Protein control of cell division

Question 1

What is the role of the cytoskeleton

Answer 1

It gives mechanical support and shape to cells

Question 2

What does the cytoskeleton consist of

Answer 2

Different protein structures including microtubules

Question 3

What are microtubules made of and where do they radiate from

Answer 3

Tubulin

The centrosome

Question 4

What do microtubules do

Answer 4

Control the movement of membrane-bound organelles and chromosomes

Question 5

What form the spindle fibres that are active during cell division

Answer 5

Microtubules

Question 6

What does interphase involve and name the phases

Answer 6

Growth and DNA synthesis
G1: growth
S phase: DNA is replicated
G2: further growth

Question 7

What phase makes up mitosis and cytokinesis

Answer 7

The mitotic (M) phase

Question 8

Describe prophase

Answer 8

DNA condenses into chromosomes
Nuclear membrane breaks down and spindle microtubules extend from centrosome and attach to chromosomes via their kinetochores

Question 9

What is a kinetochore

Answer 9

the region of centrosome that the spindle microtubules attach to

Question 10

What is metaphase

Answer 10

chromosomes align at the metaphase plate

Question 11

What is anaphase

Answer 11

spindle microtubules separate by depolymerisation

sister chromatids are separated, chromsomes are pulled to opposite poles

Question 12

What is telophase

Answer 12

chromosomes decondense and nuclear membranes are formed around them

Question 13

What is the purpose of checkpoints

Answer 13

Assess the condition of the cell during the cell cycle and halt profession to next phase until requirements are met

Question 14

What is the role of cyclins

Answer 14

They combine with CDK’s which phosphorylate proteins that regulate progression through the cycle. Progression is dependent on sufficient phosphorylation

Question 15

What the role of retinoblastoma protein in G1

Answer 15

Acts as a tumour suppressor by inhibiting the transcription of genes that code for proteins needed for DNA replication

Question 16

What is the role of the p53 protein

Answer 16

It responds to DNA damage by stimulating DNA repair, arresting the cell cycle or causing cell death

Question 17

What phase is the p53 protein produced/when is this checkpoint

Answer 17

G2

Question 18

Describe the metaphase checkpoint

Answer 18

Progression is halted until chromosomes are aligned correctly on the metaphase plate and chromosomes are attached properly to the spindle microtubules

Question 19

What is the cause of a degenerative disease

Answer 19

An uncontrolled reduction in the rate of the cell cycle

Question 20

What could be the cause of a tumour?

Answer 20

An uncontrolled increase in the rate of the cell cycle

Question 21

What is a proto-oncogene

Answer 21

a normal gene which can mutate to form a tumour promoting oncogene

Question 22

Name an example of apoptosis caused by external death signals

Answer 22

in response to death signal molecules from lymphocytes

Question 23

Name an example of apoptosis caused by internal death signals

Answer 23

in response to DNA damage

Question 24

what causes external death signal apoptosis

Answer 24

death signal binds to surface receptor protein, protein cascade within cytoplasm

Question 25

what causes internal death signal apoptosis

Answer 25

DNA damage causes the activation of the p53 protein

Question 26

How does apoptosis work

Answer 26

Activation of capsizes that cause destruction of the cell

Question 27

When might cells initiate apoptosis

Answer 27

in the absence of growth factors