Topic 2.2: The cell cycle

Question 1

What happens during prophase?

Answer 1

Chromosomes condense and become visible as pairs of chromatids joined at the centromere. Nuclear membrane starts to break down and spindle fibres begin to form from the centromeres

Question 2

What happens during metaphase?

Answer 2

The chromosomes align at the equator of the cell. Spindle fibres attach to the centromeres of each chromosome

Question 3

What happens during anaphase?

Answer 3

Spindle fibres contract, the CENTROMERE divides and sister chromatids are pulled apart to opposite poles of the cell

Question 4

What happens during telophase?

Answer 4

Chromatids uncoil (now chromatin) and reach the poles and nuclear membrane reforms around each set of chromosomes, The cell begins to divide its cytoplasm

Question 5

What is interphase?

Answer 5

The preparation phase where the cell grows and performs its normal functions

Question 6

What are the 3 sub-phases of interphase, and what happens in each?

Answer 6

G1 - cell growth, synthesis of proteins and organelles
S - DNA replication so each chromosome consists of two sister chromatids
G2 - Cell continues to grow, produces necessary proteins and organelles to prepare for mitosis

Question 7

What happens in cytokinesis?

Answer 7

The cytoplasm divides, resulting in two separate daughter cells

Question 8

How does cytokinesis occur in animal cells?

Answer 8

Through a process called cleavage: the cell equator pinches into two daughter cells

Question 9

How does cytokinesis occur in plant cells?

Answer 9

A cell plate forms along the middle of the cell, eventually developing into a new cell wall