Subject: Biology
Class XI
Time Allowed: 3 hours
Max Marks: 70
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-Chas 7 questions of 3 marks each; Section-D has 2 case-based questions of 4 marks each; and Section-E has 3 questions of S 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.
SECTION – A
1. What is the common method of reproduction found in organism shown image below?
(a) Cell division
(b) Fragmentation Protoplasm Vacuole
(c) Budding
(d) Sexual reproduction
2. Match the following and choose the correct option.
| Group A | Group B |
| A) Valvate aestivation | I) Cassia |
| B) Twisted aestivation | II) Cotton |
| C) Imbricate aestivation | III) Calotropis |
| D) Vexillary aestivation | IV) Pea |
Choose the correct match.
(a) (A)-(I), B)-(II). (C)-(III), (D)-(IV)
(b) (A)-(III), (B)-(II). (C)-(I), (D)-(IV)
(c) (A)-(IV), (B)-(II), (C)-(I), (D)-(III)
(d) (A)-(II), (B)-(IV), (C)-(I), (D)-(III)
3. The wall of parenchyma are made up off
(a) Fructose
(b) Cellulose
(c) Glucose
(d) Maltose
4. Different cells have different sizes. Arrange the following cells in an ascending order of their size. Choose the correct option among the following.
(I) Mycoplasma
(II) Ostrich eggs
(III) Human RBCs
(IV) Bacteria
Select the correct option:
(a) (I), (IV), (III), (II)
(b) (I), (III), (IV), (II)
(c) (II), (I), (III), (IV)
(d) (III), (II), (I), (IV)
5. Symbiotic association of fungi with algae is known as
(a) Mycorrhiza
(b) Lichens
(c) Parasitic
(d) Saprophytes
6. Which one of the following plants should you pick If you want to study the structure of elaters?
(a) Chara
(b) Marchantia
(c) Pinus
(d) Equisetum
7. Match the following and mark the correct options
| Animal | Respiratory Organ |
| A) Aquatic Arthropods | (I) Lungs |
| B) Fishes | (II) Gills |
| C) Earthworm | (III) Trachea |
| D) Human beings | (IV) Moist Cuticle |
a) (A) – (IV), (B) – (III), (C) – (II), (D) – (I)
b) (A) – (III), (B) – (II), (C) – (IV), (D) – (I)
c) (A) – (II), (B) – (I), (C) – (IV), (D) – (III)
d) (A) – (I), (B) – (III), (C) – (II), (D) – (IV)
8. Ribosomes are very important cell organelles and they are also called Palade granules.
Read the following statements, and choose the ones which are true for eukaryotic ribosomes.
(I) They are 80S ribosomes.
(II) They have a 50S and a 30S subunits.
(III) They are 70S ribosomes
(IV) They have a 60S and a 50S subunits
Codes:
(a) Only (I)
(b) (I) and (II)
(c) (I) and (IV)
(d) (II) and (III)
9. Choose the incorrect statement:
(a) Initially, the pace of the enzyme reaction increases as the substrate concentration increases.
(b) An enzyme’s activity can be influenced by changes in environmental circumstances, which can modify the protein’s tertiary structure.
(c) A metabolic route is a multistep chemical process in which each step is regulated by an enzyme.
(d) In the absence of an enzyme, any process tends to be very inefficient.
10. Match the following list of animals with their level of organization.
Choose the correct match showing division of labour with animal examples
(a) (B) – (I), (C) – (II), (D) – (III), (A) – (IV)
(b) (B) – (I), (D) – (II), (C) – (III), (A) – (IV)
(c) (D) – (I), (A) – (II), (B) – (III), (C) – (IV)
(d) (A) – (I), (D) – (II), (C) – (III), (B) – (IV)
11. Match the following and mark the correct option:
(a) (A) – (I), (B) – (II), (C) – (IV), (D) – (III)
(b) (A) – (II), (B) – (I), (C) – (III), (D) – (IV)
(c) (A) – (II), (B) – (I) (C) – (IV), (D) – (III)
(d) (A) – (III), (B) – (II), (C) – (IV), (D) – (I)
12. In the context of an organic reaction, what does Vmax Stand for?
(a) velocity of an enzymatically catalyzed reaction, when the enzyme is saturated with its substrate.
(b) The velocity of an enzymatically catalyzed reaction at half the concentration of initial substrate.
(c) The velocity of an enzymatically catalyzed reaction at half the concentration of the final product.
