CBSE Sample Papers for Class 11 Biology Set 9 with Solutions

students must start practicing the questions from CBSE Sample Papers for Class 11 Biology with Solutions Set 9 are designed as per the revised syllabus.

CBSE Sample Papers for Class 11 Biology Set 9 with Solutions

Time Allowed : 3 hours
Maximum Marks: 70

General Instructions :

1. All questions are compulsory.
2. The question paper has four sections: Section A, Section B, Section C and Section D. There are 27 questions in the question paper.
3. Sedion-A has 5 questions ofl mark each. Section-B has 7 questions of 2 marks each. Section-C has 12 questions of 3 marks each and Section-D 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 labelled diagrams should be drawn.

Section – A

Question 1.
As we go from species to kingdom in a taxonomic hierarchy, the number of common characteristics:
(A) will decrease
(B) will increase
(C) remain same
(D) may increase or decrease
Answer:
(A) will decrease

Question 2.
Protonema is ……….
(A) Haploid and in mosses.
(B) Diploid and in liverworts.
(C) Haploid and in pteridophytes.
(D) Haploid and in pteridophytes.
Answer:
(A) Haploid and in mosses.

Question 3.
light range is most effective in photosynthesis.
(A) Purple
(B) Green
(C) Red
(D) Violet
Answer:
(C) Red

Question 4.
Assertion (A): Uremia is an excretory disorder.
Reason (R): The accumulation of urea in blood is known as uremia.
(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.
Answer:
(B) Both A and R are true but R is NOT the correct explanation of A.
Explanation: Uremia is an excretory disorder. It is the accumulation of urea in blood due to malfunctioning of kidney.

Question 5.
Assertion (A): Binding of oxygen with haemoglobin is primarily related to the partial pressure of 02.
Reason (R): Partial pressure of C02, hydrogen ion concentration and temperature are the other factor that can interfere with this binding.
(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.
Answer:
(B) Both A and R are true but R is NOT the correct explanation of A.
Explanation:
The partial pressure of 02 in the hemoglobin is lower that the partial pressure of C02 in the alveoli.

Section – B

Question 6.
Write about sexual dimorphism in Aschelminthes.
Answer:
Aschelminthes also known as Aeschelminthes, Nemathelminthes, and Nematodes have distinct sexual dimorphism. The female is larger than the male. The tail of male is coiled like tendril and has a pair of unequal copulatory spicules. Female has an anus, while the male bears a cloacal aperture.

Question 7.
Name the enzyme that catalyses carboxylation as well as oxygenation reaction. In which cell organelle is this
enzyme found and in what way is that organelle different in the mesophyll and bundle sheath cells?
Answer:
RubisCO enzyme catalyses carboxylation and oxygenation reactions. It is found in the chloroplast (cell organelle). Chloroplasts in mesophyll cells are granal but chloroplast of bundle sheath cells are agranal. Granal chloroplasts have thylakoids stacked to form grana (as in C3 plants). Agranal chloroplasts are without grana but thylakoids are found as stroma lamellae.

Question 8.
What are the limitations of the two-kingdom system?
Answer:
Limitations of the two-kingdom system:

1. Certain organisms share the characters with animals as well as plants. For example, Euglena, a protozoan shows locomotors movement like animals, but it contains chlorophyll like plants.
2. Fungi have certain features of their own. They resemble plants as well as animals.
3. Lichen is a group of dual organisms which are formed by an association between an alga and fungus. They have neither plant character, nor any animal character.
4. Viruses and prokaryotes became well-defined.

Question 9.
Why does lymph act as the middleman of the body?
Answer:
(i) Lymph acts as a “middle man” which transports oxygen, food materials, hormones, etc., to the body cells and brings carbon dioxide and other metabolic wastes, from the body cells to blood and then finally pours the same into the venous system. Body cells are kept moist by the lymph.

(ii) Lymph capillaries present in the intestinal villi are called lacteals which are associated with absorption and transportation of fat and fat-soluble vitamins.

Question 10.
State differences between free central and axile Placentation. Sample Question Papers
Answer:

Free central placentation	Axile placentation
(i) In free central placentation, ovary is single- chambered.	In axile placentation, ovary is partitioned into chambers
(ii) Here, the ovules are borne on the central axis and lies free inside the ovary.	Here, the placenta arises from the central axis where the septa fuse to form axile column to which ovules are attached.
(iii) For e.g., Dianthus, Silensa, etc.	for e.g., Citrus, tomato, etc.

