Biodiversity, Conservation and Environmental Issues — BIOLOGY STD 12 Science — Question

Distinguish between : Adenohypophysis and neurohypophysis.

Distinguish between : Carbon cycle and phosphorus cycle.

Distinguish between: m-RNA, t-RNA and r-RNA.

Distinguish between : Unconditional reflexes and Conditional reflexes

Read the following and answer any four questions from (i) to (v) given below.
Prashant wanted to find the genotype of a pea plant bearing purple coloured flowers in his kitchen garden. For this, he crossed purple flowered plant with white flowered plant. As a result, all plants which were produced had purple flower only. Upon selfing these plants, 75 purple flower plants and 25 white flower plants were produced. Now, he can determine the genotype of a purple flowered plant by crossing it with a white flowered plant.

1. Which of the following cannot be derived from the crosses done by Prashant?

1. Mendel's law of segregation.
2. Mendel's law of dominance.
3. Mendel's law of independent assortment.
4. Both (a) and (c).

2. To determine the genotype of a purple flowered plant, Prashant crossed this plant with a white flowered plant. This cross represents a?

1. Test cross.
2. Dihybrid cross.
3. Reciprocal cross.
4. Trihybrid cross.

3. In white flowered plant, allele is expressed in?

1. Heterozygous condition only.
2. Homozygous condition only.
3. F3 generation.
4. Both homozygous and heterozygous condition.

4. The character, i.e., purple colour of the flowers that appeared in the first filial generation is called?

1. Recessive character.
2. Dominant character.
3. Dominant character.
4. Lethal character.

5. Assertion: A geneticist crossed two plants and he obtained 50% purple flowered plants and 50% white flowered plants.

Reasons: Purple coloured flower plant might be heterozygous.

1. Both assertion and reason are true and reason is the correct explanation of assertion.
2. Both assertion and reason are true but reason is not the correct explanation of assertion.
3. Assertion is true but reason is false.
4. Both assertion and reason are false.

Outcrossing and Crossbreeding.

Distinguish between : Inspiratory Reserve Volume (IRV) and Expiratory Reserve Volume (ERV).

Distinguish between : Atria and Ventricles.

Read the following and answer any four questions from (i) to (v) given below:
Disposal of untreated sewage into the river or freshwater pond causes huge water pollution. Four water samples from different sources (A, B, C, D) are collected and tested for BOD value in a lab to assess their quality. The BOD values are presented in the given table. Water samples are collected from primary effluent, secondary effluent, untreated sewage and river water. Study the given table and answer the following.

Sample	BOD
A	20mg/ L
B	5mg/ L
C	300mg/ L
D	400mg/ L

1. The source of sample 'C' is:

1. River water.
2. Primary effluent.
3. Secondary effluent.
4. Untreated sewage water.

2. If sewage in untreated condition is disposed off in a freshwater body then.

1. BOD and dissolved oxygen both will increase.
2. BOD will increase and dissolved oxygen will decreas.
3. BOD will decrease and dissolved oxygen will increase.
4. BOD and dissolved oxygen both will decrease.

3. A large number of pathogenic microbes can be present in water sample of:

1. C
2. A
3. D
4. Both (a) and (c).

4. High value of BOD in sample O is due to:

1. High amount of organic wastes and aerobic microbes.
2. High amount of inorganic wastes and anaerobic microbes.
3. High amount of organic wastes and anaerobic microbes.
4. High amount of inorganic wastes and aerobic microbes.

5. River water is represented by the sample.

1. A
2. B
3. C
4. D