of cardiac cycle is 0.8 seconds.

    Q57: Define cardiac diastole?

    Ans: Cardiac diastole:
    “Atria and ventricles relax and blood is filled in atria. This period is called cardiac diastole.”
    Duration:
    The duration of cardiac diastole is 0.4 seconds.

    Q58: Define systole and diastole. / What is difference between systole and diastole?

    Ans: Systole:
    “The period of atrial and ventricular contraction is called systole.”
    Diastole:
    When Atria and ventricles relax blood is filled in atria. This period is called diastole.

    Q59: How the sound of lubb dubh is produced during heart beat?

    Ans: When ventricles contract, tricuspid and bicuspid valves close and “lubb” sound is produced. Similarly when ventricles relax, the semilunar valves close and “dubb” sound is produced. “Lubb-dubb” can be heard with the help of a stethoscope.

    Q60: What is the average human heartbeat?

    Ans: The average human heart beats 70 times/minute. So it would beat approximately 2.5 billion times during a life time of 66 years.

    Q61: Define pulse?

    Ans: “Pulse is the rhythmic expansion and contraction of an artery as blood is forced through it by the regular contractions of heart”.
    Pulse Points:
    Pulse can be felt at areas where artery is close to skin for example at wrist, neck, groin, or
    top of foot. Most commonly, people measure their pulse in their wrist.

    62.Write any two differences between arteries and veins?

    Ans:ARTERIES,VEINS
    Carry blood away from heart.
    Carry blood towards heart.
    Thick and elastic.
    Thin and less elastic.

    Q63: What is vascular surgery?

    Ans: Definition:
    The field in surgery in which diseases of arteries and veins are managed by surgical methods is called vascular surgery.
    Example: Thrombosis
    Vascular Surgeon:
    A vascular surgeon treats diseases of all parts of blood circulatory system except that of heart and brain.

    Q64: What is the contribution of Ibn-e-Nafees in the study of human blood circulatory system?

    Ans:Period:
    He is honored to be the first scientist who described the path way of blood circulation.

    Q65: What is the contribution of William Harvey in the study of human blood circulatory system?

    Ans: Contribution:
    He discovered the pumping action of heart and the pathway of blood in major arteries and veins.

    Q66: How heart muscles are supplied with blood?

    Ans: Even though the heart chambers are continually bathed with blood, this does not nourish heart muscles. The blood supply to heart muscles is provided by coronary arteries, which emerge from the base of aorta. Heart muscles are drained by coronary veins, which empty into right atrium. Coronary arteries and veins are collectively called coronary circulation and it is a part of systemic circulation.

    Q67: Write causes of cardiovascular disorders.

    Ans: Causes of Cardiovascular disorders:
    The causes that lead to cardiovascular disorders include:
    Advanced age Diabetes
    High blood concentration of low density lipids (e.g. cholesterol)
    Tobacco smoking,High blood pressure,Obesity,Sedentary lifestyle

    Q68: What is difference between atherosclerosis and arteriosclerosis?

    Ans: ATHEROSCLEROSIS
    It is commonly referred to as a “narrowing” of arteries.
    It is a chronic disease in which there is accumulation of fatty materials, cholesterol, or fibrin in arteries.
    ARTERIOSCLEROSIS
    It is a general term describing any hardening of arteries.
    It occurs when calcium is deposited in the walls of arteries.

    Q69: What is a silent heart attack?

    Ans: Approximately one fourth of all myocardial infarctions are silent i.e. without chest pain or other symptoms. A silent heart attack is more common in the elderly, in patients with diabetes mellitus and after heart transplantation.

    Q70: Define myocardial infarction?

    Ans: The term myocardial infarction is derived from myocardium (the heart muscle) and infraction (tissue death). It is more commonly known as a heart attack. It occurs when blood supply to a part of heart is interrupted and leads the death of heart muscles.

    Q71: What is Angioplasty and bypass surgery?

    Ans: Angioplasty:
    Angioplasty is a mechanical widening of a narrowed or totally obstructed blood vessels.
    Bypass Surgery: Surgery in which arteries or veins from elsewhere in the patient’s body are grafted to the coronary arteries to improve blood supply to heart muscles.

    Download PDF Format

    We know you are looking for Class 9 Biologyclass 9 biology notes 2024 for Punjab Boards.class 9 biology notes play a critical role in every student’s life becauseclass 9 biology notes provide allclass 9 biology notes which have more chances in final exams. It is difficult to find the best and more accurateclass 9 biology notes from class 9 biology of the student. Likewise, if you are dealing with this problem, you don’t need to worry about it.

    We have uploaded important biology questions for class 9 to help you prepare for the exam. Our biology notes for Class 9 are equally useful for all Punjab Boards. Including BISE Lahore, BISE Jammu Kashmir, BISE Gujranwala, BISE Sahiwal, BISE Sargodha, BISE DG Khan, BISE Faisalabad BISE Multan.class 9 biology notes with mating scheme.

    9th Biologyclass notes 2024 PDF Download

    Since you are a 9th grade student, biology is an important and compulsory subject for you. Biology is a theoretical subject, so it is considered a difficult subject. No need to worry about the exam as we have downloaded the best class 9 biology guesses to score high in the exam. Our best guess consists of important short questions and long questions frequently asked in all Punjab boards in previous exams. We believe that any student can easily score well in class 9 Biology exam. At the request of students, our team prepared this document. You can better understand the nature of the paper by using our class 9 Biologyclass 9 biology notes. By using theseclass 9 biology notes PDF, you will understand what types of questions can be asked and how to conduct yourclass 9 biology notes. To develop this estimate, I referred to all previous exams and past papers over the last ten years, along with notes from Biology 9.

  • 9th Class Biology Chapter 2: Solving a Biological Problem

    9th Class Chapter 2: Solving a Biological Problem Short and Simple Question & Answer

    Our experienced staff has prepared the class 9 biology notes for Punjab Board Biologyclass 9 biology notes 2024 especially for class 9 science students. These areclass 9 biology notes for class 9 biology guess paper and Important Question 2024. This is one of the best ways to get good marks in the exam. Many students practice 2024 Biologyclass 9 biology notes by FAIZ UL ISLAM and get good marks in the exam.

    Q1: Do you think that “Man has always been a biologist”? If so why?

    Ans: A man has always been a biologist. He had to be a biologist in order to live. Early in history, he was hunter of animals and a gatherer of fruits, seeds, roots etc. The more he knew about animals and their habitat, the more successful hunter he was. The more he knew about plants. the better he distinguished between edible and non-edible plants.

    Q2: Define Biological Method?

    Ans: “The scientific method, in which biological problems are solved, is termed as Biological Method.”
    It comprises the steps a biologist adopts in order to solve a biological problem.

    Q3: llow biological method has played an important part in scientific research?

    Ans: The biological method has played an instrumental role in scientific research for almost 500 vears.
    From Galileo’s experiment back in the 1590’s to current research, the biological method has contributed to advancements in medicine, ecology, technology, etc.
    The biological method ensures the quality of data for public use.

    Q4: Write steps of Biological Method in a sequence?

    Ans: Biological method involves the following main steps:
    Recognition of a biological problem
    Observations
    Hypothesis formulation
    Deductions
    Experimentation
    Summarization of results (tables, graphics etc.)
    Reporting the results

    Q5: Define Biological Problem?

    Ans: “A question related to living organisms that is either asked by some one or comes in biologist’s mind by himself is called biological problem”.
    Example: Malaria

    Q6: What is the difference between qualitative and quantitative observations?

