PRACTICE PAPER SET – 6

[Time: 3 Hours] [Maximum Marks: 70]

SECTION - A
1. Which of the following statements indicates parallelism in genes and chromosomes?

2. Which of the following is not a physiological barrier of innate immunity?

(a) Acid in the gastric juice (b) Mucus coating of epithelium of digestive and respiratory tract
(c) Tear in the eyes (d) Saliva in the mouth
3. GIFT is an ART used for those females, who
(a) cannot conceive normally.
(b) cannot produce a functional ovum, but can provide suitable environment for fertilisation and embryo development.
(c) cannot provide suitable environment for fertilisation and embryo develop, but can produce a fhnctional ovum.
(d) All of the above.
4. The construction of the first recombinant DNA was achieved by using the native plasmid of
(a) Escherichia coli (b) Agrobacterium tumefaciens
(c) Salmonella lyphimurium (d) Bacillus thuringiensis
5. Which of the following statements is incorrect?
(a) Genetically engineered insulin is produced in E.coli.
(b) In man, insulin in synthesised as proinsulin.
(c) The proinsulin has three peptide chains, A, B and C.
(d) The functional insulin has two peptide chains, A and B held together by hydrogen bonds.
6. The population of an insect speéies shows an explosive increase in number during rainy season, followed by its
disappearance at the end of the season Which of the following is the correct inference of this observation?
(a) The food plants flourish during rainy season and die at the end of senson
(b) The population growth curve of the insect is J shaped.
(c) The population growth curve of the insect is sigmoid.
(d) The population of predators must have increased.
7. Which of the following statements regarding the pyramid of energy is incorrect?
(a) The base tier has the maximum amount of energy.
(b) It shows the energy content in different trophic levels.
(c) Only 10 per cent of energy is transferred from one trophic level to the next higher trophic level.
(d) It is inverted in sea ecosystem.
8. During the menstrual phase of the menstrual cycle, the endometrial lining and its blood vessels disintegrate causing
menstruation to occur, it is caused by.
(a) lack of progesterone (b) excess secretion of luteinising hormone (LH)
(c) lack of estrogens (d) excess secretion of follicle stimulating hormone (FSH)
9. Which among the following is not a method of in-situ conservation ?
(a) National Park (b) Botanical garden (c) Wildlife sanctuary (d) Ramsar sites
10. Select the correct statement from the following.
(a) Toddy is made by fermenting the sap of palms.
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 (b) Brandy having high alcohol content is produced without distillation.
(c) Wine and beer are produced after distillation.
(d) Citric acid is produced by using the bacterium, Clostridiurm.
11. In an expanding or growing population of a country.
(a) pre-reproductive individuals are more than the reproductive individuals.
(b) reproductive individuals are less than the post-reproductive individuals.
(c) pre-reproductive individuals are less than the reproductive individuals.
(d) reproductive and pre-reproductive individuals are equal in number.
12. Observe structures A and B given below Which of the following statements are correct?

(a) A is having 2’—OH group which makes it less reactive and structurally stable, whereas B is having 2’—H group
which makes it more reactive and unstable.
(b) A is having 2’—OH group which makes it more reactive and structurally unstable, whereas B is having 2’—H
group which makes it less reactive and structurally stable
(c) A and B both have —OH groups which make it more reactive and structurally stable.
(d) A and B both are having —OH groups which make them less reactive and structurally stable
Question No. 13 to 16 consist of two statements– Assertion (A) and Reason (R). Answer these questions
selecting the appropriate option given below:
(a) Both A and R are true, and R is correct explanation of A.
(b) Both A and R are true, but R is not the correct explanation of A.
(c) A is true but R is false.
(d) A is false but R is true.
13. Assertion (A): Genetic drift is the change in allele frequencies in a population due to some chance events and forms
an important factor for evolution.
Reason (R): Smaller populations have greater chances for genetic drift.
14. Assertion (A): In an aquatic/marine ecosystem, the pyramid of biomass is always inverted.
Reason (R): In the aquatic/marine ecosystem, the biomass of phytoplanktons/producers at any given time is lower
than the biomass of the consumers Like fishes.
15. Assertion (A): Self-pollen cannot effect fertilisation in self-incompatible pistil.
Reason (R): Self-incompatibility prevents the germination of pollen grains or retard the growth of pollen tube.
16. Assertion (A): During gel electrophoresis, DNA moves towards the anode. Reason (R): DNA is positively charged.
SECTION – B
17. What is palaeontology? How does palaeontological evidence support evolution of organisms on the Earth?
18. Explain the fate of inner cell mass in a human embryo immediately after implantation.
19. Why are sacred groves highly protected?
OR
‘It is possible that a species may occupy more than one trophic level in the same ecosystem at the same time’.
Explain with the help of an example.
20. List any four ways by which GMO’s have been useful for enhanced crop output.
21. Trace the life cycle of the malarial parasite in the body of Anopheles.

