Cell Division

Question 1

Reasons

Answer 1

reproduction, growth and development and tissue renewal

Question 2

chromosomes before division

Answer 2

DNA replicated and chromosomes condense, 2 sister chromatids joined at centromere

Question 3

Stages of cell cycle

Answer 3

G1, S, G2 and mitosis

Question 4

G1

Answer 4

Cell prepares to divide, grows, produces organelles and proteins needed for division and checkpoint at end

Question 5

G1 checkpoint

Answer 5

Checks if cells big enough, no damage to DNA and if external environment is favourable for S ohase

Question 6

cell doesn’t pass G1 checkpoint

Answer 6

Enters G0, stays here permanently or re-enters cell cycle once problems resolved

Question 7

S

Answer 7

DNA replication and repair

Question 8

G2

Answer 8

DNA organised and condensed, microtubules assembled and chromosomes aligned on mitotic spindle, checkpoint at end

Question 9

G2 checkpoint

Answer 9

Checks if cell has all structures needed for division and for DNA damage

Question 10

what happens if cell doesn’t pass G2 checkpoint

Answer 10

Tries to repair DNA, reparable = re-enters cell cycle and irreparable = apoptosis

Question 11

M

Answer 11

Mitosis, cell division

Question 12

Stages of mitosis

Answer 12

Prophase, prometaphase, metaphase, anaphase, telophase and cytokinesis

Question 13

Checkpoints in cell cycle

Answer 13

G1, G2 and metaphase-to-anaphase transition

Question 14

Prophase

Answer 14

Early mitotic spindle formed and sister chromatids joined at centromere

Question 15

Prometaphase

Answer 15

Nuclear envelope fragmented and mitotic spindle attaches to centromeres

Question 16

metaphase

Answer 16

chromosomes line up along equator, spindle fibres connect to chromosomes and metaphase-to-anaphase checkpoint where checks all chromosomes attached to spindle

Question 17

anaphase

Answer 17

mitotic spindle contracts and sister chromatids pulled to opposite ooles

Question 18

telophase

Answer 18

Nuclear envelopes reform, nucleolus reforms, spindle fibres disappear and chromosomes decondense

Question 19

Cytokinesis

Answer 19

Cleavage furrow splits cytoplasm and division of cytoplasm and organelles

Question 20

How is Cdk activity regulated

Answer 20

Cyclins as only active if bound to a cyclin

Question 21

Cdks in the cell cycle

Answer 21

Activities increase and decrease throughout cycle, G2/M checkpoint Cdk activity increases to phosphorylate proteins and also controls DNA condensation, nuclear envelope degradation and spindle assembly