Question

The two versions of a trait (character) which are brought in by the male and female gametes are situated on

• A. copies of the same chromosome
• B. two different chromosomes
• C. sex chromosomes
• D. any chromosome

Answer 1

The correct option is A

copies of the same chromosome

The correct option is Option A.

Explanation of correct option:

1. The two versions of a trait are brought in by the male and female gametes situated on copies of the same chromosome.
2. During fertilization one of the chromosomes comes from the father through the male gamete and the other chromosome comes from the mother through the female gamete.
3. After the process of fusion, the zygote is formed and has 23 pairs of chromosomes, with alleles for a trait present on the homologous pair of chromosomes.
4. In humans, during fertilization, one chromosome comes from the male gamete i.e. X or Y and one chromosome comes from the female i.e. X or X fuse to form a diploid organism with one of the following genotypes.
5. When the X chromosome from the male gamete fuses with the X chromosome of the female gamete then the zygote will develop into a girl.
6. When the Y chromosome from the male gamete fuses with the X chromosome of the female gamete then the zygote will develop into a boy.

Explanation of incorrect options:

Option B:

1. The two versions of a trait (character) that are brought in by the male and female gametes are not situated at two different chromosomes, if it occurs then the diploid organism will be not produced, because, fertilization refers to the fusion of male and female gametes i.e fusion of X chromosome from female gamete and X or Y chromosome from gamete.

Option C:

1. The chromosomes that determine the sex of an organism are called sex chromosomes.
2. In humans, males have XY sex chromosomes with 22 pairs of autosomes while females have XX sex chromosomes with 22 pairs of autosomes.
3. The two versions of a trait (character) that are brought in by the male and female gametes are not situated at the sex chromosome.

Option D:

1. The thread-like structures located inside the nucleus of cells of plants and animals is called a chromosome.
2. Each chromosome is composed of DNA wrapped tightly by proteins called histones
3. The number of chromosomes present in each organism differs, in humans 23 pairs of chromosomes are present i.e 46 chromosomes.

Final Answer: The two versions of a trait (character) that are brought in by the male and female gametes are situated on copies of the same chromosome.