    QUALITATIVE OBSERVATIONS
    Qualitative observations are considered less accurate
    These observations are variable and less measurable.
    These can not be recorded in terms of numbers.
    Examples:
    The freezing point of water is colder than its Boiling Point.
    A liter of water is heavier than a liter of ethanol.
    QUANTITATIVE OBSERVATIONS
    Quantitative observations considered more accurate are
    These observations are invariable and measurable.
    These can be recorded in terms of numbers.
    Examples:
    The freezing point of water is 0°C and the boiling point is 100°C.
    A liter of water weighs 1000 grams and a Liter of ethanol weighs 789 grams.

    Q7: Why quantitative observations are better in biological method?

    Ans: Quantitative observations are better because these are invariable and measureable and can be recorded in terms of numbers.
    Example:
    The freezing point t of water is 0°C and the boiling point is 100°C.

    Q8: How did Darwin formulate the theory of evolution?

    Ans: Darwin not only observed and took notes during his voyage, but he also read the works of other naturalists to form his theory of Evolution.

    Q9: Define hypothesis?

    Ans: “A tentative explanation of the observations is called hypothesis.”
    “A proposition that might be true is called hypothesis.”
    Example:
    OR
    Plasmodium is the cause of malaria

    Q10: How hypothesis is framed?

    Ans: A great deal of careful and creative thinking is necessary for the formulation of a hypothesis. Biologists use reasoning to formulate a hypothesis.

    Q11: What are the characteristics of a good hypothesis? ,

    Ans: A good hypothesis should have the following characteristics:
    It should be a general statement
    It should be a tentative idea.
    It should agree with available observations.
    It should be kept as simple as possible.
    It should be testable and potentially falsifiable. In other words, there should be a way to show that the hypothesis is false, a way to disprove the hypothesis.

    Q12: Define deductions. How deduction are formed?

    Ans: “The logical consequences of a hypothesis are called deductions”.
    Formulation:
    For this purpose, a hypothesis is taken as true and expected results are drawn from it. Generally, in a biological method, if a particular hypothesis is true, then one should expect (deduction) a certain result. It involves the use of “if-then” logic.

    Q13: Develop a deduction from the following hypothesis?
    “All plant cells have a nucleus.”

    Ans: “If1 examine cells from a blade of grass, then each one will have a nucleus.”

    Q14: Why a biologist go for experimentation during solving a biological problem?
    Ans: A biologist performs experiments to see if hypothesis are true or not.
    The deductions which are drawn from hypothesis are subjected to rigorous testing. Through experimentation, a biologist learns which hypothesis is correct.

    Q15: What is control in an experiment?

    Ans: In science, when doing an experiment, it must be a controlled experiment. A scientist must contrast an experimental group with a ‘control group”.
    The two groups are treated exactly alike except for the one variable being tested.
    Example:
    In an experiment to test the necessity for carbon dioxide during photosynthesis, one can contrast the control group (a plant with freely available carbon dioxide) with an experimental group (a plant with no carbon dioxide available). The necessity of carbon dioxide will be proved when photosynthesis occurs in the control group and does not occur in the experimental group.

    Q16: What are different ways of reporting results of biological method?

    Ans: Biologists publish their findings in scientific journals and books, in talks at national and international meetings and in seminars at colleges and universities.
    Importance:
    Publishing of results is an essential part of the scientific method. It allows other people to verify the results or apply the knowledge to solve other problems.

    Q17: How did physicians describe malaria in early days?

    Ans:The carly physicians described malaria as a disease of chills and fevers with recurring attacks.
    They also observed that the disease was more common among people living in low. marshy areas.

    Q18: What was the possible cause of malaria in early days?

    Ans: It was thought in early days that stagnant water of marshes poisoned the air and as a result of breathing in this “Bad Air”, people got malaria.

    Q19: What does the word malaria mean?

    Ans: The word malaria has been derived from two Italian words:
    “Mala’ means ‘bad’
    “Aria’ means “air”

    Q20: What was the treatment of malaria in early days?

    Ans: In the 17th century, when the New World (America) was discovered, many plants from America were sent back to Furope to be used as medicines. The hark of a tree known as ‘quina-quina” was very suitable for curing fevers. It was so beneficial that it soon became impossible to carry enough bark to Furope. Some dishonest merchants began to substitute the hark of another tree, the “cinchona’ which closely resembled quina-quina. This dishonesty proved much valuable for mankind. The cinchona bark was found to be excellent for treating malaria. The cinchona bark contains quinine which is effective in treating the disease. Quinine was the only effective remedy for malaria from 17th-20th century.

    Q21: Describe the contributions of Laveran in discovery of Plasmodium?

    Ans: Contribution of Laveran
    In 1878, a French army physician Laveran began to search for the cause of malaria.
    Experiments:
    He took a small amount of blood from a malarial patient and examined it under a microscope. He noticed some tiny living creatures. His discovery was not believed by other scientists.
    Confirmation:

    Two years later, another physician saw the same creatures in the blood of another malarial patient.
    Three years later after this second discovery, the same creatures were observed for the third time.
    Naming of Organism:
    The organism was named ‘Plasmodium”.

    Q22: What were observations for malaria until 19th century?

    Ans: In the last part of 19th century, many different causes of malaria were being suggested. By that time there were four major observations about malaria.
    Malaria and marshy areas have some relation.
    Quinine is an effective drug for treating malaria.
    Drinking water from marshes does not cause malaria.
    “Plasmodium” is seen in the blood of malarial patients.

    Q23: What is incubation period?

    Ans: “The period between the entry of parasite in host and the appearance of symptoms is called incubation period.”

    Q24: Design a deduction from following hypothesis. “Plasmodium is cause of malaria?

    Ans: One of the deductions from the above hypothesis can be:
    ‘If Plasmodium is the cause of malaria, then all persons ill with malaria should have Plasmodium in their blood’.

    Q25: Write down observations of A.F.A king about malaria?

    Ans: In 1883, a physician, A.F.A King, listed 20 observations:
    Some of his important observations were:
    People who slept outdoors were more likely to get malaria than those who slept indoors.People who slept under fine nets were less likely to get malaria than those who did not use such nets.
    Individuals who slept near a smoky fire usually did not get malaria.

    Q26: What is required for the maturation of eggs of female mosquito?

    Ans: Female mosquitoes need blood of mammals or birds for the maturation of their eggs.

    Q27: Why Ronald Ross used sparrow in his experiment?

    Ans: Ronald Ross used sparrow in his experiment because scientists avoid using human beings for experiments when results could be so serious.

    Q28: How did Ross prove that mosquitoes transmit plasmodium and spread malaria?

    Ans: Ronald Ross, a British army physician working in India, in 1880’s, performed important experiments.
    Experiment 1:
    He allowed a female Anopheles mosquito to bite a malarial patient.
    He killed the mosquito some days later.
    On examining the mosquito, Plasmodium was found multiplying in mosquito’s stomach.
    Experiment 2:
    He allowed a female Culex mosquito to bite the sparrows suffering from malaria.
    Some of the mosquitoes were killed and studied at various times.
    Ross found that Plasmodium multiplied in the wall of mosquito’s stomach and then moved into the mosquito’s salivary glands.
    He kept some of the mosquitoes alive and allowed them to bite healthy sparrows.
    Results:
    Ross found that saliva of the infected mosquitoes contained Plasmodia and these entered sparrow’s blood. When he examined the blood of these previously healthy sparrows, he found many Plasmodia in it.