Question 11.
Mention two points of differences between SER and RER.
Answer:

SER (Smooth endoplasmic reticulum)	RER (Rough endoplasmic reticulum)
(i) The Smooth endoplasmic reticulum does nothave ribosomes and is composed of vesicles and tubules.	Rough endoplasmic reticulum have ribosomes on its outer surface and is composed of cisternae.
(ii) It synthesises steroids and lipids. It is related to secretion.	Its main function is protein synthesis due to the presence of ribosomes on it.

Question 12.
What are nucleotides? Describe their structure.
Answer:
Nucleotides are the building blocks of nucleic acids. They are composed of three subunit molecules:

• Nitrogenous bases: Cytosine (C), Thymine (T), Adenine (A), Guanine (G).
• Five-carbon sugar (Pentose sugar).
• Phosphate group.

The phosphate group and 5-carbon sugar compose the backbone of the double helix, while the nitrogenous bases are located in the middle and are bonded to each other.

Section – C

Question 13.
What is hepatic portal system?
Answer:
Hepatic portal system:

• It carries blood from the alimentary canal and its associated glands to the liver.
• It consists of a large hepatic portal vein that receives a number of tributaries.
• The tributaries are namely oesophageal, gastric, duodeno-pancreatic, intestinal, splenic and rectal.

Question 14.
What are chemoautotrophic bacteria? How they obtain energy?
Answer:
Chemoautotrophic Bacteria:
(i) These bacteria are able to manufacture their organic food from inorganic raw materials with the help of energy derived from exergonic chemical reactions involving oxidation of an inorganic substance present in the external medium.

(ii) The chemical energy obtained from the oxidation reaction is trapped in ATP molecules.

(iii) For example, nitrifying bacteria, sulphur oxidising bacteria and iron bacteria.

Question 15.
Describe the three types of valves present in the human heart?
Answer:
Valves in the human heart:
(i) In the human heart, there are a number of openings through which blood passes from one chamber to another.

(ii) These openings are guarded by certain valves which regulate the flow of blood in desired direction. The bicuspid valves and tricuspid valves are present guarding the auriculoventricular apertures in between the auricles and ventricles on the left and right sides respectively. These valves open into the ventricles and prevent the back flow of the blood.

(iii) A set of semilunar valves are also present at the base of aorta in the ventricle. These allows the blood to flow only in direction of an aorta, when the left ventricle contracts.

Question 16.
Aquatic animals generally are ammonotelic in nature whereas terrestrial forms are not. Comment.
Answer:
Aquatic animals are generally ammonotelic in nature. They secrete ammonia. Since, ammonia is highly toxic, and so, needs more water for getting excreted. Therefore, such a mode of excretion is suitable for aquatic organisms which have a constant access to water. Terrestrial animals are either ureotelic or uricotelic. It is because they need to conserve water. Since ammonia is soluble in water, it cannot be eliminated continuously. Hence, it is converted into urea or uric acid. These forms are less toxic and also insoluble in water. This helps terrestrial animals conserve water.

Question 17.
(a) How do fungi form partnership with most plants?
(b) Explain the following in terms of mycorrhizal association: Nourishment, Absorption of water and Growth promotion.
OR
Difference between turtle and tortoise.
Answer:
Nourishment: In orchids, the fungi absorb nourishment from outside, transports it over to the germinating seed. Absorption of water: Fungal association increases the water availability to the root. Growth promotion: Fungus produces growth-promoting hormones and provides it to the plant.
OR

Turtle	Tortoise
(i) Marine form.	Fresh water and terrestrial form.
(ii) Limbs modified into paddles.	Limbs bears digits and claws adapted for walking on land.
(iii) Shells are more streamed.	They have round and dome-shaped shells.

Question 18.
Find out and make a list of proteins used as therapeutic agents. Find other applications of proteins. 3
Answer:

1. As antibodies: Gamma globulins are used as antibodies. These are used in the treatment of snake bite,
   tetanus, etc.
2. Human albumin: These are used in liver cirrhosis nephrotic syndrome.
3. Polypeptide hormones: Used in the treatment of hormone deficiency diseases, like diabetes, dwarfism etc.

Other applications:
(i) Cosmetic uses:
(a) Egg protein is used for skin tightening.
(b) Keratolytic proteins are used in softening of hard skin.
(ii) Glut protein enables glucose transport into cells.