SECTION – C
22. (a) Bring out the differences between a secondary follicle anda tertiary follicle in a human ovary.
(b) What stimulates the pituitary to release the hormone responsible for parturition? Name the hormone.
23. What are Cry proteins? Name an organism that produces it. How has m exploited this protein to his benefit?
24. Explain the role of RJ’JA polymerase in transcription in bacteria.
25. How can childless couples be helped by the following Assisted Reproductive Technologies?
(a) GIFT (b) ICSI

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26. It is generally believed that competition occurs only when closely related species compete for the same resources
that are limiting. Give two examples to show that the above statement is not always true.
27. Study the diagram given below:

Name the linkages X, Y, Z and the respective molecules formed by them.

28. Given below is a list of three microorganisms. State their usefulness to humans.
(a) Saccharomyces cerevisiae (b) Trichoderina polysporum
(c) Propionibacteriurn sharrmanii
OR
(a) Name the causative agent of typhoid in humans.
(b) Name the test administered to confirm the disease.
(c) How does the pathogen gain entry into the human body? Write the diagnostic symptoms and mention the body
organ that gets affected in severe cases.
SECTION – D
Question No. 29 and 30 are case — based questions. Each question has subparts with internal choice in one
subpart.
29. Development of recombinant technology has enabled scientists to isolate DNA sequences manipulate individual
genes from diverse cells. Given below is a diagram showing the basic steps involved in genetically modifying an
organism. Study the given diagram and answer the questions that follow:

(a) Name the enzyme used at step X to integrate the foreign DNA with the vector DNA.
(b) What is the term given for Y showing multiple copies of the foreign DNA in E.coli cells?
(c) Are two different types of restriction enzymes used-one to cut the vector DNA and another to cut the desired DNA
to be cloned? Justify your answer with reason.
OR
(c) Explain palindromic nucleotide sequence with the help of a suitable example.
30. The cytological observations made during gamete formation in a number of insects, led to the development of the
concept of genetic/chromosomal basis of sex determination mechanisms in Drosophila, grasshopper, honey bees,
etc. Honey bee is an interesting example to study the mechanism of sex determination. Study the schematic
representation of the cross between a male and a female honey bee given below and answer the questions that
follow:

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 (a) What forms the basis of sex determination in honey bees? What term is given to this method of sex
determination?
(b) Identify the type of cell division at ‘A’ and ‘B’ occuring during gamete formation in the female and male honey bees
respectively.
(c) Name the scientist who conducted the cytological studies during gametogenesis in insects. What did he observe?
OR
(c) How many chromosomes does a male honey bee possesses? Give reason for the difference in the number of
chromosomes between males and females of honey bees.
SECTION — E
31. (a) Describe the process of megasporogenesis in an angiosperm
(b) Draw a diagram of a mature embryo sac of angiosperm Label its any six parts.
OR
The reproductive cycle in the females of primate mammals (apes, monkeys and humans), is called menstrual cycle
Menstrual cycles occur during the reproductive phase, i. e., between menarche and menopause in human females
The cycle starts with menstruation and extends (for about 28 days) till the onset of the next menstruation, it includes
four phases.
(a) Name in proper sequence, the four phases in a menstrual cycle.
(b) How long does the menstrual phase last in a menstrual cycle ?
(c) When do the hormones estrogen and progesterone reach their peak levels, respectively, in the menstrual cycle?
Give reasons.
(d) Define ovulation.
32. (a) What is polygenic inheritance Explain with the help of a suitable example.
(b) How are pleiotropy and Mendelian pattern of inheritance different from polygenic pattern of inheritance?
OR
Describe in detail, the process of translation in bacteria.
33. (a) Define allergy
(b) Name the cells and the chemicals responsible for causing allergic reactions in our body
(c) Mention any four symptoms of allergy
(d) Name two drugs that can alleviate the symptoms of allergy
OR
Study the picture of the biogas plant given below and answer the questions that follow:
(a) Name the components gaining entry from C into the digester
(b) Name the group of bacteria and the condition in which they act on the components that entered the digester from
C.
(c) Name two sites where this group of bacteria is generally found.
(d) Name the components that get collected in B What is B
(e) How is the gas coming out of the plant used ?

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