Week 9 - Cell Cycle and Cell Division

Question 1

When does cell division occur

Answer 1

• development
• healthy homeostasis
• Wound repair
• Mis-regulation leads to cancer

Question 2

Where has the highest turnover rate of cells in the body

Answer 2

oral epithelium
probably due to an evolutionary response to the continual injury suffered by the oral lining epithelia.

Question 3

What is tumorgenesis

Answer 3

Tumorigenesis is the gain of malignant properties in normal cells including fast proliferation (increases the rate of cell division by breaking the proteins which regulate the speed of cell division normally)

Question 4

How many chromosome pairs are there in humans

Answer 4

23

Question 5

How many individual chromosomes do humans have

Answer 5

46

Question 6

What are the 2 main phases of the cell cycle

Answer 6

1. Interphase
2. Mitotic phase

Question 7

What is the interphase

Answer 7

takes up 90% of a cells life and is where the cell is undergoing its natural function and is not dividing

Question 8

What is the mitotic phase

Answer 8

includes both mitosis and cytokinesis (division of organelles)

Question 9

What are the 4 subphases in interphase

Answer 9

G1 phase
G0 phase
S phase
G2 phase

Question 10

What occurs in G1 phase

Answer 10

when the cell is ‘doing its job’ and there’s no cell division

Question 11

What occurs in G0 phase

Answer 11

A subclass of G1 which prevents cell division from occuring

Question 12

What occurs in S phase

Answer 12

When the cell is copying its chromosomes

Question 13

What occurs in G2 phase

Answer 13

When the cell is growing and preparing for cell division

Question 14

What are the intracellular signaling proteins which control the cell cycle checkpoints

Answer 14

cyclins
cyclin dependent kinases

Question 15

What are kinases

Answer 15

Enzymatic proteins which activate or inactivate other proteins by phosphorylating them (adding a phosphate group to something)

Question 16

What are cyclins

Answer 16

A family of proteins who’s concentration varies in a cyclical fashion during the cell cycle. Ultimately these proteins control the progression of a cell through the cell cycle by activating cyclin-dependent kinases

Question 17

What are cyclin dependent kinases

Answer 17

Acts as the ‘go-ahead’ signal at checkpoints. They are kinases that require the presence of cyclins to be active.

Question 18

What are the checkpoints in the cell cycle

Answer 18

G1 - checkpoint
G2 - checkpoint
M - checkpoint

Question 19

What does a cell need to pass the G1 checkpoint

Answer 19

• sufficient number of organelles
• growth factors activation

Question 20

What does a cell need to pass the G2 checkpoint

Answer 20

• completely replicated genome
• no DNA damage
• large cell volume

Question 21

What does a cell need to pass the M checkpoint

Answer 21

equal distribution of chromosomes between new daughter cells

Question 22

What is the most important cell cycle checkpoint

Answer 22

G1 checkpoint

Question 23

What is the function of the G1 checkpoint

Answer 23

if the cell does not receive a go ahead signal they will not undergo cell division and will enter G0 (state of no division)