Question 19.
List any five functions of nucleic acids.
Answer:

• DNA is a genetic material that carries all the hereditary information.
• DNA also transfers genetic information from one generation to another.
• RNAs are involved in the expression of genetic code of DNA by forming specific protein.
• Some RNAs act as enzyme.
• RNA helps in protein synthesis

Question 20.
“Green algae are ancestors of land plants’-Comment upon the statement.
OR
Classify bacteria on the basis of their shape.
Answer:
The various evidences which favour the Chlorophyceae (green algae) origin of land plants are:

1. Both green algae and land plants possess the same type of chlorophylls, a and b.
2. The carotenoid pigments are similar in the two groups.
3. Cell wall contain similar cellulose and pectic compounds in both the groups.
4. Starch is the common storage carbohydrate in the two groups. It is made of both amylose and amylopectin fractions.
5. The flagella are similar in the motile forms of the two. which do not justify that green algae are ancestors of land plants.

OR
Bacteria are classified as given below:
(i) Cocci: They are oval or spherical in shape. When they occur singly, they are called Micrococcus; if in pairs, Diplococcus; if in a chain, Streptococcus; and if occur in clusters, Staphylococcus.

(ii) Bacilli: They are rod-like, with or without flagella. Flagella may be present at one or both the ends or around cells. Bacteria may occur singly, Bacillus; or in pairs, Diplobacillus or may form filaments, Streptobadllus.

(iii) Vibrio: They are small and curved like commas. These are mostly motile.

(iv) Spirillum: These are twisted like a screw. They have flagella at one end or both the ends. Certain bacteria possess flagella for locomotion.

Question 21.
Distinguish between: Myelinated and non-myelinated neurons.
OR
Dorsal spinal roots and ventral spinal roots.
Answer:

Free central placentation	Axile placentation
(i) The axons are covered by lipid-rich myelin sheath.	The myelin sheath is absent.
(ii) Conduction of nerve impulse is faster and called saltatory conductions.	Conduction is comparatively slower.
(iii) Action potential occurs only in the Nodes of Ranvier.	Action potential occurs along the nerve fibres.
(iv) Myelinated nerve fibres are found in spinal cord.	Non-myelinated nerve fibres are found in autonomous and the somatic neural systems.

OR

Dorsal spinal roots	Ventral spinal roots
(i) They are made of sensory (afferent) nerves.	They are made of motor (efferent) nerves
(ii) They have dorsal root ganglia.	They have no ganglia.
(iii) Their cell bodies are located in dorsal root ganglia.	The cell bodies of ventral spinal root is located in ventrolateral horn or grey mater

Question 22.
Discuss “The respiratory pathway is an amphibolic pathway.”
Answer:

1. Respiration is a catabolic process as during respiration, various substrates are broken down for deriving energy. Carbohydrates are broken down into glucose before entering respiratory pathway.
2. Fats get converted into fatty acids and glycerol whereas fatty adds get converted into acetyl CoA before entering the respiration.
3. Similarly, proteins are converted into amino acids, which enter respiration after deamination.
4. During synthesis of fatty acids, acetyl CoA is withdrawn from respiratory pathway. Similarly, respiratory substrates get withdrawn.
5. Thus, respiration is also involved in anabolism.

Question 23.
What are the conditions required for growth?
Answer:
Growth is influenced by a number of conditions which are as follows:

• Water is required for cell elongation, maintenance of turgidity of growing cells and providing medium for enzyme action.
• Oxygen is essential for aerobic respiration and hence availability of energy for biosynthetic activity.
• Nutrients are raw materials for synthesis of protoplasm, as well as the source of energy.
• Light is required for tissue differentiation, synthesis of photosynthetic pigments and photosynthesis.
• The optimum temperature for proper growth is 28-30°C.
• Environmental signals such as light & gravity also affect certain stages of growth.

Question 24.
How is CAM completed in two phases? Explain.
OR
Mention the initial fixation in C₄ pathway.
Answer:
Crassulacean acid metabolism occurs in succulent plants and gets completed in two phases Phase I:
(i) Stomata are open at night. CO₂ is absorbed from outside. With the help of PEP carboxylase, it is immediately fixed.

(ii) The acceptor is Phosphoenol pyruvate or PER
PEP + HCO₃ (CO₂ + H₂OPEP Oxaloacetic acid + H₃PO₄
Oxaloacetic add + NADPH Mailc acid + NADP+

(iii) Malic add is the end product of dark fixation of CO₂. It is stored inside cell vacuoles.

