Revision

Question 1

Which AAs are hydrophobic (part of ER signal sequence)? (7)

Answer 1

• Valine
• Isoleucine
• Alanine
• Leucine
• Methionine
• Phenylalanine
• Tryptophan

Question 2

Which hypothesis suggests that eukaryotic mitochondria evolved from early prokaryotes?

Answer 2

Endosymbiotic hypothesis

Question 3

What supports the Endosymbiotic hypothesis?

Answer 3

• Mitochondria have their own circular genome

- their ribosomes resemble the 70S ones found in bacteria rather than the 80S found in eukaryotes

Question 4

Which of the following diseases can be linked to the quality control function of the endoplasmic reticulum that retains misfolded proteins?
There is more than one correct option.
Answers:	
1. alpha 1-antitrypsin deficiency
2. Buruli ulcer
3. Familial Hypercholesterolaemia
4. Cystic fibrosis
5. Alzheimer's disease

Answer 4

• alpha 1-antitrypsin deficiency

- cystic fibrosis

Question 5

Two types of mutations located in the signal sequence of [x] are linked to Diabetes. In the one case the mutations perturb the interaction of the precursor protein with the [y] complex in the ER membrane and half of the newly made protein is not translocated. In the second case the protein is correctly translocated across the membrane but it does not [z] correctly inside the ER lumen.

Answer 5

x- insulin
y- sec61 translocon
z- fold

Question 6

What has been identified as the molecular basis for chylomicron retention disease?

Answer 6

mutation to Sar1b

Question 7

which part of the microtubule does EB1-GFP bind to?

Answer 7

+ end

Question 8

where are lamins found?

Answer 8

the nucleus

Question 9

where are neurofilaments found?

Answer 9

nerve cells

Question 10

where are cytokeratins found?

Answer 10

epithelial cells

Question 11

where are vementins found?

Answer 11

fibroblasts in connective tissue

Question 12

true or false: The mitotic spindle is comprised of actin filaments and myosin filaments.

Answer 12

false

Question 13

what’s the purpose of the hydrolysis of GTP to GDP carried out by tubulin molecules?

Answer 13

allows dynamic instability of microtubules

Question 14

What would you predict would happen to the kinesin-coated silica beads if you were to add AMP-PNP (a nonhydrolyzable ATP analogue)?

Answer 14

The beads would stop moving as one molecule of ATP is hydrolyzed per step taken by kinesin

Question 15

True or false: Microtubule-dependent motor proteins and microtubule polymerization and depolymerization are responsible for the organized movements of chromosomes during mitosis.

Answer 15

true

Question 16

True or false: The centromere nucleates a radial array of microtubules called an aster.

Answer 16

false

Question 17

true or false: Each microtubule-organizing center contains a pair of centrioles and hundreds of γ-tubulin rings that nucleate the growth of microtubules.

Answer 17

true

Question 18

True or false: Aster or astral microtubules interact with the cell cortex

Answer 18

true

Question 19

true or false: Kinetochore microtubules depolymerize to contribute to chromosome movement in anaphase A

Answer 19

true

Question 20

true or false: Interpolar microtubules are stabilised by interactions with each other via motor proteins

Answer 20

true

Question 21

true or false: Interpolar microtubules link chromosomes to a spindle pole

Answer 21

false

Question 22

true or false: Astral microtubules are required for separation of duplicated centrosomes

Answer 22

false

Question 23

why must the disassembly of the nuclear envelope happen in animal cells?

Answer 23

so kinetochore microtubules can form