    Q29: Why does female mosquito injects small amount of saliva into the wound?

    Ans: When a female mosquito pierces the skin with her mouth parts, she injects a small amount of saliva into the wound before drawing blood. This saliva prevents the blood from clotting in her food canal.

    Q30: Why do welts appear after mosquito bite?

    Ans: The welts that appear after the mosquito leaves is not a reaction to the wound, but an allergic reaction to the saliva. In most cases, the itching sensation and swellings subside within several hours.

    Q31: What is scientific law? Give two examples?

    Ans: “If a theory survives doubtful approach and continues to be supported by experimental evidence, it becomes a law or principle.”
    A scientific law is a uniform or constant fact of nature. It is an irrefutable theory.
    Examples:
    Hardy-Weinberg law and Mendel’s laws of inheritance.

    Q32: What is difference between theory and law?

    Ans: Theory A hypothesis that stands the test of time (often tested and never rejected) is
    called theory.
    A theory may be challenged.
    A theory can be altered in case of new evidence.
    A theory is always subjected to new testing
    Example:
    Darwin’s theory of evolution
    Law
    A scientific law is a uniform, constant fact of nature. It is irrefutable theory.
    A law cannot be challenged.
    A law is already an established and definite entity. It cannot be altered.
    A law is not subjected to further testing.
    Example: Hardy-Weinberg Law

    Q33: Define data?

    Ans: “The information such as names, dates, or values made from observations and experimentation is called data.”

    Q34: In which formats data is organized?

    Ans: Data is organized into different formats like:
    Graphics
    Tables
    Flow-charts
    Maps
    Diagrams

    Q35: Define ratio?

    Ans: “When a relation between two numbers e.g. ‘a’ and ‘b’ is expressed in terms of quotient (a/b) it is called the ratio of one number to the other.”
    Expression of a ratio:
    A ratio is expressed by putting a division (+) or colon (:) mark between two numbers.
    Example:
    The ratio between 50 malarial patients and 150 normal patients is 1:3.

    Q36: In what major biological problems is the knowledge of Mathematics used?

    Ans: Major biological problems, in which knowledge of mathematics is used include:

    • Gene finding
    • Protein structure
    • Protein-protein interactions

    Q37: Define Bioinformatics?

    Ans: “The use of the computational and statistical techniques for the analysis of biological data is called bioinformatics.”

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    We have uploaded important biology questions for class 9 to help you prepare for the exam. Our biology notes for Class 9 are equally useful for all Punjab Boards. Including BISE Lahore, BISE Jammu Kashmir, BISE Gujranwala, BISE Sahiwal, BISE Sargodha, BISE DG Khan, BISE Faisalabad BISE Multan.class 9 biology notes with mating scheme.

    9th Biologyclass notes 2024 PDF Download

    Since you are a 9th grade student, biology is an important and compulsory subject for you. Biology is a theoretical subject, so it is considered a difficult subject. No need to worry about the exam as we have downloaded the best class 9 biology guesses to score high in the exam. Our best guess consists of important short questions and long questions frequently asked in all Punjab boards in previous exams. We believe that any student can easily score well in class 9 Biology exam. At the request of students, our team prepared this document. You can better understand the nature of the paper by using our class 9 Biologyclass 9 biology notes. By using theseclass 9 biology notes PDF, you will understand what types of questions can be asked and how to conduct yourclass 9 biology notes. To develop this estimate, I referred to all previous exams and past papers over the last ten years, along with notes from Biology 9.

  • 9th Class Biology Chapter 1: Introduction To Biology

    9th Class Chapter 1: Introduction To Biology Short and Simple Question & Answer

    Our experienced staff has prepared the class 9 biology notes for Punjab Board Biologyclass 9 biology notes 2024 especially for class 9 science students. These areclass 9 biology notes for class 9 biology guess paper and Important Question 2024. This is one of the best ways to get good marks in the exam. Many students practice 2024 Biologyclass 9 biology notes by FAIZ UL ISLAM and get good marks in the exam.

    Q1: What is Science?

    Ans: “Science is the study in which observations are made, experiments are done and logical conclusions are drawn in order to understand principles of nature.”

    Q2: Why was the scientific information not classified into different branches?

    Ans: In ancient times, the scientific information was not classified into different branches, as it exists today. All the scientific information was included under one head i.e. ‘science’.
    Reason:
    With the passage of time scientific information increased many folds and this enormous scientific knowledge was then classified into different branches like:
    Biology
    Physics
    Chemistry
    Mathematics

    Q3: What are the thoughts of Dr. Abdus Salam about science?

    Ans: According to Dr. Abdus Salam, “Scientific Knowledge is common heritage of mankind.”

    Q4: Define Biology and write also its meaning and derivation?

    Ans: The word “biology” has been derived from two Greek words.’bios’ meaning ‘life’
    logos’ meaning thought or reasoning’
    “The scientific study of life is called Biology.”

    Q5: What is the benefit of the study of living things?

    Ans: To understand and appreciate nature, it is essential to study the structures, functions and related aspects of living organisms. The study of living organisms provides information and remedies to human problems regarding:
    Health
    Food
    Environment

    6. What is difference between Zoology and Botany?

    Ans: Zoology:
    This division of biology deals with the study of animals.
    Botany:
    This division of biology deals with the study of plants.

    Q7: How would you differentiate between Morphology and Anatomy?

    Ans: MORPHOLOGY
    ANATOMY
    Morphology deals with the study of form structures of living organism.
    Anatomy deals with study of internal structure of living organisms.
    It includes study of physical features such
    It includes study of cellular and tissue
    size, shape, color of biological structures
    composition of biological structures

    Q8: Define Molecular biology?

    Ans: “Molecular biology deals with the study of the molecules of life.” It is also known as biochemistry.
    Example:
    Water
    Proteins
    Carbohydrates
    Lipids
    Nucleic acids

    Q9: Define Morphology?

    Ans: Definition: This branch deals with the study of form and structures of living organisms.”

    Q10: What is difference between genetics and inheritance?

    Ans: The study of genes and their role in inheritance is called genetics whereas transmission of characters from one generation to another is called inheritance.

    Q11: What is cell biology?

    Ans: “The study of the structures and functions of cells and cell organelles is called cell biology.” This branch also deals with the study of cell division.

    Q12: Define embryology?

    Ans: Definition:
    “It is the study of the development of an embryo to new individual.”

    Q13: What are fossils?

    Ans: Fossils are the remains of extinct organisms.
    Examples:
    Coal

    Q14: What are Parasites? Give examples.

    Ans: “The organisms that take food and shelter from living hosts and, in return, harm them are called parasites.”
    Examples:
    Viruses
    Pathogenic Bacteria
    Lices

    Q15: Define Biotechnology?

    Ans: “It deals with the practical application of living organisms to make substances for the welfare of mankind”.
    Example:
    Production of human insulin by bacteria

    Q16: What do you know about Pharmacology?

    Ans: “It is the study of drugs and their effects on the systems of human body”.
    Example:
    Paracetamol used as pain-killer

    Q17: What are the Major Biological Issues today?

    Ans: The major biological issues of today are as follows:
    Human population growth
    Infectious diseases
    Addictive drugs
    Environmental pollution

    Q18: How would you define inter-disciplinary sciences?

