Biology

NIOS Class 12 Biology Oct 2022 SET C

NIOS Biology Question Paper 2022 Oct Set C

1 MARK QUESTIONS

1. Seed coat develops from this part of the ovule:

(A) Integuments

(B) Nucellus

(D) Carpel

2. In an aquatic ecosystem, the producers are:

(A) Zooplanktons

(B) Phytoplanktons

(D) Fishes

3. Rhizome of ginger is a modified:

(A) Stem

(B) Leaf

(D) Adventitious root

4. Plasmodium belongs to phylum:

(A) Cnidaria

(B) Protozoa

(D) Arthropoda

5. Endonucleases are:

(A) Molecular scissors

(B) Plasmids

(D) DNA fragments

6. Guttation is performed by:

(A) Stomata

(B) Parenchyma

(C) Hydathodes

(D) Xylem

7. Bacteria is included in kingdom Monera because its body has:

(A) Single cell

(B) Multicellular structure

(D) Cellulose cell wall

8. Isogamy type of sexual reproduction is found in:

(A) Flowering plants

(B) Gymnosperms

(C) Chlamydomonas

(D) Amoeba

2 MARKS QUESTIONS

9. What is callus and micropropagation? Explain with an example.

Ans: The unorganised mass of tissue that grew faster in the nutrient medium of tissue culture is called a callus. Micropropagation is the method of growing plants from a single cell or tissue of a plant in a nutrient medium. Micropropagation is done in Chrysanthemum and Asparagus.

10. Falling of leaves is promoted by which phytohormone? Name any other function of the hormone.

Ans: Abscisic acid promotes the falling of leaves. It also acts as a growth inhibitor.

11. Match the following, picking up one from each column.

Column – A	Column – B
(a) China rose	(i) Reproductive organ
(b) Flower	(ii) Monadelphous stamen
(c) Pollen grains	(iii) Ovary
(d) Embryosac	(iv) Microspore

Ans:

Column – A	Column – B
(a) China rose	(ii) Monadelphous stamen
(b) Flower	(i) Reproductive organ
(c) Pollen grains	(iv) Microspore
(d) Embryosac	(iii) Ovary

12. Name any two disorders caused by single gene. How can it be rectified?

Ans: Haemophilia and Sickle cell anaemia. Somatic cell gene therapy is one way to rectify such diseases, where a gene for the production of certain proteins is inserted into the genome.

13. (a) Which type of inflorescence found in China rose?

(b) Name a plant with parallel venation and one with reticulate venation.

Ans:

Solitary axillary
Parallel venation in grass and Reticulate venation in mango.

14. Differentiate between biological and abiological N2 fixation in the soil.

Ans:

Biological nitrogen fixation is the reduction of molecular nitrogen to ammonia by a living cell in the presence of enzymes called nitrogenases.
In abiological nitrogen fixation, the nitrogen is reduced to ammonia without involving any living cell.

15. Explain the role of the enzymes RUBISCO and PEPco in C4 cycle.

Ans: In C4 plants, PEPCo or the PEP carboxylase is the primary carbon acceptor, which catalyses the carboxylation of phosphoenol pyruvic acid or PEP, to form oxaloacetic acid. This process happens in the mesophyll cells. This, when transported to the bundle sheath cell, releases a carbon dioxide molecule. In the bundle sheath, RUBISCO helps fix this CO2 molecule through the Calvin cycle, preventing photorespiration.

16. Differentiate Vasectomy from Tubectomy. Write 2 points for each.

Ans:

Vasectomy is the ligation of the vas deferens through which sperm travel out of the epididymis, to prevent sperm from going out of the body.
Tubectomy is the sterilisation of a woman by cutting the fallopian tubes and ligating them so that an ovulated egg cannot pass down for fertilisation.

17. Explain Hydrotropism and Phototropism giving one example for each.

Ans:

Hydrotropism is a type of tropic movement in plants in response to the external stimulus, water. E.g.. Roots grow towards water.
Phototropism is the tropic movement in plants in response to the external stimulus of light. E.g.. Stem grows towards the light.

18. What is leghaemoglobin? How is it formed? What is its role in plant life?

Ans: Leghaemoglobin is a special protein found in the legume nodules. It is produced as a result of the interaction between the bacterium and the legume roots. It helps in nitrogen fixation by acting as an oxygen scavenger so that the enzymes, nitrogenases, then convert N₂ to NH₃ under anaerobic conditions.

19. How do we diagnose a person suffering from (i) Goitre, (ii) Rickets? Write any two points in support of your answer for each case.

Ans:

Goitre: Enlargement of the thyroid gland visible as a swelling in the neck. It is caused due to iodine deficiency in food. Iodine deficiency caused this enlargement of the thyroid glands.
Rickets: Bow legs in children. It is caused by a deficiency of calcium. The bones become soft, get deformed or bend easily,

20. What is “Central Dogma”? How does information flow from nucleus to cytoplasm? Write in an equation form.

Ans: The transfer of information from genes to the site of protein synthesis constitutes the Central Dogma. The central dogma operates from the DNA in the nucleus to messenger RNA (transcription). mRNA moves out of the nucleus to the cytoplasm, where it is translated to form a protein.

