Unit 1 - Topic 5 - Protein control of cell division - Section B - The cell cycle

Question 1

The cell cycle consists of what to phases

Answer 1

Interphase and Mitotic (M) phase

Question 2

Describe interphase

Answer 2

Interphase involves growth and DNA synthesis including G1, a growth phase; S phase, during which the DNA is replicated; and G2, a further growth phase.

Question 3

The mitotic phase involves what two things

Answer 3

Mitosis and cytokinesis

Question 4

Describe mitosis and cytokinesis

Answer 4

In mitosis the chromosomal material is separated by the spindle microtubules. This is followed by cytokinesis, in which the cytoplasm is separated into two daughter cells

Question 5

What are the 4 phases of mitosis

Answer 5

Prophase, Metaphase, anaphase and telophase

Question 6

Describe prophase

Answer 6

DNA condenses into chromosomes each consisting of two sister chromatids. Nuclear membrane breaks down; spindle microtubules extend from the MTOC by polymerisation and attach to chromosomes via their kinetochores in the centromere region.

Question 7

Describe metaphase

Answer 7

Chromosomes are aligned at the metaphase plate (equator of the spindle)

Question 8

Describe anaphase

Answer 8

As spindle microtubules shorten by depolymerisation, sister chromatids are separated, and the chromosomes are pulled to opposite poles

Question 9

Describe telophase

Answer 9

The chromosomes decondense and nuclear membranes are formed around them.