CBSE Sample Papers Class 11 Biology 2023

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CBSE Sample Question Paper for Class 11 Biology – in PDF

We know that CBSE issues model papers for board classes only. But if you analyse the trends you will get to know that class 11 exam paper format is very similar to that of class 12 board exams. So, we have drafted CBSE Sample Papers for Class 11 Biology as the the guidelines issued by CBSE. CBSE has already released the new marking scheme and blueprint format for Class 11 Biology. We are providing Biology sample papers for Class 11 CBSE exams as per these marking schemes only. The Sample Papers are available for free download on the myCBSEguide app and website in PDF format. CBSE Sample Papers help students to prepare for CBSE exams.

Download Biology Sample Papers as PDF

CBSE Sample Papers Class 11 Biology 2023

You can access CBSE Sample Papers Class 11 Biology for the session 2023 on the myCBSEguide App. myCBSEguide provides CBSE Class 11 Sample Papers of Biology for the session 2022-23 with solutions in PDF format for free download.

Class 11 – Biology Sample Paper – 01 (2022-23)


Maximum Marks: 70
Time Allowed: : 3 hours


General Instructions:

  1. All questions are compulsory.
  2. The question paper has five sections and 33 questions. All questions are compulsory.
  3. Section–A has 16 questions of 1 mark each; Section–B has 5 questions of 2 marks each; Section– C has 7 questions of 3 marks each; Section– D has 2 case-based questions of 4 marks each; and Section–E has 3 questions of 5 marks each.
  4. There is no overall choice. However, internal choices have been provided in some questions. A student has to attempt only one of the alternatives in such questions.
  5. Wherever necessary, neat and properly labeled diagrams should be drawn.

  1. Class 11 Biology Sample Paper Section A

  2. Which pair of a common name and scientific name is not correct?
    a) Hen and Egg – Sempervivum soboliferum
    b) Forget-Me-Not – Myosotis sylvtica
    c) Widow’s Tear- Rhoeo species
    d) Touch-Me-Not- Mimosa pudica
  3. All the hormone are proteins, peptides and amino acid derivatives except:
    a) hormone of ovary
    b) pancreas hormone
    c) parathyroid hormone
    d) thyroid hormone
  4. DNA precipitation out of a mixture of biomolecules can be achieved by treatment with:
    a) Chilled chloroform
    b) Isopropanol
    c) Chilled ethanol
    d) Methanol at room temperature
  5. Conjoint and closed vascular bundles are found in:
    a) Monocot stem
    b) Monocot root
    c) Dicot stem
    d) Dicot root
  6. CO is harmful because:
    a) It releases recent O2
    b) If forms permanent compound with Hb
    c) It reacts with O2
    d) It breaks Hb

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  7. Energy required for ATP synthesis in PS-II comes from:
    a) Electron gradient
    b) Oxidation of glucose
    c) Reduction of glucose
    d) Proton gradient
  8. Which one of the following characteristics is common both in humans and adult frogs?
    a) Internal fertilization
    b) Nucleated RBCs
    c) Four- chambered heart
    d) Ureotelic mode of excretion
  9. Frogs help human as they:
    a) Maintain ecological balance
    b) Eat insect and protect the crop
    c) In some countries the muscular legs of frog are used as food by man
    d) All of these
  10. Apical dominance means:
    a) Stimulation of growth of apical bud by removal of axillary buds
    b) Suppression of growth of apical bud by axillary buds
    c) Suppression of growth of axillary buds by the presence of apical bud
    d) Inhibition of growth of axillary buds by removal of apical bud
  11. Bryophytes are also called amphibians of the plant kingdom because:
    a) Plants can live in soil but are dependent on water for sexual reproduction
    b) All of these
    c) They play an important role in plant succession on bare rocks/soil
    d) They usually occur in damp, humid and shaded localities
  12. Primary role of cortical nephrons is:
    a) Reabsorption of water
    b) None of these
    c) Reabsorption of water and Reabsorption of salt
    d) Reabsorption of salt
  13. In a child of 15 years age, plasma calcium level is diagnosed below optimum level. Which organ is malfunctioning?
    a) Posterior lobe of pituitary
    b) Parathyroid
    c) Thyroid gland
    d) Liver
  14. Assertion (A): Globigerina contains a single chambered calcareous shell.
    Reason (R): It shows sexual reproduction.

