NIOS Class 12 Biology Oct 2019 Set B (59/OSS/2)

NIOS Biology Question Paper 2019 Oct Set B

1 MARK QUESTIONS

1. Which of the following organs stores sperm in man? 

(A) Seminal vesicles 

(B) Urethra 

(C) Vas deferens 

(D) Epididymis 

2.  Inheritance of blood group in humans is an example of: 

(A) Incomplete dominance 

(B) Co-dominance 

(C) Quantitative inheritance 

(D) Multiple alleles and co-dominance 

3. In which of the following National Parks / Sanctuaries, Lion is an important species? 

(A) Kaziranga Sanctuary 

(B) Corbett National Park 

(C) Periyar Sanctuary 

(D) Gir forest 

4. Which of the following infections cause life-time immunity? 

(A) Common cold 

(B) Smallpox 

(C) Influenza 

(D) Pneumococcal pneumonia 

5. The value of vital capacity of lungs is: 

(A) 500 ml 

(B) 5500-6000 ml 

(C) 3400-4800ml 

(D) 2000-3000 ml 

6. Which of the following N2-fixing microbes is free living? 

(A) Cyanobacteria 

(B) Rhizobium 

(C) Azospirillum 

(D) Azotobacter 

7. Which of the following is an example of locomotion? 

(A) Stretching an arm to pick a fruit 

(B) A bird jumps to a tree 

(C) Frog shoots its tongue to catch an insect 

(D) Cow wags its tail to drive away flies 

8. Which of the following statements is true? 

(A) The lubb sound of the heart is due to closure of semilunar valve. 

(B) Pulmonary vein carries oxygenated blood. 

(C) Heartbeat originates at A.V. node. 

(D) Arteries have semilunar valves. 

2 MARKS QUESTIONS

9. Explain Binocular vision. 

Ans: Binocular vision. In all primates, including humans, both eyes are placed forward. Each eye views at a slightly different angle. The images from the two eyes are perceived to overlap inside the brai,n giving the impression of depth (3-dimensional/stereoscopic vision).

10. What is atherosclerosis and hypertension? 

Ans: Atherosclerosis is the condition of hardening of the arteries. Hypertension is caused by fatty substances deposited in blood arteries. 

11. Match the following: 

Column-A	Column-B
(i) Iodine	(A) Delayed blood clotting
(ii) Iron	(B) Night blindness
(iii) Vitamin K	(C) RBC
(iv) Vitamin A	(D) Goitre

Ans: (i)- (D), (ii) – (C), (iii) – (A), (iv) – (B)

12. Why C4 plants show more efficient photosynthesis as compared to C3 Plants? 

Ans: C4 plants show more efficient photosynthesis when compared to C3 plants because C4 plants have no photorespiration and thus there is no loss of additional carbon dioxide, due to breakdown of RuBP to Glycolate and CO₂.

13. How does haemoglobin help in the transportation of O₂ in the blood? 

Ans: Four molecules of oxygen form a reversible bond with haemoglobin, forming the compound oxyhaemoglobin. When the oxygenated blood reaches the tissue surface, there is a high concentration of CO2 in the tissues, oxygen having been used up and a low concentration of O2. As a result, the bonds holding oxygen and haemoglobin in Hb (4O₂) become unstable and blood releases oxygen and takes up CO₂.

14. Where does conversion of nitrates to nitrites take place in plants? Write down its equation. 

Ans: The conversion of nitrates into nitrites takes place in the cytosol of plants, catalysed by the enzyme nitrate reductase.  

15. What type of cell organelles and cell wall are found in Bacteria? 

Ans: The bacterial cell wall is made up of a chemical, peptidoglycan, unique to bacteria, lipids, polysaccharides, and some proteins. Membrane-bound organelles like the endoplasmic reticulum, mitochondria, chloroplasts, and the Golgi complex are absent. Only 70s ribosomes are present. One circular chromosome made of a double helical molecule of DNA is located in a region of the cytoplasm called the nucleoid.

16. Name the protozoa that cause malaria and amoebic dysentery. 

Ans: 

• Malarial parasite: Plasmodium
• Amoebic dysentery: Entamoeba histolytica

17. What is Diabetes mellitus? What are its symptoms? 

Ans: Non-secretion or under-secretion of insulin leading to the presence of more than normal sugar in the blood, which is called diabetes mellitus. Common symptoms are, 

• Has higher glucose in the blood;
• Excretes a great deal of urine loaded with sugar;
• Feels thirsty because of loss of water through too much urination;
• Loses weight and becomes weak. In some cases, the patient even loses eyesight.

18. Name the technique of growing plants without soil. Why vigorous bubbling of air is essential for this technique? 

Ans: Hydroponics. Vigorous bubbling of the air is routinely done to provide sufficient oxygen to the root system.

19. Express the process of photosynthesis by an equation. 

Ans: 

20. Which are the main sites through which transpiration occurs? What is the 2 effect of light on the rate of transpiration? 

Ans: Transpiration occurs through stomata found on the leaf surface. Light has no direct effect on the rate of transpiration, but indirectly it controls the stomatal opening, and secondly, affects the temperature.

4 MARKS QUESTIONS

21. Name the hormones that: 

(A) Induces parthenocarpy 

(B) Induces dormancy in seeds 

(C) Is gaseous in nature 

(D) Suppresses the growth of lateral buds 

Ans: 

1. Gibberellins
2. Abscisic acid
3. Ethylene
4. Auxin

22. Differentiate between: 

(a) Nucleotide and nucleoside 

(b) Vasectomy and Tubectomy 

Ans: 

1. When a base and a sugar combine, it forms a nucleoside. When a nucleoside combines with a phosphate group, it becomes a nucleotide.
2. 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.

