3.8 The cell cycle

Question 1

Define cancer

Answer 1

A group of diseases caused by a growth disorder of cells.
It is the result of damage to the genes that regulate mitosis and the cell cycle.This leads to uncontrollable cell growth

Question 2

What is a malignant tumour

Answer 2

A rapid growing tumour which is more likely to be life threatening as they can spread across the body
Cancerous

Question 3

What is a benign tumour

Answer 3

A slower growing tumour that stayes in one place they are also more compact
Non cancerious

Question 4

How is cancer treated

Answer 4

By blocking a part of the cell cycle (chemotherapy)

Question 5

How does chemotherapy disrupt the cell cycle

Answer 5

Prevents DNA from replicating
Inhibiting the metaphase stage of mitosis by interferring with spindle formation

Question 6

What is the problem with drugs like chemo

Answer 6

It also disrupts the cell cycle of normal cells
Chemo targets the cells that rapidly divide like cancer cells but this also attacks hair cells as they also divide rapidly

Question 7

Suggest hiw cancer treatments control the rate of cell division

Answer 7

*Some disrupt the spindle fibre activity/formation
-This is so chromosomes cant attach to spindle by thier centromere
-so chromatids cant be separated to opposite poles (no anaphase)
-So prevents/ slows mitosis
*Some prevent DNA repliation during interphase
-So cant make 2 copies of each chromosome
-So prevents/slows mitosis

Question 8

Describe hjow tumors and cancers form

Answer 8

● Mutations in DNA / genes controlling mitosis can lead to uncontrolled cell division
● Tumour formed if this results in mass of abnormal cells
○ Malignant tumour = cancerous, can spread (metastasis)
○ Benign tumour = non-cancerous

Question 9

What are the phases in Interphase

Answer 9

G1-Growth
S-DNA synthesis
G2-Growth and preparation for mtosis DNA that has been prepared is checked for mutations cell is destoryed if there is a mutation

Question 10

What ar ethe three broad stages in the cell cycle

Answer 10

Interphase-Organelles double,The cell grow and DNA replciates
Nuclear division-Creates two identical diploid cells or meiosis creating 4 differnet haloid cells. Mitosis creates cells with identical DNA for growth and repair where as meiosis creates gametes
Cytokinesis-Division of the cytoplasm to create the new cells