(d) None of the above
Question No 13 to 16 consist of two statements – Assertion (A) and Reason (R). Answer these questions selecting the appropriate option given below
(a) Both A and R are true and R is the correct explanation of A
(b) Both A and R are true and R is not the correct explanation of A
(c) A is true but R is false
(d) A is false but R is true
13. Assertion (A): Proteins which have the high catalytic power are called enzymes
Reason (R): Amino acids are also considered as they have no charge.
(a) Both A and R are true and R is the correct explanation of A
(b) Both A and R are true and R is not the correct explanation of A
(c) A is true but R is false
(d) A is false but R is true
14. Assertion (A): Obelia shows metagenesis
Reason (R): As polyps produce medusa asexually and medusa form the polyp sexually.
(a) Both A and R are true and R is the correct explanation of A
(b) Both A and R are true and 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): Frogs are important for mankind
Reason (R): Frogs eat insects and protect the crop.
(a) Both A and R are true and R is the correct explanation of A
(b) Both A and R are true and 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): There is a temporary stiffening of muscles after death.
Reason (R): there is a depletion of ATP that occurs with the stopping of cellular respiration.
(a) Both A and R are true and R is the correct explanation of A
(b) Both A and R are true and R is not the correct explanation of A
(c) A is true but R is false
(d) A is false but R is true
SECTION – B
17. In the below given image, two types of leaves are shown, pinnately compound and palmately compound. Describe them and also provide suitable examples.
Ans. Pinnate compound leaves: A common type of compound leaf in which the leaflets are divided into two rows and the rachis is long and elongated. Eg. Neem, rose.
Palmate compound leaf: At the tip of the petiole, the leaflets are arranged palmately in accordance with the number of leaflets present Leaflets attached to common points at the petiole tip. Eg. Silk, cotton.
18. What could have been the phylogenetic purpose of developing two kinds of spores?
Ans. Development of two different kinds of spores, or heterospory, has resulted in embryo development in situ. The embryo is better protected since it receives nutrients from the female gametophyte. Evolutionarily speaking. heterospory resulted in the emergence of seeds, which allowed plants to thrive and survive lengthy periods of adverse environments.
19. (A) What is mimicry?
Ans. Frogs may change their colour to blend in with their surroundings and hide from predators (camouflage). The term for this protective colouring is mimicry
(B) What is the meaning of Amplexus?
Ans. Amplexus is the mating position of amphibians in which male climbs onto females back, grasping her either behind the arms or around the waist. In frogs and toads, this position helps in fertilization. It is considered as a physical position in which cloacae of both the frogs align at such a position though which sperms and eggs meet easily.
20. Differentiate between Rough Endoplasmic Reticulum (RER) and Smooth Endoplasmic Reticulum (SER).
Ans.
| Rough Endoplasmic Reticulum (RER) | Smooth Endoplasmic Reticulum (SER) |
| Endoplasmic reticulum with ribosomes on their surface appear rough and they are called the rough endoplasmic reticulum | Endoplasmic reticulum that does not have ribosomes on their surface appear smooth and they are called smooth endoplasmic reticulum. |
| They are continuous with the outer nuclear membrane and are found in cells actively involved in protein synthesis and secretion. | It is the site of lipid synthesis and in animal cells, lipid-like steroidal hormones are produced in the SER |
OR
(A) What is the difference between inorganic catalysts and enzymes?
Ans. Inorganic catalysts perform well at high temperatures and pressures, but enzymes are destroyed at high temperatures (over 40°C)
(B) Briefly describe the modifications that may occur in a chemical compound.
Ans. There are two sorts of modifications that occur in chemical compounds. A physical change is merely a deformation that does not involve the breaking of connections. Whenever bonds are formed or broken during transformation, this is referred to as a chemical reaction.
21. How are hormones grouped into different categories?
Ans. On the basis of their chemical nature, they can be divided into various groups. These are:
(1) Peptide, polypeptide, protein hormones: glucagon, pituitary hormones.
(2) Steroids: Cortisols, estrogen, progesterone, Insulin. hypothalamic and testosterone.
(3) lodothyronines: Thyroid hormones
(4) Amino acid derivatives: Epinephrines.