23. Write short notes on: 

(a) Gout 

(b) Heart Valves 

Ans: 

1. Gout is the painful inflammation of joints due to elevated levels of uric acid in the blood. It is caused by a metabolic error. Uric acid is a product of protein metabolism. Gout can be cured.
2. Valves open only on one side like a door. They regulate the flow of blood by opening on one side to let blood flow out in one direction only and prevent the backflow of blood. The three types of valves seen in the human heart are the tricuspid valve, the bicuspid valve, and the semilunar valve.

24. Draw the following and label its parts: 

(A) Stomatal apparatus of Dicots 

(B) Parenchyma 

Ans: 

1. Stomatal apparatus of Dicots

2. Parenchyma

25. Give one term for the following relations: 

(a) One organism receives benefit at the cost of the other. 

(b) An interaction between different individuals of the same species. 

(c) An interaction between two populations in which both species are harmed to some extent. 

(d) Association between insect-pollinating flowers and pollinating insects. 

Ans: 

1. Parasitism
2. Intraspecific interaction
3. Competition
4. Mutualism

26. Assign the following plants to their respective division: 

(A) Vascular tissue present, Seeds not enclosed in ovary 

(B) Vascular tissue absent, Plant body haploid, Sex organs jacketed 

(C) Vascular tissue present, Plant body diploid, Prothallus present 

(D) Vascular tissue present, Seeds enclosed in ovary, Seeds have one cotyledon. 

Ans: 

1. Gymnosperms
2. Bryophytes
3. Pteridophytes
4. Angiosperms

6 MARKS QUESTIONS

27. (a) Name two types of phagocytic cells. Where are these found? 

Give two important features of these cells. 

(b) What are transgenic organisms? Which bacterium is used to introduce required genes in plants? Name a transgenic plant and an animal. 

Ans: 

1. Phagocytic cells: Microphages and macrophages. Microphages are found in WBCs, and macrophages are seen in the liver and spleen. Important features of phagocytic cells are,
   1. They rapidly engulf the foreign molecular agent oncoming in contact or when they come in contact.
   2. They contain digestive enzymes to break down engulfed material.
   3. They are an important link between innate and acquired immunity.
2. Genetically engineered organisms carrying foreign genes are termed transgenic organisms. Bacillus thuringiensis is used to introduce required genes in plants. Bt crops and transgenic goats are examples.

28. (a) Explain the following terms: 

(i) Allele 

(ii) Genotype 

(b) Explain the inheritance of flower colour in Mirabilis jalapa 

Ans: 

1. Explanations
2. Two or more alternative forms of a gene are called alleles.
3. Genotype is the composition of genes.
4. In the four O’clock plant, Mirabilis jalapa law of dominance does not hold good. Thus, when a homozygous red flowered plant (RR) is crossed to a homozygous white flowered plant (rr), all flowers in the F1 are pink, while when F1 plants are self-pollinated, the phenotypic ratio in the next generation is found to be 1: 2: 1.

Parents	RR x rr
Gametes	R, R, r, and r
F1	Rr (Pink)
F2	1RR: 2Rr: 1rr
Phenotype	1Red: 2Pink: 1White

29 (a) What is the relation between increasing population, agricultural development, and environmental degradation? 

(b) What is vegetative propagation? What are its advantages and disadvantages? 

Ans: 

1. Increasing population, agricultural development, and environmental degradation: In order to meet the food requirements of the ever-increasing population of the country, new agricultural techniques have been adopted. Some of these have proved to be detrimental to the environment.
2. Reproduction of new plants from the portion of the vegetative parts of a plant is very common and is called vegetative reproduction.
   1. Advantages
      1. Rapid means of reproduction and spread.
      2. Offspring are identical to parents. The desired varieties can thus be preserved genetically for use.
      3. Food storage organs allow perennation or survival in adverse conditions.
      4. Improved varieties of ornamental plants and fruit trees can be multiplied easily.
      5. Vegetative propagation is a quicker, easier, and less expensive method of multiplying plants.
   2. Disadvantages
      1. Overcrowding and competition for space occur unless separated artificially.
      2. New varieties cannot be produced by this method except by mutation.
      3. Diseases typical of the species are rapidly transmitted and can be detrimental to a crop.

30 (a) What do you understand by conservation of natural resources? Why do we need to conserve natural resources? Give any 4 reasons. 

(b) What is the chemical nature of fats? State any 4 functions of fats. 

Ans: 

1. Conservation is the proper management of a natural resource to prevent its exploitation, destruction, or degradation. We need to conserve natural resources,
   1. To maintain ecological balance to support life.
   2. To preserve different kinds of species (biodiversity).
   3. To make the resources available for present and future generations.
   4. To ensure the survival of the human race.
2. Chemically, fats are triglycerides and contain more carbon and hydrogen with less oxygen. Functions of fats are: (any four)
   1. Fats are the richest sources of energy. On biological oxidation, one gram of fat provides 37 kJ of energy.
   2. Form structural components of the cell cytoplasm and cell membrane.
   3. Help in absorption of fat-soluble vitamins A, D, E, and K
   4. It acts as a precursor of various hormones.
   5. It can be stored for subsequent use by the body.
   6. Subcutaneous fats serve as an insulator in the body, thus protecting it from cold weather and pressure.
   7. Stored fat provides padding to protect the vital organs of the body from shocks.
   8. Helps in the synthesis of vitamin D and steroid hormones in the body.

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