    Ans: Biology includes information on various aspects of living things but these information relates to the other branches of science as well. Each branch of science has relationships with all other branches. This forms the basis of interdisciplinary sciences.
    Example:
    The study of basic metabolism of photosynthesis and respiration involves the knowledge of chemistry,

    Q19: What is meant by biophysics?

    Ans: “It deals with the study of the principles of physics, which apply to biological phenomena.”
    Example:
    There is a similarity between the working principles of lever in physics and limbs of animals in biology.

    Q20: Define Biochemistry?

    Ans: “It deals with the study of the chemistry of different compounds and processes occurring in living organisms.”
    Examples:
    The study of basic metabolism of photosynthesis and respiration involves the knowledge of chemistry.

    Q21: What is meant by Biogeography?

    Ans: “It deals with study of the occurrence and distribution of different species of living organisms in different geographical regions of the world.”
    It applies the knowledge of the characteristics of particular geographical regions to determine the characteristics of living organisms found there.

    Q22: Define Bio-metry?

    Ans: “It deals with study of biological processes using mathematical techniques and tools.”
    Example:
    To analyze the data gathered after experimental work, biologists have to apply the rules of mathematics.

    Q23: Define Bio-economics?

    Ans: “It deals with the study of organisms from economical point of view.”
    Example:
    The cost value and profit value of the yield of wheat can be calculated through bioeconomics.

    Q24: Define Agriculture and discuss role of agriculturist?

    Ans: “This profession deals with the food crops and animals which are the source of food.”
    Scope of Agriculture:
    An agriculturist works for the betterment of crops like wheat, rice, corn etc and animals from which we get food.

    Q25: What do you know about Horticulture?

    Ans: “This profession includes the art of gardening.”
    Scope of Horticulture:
    A horticulturist works for the betterment of existing varieties and for the production of new varieties of ornamental plants and fruit plants.
    Adoptation of Profession:
    Biology students can adopt this profession after their higher secondary education.

    Q26: Name the professions that can be adopted after bachelor levels of zoology.

    Ans: Following professions can be adopted after bachelor levels of zoology,
    Fisheries
    Farming
    Forestry

    Q27: What is farming? Give examples of different farms.

    Ans: “It deals with the development and maintenance of different types of farms.
    Examples:
    In some farms, animal breeding technologies are used for the production of animals which are better protein and milk sources.
    In poultry farms, chicken and eggs are produced.
    In fruit farms, different fruit yielding plants are grown.

    Q28: Name any four careers in biology?

    Ans: Following are the four careers in biology,
    Medicine
    Surgery
    Fisheries
    Farming

    Q29: Quote a verse from Holy Quran that hints at common origin of all living things?

    Ans: At many places in Holy Quran, Allah hints about the common origin and characteristics of living organisms.
    Verse:
    “We made every living thing from water.”
    (Sura: Ambia, Verse: 30)

    Q30: What are the contributions of Abdul Malik Asmai in field of science?

    Ans: Ile is considered the first Muslim scientist who studied animals in detail.
    Famous Books:
    Ilis famous writings include:
    “Al-Abil (camel)”
    “Al-Khail (horse)”
    “Al-Wahoosh (animal)”
    “Khalq al-Ansan”

    Q31: Describe the services of Jabir Bin Hayan. Also give names of his two famous books?

    Ans: He was born in Iran and practiced medicine in Iraq. He introduced experimental investigation in chemistry and also wrote a number of books on plants and animals.
    Famous books:
    His famous books are.
    Al-Nabatat
    Al-Haywan.

    Q32: Name the books written by following scientists?

    Ans: Jabir-Bin-Hayan:
    Abdul Malik Asmai:
    Al-Nabatat, Al-Haywan Al-Abil (camel), Al-Khail (horse), Al-Wahoosh (animal), Khalq al-ansan Bu-Ali-Sina Al-Qanun-Fi-Al-Tib

    Q33: What is role of Bu Ali Sina in Biology?

    Ans: He is honored as the founder of medicine and called as Avicenna in the west. He was a physician, philosopher, astronomer, and poet.
    Famous Book:
    One of his books “Al-Qanun-fi al-Tib” is known as the canon of medicine in West.

    Q34: Define an atom and also tell its meaning?

    Ans: Definition:
    “An atom is defined as simplest form of matter which cannot be further sub divided” It is composed of three fundamental particles:
    Electrons
    Protons
    Neutrons
    Meaning
    “a” means not and ‘tom’means cul

    Q35: Define bio-elements and enlist them?

    Ans: “The elements that take part in making the body mass of a living organism are called bio-elements.”
    There are total of 16 bio-elements.
    Only six (O, C, H, N, Ca, & P) make 99% of the total mass.
    Other ten (K, S, Cl, Na, Mg, Fe, Cu, Mn, Zn & I) collectively make 01% of the total mass

    Q36: What is Biomolecule?

    Ans: “In organisms, bioelements usually do not occur in isolated forms rather they combine through ionic or covalent bonding. The stable particle formed by such bonding is called as biomolecule.”

    Q37: Write down names of bio-molecule groups?

    Ans: Following are the names of groups of bio-molecules.
    (i) Macromolecules
    (ii) Macromolecules

    Q38: Differentiate between Micromolecule and Macromolecule?

    Ans: MACROMOLECULE
    The biomolecules with low molecular weight a called micromolecules.
    The biomolecules with high molecular weight called macromolecules.
    Examples:
    Glucose
    Water

    Q39: Explain macro molecules with example.

    Ans: The bio-molecules which have high molecular weights are called macromolecules.
    Examples:
    Starch
    Proteins
    Lipids

    Q40: What is the difference between organelle and cell?

    Ans: ORGANELLE CELL
    Bio-molecules assemble in a particular way and The organelles are actually sub-cellular structures form organelles. and when they assemble together, cells are forn
    Examples:
    Mitochondria
    Ribosomes

    Q41: Define Tissue & Give examples?

    Ans: “Similar cells performing similar functions are organized into groups called tissues”
    OR
    “A tissue is a group of similar cells specialized for the performance of a common function”
    Examples:
    Epidermal tissue and ground tissue in plants
    Nervous tissue and muscular tissues in animals

    Q42: What is meant by organ system?

    Ans: Different organs performing related functions are organized together in the form of an organ system. In an organ system, each organ carries out its specific function and the functions of all organs appear as the function of the organ system.
    Example:
    The digestive system is an organ system that carries out the process of digestion. Major organs in its framework are oral cavity, stomach, small intestine, large intestine, liver, and pancreas. All these organs help in the process of digestion.

    Q43: What is the difference between organ system level of Animals and plants?

    Ans: The organ system level is less complex in plants as compared to animals.
    Reason:
    The less complexity of organ system level in plants is due to a greater range of functions and activities in animals than in plants.

    Q44: Define individual?

    Ans: “Different organs and organ systems are organized together to form an individual or organism.” free ilm
    Coordination in Organism: In organism, the functions, processes and activities of various organs and organ systems are coordinated.

    Q45: Define Population?

    Ans: “A group of organisms of the same species located at the same place in the same time is called population.”
    Example:
    According to Ministry of Population Welfare, Government of Pakistan, human population in Pakistan in 2010 comprised of 173.5 million individuals.

    Q46: Define Community with its types?

    Ans: “An assemblage of different populations, interacting with one another within the same environment is called community.”
    Example:
    A forest
    Types:
    Following are the types of community.
    (i) Complex Community:
    Some communities are complex.
    Examples:
    A forest community
    A pond community
    (ii) Simple Community:
    Some communities may be simple.
    Example:
    A fallen log with various populations under it.
    In a simple community number and size of populations is limited.

