REPRODUCTION

Question 1

Cell cycle consists of 4 stages. Name all 4 and briefly explain

Answer 1

G1 Phase (Presynthetic phase): Create organelles for energy + protein production and increase their size

S (Synthesis of DNA): replicates genetic material so each daughter cell will have identical copies

G2 Phase (postsynthetic gap): Checkpoint to avoid errors in sythesis

M(mitosis): Mitosis + cytokenisis

Question 2

Mitosis occurs in somatic cells. What are the four phases of mitosis

Answer 2

Prophase: 1st stage of mitosis. involves condensation of chromatins into chromosomes; and they migrate to opposite sides of the cell. (pg 56)

Metaphase: aligns the cells at opposite sides to the metaphase plate

Anaphase: sister chromatids separate

Telophase/ cytokinesis:

Question 3

Meiosis 1 and Meiosis 2 have what kind of divisions:

Answer 3

Meiosis 1 results in homologous cells being separated and producing haploid cells. this is known as reductional division.

Meiosis 2 is the separation of sister chromatids without a change in ploidy. This is known as equational division (pg 59) .

Question 4

oocytes are surrounded by two layers called zona pellucida and the corona radiata. what do they do ?

Answer 4

zona pellucida surrounds the oocyte itself and is a mixture of glycoproteins that protect the oocyte and contain compounds necessary for sperm binding.

corona radiata are layer of cells that lie outside the zona pellucida and adhere to the oocyte during ovulation.