Question

1. What is a gamete? A zygote? How many chromosomes do they have (n or 2n)? Are they haploid or diploid cells?
2. Describe two different aspects of meiosis that contribute to genetic variation between individuals.

Answer 1

A gamete is a haploid cell, produced by individuals who are capable of sexual reproduction, that take part in zygote formation. Two different types of gametes are there- sperm in males and ovum in females.

Zygote is a diploid cell, which is formed as a result of gamete fusion. Zygote developes to form an embryo.

Gametes contain half the number of chromosomes (n), present in the mature organism. Zygote, on the other hand, contain the exact number of chromosomes present in the mature organism (2n). Thus, gametes are haploid, and zygote is diploid.

Crossing over is one of the event that occurs during meiosis, which confers genetic variation. The paternal and maternal chromosomes during crossing over exchange a small portion of the genetic material, as a result of which variation is introduced. Another event occuring during meiosis that results in variation is independent assortment. During independent assortment, chromosomes combine randomly. Thus, different allelic combinations are made, which increases variability in the resulting offsprings.