Plant Growth and Mineral Nutrition — BIOLOGY STD 12 Science — Question

Read the following and answer any four questions from (i) to (v) given below:
Cleavage is the series of rapid mitotic divisions in zygote and forms blastula. The 2, 4, 8, 16 daughter cells are called blastomeres. Embryo with 64 blastomeres is known as blastocyst and has blastocoel cavity. Blastocyst gets implanted in uterine wall and leads to pregnancy.

1. Solid mass of cells with 16 blastomeres is called:

1. Morula.
2. Blastula.
3. Gastrula.
4. Zygote.

2. At which stage of embryonic development, trophoectoderm develops?

1. Zygote.
2. Morula.
3. Blastula.
4. Gastrula.

3. Site of implantation is:

1. Endometrium of uterus.
2. Cervix.
3. Uterine fundus.
4. Infundibulum of oviduct.

4. Correct sequence of various structures formed during embryonic development is:

1. Morula → Embryo → Gastrula → Blastula.
2. Zygote → Embryo → Morula → Blastula.
3. Blastula → Morula → Gastrula → Embryo.
4. Zygote → Morula → Blastula → Gastrula.

5. Assertion: Side of blastocyst with inner cell mass is called animal pole.

Reason: Inner cell mass gives rise to embryo.

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.

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

Distinguish between : External respiration and Internal respiration.

Read the following and answer any four questions from (i) to (v) given below:
In angiosperms, the pollen grains are being transferred from the anther to the stigma and is termed pollination. This phenomenon was first discovered by Camerarius (1694) in the end of seventeenth century. Pollen grains are immobile. They cannot reach the stigma by themselves. An external agent is required for this. The pollination is mainly of two types-self pollination and cross pollination. The diagram given below shows two plants of the same species showing different types of pollination.

1. What is transferred between the plants in the process indicated by arrow P?

1. Ova.
2. Pollen.
3. Nutrients.
4. Seeds.

2. Which of the following statements is correct regarding processes P, Q and R?

1. Processes P, Q and R introduce genetic variability in the offspring of sexually reproducing plants X and Y.
2. Wind serves as agent for process Q if plants X and Y belong to Genus Salvia.
3. Flowers of plants X and Y need to produce odour and nectar for completion of processes P and Q if they are entomophilous.
4. If plants X and Y belong to Genus Cannabis, then their flowers need to produce sticky and heavy pollens in very small amount for accomplishment of process Q.

3. Identify the processes P, Q and R.

S. No	P	Q	R
(a)	Geitonogamy	Xenogamy	Autogamy
(b)	Allogamy	Chasmogamy	Cleistogamy
(c)	Autogamy	Geitonogamy	Xenogamy
(d)	Geitonogamy	Allogamy	Autogamy

4. In Catliarantl1us, the growth of style brings the stigma in contact of ripe anthers present on the mouth of corolla tube. This is an example of:

1. Homogamy.
2. Cleistogamy.
3. Geitonogamy.
4. Xenogamy.

5. Which of the given processes represents a type of pollination that would result in greater adaptability of the particular species to potential environmental changes?

1. P.
2. Q.
3. R.
4. All of these.

Read the following and answer any four questions from (i) to (v) given below:
A young couple married for 5 years is unable to bear a child in spite of not practicing any birth control method. Upon consultation, doctor advised them an assisted reproductive technology involving transfer of gametes into oviducts.

1. Identify the technique adopted by the couple.

1. ZIFT
2. JUI
3. GIFT
4. ICSI

2. What is the pre-requisite of this technique?

1. Gamete formation should be normal.
2. Fallopian tubes should be normal.
3. Female should have thick endometrial lining.
4. Male should be able to copulate the female.

3. Assertion: GIFT is an in-vitro fertilisation technique.

Reason: In GIFT, gametes are fertilised outside the female body.

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.

4. The procedure advised to couple involves the transfer of:

1. Fertilised ovum.
2. Embryo with 8 blastomeres.
3. Sperms and unfertilised ovum.
4. Embryo with 16 blastomeres.

5. What is the success rate of this procedure?

1. 30-50%
2. < 20%
3. 80-85%
4. 27-30%

Distinguish Between: Phenotype and Genotype.

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.