Question

In a plant's life cycle, how many sporophyte generations occur between one gametophyte generation and the next time that eggs and sperm are produced? A)Zero B)One C)Two D)Four

Answer 1

Answer:

A) Zero

Explanation:

Alternation of generations in plants:

The 'alternation of generations' in the life cycle is between a diploid (2n) generation of sporophytes and a haploid (n) generation of gametophytes.

The following are the events involved in alternation of generations:

• Two haploid gametes with n chromosomes, fuse to form a diploid zygote i.e. 2n chromosomes in total.
• The diploid zygote germinates, dividing by mitosis to produce a multi-cellular diploid organism, called the sporophyte (because at maturity it produces spores).
• When it matures, the sporophyte produces one or more sporangia  that produce diploid spore mother cells (sporocytes). These divide by meiosis, reducing the number of chromosomes by a half. This  results in four haploid spores, each containing n unpaired chromosomes.
• The haploid spore germinates, dividing by mitosis, maintaining the number of chromosomes at n. This results in a haploid organism, called the gametophyte (because it produces gametes at maturity).

• When it matures, the gametophyte produces one or more gametangia that produce haploid gametes.