DNA (Transcription) → RNA (Translation) → Protein

4 MARKS QUESTIONS

21. Give one-word answers to the statements given below.

(a) Plant cells, that continue dividing.

(b) Xylem and Phloem called together.

(c) Plant cells having similar cells.

(d) Dead tissue that gives support to soft tissues in stem.

Ans:

22. Draw a neat and labelled diagram to show antigen – antibody binding. Name any one type of immunoglobulin found in our body.

Ans:

IgA, IgD, IgG, or IgE.

23. (a) Draw and label sigmoid growth curve. 4

(b) Explain the three important phases of growth. Which phase is the longest one?

Ans: (a)

(b) The three phases of growth are,

(i) Lag Phase – This is the initial phase of growth when the rate of growth is very slow.
(ii) Log Phase – It shows rapid growth and is maximum during the entire life span.
(iii) Stationary Phase – Here, the rate of growth starts decreasing, and finally it stops.

The log phase is the longest one.

24. (a) How does Nephron help in osmoregulation in our body?

(b) Where do we find malpighian tubules? How are they important for the organism?

Ans:

Osmoregulation is the process of maintaining the solute concentration of the body fluids. As the glomerular filtrate flows through the nephron tubules, several useful substances such as glucose, amino acids, and mineral ions are reabsorbed through the walls of the renal tubule, which helps maintain the water and salt balance.
Malpighian tubules are the excretory organs of cockroaches that help excrete uric acid and other nitrogenous waste. The cells of the tubules remove nitrogenous waste and certain salts from the haemolymph and then pump them into the lumen of the tubule. Most of the salt and water is pumped back into the haemolymph by Malpighian tubules, and in this way the nitrogenous wastes are eliminated as almost dry matter.

25. (a) What is biodiversity? What is its advantage to mankind?

(b) Write any four human activities which are destroying it.

Ans: a) Biodiversity can be defined as the flora and fauna, i.e. variety of all plants, animals, and microbes of a region.

b) Human activities that destroy biodiversity are,

Destruction of habitat by cutting down trees, filling up the wetland, ploughing of grassland or burning a forest.
Indiscriminate killing of animals for different purposes has resulted in their reduction.
Industrialisation and urbanisation has changed and destroyed the natural habitat of plants and animals.
Pollution of soil, air and water changes the habitat quality and may reduce or eliminate sensitive species.

26. (a) Draw a neat diagram of a nerve cell and label its four parts.

(b) What is the advantage of having myelin sheath around an axon?

(c) What is the association of two successive neurons called?

Ans: a)

b) The myelin sheath protects the axon during electrical impulses.

c) The association of two successive neurons is called a synapse.

6 MARKS QUESTIONS

27. (a) Write one function of each of the following:

(i) RBC

(ii) Platelets

(iii) Plasma

(b) Why a person with blood group AB can’t donate blood to the persons with other blood groups i.,e A, B, and O, explain.

Ans:

1. RBC- transports oxygen and carbon dioxide
2. Platelets help in blood clotting
3. Plasma transport of products of digestion from the small intestine to various tissues.
A person with the AB blood group contains both antigen A and antigen B in the blood. Blood group A contains antibody b, the blood group B contains antibody a and those with the O group contain both antibody a and antibody b. If their blood is mixed with blood group AB, it will cause a life-threatening transfusion reaction as the respective antibodies react with the antigens in the AB blood group.

28. (a) Why do we consider a habitat as address of an organism and niche as its profession? Write definition of both terms.

(b) What is the role of

(i) Vit.A

(ii) Ca++ and

(iii) Glucose in our body?

Ans:

Habitat is the physical environment in which an organism lives and is thus considered its address. Niche is the sum of all the activities and relationships of a species by which it uses the resources in its habitat for its survival and reproduction. In other words, a niche is the functional characteristics of the species, thus considered its profession.
1. Vitamin A is essential for the synthesis of visual pigment and helps maintain vision.
2. Calcium helps with the formation of bones and teeth. It is also essential for nerves and muscles.
3. Glucose is the main source of energy for our body and is also the only source of energy for the central nervous system.

29. (a) Draw a neat diagram of transverse section (T.S) of human ovary and label its following parts:

(i) Primary follicle
(ii) Graffian follicle
(iii) Corpus luteum
(iv) Released ovum

(b) Write location and function of each of the following:

(i) Fallopian tube
(ii) Endometrium
(iii) Fimbriae

Ans:

1. Fallopian tubes are oviducts through which the egg passes to the uterus
2. Endometrium is the innermost layer of the uterus that is rich in blood vessels.
3. Fimbriae are finger-like projections that help the egg pass through to the oviduct.

30. (a) Draw a neat and labelled diagram of ciliated columnar epithelium. 6

(b) Why do we include sponges in phylum Porifera? Write any two reasons.

(c) How do you identify cartilaginous fishes from bony fishes? Mention any two features in each. Which class of vertebrates do they belong to?

Ans: a)

b) Sponges have many pores, canals, and chambers in their body. They also have a large aperture called an osculum present at the upper end.

c) Cartilaginous fishes have a ventral mouth, while bony fishes have a terminal mouth.

Cartilaginous fishes have a cartilaginous skeleton, while the bony fishes have bony skeletons.

The operculum is absent in cartilaginous fishes, and it is present in bony fishes.