Eukaryotic Cell Cycle

Question 1

What do multicellular eukaryotes depend on cell division for?

Answer 1

Development from a fertilised egg, growth and repair

Question 2

What does mitosis result in?

Answer 2

2 daughter cells with identical genetic information (dna)

Question 3

Meiosis?

Answer 3

Yields non identical daughter cells that have half as many chromosomes as the parent cell

Question 4

What are the sub phases of interphase?

Answer 4

90% if cell cycle is interphase
G1- cells grow
S-DNA synthesis (chromosome and centrosome duplicate)
G2- organelles replicate and chromatin begin to condense

Question 5

What does the mitotic phase include?

Answer 5

Prophase
Metaphase
Anaphase
Telophase

Question 6

What happens in prophase?

Answer 6

Chromosomes condense (become visible)
Centrosome assemble (2centrosomes move away from each other)

Question 7

Metaphase?

Answer 7

Spindle forms
Nuclear membrane breaks down
Chromosomes align on spindle equator

Question 8

Anaphase ?

Answer 8

Chromatid seperate, each chromatid moves to opposite poles of the cell

Question 9

Telophase?

Answer 9

Chromosome decondenses (can’t see it anymore)
New nuclear membrane forms
Formation of 2 new cells

Question 10

What’s the mitotic spindle made of ??

Answer 10

Microtubules that control chromosome movement during mitosis

Question 11

In animal cells assembly of spindle microtubules begins where?

Answer 11

The centrosome (microtubules organising structure)

Question 12

What happens to the centrosomes during interphase?

Answer 12

They replicate so there’s 2 centrosomes that migrate to opposite ends of the cell during prophase and prometaphase

Question 13

What’s cytokinesis ?

Answer 13

Cytoplasm seperation

Question 14

What is the cell cycle controlled by?

Answer 14

Cell cycle control system (clock) this is regulated by internal and external factors
The clock has specific checkpoints where the cell cycle stops until a go-ahead signal is received

Question 15

What are checkpoints in the cell cycle?

Answer 15

M checkpoint- anaphase is blocked if chromatids aren’t properly assembled on mitotic spindle
G1- checkpoint- entrance into S is blocked if genome is damaged
S checkpoint- Dna replication is halted if genome is damaged
G2 checkpoint- entrance into m is blocked if DNA rep isn’t completed

Question 16

Controls of the cell cycle?

Answer 16

-cyclins:
Control G1, S and M phase

CDKs:

APC

Question 17

Disruption of the cell cycle leads to?

Answer 17

Dysregulation of the cell cycle is common (uncontrollable growth): leads to tumours
Increased levels of CDK and cyclins and common in tunours such as breast and brain tumours
Inhibition of certain CDKs has been shown to inhibit tumour cell growth, induce apoptosis and cause tumour regression