Final: Mitosis

Question 1

What happens in Anaphase A and what is it driven by?

Answer 1

separate sister chromatids or homologous chromosomes and move them apart
driven by shortening of kinetochore MTs

Question 2

What happens in Anaphase B

Answer 2

spindle poles move apart resulting in elongation of spindle

Question 3

What does securin do?

Answer 3

regulates timing of sister chromatid separation
acts as an inhibitor of separase (prevents separase from cleaving until the right time)

Question 4

What is the key target of APC/C?

Answer 4

Securin

Question 5

What does separase do? How is it activated?

Answer 5

cleaves Scc1 subunit of cohesin molecules
when APC/C degrades securin

Question 6

What does Cdc20 do?

Answer 6

activates APC/C and targets S and M phase cyclins for degradation

Question 7

How do cells return to interphase?

Answer 7

Mad and Bub need to get off Cdc20 so it can bind to APC/C

Question 8

What happens to the nuclear envelope when MTs are inhibited?

Answer 8

it doesn’t break down

Question 9

What does inhibiting polymerization lead to?

Answer 9

mitotic arrest

Question 10

What does dynein do?

Answer 10

anchoring force to keep towards plasma membrane

Question 11

What happens to MT ends as they enter the Ran-GTP zone near chromosomes?

Answer 11

stabilized

Question 12

When is separase inactive?

Answer 12

when interacting with securin

Question 13

What does Cohesin do and when?

Answer 13

holds together sister chromatids after DNA replication until separation is triggered