Lecture 12: cell division

Question 1

what are the 3 AAs that can accept phosphate group

Answer 1

serine
Tyrosine
Threonine

All with oh group

Question 2

What are Cdks

Answer 2

kinases that phosphorylate key proteins to control their function

Mcd is the one important in cell division

Question 3

What does M phase consist of

Answer 3

mitosis
Cytokinesis

Question 4

Stages of mitosis

Answer 4

prophase
Prometaphase
Metaphase
Anaphase
Telophase
Cytokinesis

Question 5

3 things that happen in interphase before cell div

Answer 5

dna is replicated
Cell grows in size (organelles and stuff)
Centrosome is duplicated

Question 6

What are sister chromatids held together by

Answer 6

cohesion rings
Stay together until ANAPHASE

Question 7

Three types of mixrotubule

Answer 7

Kinetochore MTs
Interpolar MTs
Astral MTs

Question 8

What causes the MT to be more dynamic

Answer 8

MAPs get inactivated via phosphorylation by M-Ckd so the MT is less stable

And some proteins that trigger ‘catastrophe’ are activated too by phosphorylation via M Cdk

Question 9

What is condensin

Answer 9

protein activated by MCdk
Allows chromosomes to condense

Question 10

Consequence of MCdk phosphorylatign nulclear lamins

Answer 10

inactivates them
Causing nuc envelope to disassemble

Question 11

What does Eg5 do in prophase

Answer 11

is a kinesin
Pushes centrosomes apart
Forms spindle poles
Also, stabilises the interpolar spindle

Question 12

what is diff about Eg5 compared to normal kinesin

Answer 12

has homotetrameric head
So, 4 instead of 2

Question 13

What marks the transition between prophase to prometaphase

Answer 13

nuclear envleopl dissasembles
Via disassembly of nuclear lamina (except in plants, they have other ways to disassemble envelope but don’t need detail)

Question 14

When do nuclear envelope and lamina reassemble

Answer 14

telophase

Question 15

Alongside the nuclear envelope, what else goes through disassembly

Answer 15

golgi apparatus
Fragments so that the daughter cell gets equal amou ts of golgi rather than one getting it all and the other getting none

Question 16

What process stops during mitozis

Answer 16

secretion and endocytosis

Question 17

Where are kinetochores

Answer 17

On centromere of chromosome

Question 18

What connects the MT to the kinetochore

Answer 18

dynamic linker proteins

Question 19

Why is dyenin and kinesin important at the kinetochore

Answer 19

allow kinetochore to move along the attached MT towards either pole

Kynesin = towards + end
Dyenin = towarxs -ve end - this is where depolymerisation would happen

Question 20

What is created when the MT at either side of chromatid (attached to kinetochore) grow and shrink

Answer 20

mostly co-ordinated movement
But there’s still some completion in which way it moves
Which creates TENSION
And this signals to the cell to control progression to anaphase