cytoskeleton and more

Question 1

What is a SNARE?

Answer 1

mediate vesicle fusion, that is, the fusion of vesicles with their target membrane bound compartments (such as a lysosome). The best studied SNAREs are those that mediate docking of synaptic vesicles with the presynaptic membrane in neurons.

Question 2

What is a CDK?

Answer 2

Of the many proteins involved in cell cycle control, cyclin-dependent kinases (CDKs) are among the most important. CDKs are a family of multifunctional enzymes that can modify various protein substrates involved in cell cycle progression.

Have to be bound to a cyclin to be active

concentration never changes in cell cycle

Question 3

What is macropinocytosis?

Answer 3

cell ruffles and invaginate molecuels it comes into contact with. non specific and non selective e.g. cancer cells

Question 4

3 fates after endocytosis?

Answer 4

1. targetted to lysosome and degraded
2. stored
3. trancsytosis

Question 5

How does cell get and make cholesterol form LDL?

Answer 5

LDL receptors produced that then cluster in a pit. Bind with LDL, internalised. Targeted to endosome via snares on vesicle
pH in early endosome = 6.5 so receptor lost
LDL to lysosome broken down and cholesterol then produced and put back in membrane

Question 6

Clathrin?

Answer 6

triskillion shape, 3 heavy 3 light, makes a cage and actin helps to bend membrane around it

Question 7

Dynamin?

Answer 7

pinches off the vesicle

Question 8

pH of early endosome and lysosome?

Answer 8

endo = 6.5 
lyso = 4.5

Question 9

Microtubules?

Answer 9

25nm

hollow, rigid, flagella. Alpha beta and gamma tubulin. alpha and beta lie end to end and form a protofilament and have same orientation. Plus end grows faster. grows with a GTP cap if removed it shrinks

roles in cell division, flagella structure

Question 10

organising centre?

Answer 10

made up of 2 centrioles with gamma tubulin around end of tubule for protection form depolarisation

Question 11

Microfiliment?

Answer 11

pure actin, 6 genes, 7nm, forms filament of actin and different proteins bid to give functions

Question 12

Intermediate filiments?

Answer 12

rope, strength, structure, 8-10nm, 5 subunits that are coil to coil. Can have more mutations as more genes than actin. Lack polarity

Question 13

Dynein?

Answer 13

• ended motor for retrograde transport binds indirectly via a protein called dynein complex

Question 14

Kinesin?

Answer 14

+ended motor for anterograde transport. Binds to cargo directly via a variable tail

Question 15

What happens to nucleur lamina in cell division?

Answer 15

dissasembles at prometaphase and is stored around cell in vesicles and then reassembled in telophase

Question 16

Role of astral?

Answer 16

to connect to cell membrane. anchored by dynein and pull spindles apart

Question 17

role of polar tubules?

Answer 17

slide past each other to move poles apart as they lengthen

Question 18

kinetechore?

Answer 18

attaches to centromere and align at metaphase plate

Question 19

axoneme? structure

Answer 19

central strand of cilia and flagella. 9 doublets of microtubules around an inner pair. dynein arms linking together so can slide past each other. nixes are the immobile proteins linking doublets

Question 20

basal body? structure

Answer 20

structure found at the base of a eukaryotic undulipodium (cilium or flagellum)
has a 9x3 array with a smaller diameter and acts as a centriole itself

Question 21

amoebiod movement?

Answer 21

membrane blebbing, detaches from actin cortex, hydrostatic pressure causes it to bleb forward, producing a fillipodia, forms new ECM adhesions using interns. get rid of adhesion proteins at rear of cell