Subject: Biology
Class XII
Time Allowed: 3 hours
Max. Marks: 70
General instructions
- There are 33 questions in this question paper. All questions are compulsory.
- Section A: Q. No. 1 to 15 are objective type questions. Q. No. 1 is passage based questions carrying 6 marks while Q. No. 2 to 15 carry 1 mark each.
- Section B: Q. No. 16 to 25 are short answer questions and carry 2 marks each.
- Section C: Q. No. 26 to 30 are short answer questions and carry 3 marks each.
- Section D: Q. No. 31 to 33 are long answer questions carrying 5 marks each.
- There is no overall choice. However, internal choices have been provided.
- Draw well labeled diagram where required.
Section A
Read the passage below and answer the following questions
As the anther develops, the cells of the sporogenous tissue undergo meiotic divisions to form microspore tetrads. As each cell of the sporogenous tissue is capable of giving rise to a microspore tetrad. Each one is a potential pollen or microspore mother cell. The process of formation of microspores from a pollen mother cell (PMC) through meiosis is called microsporogenesis.
(i) State the ploidy of sporogenous tissue and pollen mother cell.
(ii) Name the chemical which holds microspores together in tetrad.
(iii) Name the anther layer which provides nourishment to microspores & explain why cells of this layer have dense cytoplasm?
(iv) Which cell represents male gametophyte? Draw its structure at 2 celled stage.
(v) Name the 4 layers found in anther.
(vi) ______________ was imported to India as a contaminant with imported wheat & is found to cause pollen allergies.
Questions 2 to 10 are MCQ’S
2. A weekly contraceptive pill is:
a) Mala – A b) Mala- D c) Saheli d) Saheli-2
3. A cross between F1 hybrid and recessive parent is called
a) monohybrid cross c) dihybrid cross
b) test cross d) reciprocal cross
4. In an individual, haploid number is 10. Its tetrasomic number will be:
a) 40 b) 14 c) 22 d) 44
5. ZZ/ZW type of sex determination is seen in:
a) platypus b) snails c) cockroach d) peacock
6. Milky water of coconut is:
a) liquid chalaza b) liquid nucellus c) liquid endosperm d) liquid female gametophyte
7. Menstruation is caused by:
a) increase in FSH level c) fall in oxytocin level
b) fall in progesterone level d) increase in estrogen level
8. Sterilisation techniques are generally fool proof methods of contraception with least side effects, yet it is the last option for couples because:
a) it is almost irreversible iii) it is a surgical procedure
b) of the misconception that it reduces sexual drive iv) lack of sufficient facilities in country
i) & iii) b) ii) & iii) c) ii) & iv) d) i), ii), iii) & iv)
9. Acrosomal reaction of the sperm occurs due to:
(a) its contact with zona pellucida of ovum
(b) reaction within uterine environment of the female
(c) reaction within urethral environment of the male
10. To produce 100 pollen grains how many microspores are required?
(a) 25 b) 50 c) 75 d) 100
In the following questions (Q. No. 11 – 15) a statement of assertion followed by a statement of reason is given. Choose the correct answer out of the following choices.
11. Assertion: Reproductive tract infections are due to bacteria, viruses or protozoans
Reason: These infections are usually not curable
A. both reason and assertion are correct statement and reason is the correct explanation of assertion
B. both reason and assertion are correct statement but reason is not the correct explanation of assertion
C. assertion is correct but reason is wrong
D. Both assertion & reason are wrong
12. Assertion: Tallest flower Amorphophallus is pollinated by insects
Reason: Yucca flower also shows symbiotic relationship with insects
A. both reason and assertion are correct statement and reason is the correct explanation of assertion
B. both reason and assertion are correct statement but reason is not the correct explanation of assertion
C. assertion is correct but reason is wrong
D. Both assertion & reason are wrong
13. Assertion: In Grasshopper, sex is determined by male
Reason: In birds, sex is determined by female
A. both reason and assertion are correct statement and reason is the correct explanation of assertion
B. both reason and assertion are correct statement but reason is not the correct explanation of assertion
C. assertion is correct but reason is wrong
D. Both assertion & reason are wrong
14. Assertion: Myotonic dystrophy is an autosomal dominant disease
Reason: Sickle cell anaemia is an autosomal recessive disease
A. both reason and assertion are correct statement and reason is the correct explanation of assertion
B. both reason and assertion are correct statement but reason is not the correct explanation of assertion
C. assertion is correct but reason is wrong
D. Both assertion & reason are wrong
15. Assertion: Seminiferous tubules are lined by male germ cells & sertoli cells
Reason: Seminiferous tubules are structural & functional unit of testis
A. both reason and assertion are correct statement and reason is the correct explanation of assertion
B. both reason and assertion are correct statement but reason is not the correct explanation of assertion
C. assertion is correct but reason is wrong
D. Both assertion & reason are wrong
Section B
16. A pea plant having violet coloured flowers was crossed with another pea plant having white flowers. In F1 generation, both violet as well as white flowers were obtained. Predict the genotype of parent having violet flowers and name the type of cross
17. The phenotypic and genotypic ratio in F2 generation are same in certain kind of inheritance. Name an organism in which it occurs and mention the kind of inheritance involved.
18. Draw well labeled diagram of 7 celled 8 nucleated female gametophyte.
19. Write the function of each of the following:
a) Middle piece in human sperm
b) LH in human males
20. How is it possible in Oxalis & Viola plants to produce assured seed sets even in the absence of pollinators.
21. Give one example of each: a) anemophilous plant b) entomophilous plant
22. Mention the function of progesterone and FSH in human females.
23. What is colostrum? State its significance.
24. Why CuT is considered a good contraceptive to space children?
25. A man with blood group A has a wife of blood group B. They have a child with blood group O. Give the genotype of man and his wife, make cross.
Section – C
26. Expand AIDS, RCH, ZIFT, IVF, ICSI, IUDs
27. What is inbreeding depression? Explain any two outbreeding devices which can be used to prevent it.
28. Draw well labeled diagram of human female reproductive system
OR
Read the graph below. Correlate the ovarian events that take place in the human female according to the levels of pituitary hormones during the following days:
i) a) 10-14 days b) 14-15 days
ii) What are the uterine changes that follow beyond 29th day if the ovum is not fertilized?
29. Write the scientific name of fruit fly. Why did Morgan prefer to work with fruit fly for his experiments? State any three reasons.
30. a) What sickle cell anaemia patients are resistant to malaria?
b) Why Thalassemia is called quantitative disease and name the genes involved in this disease.
Section D
31. a) What is emasculation? When & why does a plant breeder employ this technique?
b) State the difference between true fruits & false fruits with the help of 2 examples of each.
c) Why do you think the zygote remains dormant for sometime in fertilized ovule?
d) Draw diagram of monocot embryo.
32. What is linkage and recombination? Explain the phenomenon of linkage with the help of a cross between yellow body white eyed female and brown body red eyed male.
OR
a) Why is Colour blindness generally observed in human males? Explain the conditions under which human female can be colour blind.
b) A pregnant human female was advised to undergo MTP. It was diagnosed by her doctor that the foetus she is carrying has developed from a zygote formed by an XX egg fertilized by Y carrying sperms. Why she was advised to go for MTP?
33. a) The path of sperm transport is given below. Provide the missing steps in blank boxes:
b) Why menstrual cycle is absent during pregnancy?
c) Study the diagram and answer the questions that follow:
i) Name the stage of the human embryo the figure represents
ii) Identify ‘a’ in the figure and mention its function.
iii) Where are the stem cells located in this embryo?