    Q47: Name the levels of organization in correct order.

    Ans: Levels of organization:
    (1) Sub atomic and atomic level
    (ii) Molecular level
    (iii) Organelle and cell level
    (iv) Tissue level
    (v) Organ and organ system level
    (vi) Individual level
    (vii) Population level
    (viii) Community level
    (ix) Bio-sphere level

    Q48: What is biosphere level?

    Ans: “The part of the Earth inhabited by organism communities is known as biosphere.” It constitutes all ecosystems (areas where living organisms interact with the nonliving components of the environment) and is also called the zone of life on Earth.

    Q49: Name the types of cellular organizations.

    Ans: In living organisms the cells organize in three ways to make the bodies of organisms.
    (1) Unicellular Organization
    (ii) Colonial Organization
    (iii) Multicellular Organization

    Q50: Name any four unicellular organisms.

    Ans: The names of unicellular organisms are given below,
    Amoeba
    Paramecium
    Euglena
    Bacterium

    Q51: Describe colonial type of cellular organization with example?

    Ans: In colonial type of cellular organization, many unicellular organisms live together but do
    not have any division of labor among them. Each unicellular organism in a colony lives its own life and does not depend on other cells for its vital requirements.
    Example:
    Volvox is a green alga found in water that shows colonial organization. Hundreds of Volvox cells make a colony.

    Q52: What is multicellular organization? Explain with an example.

    Ans: In multicellular organization, cells are organized in the form of tissues, organs and organ systems.
    Examples:
    •Frog and mustard plants are familiar examples of multicellular organization.
    Explanation:
    Frog shows the multicellular organization. The body is made of organ systems and each organ system consists of related organs. All the organs are made of specific tissues (epithelial, glandular, muscular, nervous etc).

    Q53: Write down scientific Names of Mustard Plant and Frog?

    Ans: Scientific name of mustard plant is, Brassica campestris Scientific name of Frog is,
    Rana tigrina

    Q54: Write the importance of mustard plant.

    Ans: Mustard plant (scientific name: Brassica compestris) is sown in winter and it produces seeds at the end of winter. The plant body is used as vegetable and its seeds are used for extracting oil.

    Q55: What is difference between vegetative and reproductive organs of plants?

    Ans: VEGETATIVE ORGANS
    The organs which do not take part in the sexual reproduction of the plant are called vegetative organs The organs which take part in the sexual reproduction of the plant and produce fruits and seeds are called reproductive organs
    Examples:
    Root
    Stem
    Branches
    Leaves
    REPRODUCTIVE ORGANS
    Example:
    Flower

    Download PDF Format

    We know you are looking for Class 9 Biologyclass 9 biology notes 2024 for Punjab Boards.class 9 biology notes play a critical role in every student’s life becauseclass 9 biology notes provide allclass 9 biology notes which have more chances in final exams. It is difficult to find the best and more accurateclass 9 biology notes from class 9 biology of the student. Likewise, if you are dealing with this problem, you don’t need to worry about it.

    We have uploaded important biology questions for class 9 to help you prepare for the exam. Our biology notes for Class 9 are equally useful for all Punjab Boards. Including BISE Lahore, BISE Jammu Kashmir, BISE Gujranwala, BISE Sahiwal, BISE Sargodha, BISE DG Khan, BISE Faisalabad BISE Multan.class 9 biology notes with mating scheme.

    9th Biologyclass notes 2024 PDF Download

    Since you are a 9th grade student, biology is an important and compulsory subject for you. Biology is a theoretical subject, so it is considered a difficult subject. No need to worry about the exam as we have downloaded the best class 9 biology guesses to score high in the exam. Our best guess consists of important short questions and long questions frequently asked in all Punjab boards in previous exams. We believe that any student can easily score well in class 9 Biology exam. At the request of students, our team prepared this document. You can better understand the nature of the paper by using our class 9 Biologyclass 9 biology notes. By using theseclass 9 biology notes PDF, you will understand what types of questions can be asked and how to conduct yourclass 9 biology notes. To develop this estimate, I referred to all previous exams and past papers over the last ten years, along with notes from Biology 9.

  • 9th Class Physics Chapter 9: Transfer of Heat

    9th Class Chapter 9: Transfer of Heat Short and Simple Question & Answer

    On this page, you will find the Physics Estimate Paper for Class 9 for the year 2024, available in both English and Urdu. We offer two formats for downloading the most important questions for Class 9 Physics. This estimate paper is suitable for all boards in Punjab, including BISE boards in Faisalabad, Lahore, Gujranwala, Dera Ghazi Khan, Sargodha, Sahiwal, Multan, and Jammu Kashmir. Many students have successfully used the Physics Estimate Paper 2024 by Faiz Ul Islam to achieve good results in their exams.

    Q1.How many method of transmission of heat are used?

    Ans: Heat can be transmitted from one object to the other by the following three processes, if these objects are at different temperatures.

    • Conduction
    • Convection
    • Radiation

    Q2.What is Conduction? Explain the process and write down it usage in our daily life.

    Ans: “The mode of transfer of heat by vibrating atoms and free electrons in solids from hot to cold parts of a body is called conduction of heat”.

    OR

    “Conduction is the process in which heat is transmitted from one body to another by the interaction of atoms and electrons”.

    Q3.What are Bad conductors or Insulator?

    Ans: The substances through which heat does not conduct easily are called bad conductors or insulators.

    Example

    Wood, cork, cotton, wool, glass, rubber etc.

    Q4.What are Conductors?

    Ans: All metals are good conductors of heat. The substances through which heat conduct easily are called conductors.

    Example

    Copper, iron, aluminum etc.

    Q5.Write down some uses of conductors and non – conductors.

    Ans: In houses, good thermal insulation means lower consumption of fuel. For this, following measures may be taken to save energy.

    • Hot water tanks are insulated by plastic or foam lagging
    • Ceiling of room is covered by insulating materials (false ceiling)
    • Good conductors are used when quick transfer of heat is required through a body. Thus cookers, cooking plate, boiler, radiators and condensers of refrigerators etc. are made of metals such as aluminum or copper. Similarly metal boxes are used for making ice, ice cream etc.

    Q6.Define convection?

    Ans: “Transfer of heat by actual movement of molecules from hot place to a cold place is known as convection”.

    Liquids and gases are poor conductors of heat. However, heat is transferred through fluids (liquids or gases) by another method called convection.

    Q7.What do you know about convection currents in Air? Write down some uses.

    Ans:  Gases also expand on heating, thus convection currents are easily set up due to the differences in the densities of air at various parts in the atmosphere.

    Uses of Convection currents

    • Convection currents set up by electric, gas or coal heaters help to warm our homes and offices.
    • Central heating systems in buildings work on the same principle of convection.

    Q8.How land and sea breezes are produced?

    Ans: Land and sea breezes are the result of convection.

    Sea Breeze

    On a hot day, the temperature of the land increases more quickly than the sea. It is because the specific heat of land is much smaller as compared to water. The air above land gets hot and rises up. Cold air from the sea begins to move towards the land. It is called sea breeze.

    Land Breeze

    At night, the land cools faster than the sea. Therefore, air above the sea is warmer, rises up and the cold air from the land begins to move towards the sea. It is called land breeze.

    Q9.What is gliding?

