NIOS Class 12 Biology Apr 2022 Set C (63/OSS/1)

Class 12 NIOS Biology Question Paper April 2022 Set C

1 MARK QUESTIONS

1. One of your class fellow put some dry grams in water overnight. Next morning, it was fully swollen. Name the phenomenon involved. 

(A) Osmosis 

(B) Imbibition 

(C) Plasmolysis 

(D) Diffusion 

2. Which of the following is an example of a dorsoventrally flattened organism? 

(A) Neries 

(B) Ascaris 

(C) Leech 

(D) Planaria 

3. Which of these plants exhibits Saprophytic mode of nutrition? 

(A) Monotropa 

(B) Cuscuta 

(C) Nepenthes 

(D) Money plant 

4. What does the following sequence represent? 

(A) Genetic Drift 

(B) A food Pyramid 

(C) Ecological Succession 

(D) Phylogenetic trend 

5. The cell wall is made up of a chemical which is unique in bacteria. Name the chemical. 

(A) Peptidoglycan 

(B) Chitin 

(C) Lignin 

(D) Cellulose 

6. A girl is born with a genetic disorder having 45 chromosomes. Her Karyotype is 44 + XO. Identify the disorder from the following. 

(A) Down’s syndrome 

(C) Turner’s syndrome 

(B) Haemophilia 

(D) Klinefelter’s syndrome 

7. Which of the following antibodies is present in Colostrum that provides immunity to the newborn infant? 

(A) IgG 

(B) IgE 

(C) IgM 

(D) IgA 

8. Which of the following is a broad-spectrum antibiotic? 

(A) Penicillin 

(B) Erythromycin 

(C) Paracetamol 

(D) Streptomycin 

2 MARKS QUESTIONS

9. Draw a neat diagram of a longitudinal section of an Ovule in an Angiosperm and label the embryo sac and micropyle. 

Ans: 

10. Name the surgical methods of Contraception in human males and females. Also mention the basic procedure involved in the two methods. 

Ans: 

• Vasectomy in males, where the vas deferens is ligated (tied) by the surgeon to prevent sperm from going out of the body.
• Tubectomy in females, where the fallopian tubes are cut and ligated to prevent the ovulated egg from passing down for fertilisation.

11. Draw a neat and labelled diagram of an Open Stomata in a Dicot Plant. 

Ans: 

12. Why do insectivorous plants eat insects when it is capable of carrying out photosynthesis? 

Ans: Insectivorous plants eat insects when it is capable of carrying out photosynthesis to overcome nitrogen deficiency, as they grow in soils having acute nitrogen deficiency. 

13. (a) Write the name of the hormone secreted by the Human Placenta. 

(b) Write the name of the hormone which stimulates the development of male characteristics during puberty. 

Ans: 

1. The placenta produces the hormone progesterone.
2. Testosterone

14. (a ) Expand the abbreviation PEM. 

(b) Write the Name of one disease caused due to PEM. 

Ans: 

1. Protein Energy Malnutrition (PEM)
2. Marasmus

15. Name the Phytohormones involved in the following functions: 

(a) Helps in the elongation of stems in genetically dwarf plants. 

(b) Delays fall of leaves. 

Ans: 

1. Gibberellins
2. Auxins

16. After a surgery, a man was advised to include more protein and Iron in his diet. Give reasons and also mention one source of each nutrient. 

Ans: Protein – body-building food required during healing after surgery.

Source: Dal, pea, beans, soybean, gram (any one)

Iron: Builds blood as it is part of the Hb molecule.

Source: Liver, Leafy vegetables like spinach, egg, molasses, grains, peanuts (any one)

17. Expand the following abbreviations and state how they are useful in daily life. 

(a) CNG 

(b) PNG 

Ans: 

1. CNG: Compressed Natural Gas
2. PNG: Piped Natural Gas

18. Distinguish between Mutualism and Symbiosis. Write one suitable example 

Ans: Mutualism is a close association between two species in which both species benefit. Symbiosis is a type of mutualism where the interacting species cannot live without each other, as they depend completely on each other for their survival. 

19. Distinguish between Antigen and Antibody. 

Ans: An antigen is any foreign molecule that can trigger a specific immune response. An antibody is a protein molecule produced in animals in response to an antigen.

20. Where can you locate the following structures in plants? 

(a) Perianth 

(b) Bulliform cells 

Ans: 

1. On the flower whorls
2. Inside the epidermis of monocot leaves

4 MARKS QUESTIONS

21. (a) With the help of a flow chart, show the Calvin cycle. Write the names of the main products formed in this cycle. 

(b) Where does this cycle take place in plants? 

Ans: 

1. Calvin Cycle

The main products are 3-phosphoglycerate, triose phosphate, which will form glucose. and RuBP.  

2. It takes place in the stroma of the chloroplast.

22. With the help of well-labelled diagrams, distinguish between: 

(a) Androecium in Peaflower and Hibiscus. 

(b) Venation in the leaves of Dicot and Monocot plants. 

Ans: 

1. Androecium in Pea flower and Hibiscus
   1. Pea flower: Androecium has 10 stamens, arranged in two whorls (9+1), which is a diadelphous condition.
   2. Hibiscus: Androecium consists of an indefinite number of monadelphous stamens. The lower parts or filaments join together to form the staminal tube.
2. Venation in dicots and monocots.
   1. Reticulate venation – veins forming a network in dicots.
   2. Parallel venation – veins arranged in parallel rows in monocots

23. (a) Draw a neat diagram of the Male Reproductive system in humans and label any six parts. 

