Categories: Biology

NIOS Class 12 Biology Oct 2016 Set A (53/HIS/1)

NIOS Biology Exam Paper October 2016

1 MARK QUESTIONS

1. Cretinism and myxoedema are caused due to undersecretion of

(A) parathormone

(B) thyroxine

(D) calcitonin

2. The sea anemone gets attached to the shell of the hermit crab is an example of

(A) parasitism

(B) competition

(C) mutualism

(D) amensalism

3. Which of the following is a true fish?

(A) Jellyfish

(B) Silverfish

(D) Dogfish

4. The antibody present in colostrum that provides passive immunity to the newborn infant is

(A) IgM

(B) IgG

(D) IgA

5. —— is a sex-linked disorder.

(A) Down syndrome

(B) Haemophilia

(D) Transgender

6. Identify the kingdom to which Plasmodium, Euglena and Diatom belong to.

(A) Monera

(B) Fungi

(C) Protoctista

(D) Protozoa

7. Antibiotic properties of Penicillium was discovered by

(A) Alexander Fleming

(B) Edward Jenner

(D) Gregor Mendel

8. Neha puts some dry grams in water overnight. Next morning they were fully swollen. Name the biological phenomenon involved.

(A) Osmosis

(B) Diffusion

(C) Imbibition

(D) Plasmolysis

2 MARKS QUESTIONS

9. Name the plant hormones concerned with the following:

(a) Ripening of fruits

(b) Breaking of seed dormancy

(c) Elongation of cell

(d) Shedding of leaves

Ans:

Ethylene
Auxin
Auxin
Abscisic acid

10. Define the term ‘broad-spectrum antibiotics’. Give two examples.

Ans: Broad-spectrum antibiotics are those that can be used against more than one type of pathogenic bacterium. E.g.. Erythromycin and tetracycline.

11. Name the locomotory or gans of the following:

(a) Mollusc

(b) Starfish

Ans:

Muscular foot
Tube feet

12. State two points of difference between innate immunity and acquired immunity.

Ans: Any two

Innate Immunity	Acquired Immunity
Natural defence mechanisms which prevent the entry of germs	Mediated through lymphocytes reacting to an antigen.
Mediated through the general body surface, phagocytes, secretions, etc. General prevention has no specificity	Antigenic specificity
No memory	Memory cells

13. Match the items given in Column I with those of Column II:

Column–I	Column–II
(a) Cerebellum	(i) Controls in voluntary action, like movement of the alimentary canal, etc.
(b) Cerebral cortex	(ii) Largest part of brain
(c) Medulla oblongata	(iii) Coordinates muscular activities
(d) Cerebrum	(iv) Controls and initiates voluntary muscle contraction

Ans: (a) – (iii) , (b) – (iv) . (c) – (i), (d) – (ii)

14. Draw a neat diagram of a unicellular alga and label the following parts:

Chloroplast; Pyrenoid; Flagellum; Nucleus

Ans: Chlamydomonas

15. With the help of diagrammatic representations and an appropriate example, distinguish between the following types of inflorescence:

(a) Monochasial cyme and dichasial cyme

(b) Corymb and umbel

Ans:

Monochasial cyme and dichasial cyme:

(a) Monochasial cyme- The main axis ends in a flower, and the lateral branch comes from one side and ends in a flower. Eg. Cotton

(b) Dichasial cycle- Two lateral branches develop from either side of the terminal flower, and each branch ends in a flower. Eg., Jasmine.

Corymb and umbel

Corymb: Lower (older) flowers have longer stalks than the upper, younger ones, thus all flowers come to lie at the same level. Eg. Candytuft
Umbel: Flower with stalks of equal length arising from the same point. Eg. Coriander

16. List four applications of biotechnology.

Ans:

Cleaning up the environment using living organisms is called bioremediation.
More effective pharmaceuticals can be developed.
Microorganisms are used to develop antibiotics and vaccines to cure diseases.
Technology such as DNA fingerprinting can be used in forensic science

17. Define the term ‘hydroponics’. State three significance of such culture experiments.

Ans: The technique of growing plants in a nutrient solution in the complete absence of soil is known as Hydroponics/water culture. It helps us to understand :

Which element is essential for the normal growth of the plant.
Which element is not essential and is absorbed along with other nutrients.
How much quantity of each mineral is essential.

