Question

(i) How gamete transfer takes place in various organisms?

(ii) how haplontic life cycle does differ from diplontic life cycle?

(iii) why we say that single celled organisms are immortal?

Answer 1

1. Male and female gamete must be physically brought together to facilitate fusion called fertilization. In most cases male gametes are motile, female gametes are non-motile. In case of few fungi and algae, both male and female gametes are motile. In most cases water is the medium for gamete transfer. Male gametes are produced in several thousand times than the number of female gametes produced to compensate the loss during transfer.

• In seed plants, pollination and fertilization are transferring the gametes.

ii. In Haplontic life cycle, the zygote undergoes meiosis and in Diplontic lifecycle, the zygote undergoes mitosis.

iii. There is no natural death in single – celled organism, as they multiply cell division. That is why single cell organisms are said to be immortal.