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

NIOS Biology Question Paper 2019 Oct Set C

1 MARK QUESTIONS

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

(A) Seminal vesicles 

(B) Urethra 

(C) Vas deferens 

(D) Epididymis 

2 In a DNA helix, a complete turn occurs after every: 

(A) 3.1 nm 

(B) 3.2nm 

(C) 4.3nm 

(D) 3.4 nm 

3. Zebra is found in which of the following Biome? 

(A) Grassland 

(B) Temperate deciduous forest 

(C) Tropical rain forest 

(D) Tundra 

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) 2000-3000ml 

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 is 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 brain, giving the impression of depth (3-dimensional/stereoscopic vision).

10. What should be the blood group of the donor, if: 

(i) Blood group of the Recipient is ‘AB’ 

(ii) Blood group of the Recipient is ‘O’.

Ans: 

• The donor can be O, A, B, or AB, as AB is a universal recipient
• Blood group O can receive blood only from the O group.

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. Which are the two major pathways by which plants fix CO₂? Which are the initial CO₂ acceptors in each pathway? 

Ans: The two major pathways by which plants fix CO2 are C3 cycle and C4 cycle. The initial CO₂ acceptors are, 

• C3 Cycle: 5-carbon sugar ribulose bisphosphate (RuBP)
• C4 Cycle: Phosphoenol pyruvic acid or PEP

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. How and where is nitrite reduced to ammonia in plants? Write down its equation. 

Ans: In plants, nitrite is reduced to ammonia in the chloroplast. 

15. What type of cell organelles and cell walls 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. What is the mode of nutrition, respiration, and reproduction in yeast? 

Ans: 

• Nutrition:  Saprophytic
• Respiration: Anaerobic
• Reproduction: Asexually by budding

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 are the 2 effects 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) Maize Seed and Gram Seed 

(b) Thalassemia and Sickle cell anaemia 

Ans: 

1. Maize seed and Gram seed

Testa and tegmen are fused together, which are further inseparably fused with the pericarp.	Gran Seed (Dicot)
The maize grain is broader in shape.	It is somewhat conical in shape.
Testa and tegmen are fused together which are further inseparably fused with the pericarp.	Testa is the brown seed coat, fused with the inner coat, the tegmen
The embryo consists of one large cotyledon, called the scutellum.	The embryonal axis is enclosed by the two fleshy cotyledons.
The embryo is towards the narrower side of the endosperm.	The seed is attached to a small stalk.

2. Thalassemia and Sickle cell anemia
   1. Thalassemia: It is an autosomal disorder in which normal haemoglobin is not synthesised. So, frequent blood transfusions are required for survival. The defective gene is recessive and present on an autosome in heterozygous parents may not show the disorder. The child who gets the defective genes from both parents (homozygous recessive) suffers from Thalassemia.
   2. Sickle cell anemia: This is another hereditary abnormality due to a mutation of a single autosomal gene in which red blood corpuscles lose their shape and become sickle-shaped because of defective Haemoglobin. Individuals possessing two defective genes (homozygous recessive), cannot survive. In the heterozygous individuals, one gene is normal, and so half the number of total red blood corpuscles are normal, containing normal haemoglobin, while the others are defective.

23. Write short notes on: 

(a) Breathing 

(b) Lymph 

Ans: 

1. Breathing is the exchange of gases between the animal body and its external environment. This physical process is also called ventilation. It is an extracellular process that involves the exchange of gases between the individual and its external environment.
2. Lymph: Lymph is a clear and colorless circulating liquid that moves out of the capillary wall. It comes in direct contact with the body cells. Its flow is very slow and carries plasma and WBC. It flows from the tissue spaces to the capillaries to the lymph vessels and from there to the subclavian vein to end up in the heart.

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 law of independent assortment. 

(b) Explain the various steps of DNA replication. 

Ans: 

1. According to the Law of independent assortment, in the inheritance of two features (each feature controlled by a pair of genes), genes for the two different features are passed down into the offspring independently, i.e. the segregation of one pair of factors is independent of the segregation of the factors belonging to any other pair of factors or allelic pair.
2. DNA Replication: Replication occurs through the following steps :
   1. 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.
   2. 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.
   3. Synthesis of a new DNA strand: The opened strands of DNA form the template. New strands complementary to the template get synthesized. 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 synthesized. The new strand of DNA continues to be synthesized uninterrupted and is termed as the leading strand.

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.

Additional Study Materials

• NIOS Class 12 Biology PYQ Oct 2019 Set A
• NIOS Class 12 Biology PYQ Oct 2019 Set B
• NIOS Class 12 Biology PYQ April 2018 Set A
• NIOS Class 12 Biology PYQ Oct 2017 Set A
• NIOS Class 12 Biology PYQ April 2017 Set A
• NIOS Class 12 Biology PYQ Oct 2016
• NIOS Class 12 Biology PYQ April 2016