BIOLOGY (Summative)

Question 1

It is a diploid cell (2n) that undergoes mitosis to produce two primary spermatocytes, it is also the starting point of spermatogenesis.

Answer 1

Spermatogonium

Question 2

True or False

Meiosis I occurs in the primary spermatocyte, resulting into two secondary spermatocytes

Answer 2

True, 2 primary spermatocytes are derived from one spermatogonium during mitosis but only one is shown for the sake of illustration.

Note:
Meiosis II takes place when the 2 secondary spermatocytes divides further into 4 spermatids.

One primary spermatocyte (PS) is equal to 2 secondary spermatocytes (SS), resulting in 4 spermatids (non-motile).

1 PS = 2 SS
1 SS = 2 Spermatids; 2 SS = 4 spermatids

There are 2 primary spermatocytes produced during mitosis of spermatogonium, hence there would be 4 secondary spermatocytes, leading in 8 spermatozoa or sperms

2 PS = 4 SS
4 SS = 8 Spermatids = 8 Spermatozoa (with flagellum)

1 Spermatogonium -> 2 primary spermatocyte -> 4 secondary spermatocytes -> 8 spermatids (immature sperm) -> 8 matured sperm cells/spermatozoa (with flagellum)

Why 8 sperms? One primary spermatocyte includes 4 spermatids, we have 2 primary spermatocytes, so one spermatogonium produces 8 sperm cells.

Question 3

True or false, justify

It is said that oogenesis (production of ovum) occurs after birth.

Answer 3

False, it occurs PRIOR to birth. This means that a female embryo’ oogonia is already undergoing mitosis to produce 2 primary oocytes.

Question 4

It is the actual division of the cell into new cells

Answer 4

Cytokinesis

Question 5

Point where sister chromatids are joined together

Answer 5

Centromere

Question 6

Cell’s control system
Give go-ahead signals

Answer 6

Checkpoints