    Ans: A glider looks like a small aeroplane without engine. Glider pilots use upward movement of hot air current due to convection of heat. These rising currents of hot air are called thermals. Gliders ride over these thermals. The upward movement of air currents in thermals helps them to stay in air for a long period.

    Q10.What do you know about birds gliding?

    Ans: The birds stretch out their wings and circle in these thermals. The upward movement of air helps birds to climb up with it. Eagles, hawks and vultures are expert thermal climbers. After getting a free lift, birds are able to fly for hours without flapping their wings. They glide from one thermal to another, and thus travel through large distances and hardly need to flap their wings.

    Q11.Define Radiation.

    Ans: Radiation is the mode of transfer of heat from one place to another in the form of waves called Electromagnetic waves.

    Q12.Why tea in a cup becomes cold earlier as compared to a teapot?

    Ans: In a teapot there is a large amount of tea and also the mouth of the teapot is narrow, so loss of heat is minimum. On the other hand in a tea cup, there is little amount of tea and the mouth of cup is also large as compared to teapot. Since, larer the surface area, greater will be the heat loss by convection. That is why tea in a cup becomes cold earlier as compare to teapot.

    Download PDF Format

    When preparing for their final exams, students can utilize the 9th-grade Physics assessment paper. Every chapter from the textbook is covered, along with questions that may appear on the exam. These essential questions serve as valuable study aids after students have completed the entire syllabus. By focusing on these key concepts, students can gauge their understanding and boost their confidence, ultimately enhancing their exam performance.

    Class 9 Physics Estimate Paper 2024 for Punjab Board Students

    Physics is often considered a challenging subject. The exam date for Class 9 Physics papers has been released, with all Punjab Boards conducting these papers on Friday. With limited time for preparation, using these important questions can significantly aid in covering the essential topics.

    Additionally, these questions will enhance your knowledge and help you prepare for the crucial questions expected in the exams. One of the standout features of our estimate paper is that it can be downloaded for free, allowing you to print these important questions at no cost.

  • 9th Class Physics Chapter 8: Thermal Properties of Matter

    9th Class Chapter 8: Thermal Properties of Matter Short and Simple Question & Answer

    On this page, you will find the Physics Estimate Paper for Class 9 for the year 2024, available in both English and Urdu. We offer two formats for downloading the most important questions for Class 9 Physics. This estimate paper is suitable for all boards in Punjab, including BISE boards in Faisalabad, Lahore, Gujranwala, Dera Ghazi Khan, Sargodha, Sahiwal, Multan, and Jammu Kashmir. Many students have successfully used the Physics Estimate Paper 2024 by Faiz Ul Islam to achieve good results in their exams.

    Q1.Define heat.

    Ans: Heat is the energy that is transferred from one body to the other in thermal contact with each other as a result of the difference of temperature.

    Q2.Define thermometry and temperature.

    Ans:   

    Thermometry

    “The art of measuring temperature is termed as thermometry.”

    Temperature

    “Degree of coldness or hotness of the body is a measure of its temperature”

    Q3.Define internal energy.

    Ans: The sum of kinetic energy and potential energy associated with the atoms, molecules and particles of a body is called the internal energy.

    Q4.Define thermal equilibrium.

    Ans: “According to the principle of thermometry, if two objects at different temperatures are joined together, after a certain time they attain the same temperature. This is known as the state of thermal equilibrium”

    Q5.Define thermometer.

    Ans: “The instrument which is used to measure the temperature is called a thermometer”

    Q6.Write down the conversions of thermometer scales.

    Ans: Conversion of one temperature scale to the other by the given formulae TF, Tc, TK representing the Fahrenheit, centigrade (Celsius) and Kelvin temperatures respectively.

    Conversion of Celsius (centigrade) to Fahrenheit scale

    TF =

    Conversion of Fahrenheit to Celsius scale

    Tc =

    Relationship between Kelvin and Celsius scales

    Tk = Tc + 273

    Q7.Define specific heat?

    Ans: “Specific heat of a substance is the amount of heat that required to raise the temperature of 1 kg mass of that substance through 1K”.

    Q8.Define heat capacity.

    Ans: Heat capacity of a body is the quantity of thermal energy absorbed by it for one Kelvin (1K) increases in its temperature.

    Q9.Define latent heat of fusion.

    Ans: “Heat energy required to change unit mass of a substance from solid to liquid state at its melting point without change in the temperature is called its latent heat of fusion”.

    Q10.Define latent heat of vaporization.

    Ans: “The quantity of heat that changes unit mass of a liquid completely into gas at its boiling point without any change in its temperature is called its latent heat of vaporization”

    Q11.Define evaporation.

    Ans: “Evaporation is the changing of a liquid into vapors (gaseous state) from the surface of the liquid without heating it”.

    Q12.What is linear Expansion?

    Ans:  “If a thin rod is heated, there is a prominent increase in its length as compared to its cross-sectional area. The expansion along length or in one dimension is called linear expansion”.

    Q13.What is volume expansion?

    Ans: “Heating a block causes an increase in length, breadth and thickness, i.e., volume of the block increases that is known as volume expansion”.

    Volume of a solid also changes with the change in temperature and is called volume thermal expansion or cubical thermal expansion.

    Q14.Write down some consequences of thermal expansion.

    Ans:  The expansions of solids many damage bridges, railway tracks and roads as they are constantly subjected to temperature changes.

    • Prevision is made during construction for expansion and contraction with temperature.
    • Railway tracks buckled on a hot summer day due to expansion if gaps are not left between sections.

    Q15.Write down some applications of thermal expansion.

    Ans: Thermal expansion is used in our daily life. In thermometers, thermal expansion is used in temperature measurements.

    • To open the cap of a bottle that is tight enough, immerse it in hot water for a minute or so. Metal cap expands and becomes loose. It would now be easy to turn it to open.
    • To join steel plates tightly together, red hot rivets are forced through holes in the plates as shown in figure. The end of hot rivet is then hammered. On cooling, the rivets contracts and bring the plates tightly griped.

    Q16.What do you know about bimetallic strip (thermostat)?

    Ans: A bimetal strip consists of two thin strips of different metals such as brass and iron joined together as shown in figure. On heating the strip, brass expands more than iron. This unequal expansion causes bending of the strip.

    Usage

    Bimetal strips are used for various purposes.

    • Bimetal thermometers are used to measure temperature especially in furnaces and ovens.
    • Bimetal thermo state switch is used to control the temperature of heater coil in an electric iron.

    Q17.Write down some examples of expansions of solids.

    Ans:

    • Pipes passing through deserts and plains are curved to allow expansion and contraction due to change of season.
    • While laying rail tracks gaps are left at joints so as to avoid damages caused by expansion or contraction.
    • While constructing bridges, one end of the beam is placed on rollers. Explain why?

    Ans: This is because the iron beam of the bridges expands due to heat in summer. The iron beams are frightened at one end, keeping the other moveable as provision for their expansion. In the absence of such provision, bridge may be damaged in summer due to heat.

    Download PDF Format

    When preparing for their final exams, students can utilize the 9th-grade Physics assessment paper. Every chapter from the textbook is covered, along with questions that may appear on the exam. These essential questions serve as valuable study aids after students have completed the entire syllabus. By focusing on these key concepts, students can gauge their understanding and boost their confidence, ultimately enhancing their exam performance.

    Class 9 Physics Estimate Paper 2024 for Punjab Board Students

    Physics is often considered a challenging subject. The exam date for Class 9 Physics papers has been released, with all Punjab Boards conducting these papers on Friday. With limited time for preparation, using these important questions can significantly aid in covering the essential topics.