    a) Both A and R are true and R is the correct explanation of A.
    b) Both A and R are true but R is not the correct explanation of A.
    c) A is true but R is false.
    d) A is false but R is true.
  15. Assertion (A): Organisms are made up of cells.
    Reason (R): Cells are structural unit of living organisms. A cell keeps its chemical composition steady within its boundary.

    a) Both A and R are true and R is the correct explanation of A.
    b) Both A and R are true but R is not the correct explanation of A.
    c) A is true but R is false.
    d) A is false but R is true.
  16. Assertion (A): Hydrolysis of starch into glucose is an organic chemical reaction.
    Reason (R): Bonds are broken and new bonds are formed during transformation of starch into glucose.

    a) Both A and R are true and R is the correct explanation of A.
    b) Both A and R are true but R is not the correct explanation of A.
    c) A is true but R is false.
    d) A is false but R is true.
  17. Assertion (A): If there is no air in trachea, it will not collapse.
    Reason (R): Trachea is having the cartilagenous ring.

    a) Both A and R are true and R is the correct explanation of A.
    b) Both A and R are true but R is not the correct explanation of A.
    c) A is true but R is false.
    d) A is false but R is true.
  18. Class 11 Biology Sample Paper Section B

  19. What are the components of stomata?
  20. How do different senses work in frog? Explain in brief.
  21. Mention any four activities regulated by the estrogen hormone.
  22. Differentiate between obligate categories and intermediate categories. Demonstrate with the help of a flowchart.
  23. Suppose there were plants that had a high concentration of Chlorophyll b but lacked chlorophyll a, would it carry out photosynthesis? Then why do plants have chlorophyll b and other accessory pigments?

    OR

    A type of anatomy of leaves possessed by C4-plants is different from those of C3-plants. Explain.

  24. The male and female reproductive organs of several pteridophytes and gymnosperms are comparable to floral structures of angiosperms. Make an attempt to compare the various reproductive parts of pteridophytes and gymnosperms with reproductive structures of angiosperms.
  25. Why the blood vascular system of leeches is also called haemocoelomic system? Write its details.
  26. Succinic dehydrogenase is an enzyme that causes the substrate, succinate, to breakdown into fumarate. Malonate is a substance that resembles succinate and inhibits the activity of succinic dehydrogenase.
    1. State the type of inhibition of succinic dehydrogenase by malonate.
    2. Explain how this type of inhibition affects the activity of the enzyme.
  27. “The role of ethylene and abscisic acid is both positive and negative”. Justify the statement.
  28. Name the essential components for the synthesis of haemoglobin and maturation of erythrocytes. What happens to old and worn out erythrocytes in the body of humans?

    OR

    One of the ABO blood groups is sometimes called the universal donor. Which group do you think it is and why?

  29. Given below is a diagram of different types of muscles. Based on the diagram answer the following questions:

    1. Mention the causes of osteoporosis.
    2. Mention the preventive measures of osteoporosis.
    3. Why osteoporosis is regarded as a silent disease.
  30. Distinguish between
    1. Grey matter and White matter
    2. A stimulus and An Impulse
  31. Class 11 Biology Sample Paper Section C

  32. Read the text carefully and answer the questions:
    The morphology of the mycelium, mode of spore formation, and fruiting bodies form the basis for the division of the fungi kingdom into various classes which include four sub-division Phycomycetes, ascomycetes, basidiomycetes, Deuteromycetes. Members of Phycomycetes are found in aquatic habitats and on decaying wood in moist and damp places or as obligate parasites on plants, ascomycetes are mostly multicellular. The asexual spores are conidia produced exogenously on the special mycelium called conidiophores. Basidiomycetes are mushrooms, bracket fungi or puffballs. They grow in soil, on logs and tree stumps and in living plant bodies as parasites. The basidiospores are exogenously produced on the basidium.

