Cell cycle

Question 1

How long does the cell cycle usually last?

Answer 1

Around 12 hours

Question 2

What are the two main phases of the cell cycle?

Answer 2

• Mitotic phase
• Interphase

Question 3

What is the role of cyclins in the cell cycle?

Answer 3

Activate cyclin dependant kinases which are important for the regulation of the cell cycle

Question 4

What is the interphase?

Answer 4

The interval between the end of mitosis and the beginning of the next

Question 5

What are cycling cells?

Answer 5

Cells that continue to divide regularly in definite intervals

Question 6

Which cyclins are involved in the cell cycle?

Answer 6

A,B and E

Question 7

What are the 3 stages of interphase?

Answer 7

• G1
  -S
  -G2

Question 8

What occurs during the G1 phase?

Answer 8

-cells respond to growth factors
- Most of the molecular machinery required to complete another cycle is generated

Question 9

how long does G1 phase last?

Answer 9

2-100 hours

Question 10

which cyclins control the G1 phase?

Answer 10

Cyclin E

Question 11

What occurs during the S phase?

Answer 11

The period in which new DNA is synthesised.

Question 12

Which cyclins are involved in the S phase?

Answer 12

Cyclin A

Question 13

What can happen during replication which would cause the cell cycle to be arrested?

Answer 13

DNA damage.

Question 14

What type of cells enter the G0 phase of the cell cycle?

Answer 14

Clles that retain the capacity for proliferation and are in the process of differentiation but which are no longer dividing

Question 15

How can cells be stimulated to leave G0?

Answer 15

By the production of growth factors

Question 16

What occurs during the G2 phase?

Answer 16

the cell prepares for division, this period ends with the breakdown of the nuclear membrane and the beginning of chromosome condensation

Question 17

Which cyclin controls the G2 phase?

Answer 17

Cyclin B

Question 18

What does mitosis result in?

Answer 18

the distribution of identical copies of the parent cell genome to the two daughter cells

Question 19

What are the 4 stages of mitosis?

Answer 19

• Prophase
  -Metaphase
  -Anaphase
  -Telaphase

Question 20

What occurs during the prophase?

Answer 20

• Each chromosome splits longitudinally into two chromatids
• The two paired centriole are separated from each other and occupy opposite poles of the nucleus

Question 21

What occurs during the metaphase?

Answer 21

Centromere from each chromosome presents kinetochores

• a set of microtubules are organised and extend from kinetochores towards opposite centrioles
• chromosomes occupy equatorial plate of the spindle

Question 22

What is the role of colchicine in the cell cycle?

Answer 22

-Arrest the cell division at metaphase by preventing the formation of microtubules from the spindle.

Question 23

What occurs during the anaphase?

Answer 23

• Centromere splits and chromatids separate to form two new chromosomes
• microtubules contract causing chromosomes to migrate to opposite poles of the spindle

Question 24

What occurs during the telophase?

Answer 24

• daughter chromosomes are enveloped by a new nuclear membrane
• cytoplasm divides and two complete cells are formed = cytokinesis