Biology 2:cells - mitosis

Question 1

explain how chromosomes replicate

Answer 1

chromosomes duplicate forming sister chromosomes
mitosis occurs and two daughter b

Question 2

what are the 5 stages of cell division

Answer 2

g1 PHASE
s phase
g2 phase
m phase
G0 phase

Question 3

what are the phases in the interphase(90% of cell cycle)

Answer 3

g1
s phase
g2

Question 4

what happens in g1

Answer 4

cell increases in size
and produces more proteins to prepare to divide

Question 5

what happens in the s phase

Answer 5

duplication of dna for division

Question 6

what happens in g2

Answer 6

cell grows rapidly and synthesises more proteins
checks for any damage in dna

Question 7

what happens in g0

Answer 7

cell stops dividing once they are fully grown and differentiated

Question 8

state the stages in mitosis

Answer 8

interphase
prophase
metaphase
anaphase
telophase

Question 9

what happens in the interphase and prophase

Answer 9

dna duplicates to form sister chromatids

nucleus starts to disintergate and chromosomes condense

Question 10

what ahppens in the metaphase and anaphae

Answer 10

spindles are formed and chromosomes line up in the middle

chromosomes are pulled apart at centromeres to poles

Question 11

what happens in telophase and cytokinesis

Answer 11

chromosomes are now at opposite ends

cytoplasm splits to make 2 new daughter cells

Question 12

where in the cell cycle does checkpoints occur

Answer 12

g1 g2 m(metaphase)

Question 13

why is there a checkpoint in g2

Answer 13

that dna has been replicated properly in s phase

Question 14

why is there a checkpoint in mitosis

Answer 14

metaphase checks all chromosomes are lined up

Question 15

what genes control mitosis

Answer 15

oncogenes

Question 16

what happens if the oncogenes mutate

Answer 16

cell cycle can run too fast or too slow which results in a ball of genes(tumors)

Question 17

how does chemotherapy drugs work

Answer 17

interfere with the control of cell cycle by blocking the s phase
or interferes with spindle formation in metaphase

stops tumours form growing uncontrollably

Question 18

why doesnt bacteria do mitosis(3 reasons why)

Answer 18

doesnt have a separate chromosome and nucleus
doesn’t have loads of chromosomes
so they don’t need to divide carefully

Question 19

how does binary fission work(5 things)

Answer 19

replicates circular pieces of dna (nucleoid)
replicates plasmids
cell lengthens
cytoplasm divides(cytokenisis)
new cell wall formed where cytoplasm is divided

Question 20

name 3 reasons why binary fission is different to mitosis

Answer 20

daughter cells are not always genetically identical - because there could be an uneven distribution if organelles

variation in the number of plasmids copied

sometimes nucleoid doesn’t separate properly so only one cell of DNA