    Classification of Fungi
    Phycomycetes (Lower Fungi)Ascomycetes (Sac Fungi)Basidiomycetes (Club Fungi)Deuteromycetes (Fungi imperfecti)
    SaprolegniaYeastAgaricusCercospora
    RhizopusAspergillusPolyporusCollectotrichum
    MucorPencilliumPucciniaTrichoderma
    AlbugoNeurosporaUstilagoPyricularia
    PythiumPezizaLycoperdonFusarium
    1. Observed given table of Classification of Fungi and identify the class of fungi in which asexual spores are not found, vegetative reproduction occurs by fragmentation, and sexual organs are absent.
    2. Where are Members of Phycomycetes found?
    3. What is ascomycetes? What is the characteristic feature of ascomycetes and basidiomycetes?
    4. OR

      Identify the figure given below. Also, mention its characteristics.

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  33. Read the text carefully and answer the questions:
    The flower is the reproductive unit in the angiosperms. It is meant for sexual reproduction. A typical flower has four different kinds of whorls arranged successively on the swollen end of the stalk or pedicel, called thalamus or receptacle. These are calyx, corolla, androecium and gynoecium. Calyx and corolla are accessory organs, while androecium and gynoecium are reproductive organs. In symmetry, the flower may be actinomorphic (radial symmetry) or zygomorphic (bilateral symmetry). Based on the position of calyx, corolla and androecium in respect of the ovary on the thalamus, the flowers are described as hypogynous, perigynous and epigynous. A flower may be trimerous, tetramerous or pentamerous when the floral appendages are in multiple of 3, 4 or 5, respectively.

    1. Observe the diagram given below. and mention what happens after the given stage.
    2. Is Actinomorphic – datura the incorrect match?
    3. When the ovary is superior it is called?
    4. OR

      Which of the following represents epigynous? Also, mention what an epigynous flower is.

  34. Class 11 Biology Sample Paper Section D

  35. With the help of suitable diagrams describe mitosis.

    OR

    Eukaryotic cells have organelles which may

    1. not be bound by a membrane
    2. bound by a single membrane
    3. bound by a double membrane

    Group the various sub-cellular organelles into these three categories.

  36. In the following flow chart, replace the symbols a,b,c and d with appropriate terms. Briefly explain the process and give any two application of it.

    OR

    Enumerate the assumptions that we have undertaken in making the respiratory balance sheet. Are these assumptions valid for a living system?

  37. The cells of a unicellular organism are usually spherical whereas those of multicellular tend to be many-sided. Why?

    OR

    The diagram shows some of the structures present in an animal cell.

    Which of these structures is responsible for

    1. Manufacture of lipids and steroids
    2. Release of energy
    3. Manufacture of hormones and digestive enzymes
    4. Production of spindle fibres in cell division
    5. Endo and exocytosis?

Class 11 – Biology Sample Paper – 01 (Solution)


Solution

  1. Class 11 Biology Paper Solution Section A

  2. (a) Hen and Egg – Sempervivum soboliferum
    Explanation: The scientific name of touch-me-not plant is Mimosa pudica, Forget-me-not plant is Myosotis sylvatica and Windows tear is Rhoeo species.
  3. (a) hormone of ovary
    Explanation: hormone of ovary
  4. (c) Chilled ethanol
    Explanation: During the isolation of the desired gene, chilled ethanol is used for the precipitation of DNA.
  5. (a) Monocot stem
    Explanation: In Monocot stem vascular bundles are found scattered throughout the ground tissue. The vascular bundles contain no cambium. Hence vascular bundles are conjoint, collateral, exarch, and closed.
  6. (b) If forms permanent compound with Hb
    Explanation: If forms permanent compound with Hb
  7. (d) Proton gradient
    Explanation: 2H2{tex}\rightarrow{/tex} 4H+ + O2 + 4e
    This reaction takes place in the inner side of the thylakoid membrane, and so the protons formed are thus trapped in the lumen of thylakoid. As electrons move through photosystems, these protons are transported across the membrane. This gradient is important because the breakdown of this leads to the release of energy.
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  8. (d) Ureotelic mode of excretion
    Explanation: Adult frog and human exhibit ureotelism because there excretory waste product is urea.
  9. (d) All of these
    Explanation: Frogs are beneficial for mankind because they eat insects and protect the crop. Frogs maintain ecological balance because these serve as an important link of the food chain and food web in the ecosystem. In some countries, the muscular legs of the frog are used as food by man.
  10. (c) Suppression of growth of axillary buds by the presence of apical bud
    Explanation: Suppression of growth of axillary buds by the presence of apical bud
  11. (a) Plants can live in soil but are dependent on water for sexual reproduction
    Explanation: Bryophytes are also called amphibians of the plant kingdom because these plants can live in soil but are dependent on water for sexual reproduction. They usually occur in damp, humid, and shaded localities.
  12. (c) Reabsorption of water and Reabsorption of salt
    Explanation: Reabsorption of water and Reabsorption of salt
  13. (b) Parathyroid
    Explanation: When blood calcium levels drop, the parathyroid gland secretes a parathyroid hormone which helps to raise blood calcium levels. Hence, the parathyroid gland is malfunctioning in a child whose plasma calcium level is found below the optimum level.
  14. (d) A is false but R is true.
    Explanation: Globigerina contains a multi-chambered calcareous shell. Sexual reproduction involves the formation and fusion of flagellate gametes.
  15. (a) Both A and R are true and R is the correct explanation of A.
    Explanation: Cells are the basic structural and functional unit of organism.
  16. (a) Both A and R are true and R is the correct explanation of A.
    Explanation: Hydrolysis of starch into glucose in an organic chemical reaction. Bonds are broken and new bonds are formed during the transformation of starch into glucose.
  17. (a) Both A and R are true and R is the correct explanation of A.
    Explanation: There is no air in the trachea, it does not collapse due to the presence of a C-shaped narrow cartilagenous rings or discs.
  18. Class 11 Biology Paper Solution Section B

