Week 12

Question 1

does DNA replication occur in mitosis?

Answer 1

NO, happens in S phase

Question 2

is M phase just mitosis?

Answer 2

NO, has mitosis (nuclear division) AND cytokinesis (cytoplasmic division)

Question 3

do all body cells divide?

Answer 3

NO! some don’t, all depends on kind
- mature cells
- RBCs
- only under certain stimulus

in G0 phase, NOT DEAD just not dividing

Question 4

G0

Answer 4

cycle exit
resting
doing it’s thing, metabolically active

Question 5

major checkpoints

Answer 5

start - enter S phase?
G2/M - enter mitosis? is DNA okay?
metaphase-to-anaphase transition or SAC (spindle assembly checkpoint) - are all chromosomes properly attached to mitotic spindle?

Question 6

how to pass checkpoint

Answer 6

specific Cdk (cyclin-dependant protein kinase) and specific cyclin to phosphorylate proteins

Question 7

what can a problem in checkpoint cause?

Answer 7

chromosome segregation defects, like always getting green light

Question 8

cohesin protein

Answer 8

holds together sister chromatids

Question 9

centriole

Answer 9

9 fibrils of 3 microtubules each

Question 10

centrosome matrix

Answer 10

pericentriolar containing material (PCM)
gama tubuline ring complexes

Question 11

astral microtubules

Answer 11

position spindle, push apart cell membrane

Question 12

interpolar microtubules

Answer 12

cross linked

Question 13

what separates metaphase and anaphase

Answer 13

spindle assembly checkpoint

Question 14

kinetochore

Answer 14

between microtubules and chromosome

Question 15

kinetochore microtubules bundles

Answer 15

20-30 microtubules

Question 16

anaphase

Answer 16

separase activated that cuts cohesin complex and separates sister chromatids

Question 17

metaphase

Answer 17

chromosomes lined up

Question 18

what pulls apart chromosomes in anaphase A and B?

Answer 18

A: lose GTP cap so plus ends of kinetochore microtubules gets shorter and cytoplasmic dynein removing stuff on minus end

B: poles pushed apart by kinesin

Question 19

telophase

Answer 19

still some interdigitation - overlapping microtubules

mitotic spindle disassembles, nuclear envelope reassembles, chromosomes decondense

Question 20

phosphatases

Answer 20

remove specific phosphate groups (nuclear and lamins)

Question 21

cytokinesis in animal cells

Answer 21

contractile ring of actin and myosin

Question 22

prophase

Answer 22

chromosomes condense