Lecture 4

Question 0

What are stress fibres?

Answer 0

Stretch from one end of the cell to the other

Important for cell shape and permit the cell to attach to the surface over which it is moving (the cortex)

Question 1

What are the advantages of using GFP?

Answer 1

fuse with other proteins to form a hybrid without disrupting its ability to show up green under uv light so. can be used as a tag and also does not disturb the function of the protein it is bound to
can do it in living cells
can produce colour variants

Question 2

How many actin filaments are contained in a stress fibre?

Answer 2

5-10

Question 3

What was does actin switch between G-actin and F-actin

Answer 3

Using
ions e.g the calcium pathway
actin binding proteins
ATP

Question 4

Describe the action of profilin

Answer 4

Can mind to G-actin and prevent it from polymerisation but can also promote pokymerisagion depending in conditions

Question 5

Describe the actin binding protein Vilin

Answer 5

polymerises actin forming parallel fibres but can also sever these depending on conditions

Question 6

Describe the action binding proteins fimbrin/fodrin and filaman

Answer 6

they bundle and. ross link actin filaments into stress fibres

Question 7

Describe the actin binding proteins viniculin and alpha actinin

Answer 7

caps the ends of the filaments and binds them to the membrane allowing them to make contact with the surface over which it moves

Question 8

Describe the abp gelosin

Answer 8

severs filaments when they are no longer needed

Question 9

Describe the abp myosin

Answer 9

allows movement of other proteins along actin filaments

Question 10

What are adhesion plagues in fibroblasts?

Answer 10

Point of contact with the cell surface

Question 11

What are micro spikes in fibroblasts?

Answer 11

Goes out in the direction the cell wants to move

once it’s formed contains actin microfilaments along it with v and alpha a

Question 12

what is the process of the fibroblast moving called

Answer 12

ruffling as it looks like a wave

Question 13

What are the two types of cytoplasm in an amoeba

Answer 13

gel on the outside which contains polymerised actin

and sol on the inside which contains g actin

Question 14

How does amoeba carry out the switch between g actin and f actin

Answer 14

Creates pseudopods
converts sol to gel using FF and F
converts gel to sol using gelsolin and Vilin

Question 15

What controls the abps?

Answer 15

The ca2+ concentration e.g Vilin will either polymerise or sever depending on this
the ph