SECTION – C
22. Write about the floral characters of Solanum nigrum and Petunia alba?
| Floral Characters | Solanum nigrum | Petunia alba |
| Inflorescence | Extra axillary cyme | Solitory axillary |
| Flower | Ebracteate, pedicellate, actinomorphic, bisexual pentamerous except gynoecium regular, hypogynous, cyclic, white coloured | Bracteate, pedicellate, complete actinomorphic, bisexual, hypogynous, variously coloured |
| Corolla | Five, gamopetalous, rotote, white, inferior | Five, gamopetalous, infundibuliform, pentafid, inferior |
| Androecium | Five in number, polyandrous, epipetalous, filaments short, dithecous anthers, basifixed, alternipetalous, dehiscence porous, inferior | Five in number, polyandrous, epipetalous, alternate to the petals, basifixed, filaments long, longitudinal dehiscence, inferior |
| Gynoecium | Bicarpellary, syncarpous, hypogynous (superior obliquely placed ovary), placenta swollen, axile placentation, bilocular, style is long, stigma bilobed, capitate and green | Bicarpellary, syncarpous, hypogynous (superior obliquely placed ovary), placenta swollen, each loculus with with numerous ovules, axile placentation, style is long, stigma bifid, capitate |
23. Identify the given images and write their phyla.
Ans. (A) Hirudinaria (Blood sucking leech) and it belongs to phylum annelida.
(B) Fosciola (iver fluke) and it belongs to phylum platyhelminthes.
(C) Adamsia (Sea anemone) and it belongs to phylum coelenterata.
24. On an educational trip to Uttaranchal, Ketki and her friends observed that many local people were having swollen necks. Please help Ketki and her friends to find out the solutions to the following questions.
(A) From which probable disease these people are suffering from?
Ans. Enlargement of thyroid gland, causes disease name goitre.
(B) How is it caused?
Ans. Hypothyroidism is caused due to deficiency of iodine in diet causing low secretion or thyroid hormone.
(C) What effect does this condition have on pregnancy?
Ans. During pregnancy, it causes defects in growing fetuses, stunted growth (cretinism) mental retardation, low 1Q, abnormal skin. deaf mutism. In adult women, it causes irregular menstrual cycles.
25. State true or false giving reason.
(A) ADH aids in the removal of water by making the urine hypotonic.
Ans. False: ADH is a hormone which regulates the amount of water in the body. It is a small peptide hormone which regulates the body’s retention of water.
(B) The Henle’s loop is an important part of the urine concentration process.
Ans. True it indeed is an important part of the urine concentration process.
26. Write about the factors that affects the Hypertension.
Ans. factors affecting hypertension are as follow:
(1) Elasticity of vessels
(2) Age
(3) Blood volume
(4) Venous return
(5) Obesity
(6) Sleep
As elasticity of vessels increases, hypertension decreases, i.e., elasticity of vessels is inversely proportional to hypertension. As age increases, blood pressure also increases but heart rate decreases, age is directly proportional to hypertension but inversely proportional to heart rate. Blood pressure increases with increase in blood volume, increases with increase in body weight. As sleeping hours are increased hypertension decreases, i.e, sleep is inversely proportional to blood pressure
OR
What could be done if the new transplanted kidney is rejected by the body?
Ans. Rejection indicates that the immune system has recognized the new kidney as foreign tissue and is attempting to eliminate it The first priority is to prevent rejection with immune-suppressing medication. A change in kidney function (an increase in creatinine, a waste product) measured by a blood test is the most common sign of rejection. This is why, for the first three months after transplantation. patients should have gone through frequent blood tests. followed by regular tests. If a kidney biopsy and ultrasound confirm the rejection episode, the transplant team will either increase the amount of anti-rejection medication or prescribe a different anti-rejection drug combination. We Can successfully reverse most rejection episodes with medicine if we detect them early enough. However, if the episode is severe, the new kidney’s overall life span may be shortened.
27. (A) Define Zwitter ion.
Ans. Zwitter ion is the ionic form of amino acids found in aqueous environment. The hydrogen from the carboxyl group moves to the amino group making the carboxyl group negative and amino group positive. The overall charge of zwitterion remains zero.
(B) What is an amino acid?
Ans. Amino acid is a monomer of protein. The amino acid contains a central carbon atom linked with an amino group (positively charged group), a carboxyl group (negatively charged group), a hydrogen atom and an ‘R’ group
(C) Draw the diagrams of primary, secondary, tertiary and quaternary structures of protein.
Ans. The diagrams of primary, secondary. tertiary and quaternary structures of protein are
28 (A) What is Photorespiration? Which plants show Photorespiration?
