AP BIOLOGY

CELL DIVISION

MEIOSIS

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Question [CLICK ON ANY CHOICE TO KNOW THE RIGHT ANSWER]

If the haploid number of an organism is 8, how many different varieties of gametes are possible, not considering the effects of crossing over?

A	256
B	128
C	64
D	16

Explanation:

Detailed explanation-1: -1. How many different chromosomal combinations can result from meiosis in a species that has a diploid (2N) number of 8? Assume no crossing-over occurs. Sixteen different combinations.

Detailed explanation-2: -since the haploid number is 8 then the diploid which is the full number of chromosomes is double this number, so it is 16.

Detailed explanation-3: -Assume that the members of each pair are not identical. A gamete for this organism will have three chromosomes. Each chromosome is one of two possibilities. Thus, there will be 2 x2 x 2 = 8 possible arrangements (or (2)3 = 8).

Detailed explanation-4: -Ignoring crossover, how many kinds of gametes can be produced by an organism with a diploid number of 8? 16 Correct. The number of combinations possible when chromosomes assort independently into gametes during meiosis is 2n, where n is the haploid number of chromosomes.

Detailed explanation-5: -Hence, if the mother cell has 8 chromosomes, after meiosis I the progeny cells will have 4 chromosomes. Each chromosome in daughter cells will have two chromatids.

There is 1 question to complete.