CSF: cell division and cancer

Question 1

what makes up the miotic phase

Answer 1

mitosis plus cytokinesis

Question 2

4 stages of meiosis 1

Answer 2

• prophase
• metaphase
• anaphase
• telphase

Question 3

4 stages of meiosis 2

Answer 3

• prophase
• metaphase
• anaphase
• telophase

Question 4

whats the difference between meiosis 2 and mitosis?

Answer 4

mitosis is not preceded by DNA replication

Question 5

what are the three main parts of interphase

Answer 5

1. growth and gap phase 1
2. synthesis of DNA
3. Growth or Gap phase 2

Question 6

why do cells divide?

Answer 6

growth and development
tissue renewal
results in two ‘cloned’ daughter cells

Question 7

during interphase

Answer 7

DNA replicates

Question 8

during prophase

Answer 8

DNA condenses further in:

- two identical chromatids per chromosome - sister chromotids

Question 9

during metaphase

Answer 9

sister chromatids line up

Question 10

During anaphase

Answer 10

sister chromatids separate

Question 11

daughter cells are

Answer 11

identical to parent cell

Question 12

what are the points of mitotic checkpoints

Answer 12

Mitotic check points are molecules that check how the replication process is going
halt the reproductive process if DNA is faulty/damaged

Question 13

what are the mitotic cell points

Answer 13

M, G1, G2

Question 14

What are the key signals to pass G1

Answer 14

• undamaged DNA
• good cell size and nutrition
• appropriate signals are present

Question 15

What are the key signals to pass M

Answer 15

• all spindles are attached

Question 16

3 key molecules for G2 checkpoint

Answer 16

• cyclin
• cyclin dependant kinase
• M-phase promoting factor

Question 17

what is the function of cyclin

Answer 17

protein that fluctuates throughout the cell cycle

Question 18

what is cyclin dependant kinase (CDK)

Answer 18

kinase activated when attached to a cyclin

Question 19

what is M-phase promoting factor

Answer 19

• Cycling/CDK complex

- key for G2 checkpoint

Question 20

mutations in the cell cycle can cause what?

Answer 20

CANCER

Question 21

cancer causing DNA changes can be

Answer 21

• small scale alterations (point mutations)

- gain/loss/translocation of chromosomes/genes

Question 22

DNA changes can be results of

Answer 22

• aquired changes that target single cells i.e. carcinogens

- Inherited changes that target all cells - susceptibility genes

Question 23

cancer genes effected by DNA changes are (2)

Answer 23

• proto-oncogenes

- tumour supressor genes

Question 24

Proto-oncogenes function

Answer 24

stimulate cell proliferation

Question 25

tumour suppressor genes

Answer 25

genes that keep proliferation in check

Question 26

activation of proto-oncogenes is like?

Answer 26

pressing the accelerator

Question 27

deactivation of tumour suppressor genes is like

Answer 27

a loss of brakes

Question 28

Growth gap stage 1 (2 points)

Answer 28

- most cellular activities occur | - duration varies depending on cell type

Question 29

Synthesis of DNA (3 points)

Answer 29

- DNA replicates - strands separated at the hydrogen bonds holding nucleotides together - new strands of DNA synthesised as opposite of each old strand

Question 30

Growth Gap stage 2 (3 points)

Answer 30

- checks correct DNA synthesis - prepares for the miotic phase (synthesis of proteins and enzymes + gathering reactants) - replication of centrosomes is completed

Question 31

meiosis vs mitosis - property

Answer 31

meiosis - only diploid cells | mitosis - diploid and haploid

Question 32

meiosis vs mitosis - DNA replication

Answer 32

meiosis - during interphase, between meiosis 1 and 2 | mitosis - during interphase before mitosis begins

Question 33

Number of divisions in Meiosis

Answer 33

One inc. prop, prometa, meta, ana and telo

Question 34

number of divisions in Mitosis

Answer 34

Two inc. prop, meta, ana, telo

Question 35

synapsis of homologous chromosomes meiosis

Answer 35

occurs during phase 1 w/ crossing over between non-sister chromotids; resulting chiasmata hold pairs together due to sister chromatid cohesion

Question 36

synapsis of homologous chromosomes mitosis

Answer 36

does not occur

Question 37

meiosis vs mitosis - Number of daughter cells and genetic comp.

Answer 37

Meiosis - 4, each haploid (n); genetically dif from everything (parents and sisters) Mitosis - 2, identical to parents w same number of chromosomes

Question 38

3 sources of cellular variation

Answer 38

- independent assortment at metaphase - crossing over at metaphase - fusion between two gametes