    Additionally, these questions will enhance your knowledge and help you prepare for the crucial questions expected in the exams. One of the standout features of our estimate paper is that it can be downloaded for free, allowing you to print these important questions at no cost.

  • 9th Class Physics Chapter 7: Properties of Matter

    9th Class Chapter 7: Properties of Matter Short and Simple Question & Answer

    On this page, you will find the Physics Estimate Paper for Class 9 for the year 2024, available in both English and Urdu. We offer two formats for downloading the most important questions for Class 9 Physics. This estimate paper is suitable for all boards in Punjab, including BISE boards in Faisalabad, Lahore, Gujranwala, Dera Ghazi Khan, Sargodha, Sahiwal, Multan, and Jammu Kashmir. Many students have successfully used the Physics Estimate Paper 2024 by Faiz Ul Islam to achieve good results in their exams.

    Q1.What is Kinetic molecular theory? Write down its postulates.

    Ans: Most of the properties of solids, liquids, and gases can be explained on the basis of the intermolecular forces. Kinetic molecular model has some important features.

    • Matter is made up of particles called molecules.
    • The molecules remain in continuous motion. The motion of molecules could be linear, vibrational, or rotational.
    • The molecules attract each other.

    Q2.What is plasma?

    Ans: The kinetic energy of gas molecules goes on increasing if a gas is heated continuously. This causes the gas molecules move faster and faster. The collisions between atoms and molecules of the gas become so strong that they tear off the atoms. Atoms lose their electrons and become positive ions. This ionic state of matter is called plasma.

    Q3,What do you know about density?

    Ans: Density of a substance is defined as its mass per unit volume.

    Unit

    SI unit of density is kilogram per cubic meter (kg m-3).

    Density Equations

    Mass = Density x Volume

    Q4.Define pressure and write down its unit.

    Ans: The force acting normally per unit area on the surface of a body is called pressure.

    Thus

    Or

    Quantity

    Pressure is a scalar quantity.

    Unit

    In SI units, the unit of pressure is N m-2 also called Pascal (Pa). Thus, 1N m-2 = 1Pa

    Q5.Define pressure in liquids.

    Ans: Liquids exert pressure. The pressure of a liquid acts in all directions. If we take pressure sensor (a device that measures pressure) inside a liquid, then the pressure of the liquid varies with the depth of sensor.

    Q6.State Pascal’s Law.

    Ans: Pressure applied at any point of a liquid enclosed in a container, is transmitted without the loss to all other parts of the liquid.

    An external force applied on the surface of a liquid increases the liquid pressure at the surface of the liquid. This increase in liquid pressure is transmitted equally in all direction and to the walls of the container in which it is filled.

    Q7.Explain the braking system of the vehicles.

    Ans: The brakes of cars, buses etc. work on the principle of Pascal’s law. In such a type of brakes, when brake pedal is pushed, it exerts pressure on the master cylinder, which increases the liquid pressure in the cylinder. The liquid pressure is transmitted equally through the liquid in the metal pipes. Due to the increase pressure of the liquid pressure, the pistons in the cylinder mover outwards pressing the brakes pad with brake drums. The force of friction between friction the brake pads and the brake drum stops the wheels.

    Q8.State Archimedes Principle.

    Ans: When object is totally or partially immersed in a liquid, an upthrust act on it equal to the weight of the liquid it displaces.

    Q9.Define principle of floatation

    Ans: A floating object displaces a fluid having weight equal to weight of the object.

    Q10.What is atmospheric pressure?

    Ans: The earth is surrounded by a cover of air is called atmosphere. It extends to a few hundred kilometers above sea level. Just as certain sea creatures live at the bottom of ocean, we live at the bottom of a huge ocean of air. Air is the mixture of gases. The density of air in the atmosphere is not uniform. It decreases continuously as we go up.

    Q11.What is barometer?

    Ans: The instruments that measure atmospheric pressure are called barometers. One of the simple barometers is a mercury barometer. It consists of a glass tube 1 m long closed at one end.

    Q12.Why mercury is used in barometer instead of water?

    Ans: Mercury is 13.6 times denser than water. Atmospheric pressure can hold vertical column of water is about 13.6 times the height of mercury column at a place. Thus, at sea level, vertical height of water column would be 0.76 m x 13.6 = 10.34 m. Thus, a glass tube more than 11 m long is required to make a water barometer.

    Q13.What weather changes can be expected due to decrease of atmospheric pressure?

    Ans:

    • A gradual and average drop in atmospheric pressure means a low pressure in a neighboring locality.
    • Minor but rapid fall in atmosphere indicates a windy and showery condition in the nearby region.
    • A decrease in atmospheric pressure accompanied by breeze and rain.
    • A sudden fall in atmospheric pressure often followed by a storm, rain and typhoon to occur in few hours time.

    Q14.What weather changes can be expected due to increase of atmospheric pressure?

    Ans:

    • An increasing atmospheric pressure with a decline later on predicts an intense weather conditions.
    • A gradual large increase in the atmospheric pressure indicates a long spell of pleasant weather.
    • A rapid increase in atmospheric pressure means that it will soon be followed by a decrease in the atmospheric pressure indicating poor weather ahead.

    Q15.What is Elasticity?

    Ans: The property of a body to restore its original size and shape as the deforming force ceases to act is called elasticity.

    Deforming force

    The applied force that changes shape, length or volume of a substance is called the deforming force.

    Q16.What is stress?

    Ans: The force that acts on unit area at the surface of a body and thus changes its shape or size is called stress.

    Mathematical form

    If a force F is applied on an area A of an object, the stress is) mathematically defined as:

    Unit

    In System International, the unit of stress is Nm-2.

    Q17.What is strain?

    Ans:  A stress can produce a change in shape, length or volume of an object.

    A comparison of change caused by the stress with the original length, volume or shape is called the strain.

    Tensile strain

    If a stress produces a change in length of an object then the stain is called tensile strain. Therefore,

    Unit

    As the strain is a ratio between two similar quantities so it has no unit.

    Q18.Hooke’s Law

    Ans: The strain produced in a body by the stress applied to it is directly proportional to the stress within the elastic limit of the body.

    Mathematical Formula

    Stress α strain

    Stress = constant x strain

    Or         = constant

    Hooke’s law is applicable to all kinds of deformation and all types of matter i.e. solids, liquids or gases within certain limit.

    Q19.Define Young’s Modulus.

    Ans: The ration of stress and strain is a constant within the elastic limit, this constant is called the Young’s Modulus.

    Unit

    SI unit of Young’s Modulus is Newton per square metre (N m-2)

    Q20.What is elastic Limit?

    Ans:  When stress is increased, the strain also goes on increasing until there comes a limit. When stress is removed, the object does not come back to its initial state. This limit of stress is called elastic limit.

    Q21.What are the elastic materials? Give some examples.

    Ans: An object is said to be elastic if it restores its original size and shape after the external force ceases to act. For example rubber, plastic, nylon, iron etc.

    Q22.How property of elasticity is used in our body?

    Ans: Not only metals and other materials are elastic, our body muscles are also elastic. Most of the actions of our body are possible due to expansion and contraction of the muscles.

    Q23.Prove that the SI unit of Young’s modulus is Pascal or Nm-2.

    Ans: Pressure is calculated mathematically as:

    P =  = Nm-2

    Thus, SI unit of pressure is Nm-2 and it is also named as Pascal (pa).