Ans. Photorespiration is a light dependent process of oxygenation RuBP and release of CO₂ by the photosynthetic organs of a plant. It is initiated in chloroplast and happens in the condition of high light intensity, reduced carbon dioxide levels and raised oxygen level C₃ plants carrying out photorespiration.
(B) What steps are common in C₃ and C₄ photosynthesis.
Ans. The steps which are common in C₃ and C₄ photosynthesis are:
(1) Photolysis of water in light reaction.
(2) Dark reaction occurs in stroma region
(3) Calvin cycle result in the formation of sugar
(4) Both undergo a phase of carboxylation and regeneration of RUBP in a dark reaction.
SECTION – D
29. Rohit is a curious kid having good knowledge of plants. One day, he was watching two plants, the first one being very tall and the second one having thick stems. The first plant is redwood, which is one of the tallest plants in the world, and the second plant is the banyan tree. Both of these plants are grown in the same area, suffering from the same climatic conditions, and the same human care. Rohit is having a problem and is confused due to the difference in the morphology of both plants. Help Rohit.
(A) What are the two types of growth seen here?
Ans. Primary growth and secondary growth
(B) Which type of growth is predominant in each plant?
Ans. In first plant, primary growth is predominant, and in second plant, secondary growth is predominant.
(C) Write one difference and one similarity between these two types of growth.
Ans. The one difference that is in primary growth the length of the plant increases, whereas in secondary growth the girth of the plant increases. And one similaring is that in both of these growths, meristematic tissues are involved
OR
(C) What are the different phases of growth?
Ans. Phases of growth: The period of plant growth is divided into three stages.
- Meristematic phase
- Phase of elongation
- Phase of maturation
Meristematic phase: During this phase, the cells in the growing region undergo mitotic division to form numerous cells. These cells are iso-diametric with prominent, large and conspicuous nucleus and rich protoplasm without vacuoles. They have thin cellulosic cell wall with many plasmodesmata. in higher plants, the meristematic phase takes place in meristems at root apex and shoot apex.
Phase of elongation: It is the dominant phase in growth of plants. During this phase, the newly formed cells absorb more water. As a result, the turgidity and the amount of protoplasm increase. Vacuoles appear at the centre. The cell walls become more thickened. Due to these events, the cells enlarge. Enlargement of cells takes place in all directions.
Phase of maturation: During this phase, the enlarged cells become differentiated to perform specific functions. The matured cells gradually get differentiated into permanent tissues by attaining their maximum size in terms of wall thickening and protoplasmic modifications.
30. Allergic reactions can cause symptoms in your nose, lungs, throat, sinuses, ears, lining of the stomach or on the skin. Allergies can trigger the symptoms of asthma, making it more difficult to breathe. An environmental allergy can affect your airway in two distinct ways, potentially resulting in shortness of breath. Allergic rhinitis, also known as hay fever, affects your nose and sinuses. It can lead to sneezing, congestion, an itchy nose, and itchy eyes. If you are especially congested, you may find it difficult to breathe through the nose. Allergic asthma primarily affects airways in the lungs, and can develop among people who have been diagnosed with asthma. It can cause coughing, wheezing, tightness in the chest, and shortness of breath or rapid breathing. In the case of allergic asthma, these symptoms can develop simultaneously.
A person had difficulty breathing when he/ she came across certain factors like change (B) Which in weather. pollens, dust, etc.
(A) Do these symptoms necessarily mean that the patient is suffering from a certain respiratory disease or disorder?
Ans. No, these can also be a common symptoms of disease like cold and cough and these symptoms do not depict that the person necessarily has a certain respiratory disease or disorder.
(B) How do you define Dyspnea?
Ans. Dyspnea, or breathlessness or shortness of breath, is an unpleasant condition that finds it challenging to get enough oxygen into your lungs.
(C) Name the factors which might be responsible for difficulty in breathing.
Ans. The factors may include dust allergies, mildew, or pollen allergies, stress and worry, clogged airways due to a stuffy nose or throat phlegm, and decreased oxygen consumption due to high altitude heights.
OR
(C) What medications are involved for treating patients suffering from breathlessness due to allergies?
Ans. Antihistamine is prescribed for avoiding immunogenic response due to allergen triggers. Use of bronchodilator drugs and inhalers for relief.
SECTION – E
31. (A) “Catalyzed processes have been observed to proceed at significantly faster rates than uncatalyzed ones.” Justify the statement with an example.
