PRACTICE QUESTION PAPER

SECTION A

Q1. Dead parts of plants and animals that fall on the earth surface constitute:
a) Humus
b) Litter
c) Detritus
d) Detritivore

Q2. High increase in the human population is due to:
a) The decrease in the birth rate
b) Genetic change
c) Increase in the death rate
d) Better medical facilities

Q3. Commercial latex is obtained from:
a) Euphorbiaceae
b) Acacia arabica
c) Manihot esculenta
d) Tectona grandis

Q4. Progesterone is generally present in contraceptive pills. Its function is to:
a) Prevent cleavage
b) Prevent fertilization
c) Check ovulation
d) Prevent implantation

Q5. The introduction of Cry genes is not being effective for long duration as:
a) Specificity
b) Less concentration of toxins
c) Insects develop resistance
d) Neutralization by pests

Q6. Match the following list of bacteria and their commercially important products:

(i) Aspergillus niger
(ii) Acetobacter aceti
(iii) Clostridium
(iv) Lactobacillus

(a) Lactic acid
(b) Butyric acid
(c) Acetic acid
(d) Citric acid

Choose the correct match:
a) i-(b), ii-(d), iii-(c), iv-(a)
b) i-(d), ii-(a), iii-(c), iv-(b)
c) i-(b), ii-(c), iii-(d), iv-(a)
d) i-(d), ii-(c), iii-(b), iv-(a)

Q7. Which Mendelian idea is depicted by a cross in which the F₁ generation resembles both the parents?
a) Incomplete dominance
b) Law of dominance
c) Co-dominance
d) Inheritance of one gene

Q8. What was the resultant found in the place marked E?
a) Organic esters only
b) Some fatty acids and organic acids
c) Some amino acids as glycine and alanine
d) Glucose, fatty acids and lipids

Q9. The length of the food chain in an ecosystem is generally limited to 3–4 trophic levels because:
a) Quality of energy increases from lower to higher trophic levels
b) Quantity of energy increases from lower to higher trophic levels
c) Flow of energy is unidirectional
d) Quantity of energy decreases from lower to higher trophic levels

Q10. Which one of the following symbols and its representation used in the human pedigree analysis is correct?
a) Mating between relatives
b) Unaffected female
c) Affected male
d) Unaffected male

Q11. The technology of biogas production from cow dung was developed in India largely due to the efforts of:
a) Oil and Natural Gas Commission
b) Indian Agricultural Research Institute and Khadi & Village Industries Commission
c) Indian Oil Corporation
d) Gas Authority of India

Q12. Arrange the following steps that are shown in the figure:

1. The plasmid is taken up into a bacterial cell which makes protein directed by human DNA

2. DNA segment incorporated into the bacterial plasmid

3. The segment of DNA removed from human cell

4. In genetic engineering (recombinant DNA technology)

a) 1 4 3 2
b) 1 2 3 4
c) 4 3 2 1
d) 2 3 4 1

Q13.
Assertion (A): Contraceptives are methods to prevent unwanted pregnancies.
Reason (R): Unwanted pregnancies can only be prevented by using oral contraceptives.

a) Both A and R are true and R is the 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

Q14.
Assertion (A): Yeasts such as Saccharomyces cerevisiae are used in baking industry.
Reason (R): Carbon dioxide produced during fermentation causes bread dough to rise by thermal expansion.

a) Both A and R are true and R is the 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

Q15.
Assertion (A): The ecosystem shows only negative feedback system.
Reason (R): Resilience is the ability of a system to tolerate disturbances.

a) Both A and R are true and R is the 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

Q16.
Assertion (A): The homologous organs show convergent evolution.
Reason (R): The analogous organs show divergent evolution.

a) Both A and R are true and R is the 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) Both A and R are false

SECTION B

Q17. What happens when Meloidegyne incognita consumes cells with RNAi gene?

Q18. Mention the polarity of the DNA strands a–b and c–d shown in the replicating fork.

Q19.
i. Given below is a T.S. of an apple. Identify A, B and C.
ii. Why is an apple categorised as a false fruit?

Q20. In the given figure, give the name and functions of parts labelled A and B.

Q21. Discuss in brief the general methods for the production of antibiotics.
OR
Study the picture of biogas plant and answer:
a) Name the components gaining entry from A into the chamber.
b) Mention the group of bacteria and the condition in which they act in the digester.
c) Name the components collected in gas holder.

SECTION C

Q22. Answer the following based on the dinucleotide shown:
i. Name the type of sugar to which guanine base is attached.
ii. Name the linkage connecting the two nucleotides.
iii. Identify the 3′ end of the dinucleotide with reason.

Q23. Rohit (AB blood group) needs blood transfusion. Iqbal also has AB blood group but Rohit’s mother objects due to community difference. Is she right or wrong? Explain using allelic composition of blood group AB.

Q24. Study the table showing population interaction between species Z and Y. Assign appropriate +/– signs for A, B, D, E and name interactions C and F.

Q25. How is the formation of human insulin naturally different from its formation by rDNA technology? Explain.

Q26. Alien species invasion threatens biodiversity. Justify with an example and list any three other causes responsible for such loss.
OR
Explain why biodiversity is greater in tropical regions than temperate regions.

Q27. Who proposed the theory of natural selection? Explain differential reproduction as a major component of the theory.

Q28. What are the misconceptions about transmission or acquiring AIDS?

SECTION D

Q29. Case-based question on chorionic villi and parturition:
i. Name the hormone crucial in parturition. Does the signal originate from mother or fetus?
ii. When and where do chorionic villi appear in humans?
iii. Discuss the impact of progesterone and estrogen after implantation.
OR
Fetal ejection reflex leads to parturition. Justify.

Q30. Case-based question on retrovirus replication:
i. Fill in the missing data in boxes 1 and 2.
ii. Why is it called a retrovirus?
iii. While the virus is replicated and released, does the infected cell survive and how do virus-infected cells prevent spreading to healthy cells?

SECTION E

Q31. Development of megaspore in angiosperm:
i. Describe developmental events in the nucellus and name the type of development.
ii. How many free nuclear mitotic divisions occur?
iii. Describe the structure of a typical female gametophyte.
OR
Explain post-pollination events up to double fertilisation.

Q32. Explain the relationship of ribosomes, t-RNA and m-RNA during translation in prokaryotes.
OR
Explain DNA fingerprinting and mention two applications other than forensic science.

Q33. Selectable marker in recombinant DNA technology:
i. Name the mechanism involved.
ii. Which enzyme produces colour?
iii. How is it advantageous over antibiotic-resistant marker?
OR
List 10 recombinant proteins used in medical practice and their uses.