mitosis

Question 1

what is the definition of mitosis?

Answer 1

the division of nuclear genetic material

Question 2

what is cytokinesis?

Answer 2

the division of the cytoplasm to form two identical daughter cells

Question 3

what are the stages of the cell cycle?

Answer 3

G1
S
G2
M

Question 4

what is the G1 phase?

Answer 4

gap phase 1

Question 5

what is the S stage?

Answer 5

synthesis stage - replication

Question 6

what is the G2 stage ?

Answer 6

gap phase 2

Question 7

what is the M phase?

Answer 7

mitosis and cytokinesis

Question 8

what do K-fibres do?

Answer 8

they also shrink to pull chromatids apart

Question 9

what happens in the G1 phase?

Answer 9

the cell decides it wants to divide

Question 10

what happens during the S phase?

Answer 10

the genome is duplicated and chromosomes are replicated to give two sister chromatids

Question 11

what happens during the G2 phase?

Answer 11

checks occur to ensure there were no mistakes made during chromosome duplication

Question 12

what happens during the M phase?

Answer 12

mitosis - the division of the nuclear genetic material and transport into the daughter cells

Question 13

what are the signals for division in the G1 phase?

Answer 13

external and internal

Question 14

what are external signals for cell division?

Answer 14

growth factors, cell density

Question 15

what are internal signals for cell division?

Answer 15

sufficient cellular resources
DNA duplicated
absence of DNA damage

Question 16

what are the stages of the S phase?

Answer 16

chromosomes are duplicated and condensed
the chromosomes are aligned on the equator of the cell
the chromosomes are moved to the daughter cells

Question 17

what happens during open mitosis?

Answer 17

the nuclear envelope breaks down during division

Question 18

what happens during closed mitosis?

Answer 18

the nuclear envelope stays intact and division takes place within the envelope

Question 19

how are chromosomes moved?

Answer 19

mitotic spindle

Question 20

what are mitotic spindles made of?

Answer 20

microtubule filaments

Question 21

what are microtubule filaments made of?

Answer 21

alpha and beta tubulin dimers which polymerise to form hollow tubes

Question 22

how are the mitotic spindles organised?

Answer 22

centrosomes

Question 23

what do the centrosomes consist of

Answer 23

2 centrioles

Question 24

what happens to the centrosome during the S phase?

Answer 24

duplicate and divide and form new spindle

Question 25

what are the three different types of microtubule within spindle?

Answer 25

interpolar aster K- fibres

Question 26

what do interpolar microtubules do?

Answer 26

they stabalise and elongate the spindle during mitosis

Question 27

what do the aster microtubules do?

Answer 27

stabalise and orientate the spindle at the cell cortex

Question 28

where do the microtubules attach to the chromosomes?

Answer 28

the centromere

Question 29

what are kinetocores?

Answer 29

the protein cmplexes that mediate microtubule - DNA attachment

Question 30

what do the K-fibres do in order to pull the chromatids apart?

Answer 30

shrink

Question 31

what is the cleavage furrow?

Answer 31

the divide between two daughter cells by a contractile ring

Question 32

what does the contractile ring consist of ?

Answer 32

actin and myosin

Question 33

what is the midbody?

Answer 33

the mark left on a divided cell by the contractile ring squeezing the spindle

Question 34

why can the midbody be important to the cell?

Answer 34

it can be a cell marker

Question 35

what happens during prophase?

Answer 35

spindle begins to form aster will for on both sides of the spindle the interpolar MT will extend to make the spindle longer the chromosomes will start to condense and the 2 sister chromatids are visible together and attached to each other

Question 36

what happens during prometaphase?

Answer 36

the nuclear envelope starts to fragment | the mitotic spindle is formed and the Kfibres have attached to the 2 sister chromatids

Question 37

what happens during metaphase?

Answer 37

the chromosomes are lined along the metaphase plate

Question 38

what happens during anaphase?

Answer 38

the chromosomes are pulled towards the poles of the cell

Question 39

what happens during telophase?

Answer 39

the nuclear membrane begins to reform

Question 40

which enzymes drive the cell cycle?

Answer 40

CDK's - cyklin dependant kinases

Question 41

what controls the beginning of M phase?

Answer 41

CDK's

Question 42

how do CDK's work?

Answer 42

they require cyclin to bind to them in order to be activated and carry out phosphorylation. these phosphorylation event can be used as signals to drive the cell cycle.

Question 43

what are the stages of binary fission within bacterial cells?

Answer 43

chromosome replication begins one copy of the origin is now attached at each end of the cell replication finishes

Question 44

how do bacterial cells know where to divide?

Answer 44

YFP-MinD protein indicates the centre of the cell for the bacteria