    Q24.Prove that liquid pressure does not depend upon mass of the liquids.

    Ans: Liquid pressure is given by the formula:

    P = ρgh

    Above equation is independent of mass of the liquid. So, liquid pressure does not depend upon the mass of the body.

    Q25.Under what condition the object floats in water?

    Ans: If the buoyant force ‘F’ is greater than the ‘w’ of the immersed object, the resultant force (F – w) will act in the upward direction and it will push the object in upward direction. In this situation, some part of the object will be raised above the water so that the buoyant force ‘F’ becomes equal to the weight. So, equilibrium is established and the object floats.

    Q26.Write any three applications of the Pascal’s law in our daily life.

    Ans:

    • Raw cotton and clothes are pressed to form their bundles for their easy transportation.
    • For the service of heavy vehicles, these are lifted by the use of hydraulic press.
    • The brakes of certain vehicles work on the principle of hydraulic press.

    Q27.When an inflated balloon is heated it bursts. Why?

    Ans: When inflated balloon is heated then motion of the molecules of the gas increases in the balloon and they will increase pressure on the walls of the balloon so it will burst because of this increased gas pressure on it.

    Q28.Under what condition the object sinks in water?

    Ans: If the weight ‘w’ of the immersed object is greater than the buoyant force ‘F’ of the liquid, the resultant force (w – F) will act in the downward direction and the object will sink.

    Download PDF Format

    When preparing for their final exams, students can utilize the 9th-grade Physics assessment paper. Every chapter from the textbook is covered, along with questions that may appear on the exam. These essential questions serve as valuable study aids after students have completed the entire syllabus. By focusing on these key concepts, students can gauge their understanding and boost their confidence, ultimately enhancing their exam performance.

    Class 9 Physics Estimate Paper 2024 for Punjab Board Students

    Physics is often considered a challenging subject. The exam date for Class 9 Physics papers has been released, with all Punjab Boards conducting these papers on Friday. With limited time for preparation, using these important questions can significantly aid in covering the essential topics.

    Additionally, these questions will enhance your knowledge and help you prepare for the crucial questions expected in the exams. One of the standout features of our estimate paper is that it can be downloaded for free, allowing you to print these important questions at no cost.

  • 9th Class Physics Chapter 6: Work and Energy

    9th Class Chapter 6: Work and Energy Short and Simple Question & Answer

    On this page, you will find the Physics Estimate Paper for Class 9 for the year 2024, available in both English and Urdu. We offer two formats for downloading the most important questions for Class 9 Physics. This estimate paper is suitable for all boards in Punjab, including BISE boards in Faisalabad, Lahore, Gujranwala, Dera Ghazi Khan, Sargodha, Sahiwal, Multan, and Jammu Kashmir. Many students have successfully used the Physics Estimate Paper 2024 by Faiz Ul Islam to achieve good results in their exams.

    • Define work and its unit.

    Ans:    Definition

    Work is done when force acting on a body displaces it in the direction of a force.

    OR

    The product of force and distance covered in the direction of force is equal to the work done.

    Unit of work

    In System International, its unit is joule (J).

    Joule

    “The amount of Work done will be one joule if a force of one Newton displaces a body through a distance of one meter in the direction of the force.”

    • Define Energy and write down its unit. 

    Ans: A body possesses energy if it is capable to do work.

    OR

    Ability of a body to do work is known as energy.

    Quantity

    It is a scalar quantity

    Unit

    Joule is the unit of energy same as that of work.

    Types of Energy

    Energy exists in various forms such as mechanical energy, heat energy, light energy, sound energy, electrical energy, chemical energy and nuclear energy etc.

    Types of Mechanical Energy

    Mechanical energy possessed by a body is of two types:

    • Kinetic Energy
    • Potential Energy
    • Define kinetic energy and give at least one example.

    Ans: “The energy possessed by a body due to its motion is called kinetic energy”

    Example

    • Moving water in a river can carry wooden logs through large distances and can also be used to drive turbines for generating electricity.
    • Define Potential Energy and give examples.

    Ans: The energy possessed by a body due to its position is known as its potential energy.

    Examples

    • Stored water in dam
    • A hammer is raised up to some height has the ability to do work
    • A stretched bow has potential energy due to its stretched
    • Define Gravitational Potential Energy and give at least one example.

    Ans: The energy present in a body due to its height is called gravitational potential energy.

    Example

    • Stored water in dam
    • Energy of a stone lying on the roof
    • Define Efficiency.   

    Ans: Efficiency of a system is the ratio of required form of energy obtained from a system as output to the total energy given to it as input.

    • What do you know about Ideal machine?

    Ans: An ideal machine is that which gives an output equal to the total energy used by it. In other words, its efficiency is 100 %. People have tried to design a working system that would be 100% efficient. But practically such system does not exist.

    • Can we say that practical systems can be 100% efficient?

    Ans: Every system meets energy losses due to friction that causes heat, noise etc. these are not the useful forms of energy and go waste. This means we cannot utilize all the energy given to working system. The energy in the required form obtained from working system always less than the energy given to it as input.

    • Define Power. Write down its unit and define it.

    Ans: “Rate of doing work with respect to time is called the power.”

    Unit of power

    In System International, the unit of power is watt (W).

    Watt

    “If a body does a work of one joule in one second then its power will be one watt”.

    • Do we do any work when we lift a load from the Earth to some height?

    Ans: Yes, we do work when we lift a load from the earth to some height because we have to do work against the gravitational pull of the earth. Mathematically, it can be expressed as,

    As we know that                     W = FS

    As        F = mg             and       S = h

    So the work done is                W = mgh

    • How much power is used by a 40 kg athlete by climbing 10m high ladder in 10s?

    Ans:   

    We have                      Mass = m = 40 kg

    Time = t = 10 s

    Height = h = S = 10 m

    As we know that         Force = weight = w = mg = 40 x 10 = 400N

    Work = W = FS = 400 x 10 = 4000 J

    As we know that         Power = P = W/t

    So,                               Power = P = 4000/10 = 400 W

    • Give some examples of energies used in our body?

    Ans:  There are many kinds of energies are used in our body. Some of them are given below:

    Mechanical Energy

    For the moving of our body.

    Chemical Energy

    For making body molecules.

    Electrical Energy

    For the propagation of electrical signals in the body.

    Heat Energy

    For maintaining the body temperature.

    • How much work is done when a body moves with uniform velocity?

    Ans: When a body moves with uniform velocity means moving with zero acceleration then work done will be zero because according to Newton’s second law of motion if a = 0 then the net resultant force acting on the body is zero.

    As we know that                                 W = FS

    If         F = 0                 then                W = 0 x S = 0

    Download PDF Format

    When preparing for their final exams, students can utilize the 9th-grade Physics assessment paper. Every chapter from the textbook is covered, along with questions that may appear on the exam. These essential questions serve as valuable study aids after students have completed the entire syllabus. By focusing on these key concepts, students can gauge their understanding and boost their confidence, ultimately enhancing their exam performance.

    Class 9 Physics Estimate Paper 2024 for Punjab Board Students

    Physics is often considered a challenging subject. The exam date for Class 9 Physics papers has been released, with all Punjab Boards conducting these papers on Friday. With limited time for preparation, using these important questions can significantly aid in covering the essential topics.

    Additionally, these questions will enhance your knowledge and help you prepare for the crucial questions expected in the exams. One of the standout features of our estimate paper is that it can be downloaded for free, allowing you to print these important questions at no cost.