Ans. When enzyme-catalyzed reactions are seen; the rate is much higher than the identical but uncatalyzed process. An example of this is shown as follows:
In the absence of an enzyme, the processes become very inefficient, producing just around 200 molecules of H₂CO₃ each hour. However, by utilizing a cytoplasmic enzyme called carbonic anhydrase, the reaction is sped up substantially, with around 600,000 molecules generated every second. The enzyme has thus increased the rate of the reaction by about 10 million times.
(B) Name the coenzyme of riboflavin (B₂) and state the nature of an enzyme.
Ans. The coenzyme of riboflavin (B2) are FAD and FMN. The nature of enzyme are proteins.
OR
(A) Define Proteins.
Ans. Proteins are the polypeptides, having linear chains of amino acids which are linked together with the help of peptide bonds. These bonds are formed when –COOH group of one amino acid reacts with -NH₂ group of next amino acid by releasing a molecule of water.
(B) Differentiate proteins on the basis of their shape.
Ans. On the basis of shape, proteins generally are of two types:
(1) Fibrous: In this, spiral secondary polypeptide chains wound around each other.
(2) Globular: these are spherical shape.
(C) Describe one function of each one of them: collagen, trypsin, insulin and GLUT-4
Ans. Proteins perform several functions such as
(1) Collagen: It is the most abundant protein in animal world which acts as intercellular ground substance. Due to its rigidity and resistance to stretching, it is the perfect matrix for skin, tendons, bones, and ligaments.
(2) Trypsin: It acts as enzyme that helps us digest protein. In the small intestine, it breaks down proteins, continuing the process of digestion that began in the stomach.
(3) Insulin: It acts as hormone which regulates the blood sugar level
(4) GLUT-4: It enables glucose transport into the cell that is responsible for insulin-regulated glucose uptake into fat and muscle cells.
32. Write the similarities and differences between plants and fungi.
Ans. Similarities:
(1) Both the kingdoms consist of eukaryotic organisms.
(2) Cell walls are present in both
(3) Cell comprises of numerous organelles
(4) Both can reproduce sexually and asexually.
(5) Mostly anchored in soil or some other substrate
(6) Stationary i.e., cannot move on their own.
Differences:
OR
Differentiate between:
A) Oviparity and viviparity
Ans. Oviparity: In this, Oviparous animals give birth to their young ones by laying an egg. Viviparity: In this, viviparous animals give birth to the live young ones.
(B) Direct and indirect development
Ans. Direct development: It is a type of development in which an embryo develops into a mature individual without involving a larval stage.
Indirect development: It is a type of development that involves a sexually immature larval stage.
(C) Notochord and nerve cord
Ans. Notochord It is a mesodermally derived rod-like-structure formed on the dorsal side during embryonic development in some animals and it is the part of the skeletal system.
Nerve cord: It is a part of the nervous system.
(D) Polyp and medusa
Ans. Polyp: It is a sessile and cylindrical form like Hydra, Adamsia, etc
Medusa: It is umbrella-shaped and free-swimming like Aurelia or jellyfish.
33. The entire process of photosynthesis consists of a number of reactions. Where in the cell do each of these take place?
(A) Synthesis of ATP and NADPH
Ans. Synthesis of ATP and NADPH: Membrane system (Grana).
(B) Photolysis of water
Ans. Photolysis of water: Inner side of the membrane of thylakoid.
(C) Fixation of CO₂
Ans. Fixation of CO₂: Stroma of chloroplast
(D) Synthesis of sugar molecule
Ans. Synthesis of sugar molecule: Stroma of chloroplast.
(E) Synthesis of starch
Ans. Synthesis of starch: Stroma of chloroplast
OR
Give reasons:
(A) Calvin cycle occurs in C₄ plants
Ans. Calvin cycle takes place in the mesophyll cells of C₃ plants whereas it occurs in the bundle sheath of C₄ plants where malate is translocated to bundle sheath where breakdown starts to release carbon dioxide. Then it is fixed by RuBisCO and formed sugar through the Calvin cycle.
(B) Photorespiration is considered as a wasteful process.
Ans. Photorespiration is considered as a highly wasteful process because it does not produce energy. On the other hand, it also consumes energy and loses some amount of fixed CO₂. There is a 25% loss in C₃ plants. It does not occur in C₄ plants.
(C) Chloroplasts are generally located at the outer margins of mesophyll cells.
Ans. Chloroplasts are generally margins of mesophyll cells which helps in easy diffusion of gasses required for photosynthesis from the atmosphere to the inside of chloroplasts.