Cell Cycle

Question 1

What are the main phases of cell cycle?

Answer 1

Interphase
Longest period of cycle
Normal cell functions (existing)

G1
S - replication of DNA
G2

Mitosis
Cell divides nuclear contents

Prophase → Metaphase → Anaphase → Telophase

Cytokinesis
Final split and formation of new, identical
cells

Question 2

What is the cell cycle

Answer 2

The cell cycle is the series of events which cells undergo to divide and create two identical daughter cells.

Question 3

What is occurring in each of the phases

Answer 3

Interphase
cell carries out normal functions.
G1. The cell prepares for cell division by:
- making proteins
- the cell getting bigger in mass

S - genetic material (DNA) is synthesised / replicated using

G2 - Final growth period before cell divides into two, through Mitosis.

Mitosis: contents of the nucleus are divided into two equal parts.

Cytokinesis: separation of two nuclei and cell contents
into two daughter cells.

Question 4

What phases are apart of interphase

Answer 4

G1 phase ( gap 1)
S phase ( synthesis)
G2 phase ( gap 2)

Question 5

what proportion of the cell is taken up by mitosis?

Answer 5

Mitosis accounts for about 10 percent of the cell cycle

Question 6

what is occurring in the mitosis

Answer 6

Prophase–> metaphase—> Anaphase—> telaphase

Question 7

What happens in Prophase

Answer 7

Chromosomes become visible
Nucleus membrane disappears
Centrioles begin to move to poles

Question 8

metaphase

Answer 8

Chromosomes line up at equator
Spindle fibres are attached to centromere

Question 9

Anaphase

Answer 9

Spindle fibres pull sister chromatids apart

Question 10

Telephase

Answer 10

Chromosomes are separated
Nuclear membrane reforms
Cell plate or cleavage furrow forms

Question 11

What are the difference between cytokinesis in animal and plant cells?

Answer 11

In plants:
Cell plate forms and will become the new cell wall

Plant cells cannot be “pinched” into two new daughter cells, because of the cell wall.

In animals:
Cell pinches down the middle (cleavage furrow) to split the daughter cells

Question 12

How is the cell regulated to deal with problems.

Answer 12

The cell checks its DNA during different stages. If there’s a problem, it stops dividing, fixes the issue, or destroys itself to prevent errors.

Question 13

How do mutations result in a lack of control of the cell cycle?

Answer 13

Eg. Disruption of normal regulation of the cell cycle can lead to diseases such as cancer. When the cell cycle proceeds without control, cells can divide without order and accumulate genetic errors that can lead to a cancerous tumor.

Mutations can disrupt genes controlling cell cycle, causing uncontrolled division, leading to cancer or cell death.