18. State two functions of oxytocin.

Ans:

The hormone Oxytocin is responsible for uterine contractions for childbirth.
It stimulates the release of milk from the mammary glands.

19. After recovering from a major ailment, a man was advised to include more proteins and iron in his diet. Give reason and mention one source of each.

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)

20. Name any two disorders of the musculoskeletal system which are hereditary.

Ans:

Myasthenia gravis is caused by a gene on the X chromosome and is hereditary. The muscles slowly waste away, and the patient gradually becomes immobile. In the last stage, even the jaw muscles do not work, and the patient is unable to eat.
Muscular dystrophy is an autosomal dominant disorder. In this hereditary disorder, muscles waste away, and the person becomes immobile.

4 MARKS QUESTIONS

21. (a) Name the male and female sex organs in Bryophytes and Pteridophytes and give their locations.

(b) Give any four points to distinguish between Monocots and Dicots.

Ans:

Male and Female sex organs in Bryophytes and Pteridophytes
Bryophytes: They are called antheridia and archegonia, which arise from the main plant body.
Pteridophytes: They are also called antheridia and archegonia, which arise from the gametophytic prothallus.
Monocots and Dicot Plants

Monocot Plant	Dicot Plant
1. Floral parts in three.	Floral parts are five.
2. Parallel venation in leaves.	Reticulate (Netlike) venation in the leaves.
3. Vascular bundles are scattered in the stem.	Vascular bundles are arranged in a ring.
4. Monocots have adventitious roots.	Dicots possess both tap and adventitious roots.
5. e.g., Sugarcane, wheat, rice, etc.	e.g., Pulses, hard-wood trees, etc.

22. Explain in four steps how a long DNA molecule is packaged in the chromosome.

Ans:

At intervals, DNA molecules are coiled around a “core particle” which is an octamer, that is made of 8 histone proteins forming a ball-like structure.
Each core particle with DNA around it is called a nucleosome. Under the electron microscope, the eukaryotic chromosome looks like a string of beads (string being the DNA molecule and beads the nucleosomes).
The string is then coiled to form a solenoid, and the solenoid is coiled again (supercoiling), ultimately to form the chromosome.
In this way, the long DNA molecule becomes thicker and thicker and shorter and shorter

23. Define the term ‘phyllotaxy’. Mention the types giving diagrammatic representations and appropriate examples.

Ans: Phyllotaxy is the arrangement of leaves on a stem or branch. The orientation and arrangement of leaves is such that they get an appropriate amount of sunlight for photosynthesis. It is of three types

Alternate – a single leaf arising at each node, e.g. China rose, mango.
Opposite – Leaves occur in pairs at each node. This arrangement may be
- Decussate – When the successive pairs of leaves at upper and lower nodes are at right angles e. g., “Tulsi”, Calotropis
- Superposed – when the successive leaf pairs at upper and lower nodes are exactly in the same plane, e.g. Guava
Whorled – When there are more than two leaves at each node arranged in a circle or whorl, e.g. Nerium.

a- Decussate, b- Superposed, c- Whorled, d- Alternate

24. (a) What do you understand by sustainable development? Mention any four activities which will help in attaining sustainable development.

(b) Name a plant species which is most suitable for yielding biofuel.

Ans:

Sustainable development is the development that meets the needs of the present generation and conserves resources for future generations. Activities that help attain sustainable development are
1. Reducing excessive use of resources and enhancing resource conservation.
2. Recycling and reuse of waste materials.
3. Scientific management of renewable resources, especially bio-resources.
4. Planting more trees.
5. Green grassy patches are to be interspersed between concrete buildings.
6. Using more environmentally friendly materials or biodegradable materials.
7. Use of technologies that are environmentally friendly and based on efficient use of resources.
Plant species for biodiesel: Jatropha curcus

25. (a) Draw a neat and labelled diagram of the excretory system in humans.