  19. Stomatal opening, guard cells and companion cells.
  20. Sense Organs in Frog:
    Frog has different types of sense organs which are as follows:
    (a) Sensory papillae or organs of touch,
    (b) Taste buds.
    (c) Nasal epithelium for the sense of smell,
    (d) Eyes for vision and
    (e) Tympanum with internal ears for hearing.
    Out of these, eyes and internal ears are well-organised structures and the rest are cellular aggregations around nerve endings. Eyes in a frog are a pair of spherical structures situated in the orbit in skull. These are simple eyes. External ear is absent in frogs and only tympanum can be seen externally. The ear is an organ of hearing as well as balancing.
  21. Four Activities Regulated by Estrogen Hormone are:
    1. The stimulation and growth of secondary sex organs.
    2. The development of growing follicles.
    3. The appearance of female secondary sexual characteristics like voice pitch is high, mammary glands development and other features, etc.
    4. To regulate female sexual behaviour.
  22. Obligate CategoriesIntermediate Categories
    KingdomSubkingdom
    Phylum or DivisionSubphylum or subdivision and superclass
    ClassInfra class and subclass
    OrderSuperorder and suborder
    FamilySubfamily and tribe
    GenusSubgenus
    SpeciesSubspecies, variety or race

    The flow chart is as follows:

  23. Chlorophyll ‘b’: Chlorophyll ‘b’ xanthophylls and carotenoids are accessory pigments. These absorb light and transfer the energy to chlorophyll ‘a’. They enable a wider range of incoming light to be used for photosynthesis. They protect chlorophyll ‘a’ from the photo-oxidation. Chlorophyll ‘a’ is known as the prim ary photosynthetic pigment.

    OR

    C-plants possess special anatomy of leaves called Kranz anatomy, which means the presence of two types of chloroplasts, agranal in bundle sheath cells and granal in mesophyll cells.

