Question

(a) About 300 million spermatozoa may be present in a human male ejaculation at one time. Calculate how many spermatocytes will be involved to produce this number of spermatozoa.
(b) How many spermatids will be formed?
(c) How many chromatids are found during oogenesis in primary oocyte and first polar body in a human female? [1+1+1]

Answer 1

(a) One spermatocyte produces four spermatozoa. The number of spermatocytes to produce 300 million spermatozoa = 300/4 = 75 million. [1]

(b) One spermatozoa is formed from one spermatid. 300 million spermatids will be formed. [1]

(c) 46 chromatids (2n) and 23 (n) chromatids are found in primary oocyte and first polar body respectively. This is because first polar body is formed after the first meiotic division.[1]