(b) To which category would humans belong based on the nitrogenous waste produced by them?

Ans:

Human Excretory System

Humans belong to the Ureotelic category.

26. With the help of a flowchart, explain incomplete dominance. Give the scientific name of an organism which exhibits this inheritance. Also mention the phenotype and genotype ratios.

Ans: Inheritance dominance.

In Mirabilis jalapa, a homozygous red-flowered plant (RR) is crossed to a homozygous white flowered plant (rr), all flowers in the F1 are pink, while the self-pollinated F1 plants show a phenotypic ratio in the next generation as 1:2:1. The heterozygous Rr plants have an intermediate colour, pink.

Incomplete dominance is exhibited by Snapdragon or Antirrhinum.

6 MARKS QUESTIONS

27. (a) Why is roughage considered important in our daily diet?

(b) Give two reasons why children of 1–5 years develop PEM. Name two diseases to which such children are prone to suffer from, giving the main distinguishing symptoms of the diseases.

(c) Mention two symptoms of excessive intake of iron. What is this condition called?

Ans:

Roughage is mainly composed of cellulose, which helps in bowel movement and prevents constipation. It helps clean out the digestive system and protects the body from various digestive ailments. It also helps retain water in the body and thus is considered an important part of our daily diet.
PEM is due to two reasons :
1. Lack of proteins or carbohydrates or both in the diet.
2. More intake of carbohydrates than proteins.
3. Protein energy malnutrition results in two diseases: Marasmus and Kwashiorkor
Excessive intake of iron causes hemosiderosis. Its symptoms are heartburn and epigastric pain.

28. (a) What are meristematic tissues of plants? Name the types giving their locations.

(b) Name the complex tissues of plants. Give their main functions. Also name the components each one is made of.

Ans:

Meristematic tissues are constantly dividing, immature and undifferentiated cells without any intercellular spaces. There are three types of meristematic tissue.
1. Apical meristem: In the root and shoot tips
2. Intercalary meristem: At the base of leaves or bases of internodes
3. Lateral meristem: Cambium, which is found between xylem and phloem, as well as in the bark.
Complex tissues in plants are xylem and phloem.
1. Xylem: Xylem is a conducting tissue which conducts water and salts upward from roots to leaves. It is composed of Tracheids, Vessels, Fibres and Xylem parenchyma.
2. Phloem: Phloem too is a conducting tissue which conducts the metabolites food synthesised in the leaves to different parts of the plant. It is composed of the Sieve tube element, Companion cells, Phloem fibre, and Phloem Parenchyma.

29. (a) Give a generalized balanced equation of photosynthesis.

(b) Draw a diagrammatic representation of the Calvin cycle and highlight the three main steps taking place in the process. Where does this cycle take place, and what is the main product formed?

Ans:

Photosynthesis

Calvin Cycle

It takes place in the thylakoids of the chloroplast. The main products formed are glyceraldehyde-3-phosphate (G3P), which will later form glucose molecules, ADP, and NADP⁺.

30. (a) A son and a daughter were colour-blind. The father was colour-blind, but mother had a normal colour vision. Draw a self-explanatory flowchart to indicate the above.

(b) Give the karyotypes of the following:

(i) Down syndrome female

(ii) Turner’s syndrome

(iii) Klinefelter’s syndrome

(iv) Normal male

(c) Define the term ‘amniocentesis’.

Ans:

For both the son and daughter to be colour blind, the mother has to 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)	X^c (mother)
Xᶜ (father)	XᶜXᴺ	XᶜXᶜ
	(daughter — carrier, normal vision)	(daughter — colour blind)
Y (father)	XᴺY	X^cY
	(son — normal vision)	(son — colour blind)

Karyotypes
1. Down syndrome female: 44+ XX
2. Turner’s syndrome: 45, X
3. Klinefelter’s syndrome: 47, XXY
4. Normal male: XY
Amniocentesis is a technique by which hereditary disorders due to defects in genes can be detected.