Phase II:
(i) During day time, stomata are closed. However, light is available for photosynthesis.
(ii) Malic add moves out of the cell vacuoles.
(iii) It is decarboxylated with the help of malic enzyme.
(iv) Pyruvate is produced and is metabolised.

Malic add (malate) + NADP+ Pyruvate + CO₂ + NADPH

OR
(i) Initial fixation of CO₂ occurs in mesophyll cells.

(ii) The primary acceptor of CO₂ is phosphoenol pyruvate or PEP It combines with CO₂ in the presence of PEP carboxylase to form oxaloacetic add or oxaloacetate.
PEP + CO₂ + H₂ O → Oxaloacetic add + H₃PO₄,

(iii) Oxaloacetic acid is reduced to malic add or transmitted to form aspartic add.
Oxaloacetic acid + NADPH Malic  acid+ H₃PO₄,
Oxaloacetic add + AlanineAspartic add + Pyruvic add

Section – D

Question 25.
Read the given passage on frog and answer the questions that follows: 5×1 = 5
During the rainy season, which is also the breeding season of the frog, the frogs make a peculiar sound with the help of their vocal cords, known as croaking. The male frogs croak louder than the females. The vocal sacs act as resonators. Being a cold-blooded (poikilotherm) animal, the frog cannot withstand very cold weather and therefore, buries itself deep in the mud. During this period it lives in a dormant life of very slow vital body activities. Whatever little energy required during this period is obtained from the fat-bodies and from the stored glycogen of the liver, which had been stored in sufficient quantity earlier.

The oxygen need of the animal is met with by respiration through the skin. In the mid-summer, when the temperature is very high, the frogs escape to the places of concealment (mud, etc.) temporarily, but often coming out to feed themselves. However, it is believed that during this period frog takes rest and recuperates its energy. The frog is capable of changing its body colour, though gradually, with the change in its surroundings and climatic conditions. This capability of changing colour is known as metachrosis.

(i) Croaking of frog is:
(A) Hunger call
(B) Danger call
(C) Musical tone
(D) Sex call for female
Answer:
(D) Sex call for female
Explanation:
The croaking is a mating call to attract the females.

(ii) Croaking is louder in male frogs than females because of:
(A) Two vocal sacs
(B) Being stronger
(C) Being larger in size
(D) Having larger sound box.
Answer:
(A) Two vocal sacs
Explanation:
Male frog croaks more loudly because it possesses two vocal sacs over its throat which act as resonators.

(iii) Frog aestivate during:
(A) Winter
(B) Spring
(C) Summer
(D) Autumn
Answer:
(C) Summer
Explanation:
Being cold blooded or poikilothermous (the body temperature changes with (environment) frogs undergo aestivation or summer sleep in summer and hibernation or winter sleep in winter.

(iv) How frog respires during hibernation and aestivation?
(A) Through lungs only
(B) Through moist skin only
(C) Through buccal cavity only
(D) Through external gills and lungs
Answer:
(B) Through moist skin only
Explanation:
Respiration through skin is known as cutaneous respiration. In frog, cutaneous respiration occurs in water, during hibernation and even aestivation.

(v) The winter sleep of frog is termed as:
(A) Neoteny
(B) Aestivation
(C) Paedogenesis
(D) Hibernation
Answer:
(D) Hibernation
Explanation:
Hibernation is a way of coping to cold winters, without having to forage for food. It’s also known as winter sleep.

OR
Dedduous plants shed their leaves during hot summer or in autumn. This process of shedding of leaves is called absdssion. Apart from physiological changes what anatomical mechanism is involved in the absdssion of leaves?
Answer:
Absdssion is the process of shedding of leaves during hot summer or in autumn by dedduous plants. The absdssion layer is made up of two layers of cambium- like cells. The cells are thin-walled and without deposition of lignin or suberin. At the time of absdssion, the middle lamella may dissolve between the cells of two middle layers but the primary wall remains intact. The middle lamella as well as the primary walls of the adjacent cells is dissolved. Ultimately, the whole cells of the middle layer found in the absdssion layer gets dissolved completely. Thus, the leaf gets separated from the stem and falls down from the stem by wind and rain.

Question 26.
Briefly describe various kinds of lipids.
OR
Structure and function are co-relatable in living organisms. Can you justify this by taking plasma membrane as an example?
Answer:
Following are the different types of lipids:
(i) Simple lipids: These are esters of fatty acid with glycerol. They are of two types.
(a) Neutral or true fats: These are esters of fatty add with glycerol. They are also called glycerol. A fat molecule consists of one molecule of glycerol and one to three molecules of the same or different long-chain fatty adds.
1. Glycerol has 3 carbons, each bearing a hydroxyl (-OH) group.