  24. StructurePteridophyteGymnospermAngiosperm
    Main reproductive partGametophyte bears antheridia and archegoniaMicrosporophylls and megasporophylls represent the gametophyte.Flower bears antheridium and gynoecium.
    Male reproductive partAntheridia produce male gamete.The male cone is highly reduced in size.Antheridia are composed of an anther and a slender stalk. Anther produces the pollen grains, i.e. male gametes.
    Female reproductive partArchegonia produce the female gamete.The megasporophyll is large in size and is easily apparent as the female cone.The gynoecium contains the ovary, style and stigma. The fertilised egg develops inside the ovary and eventually, seeds are produced.
  25. In leeches, there is no true blood vascular system, the coelomic space and fluid have been modified to form the circulatory system. Hence, it is called haemocoelomic system and the coelomic fluid is called haemocoelomic fluid. Blood is red due to the presence of respiratory pigment haemoglobin or erythromycin found dissolved in the plasma. Free amoeboid blood corpuscles are present, but there are no red blood corpuscles.
    1. The type of inhibition of succinic dehydrogenase by malonate is competitive inhibition.
    2. The inhibitor competes with the substrate for the active sites of enzyme molecules as it has a structure similar to the substrate that allows it to combine with the active site, preventing any substrate molecule from occupying that site. This reduces the rate of the reaction since, the substrate can only use the enzyme molecules that are not occupied by the inhibitor, resulting in the same quantity of product being formed at a slower rate.
  26. Ethylene is a gaseous hormone. It influences the horizontal growth of seedlings and promotes senescence and abscission of leaves. It is effecting in fruit ripening. It causes epinasty also.
    Abscisic acid (ABA) is essential for the regulation of abscission and dormancy of bud. It acts as a growth inhibitor. It has a role in abscission of leaves and bud dormancy. It inhibits seed germination.
    So the role of ethylene and ABA is both positive and negative also.
  27. Proteins and iron are essential components required for the synthesis of haemoglobin and erythrocytes. Vitamin B12 and folic acid help in their maturation.
    The old and worn-out erythrocytes are destroyed by phagocytosis in the blood, liver, and spleen. Their iron content is returned to the bone marrow. The pigment is degraded into bilirubin which is excreted in bile.

    OR

    Individuals with blood group O are called universal donors. These individuals do not have either A on B antigens on the surface of their RBCs, but their blood serum contains antibodies against both A and B antigens.
    Therefore, group individuals can only receive blood from a group O individual, but they can donate blood to individuals of any ABO blood group (i.e., A, B, O or AB).

    1. The causes of osteoporosis are as follows:
      1. Low calcium diet
      2. Lack of physical activity
      3. Family history
      4. Ethnicity- White and Asian people are more likely to be affected by osteoporosis.
    2. The preventive measures of osteoporosis are as follows:
      1. Increase calcium intake in the diet
      2. Increase Vitamin D in the diet.
      3. Exercise regularly to create stronger and healthier bones.
    3. Osteoporosis is called a silent disease because most people don’t even realize they have osteoporosis until one of the bone is fractured.
    1. Difference between Grey matter and White matter:
      Grey MatterWhite matter
      It is composed of cell bodies (cytons) of a nerve cell. It is inside the brain but outside the spinal cord.It is composed of axons from the nerves cells. It is inside the brain but outside the spinal cord.
    2.  Difference between A stimulus and An impulse:
      A stimulusAn impulse
      Any change in the environment of an organism that evokes response or impulse.It is a self-propagating wave electrochemical in nature; negatively travelling along the axon of a nerve cell.
  28. Class 11 Biology Paper Solution Section C

    1. In basidiomycetes asexual spores are not found, vegetative reproduction occurs by fragmentation, and sexual organs are absent.
      1. Aquatic habitats
      2. On decaying wood
      • Ascomycetes are commonly known as sac-fungi as they are produced in a sac-like structure known as ascus.
      • Dikaryon formation is the characteristic feature of ascomycetes and basidiomycetes.
    2. OR

      • Agaricus
      • Agaricus is a fleshy saprophytic fungus with over 300 species and  contains both edible and poisonous species. It is found in wet and damp climates. It grows on wood and in humus-rich soil.
    1. Ovary develops into a fruit and ovules into seeds.
    2. Mustard, datura, and chili are the actinomorphic flowers as they are divided into two half from any plane.
    3. When the gynoecium is present in the topmost position of the thalamus, the ovary is known as: superior.
    4. OR


      Epigynous flower: The margin of the thalamus grows over and encloses the ovary completely. The margins of the flower get fused with the other parts of the flower which rise above the ovary.

