cell replication

Question 1

What factors affect the rate of cell division?

Answer 1

system complexity
necessity for renewal
age
state of differentiation
tumour

Question 2

what does aneuploid mean?

Answer 2

abnormal chromosome number and content

Question 3

Why must cell division be regulated?

Answer 3

• premature, abnormal mitosis can cause cell death
• tumours = stations in oncogenes and tumour suppression genes and are also aneuploid
• contact inhibition of growth
• various cancer cell lines show chromosome instability (lose/gain whole chromosomes during cell division)
• perturbation of protein levels of cell cycle regulators is found in different tumours - abnormal mitosis

Question 4

What is the cell cycle?

Answer 4

orderly sequence of events in which a cell duplicates its contents and divides into 2

Question 5

What are the brief steps of the cell cycle?

Answer 5

duplication
division
co-ordination

(cell growth and chromosome replication, chromosome segregation and division)

Question 6

what is the most vulnerable period of the cell cycle and why?

Answer 6

mitosis: 
DNA damage cannot be repaired
Cells are more easily killed (irradiation, heat, shock, chemicals)
Gene transcription is silenced
Cell metabolism is low

Question 7

What is a centrosome?

Answer 7

its made up of 2 centrioles which are barrels of 9 triplet microtubules

Question 8

What is the function of centrosomes?

Answer 8

microtubule organising centre (MTOC)

formation of mitotic spindle

Question 9

structure of centrosome?

Answer 9

2 centrioles w rings of gamma tubular acting as nucleating sites on the outside - this is where microtubules grow

Question 10

What are the phases of the cell cycle?

Answer 10

unidirectional:
G1
S
G2
M 

G= gap
M=mitosis
s= synthesis

Question 11

What stages make up interphase?

Answer 11

G1, S, G2