2. A fatty add molecule is an unbranched chain of carbon atoms having a carboxylic group attached to an R group. The R group could be a methyl (-CH₃) or ethyl (-C2H₅) or higher number of -CH2 groups (C to 19-C). e.g., Palmitic acid has 16-C.

Fatty adds are of two types:
1. Saturated fatty acids: These are fatty acids without double bonds., e.g., Palmitic add.

2. Unsaturated fatty acids: These are fatty adds with one or more double bonds., e.g., oleic acids.
Neutral fats may be monoglycerides if there is only one molecule of fatty add attached to a glycerol molecule. If the number of fatty adds attached is two then it is a diglyceride or triglyceride if it is three.

(b) Waxes: These are esters of fatty adds with alcohol of high molecular weight instead of glycerol, e.g., bee wax, lanolin, etc.

(ii) Compound lipids: These are esters of fatty adds with alcohol, but contain some other substances also. For e.g., phospholipids, glycolipids.

(iii) Derived lipids such as steroids, prostaglandins, etc.

OR
In living organisms, the structure and function of the cell organelle are correlated. For example, every living cell is covered by a thin, elastic, transparent, semi-permeable membrane called plasma membrane. The cell membrane is composed of a lipid bilayer of phospholipids molecules into which variety of globular proteins are embedded. These proteins often recognise spedfic materials and allow them to pass through the membrane or they transport them across. This is why plasma membrane is called selectively permeable membrane.

The oligosaccharides attached to the membrane serve as recognition centres and help in recognising foreign entities before allowing their entry into the cell. The lipid content of plasma membrane is arranged with their hydrophilic polar head directed outwards and non-polar hydrophobic tails directed inwards providing fluidity to the membrane. Glycocalyx present in cell membrane also helps in cellular attachment.

Question 27.
Explain the role of Na+ in the generation of an action potential.
OR
The juxtaglomerular cells of the kidney produce a peptide hormone called erythropoietin which stimulates erythropoiesis (formation of RBC). Endocrine cells present in different parts of the gastrointestinal tract secrete four major peptide hormones, namely gastrin, secretin, cholecystokinin (CCK) and gastric inhibitory peptide (GIP). Gastrin acts on the gastric glands and stimulates the secretion of hydrochloric add and pepsinogen. Secretin acts on the exocrine pancreas and stimulates the secretion of water and bicarbonate ions.

CCK acts on both the pancreas and gall bladder and stimulates the secretion of pancreatic enzymes and bile juice, respectively. GIP inhibits gastric secretion and motility. Several other non-endocrine tissues secrete hormones called growth factors. These factors are essential for the normal growth of tissues and their repairing/regeneration.
Answer:
(a) Stimulation of an axon enhances its membrane permeability to Na+.

(b) As a result, Na⁺ ions diffuse across the membrane from the extracellular fluid (ECF) where their concentration is higher, to the interior of the fiber where the concentration is much lower.

(c) The membrane permeability to K⁺ start rising somewhat later only. So, there is simultaneous rise in the outward diffusion of K+ from the cell interior having a higher K⁺ concentration.

(d) These effects lower the overall cation concentration outside and enhance that inside the membrane.

(e) The membrane is, thus deposited, with its interior becoming electropositive to the exterior.

(f) The Depolarisation spreads producing a local current. It induces nearby passive Na⁺ channels to open and so to depolarise the nearby site.

(g) Hence, the initial depolarisation passes outward over the membrane and spread out in all directions from the site of stimulation

OR
(i) Write the name of some gastro-intestinal hormones.
Answer:
Gastrin, secretin, cholecystokinin (CCK) and gastric inhibitory peptide (GIP).

(ii) What is the name of RBC formation process?
Answer:
Erythropoiesis.

(iii) Which hormone helps in the digestion of protein and how?
Answer:
Gastrin helps in the digestion of protein because it stimulates the secretion of the pepsinogen enzyme.

(iv) Which hormone helps in breaking down fat molecules?
Answer:
Cholecystokinin [CCK] helps in breaking down fat molecules because it stimulates the secretion of bile juice.

(v) ………. inhibits gastric secretion and motility.
Answer:
Gastric inhibitory peptide (GIP).