  29. Class 11 Biology Paper Solution Section D

  30. Mitosis is divided into the following four stages:
    1. Prophase
      • Condensation of chromosomal material starts. The chromosomal material becomes untangled during the process of chromatin condensation.
      • The centriole, which had undergone duplication during S phase of interphase now begins to move towards opposite poles of the cell.
      • At the end of prophase, Golgi complexes, endoplasmic reticulum, nucleolus and the nuclear envelope disappear.
    2. Metaphase
      • The metaphase is characterized by all the chromosomes coming to lie at the equator.
      • One chromatid of each chromosome connected by its kinetochore to spindle fibres from one pole and its sister chromatid connected by its kinetochore to spindle fibres from the opposite pole.
      • The plane of alignment of the chromosomes at metaphase is referred to as the metaphase plate.
    3. Anaphase
      • At the onset of anaphase, each chromosome arranged at the metaphase plate is split simultaneously and make the two daughter chromatids.
      • They are now referred to as chromosomes of the future daughter nuclei and begin their migration towards the two opposite poles.
      • As each chromosome moves away from the equatorial plate, the centromere of each chromosome is towards the pole and hence at the leading edge, with the arms of the chromosome trailing behind.
    4. Telophase
      This is the stage which shows the following key events:

      • Chromosomes cluster at opposite spindle poles and their identity is lost as discrete elements.
      • Nuclear envelope assembles around the chromosome clusters.
      • Nucleolus, Golgi complex and ER reform.
    5. Cytokinesis
      Karyokinesis is followed by cell division to form two daughter cells. This process is called cytokinesis at the end of which cell division is complete.

    OR

    1. Ribosome are the organelles which are not bound by a membrane. Rather ribosome is composed of two subunits and lie interspersed in the protoplasm. Ribosomes are also found attached to the surface of the Rough Endoplasmic Reticulum. They are also found in mitochondria and plastids.
    2. Lysosome is the cell organelle which is bound by a single membrane. It is a small sac-like structure. Lysosomes are found in animal cells but not in prokaryotes. Lysosome play an important role in destroying harmful substances and foreign materials.
    3. Most of the cell organelles are bound by double membranes. Mitochondria, plastids, nucleus, endoplasmic reticulum are the examples of double-membrane cell organelles. These organelles serve important functions in the cell.

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  31. This figure shows the major pathways of anaerobic respiration or fermentation. Glycolysis is shown on the lefthand side, while further processing of pyruvic acid is shown on the right-hand side.
    In animal cells also, like muscles during exercise, when oxygen is inadequate for cellular respiration pyruvic acid is reduced to lactic acid by lactate dehydrogenase. In certain organisms, pyruvic acid is processed to produce ethanol and carbon dioxide. Some amount of energy is released in both cases.
    Two applications of anaerobic respiration are as follows:

    1. In making fluffy cakes and bread anaerobically reproducing fungi yeast is used.
    2. In making curd lactobacillus is added as inoculum.

    OR

    Respiratory Balance Sheet: Some assumptions in preparing respiratory balance sheet are :

    1. None of the intermediates produced in this pathway is used to make any other compound.
    2. Only glucose is being respired—no other alternative substrates enter in the pathway at any of intermediary stages in any case.
    3. There seems to be a sequential, orderly pathway that is functioning, with a single substrate forming next as well as with glycolysis. Kreb’s cycle and ETS pathway following one after the other pathway.
    4. NADH synthesised in glycolysis transferred to mitochondria; it undergoes oxidative phosphorylation also.

    This assumption is not really valid in a living system since all the pathways work simultaneously; moreover, the substrates enter pathways and also are withdrawn from the pathways as and when required; ATP used when needed and enzymes control the reactions also. It is only useful in the extraction and storing energy; there is a net gain of 36 ATP mols in aerobic respiration for one mol of glucose.

  32. It is true that the cells of unicellular organisms tend to be spherical. It is because of the following reasons:
    1. Surface tension: Surface tension shapes the spherical way as in the case in air-borne soap bubbles.
    2. The free-floating cells with thin membranes tend to be spherical as it is the most economical shape that can confine a given mass of protoplasm. The shape and the size of the cell depend upon the place where they are present and the functions they have to perform. In multicellular animals, the cells tend to become faceted as they come in contact with each other in the same way as the spherical soap bubbles become flattened when they are jammed together in a small space.

    OR

    Structures responsible are

    1. Smooth endoplasmic Reticulim (SER) is responsible for the manufacture of lipids and steroids.
    2. Mitochondrion is responsible for the release of energy.
    3. Ribosomes are responsible for the production of hormones and digestive enzymes.
    4. Centrioles are responsible for production of spindle fibres.
    5. Plasma membrane is responsible for endo and exocytosis.

 

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