(b) Name the Male Sex hormone of man. 

Ans: 

24. Briefly explain the various steps involved in the mechanism of DNA replication. Also, draw a diagram to show the formation of new DNA strands. 

Ans: Replication occurs through the following steps :

• Unwinding of the DNA double helix: The two strands of the replicating DNA molecule separate by the action of the enzyme Helicase. The topoisomerase enzyme keeps it open.
• Synthesis of the primer: A Primer is a short RNA molecule of about 5 to 10 bases. It is formed in the presence of the enzyme primase. The primer provides a 3’-OH group for attachment of the new DNA strand.
• Synthesis of a new DNA strand: The opened strands of DNA form the template. New strands complementary to the template get synthesised. At the replication fork, a new DNA strand begins to synthesise, attaching itself to the primer, in the presence of the enzyme DNA polymerase. It begins synthesis from its 5’ end, and a DNA strand complementary to one of the unwound parental DNA strands gets synthesised. The new strand of DNA continues to be synthesised uninterrupted and is termed the leading strand.

25. (a) What are Vaccines? What do you understand by second-generation vaccines? Write the names of any two diseases for which these vaccines are already in use. 

(b) Expand BCG and mention its usage. 

Ans: 

1. They are biological preparations that contain mild or attenuated (weakened) germs that are introduced into the body to induce the immune system to produce necessary antibodies. Second-generation vaccines are vaccines that are produced by genetic engineering or recombinant DNA technology. Eg., Vaccines for Hepatitis B and Herpes.
2. BCG – Bacillo Calmette-Guérin. It is given to prevent tuberculosis.

26. (a) Where are the two biodiversity hotspots found in India?  

(b) Distinguish between In Situ Conservation and Ex-situ Conservation. Also, write one suitable example of each. 

(c) With the help of a suitable example, define the term Endangered species.

Ans: 

1. The eastern Himalayan hot spot extends to the north–eastern India and Bhutan. The Western Ghats extend from the southwest towards Gujarat.
2. In-situ conservation includes the protection of plants and animals within their natural habitats or in protected areas. Ex-situ conservation is the conservation of plants and animals outside their natural habitats.
3. Endangered species are those which have been reduced in number to a critical level and are facing a high risk of extinction in the near future. E.g.. Asiatic lion.

6 MARKS QUESTIONS

27. (a) Write the four characteristic features of the Phylum Arthropoda. 

(b) Mention two aerial adaptations found in birds. 

(c) Write the scientific names of the following organisms. 

(i) an egg-laying mammal 

(ii) Pea plant. 

Ans: 

1. The main characters of Phylum Arthropoda are,
   1. Segmented body, can be differentiated into head, thorax and abdomen
   2. The head and thorax are often fused to form a cephalothorax
   3. Jointed legs for locomotion, one pair each on some or all body segments
   4. Exoskeleton of chitinous cuticle, shed at intervals (moulting)
   5. Sexes usually separate.
2. Aerial adaptations of birds
   1. Forelimbs modified into wings for flight.
   2. The body is covered with feathers, and scales are present only on hind limbs
3. Scientific names
4. Oviparous
5. Pisum sativum

28. (a) Draw a neat and labelled diagram of the Excretory organs in humans. 

(b) List the role of liver in Excretion. (2 points) 

(c) Write the name the excretory organ in Cockroach. 

Ans: 

1. Excretory organs in humans

2. The liver breaks down excess amino acids into urea and sugar. Urea is excreted in urine, and sugar is stored for use.
3. Malpighian tubules.

29. (a) With the help of a flow chart, describe the steps involved in the  Coagulation of blood. 

(b) Why is a person with blood group ‘AB’ called a Universal recipient? 

(c) Give an example of a lymphoid organ? Name the two major types of cells present in them and state the general function they perform in the body. 

Ans: 

1. Steps in the coagulation of blood.

2. Blood group AB can receive blood from all other groups and is thus called a Universal Recipient. No Antibodies present in the blood of Group AB, so no reaction with antigens of other blood groups.
3. The spleen is the largest lymphoid organ that helps destroy old and worn-out blood cells or RBCs. Cells found in the spleen are T-cells and B-cells.

30. (a) Explain the Sex Determination in Humans. Differentiate between Homogametic and Heterogametic individuals. 

(b) A colour blind man marries a woman who has normal colour vision. A son and a daughter born to them are colour blind. Explain this with the help of a self-explanatory flow chart. 

Ans: 

1. Sex chromosomes in human males are morphologically dissimilar – XY. They produce two different gametes- X and Y. They are called heterogametic individuals. Human females carry similar sex chromosomes, XX, and they produce similar gametes, such as X and X. They are called homogametic individuals. When an egg (X) is fertilised by an X gamete from the father, the child becomes a female, and if the egg is fertilised by a Y gamete, the child will be a male.
2. For both the son and daughter to be colour blind, the mother must not be a carrier, as the gene for colour blindness comes from the X chromosome. Since the mother has normal vision, she carries a normal gene. Thus, their genotypes could be

Father: XᶜY (affected) and Mother: XᴺXᶜ (carrier)

	Xᴺ (mother)	Xc (mother)
Xᶜ (father)	XᶜXᴺ	XᶜXᶜ
	(daughter — carrier, normal vision)	(daughter — colour blind)
Y (father)	XᴺY	XcY
	(son — normal vision)	(son — colour blind)

Additional Study Materials

• NIOS Class 12 Biology PYQ April 2022 Set A
• NIOS Class 12 Biology PYQ April 2022 Set B