Cells - Mitosis

Question 2

What are 3 uses of mitosis?

Answer 2

Growth of tissues

Repair of damaged tissue

Formation of clones of lymphocytes

Question 3

Define chromatin

Answer 3

The state of DNA when it isn’t wound up tightly as a chromosome

Question 4

Define a chromosome

Answer 4

Compact X or I shaped form of chromatin formed during cell division

Question 5

Define chromatids

Answer 5

The 2 identical arms of an X shaped chromosome

Question 6

Define centromere

Answer 6

The point at which chromatids are joined

Question 7

Define homologous chromosomes

Answer 7

2 chromosomes originating from the same parent, containing the same genes but different alleles

Question 8

Define a centriole

Answer 8

Centriole are organelles that pull chromatids apart during cell division

Question 9

Define the spindle apparatus

Answer 9

A group of spindle fibres that divides genetic material in a nucleus

Question 10

What are the 6 stages of the cell cycle

Answer 10

Interphase

Prophase

Metaphase

Anaphase

Telophase

Cytokinesis

Question 11

Describe the interphase

Answer 11

Not strictly part of mitosis

The cell grows and DNA replicates

Chromosomes aren’t visible

Question 12

Describe the prophase

Answer 12

Chromosomes condense and become visible

Centrioles move to opposite poles of the cell

Spindle apparatus form from spindle fibres at the centriole

Question 13

Describe metaphase

Answer 13

Nuclear envelope breaks

Chromosomes align along equator of the cell -> pulled by spindle apparatus

Question 14

Describe anaphase

Answer 14

Centromeres split, allowing chromatids to separate

Chromatids move towards poles, pulled by spindle fibres

Question 15

Describe telophase

Answer 15

Spindle fibres disperse

Nuclear envelopes reform

Chromosomes decondense

Question 16

Define cytokinesis

Answer 16

A ring of protein filaments form around equator of cell, which then tightens and splits the cell into 2

Question 17

How is cell division regulated?

Answer 17

There are checkpoints between each stage of the cell cycle, regulated by control genes

Question 18

What is the effect of mutated control genes?

Answer 18

Cells dividing uncontrollably -> leading to tumours

Question 19

Define a benign tumour

Answer 19

Slow growing Doesn’t spread to other parts of the body Not classed as cancer

Question 20

Define a malignant tumour

Answer 20

Fast growing Often spreads throughout the body Classed as cancer

Question 21

Name 5 lifestyle changes the can prevent cancer

Answer 21

Smoking

Diet (high fat, low fibre)

Obesity

Physical activity

Sunlight

Question 22

Name 3 treatments for tumours

Answer 22

Surgery

Radiotherapy

Chemotherapy

Question 23

Name the 4 types of chemotherapy functions

Answer 23

Blocking enzymes in DNA synthesis

Preventing DNA unwinding

Inhibiting synthesis of new nucleotides

Preventing development of the mitotic spindle