2nd half Term 1 Cell Biology cytoskeleton - Microtubules

Question 1

Define doublet

Answer 1

9 x 2 structure

Question 2

Define triplet

Answer 2

9 x 3 structure

Question 3

Describe single non-motile cilia

Answer 3

1 non-moving cilia per cell, almost in all cells in body

Question 4

Describe single motile cilia

Answer 4

sensory organs, transport physical impulses (light, odour)

Question 5

Describe multiple motile cilia

Answer 5

respiratory system, fallopian tube, thousands per cell, co-ordinated pattern beating, move liquid

Question 6

describe function of beating cilia

1. power stroke
2. recovery stroke

Answer 6

1. power = moves liq. out
2. goes back in position, w/out moving liq.

Question 7

what do the three structures of kinesins and dyneins do:

1. Globular heads
2. Coiled stalk
3. Light chain

Answer 7

1. bind to MT
2. flexibilty
3. attach cargo

Question 8

what is the base of cilia and flagella?

Answer 8

Basal body (triplet)

Question 9

Describe 2 main functions of centriole and centrosomes

Answer 9

1. Nucleation point for MT joining together and stabilising -ve end
2. 1 centrosome for mitosis

Question 10

Describe the structure and shape centrioles

Answer 10

1 triplet, cylinder

Question 11

Describe the location of centrosomes

Answer 11

near the Golgi, surrounded by pericentriolar material.

Question 12

Decribe the arrangement of centrioles and centrosomes

Answer 12

perpendicular arrangement

Question 13

what makes up a centrosome

Answer 13

2 centrioles

Question 14

Define ciliopathies (caused by mutations in kinesin and dynein

Answer 14

genetic disorder that fx cellular cilia/ the cilia anchoring structures, the basal bodies/ ciliary func.

Question 15

Give the role of gamma tubulin complex

Answer 15

helps protect -ve end of MTs asscociated with MTOCs (MT organising centre)

Question 16

what is a protofilament

Answer 16

a linear polymer in MTs (i.e. each vertical column of heterodimers)

Question 17

Where are doublets found in cell organelles

Answer 17

Doublets are found in cilia and flagella;

Question 18

Where are triplets found?

Answer 18

triplets are found in basal bodies & centrioles.

Question 19

Define nucleation

Answer 19

process by which new MTs can grow from ogliomers (which act as seeds for new MTs to grow from)

Question 20

What does MT growth depend on

Answer 20

Microtubule growth in vitro depends on the concentration of tubulin dimers.

Question 21

Define overall nucleation point

Answer 21

MT assembly is exactly balanced with disassembly , I.e MT assembly = MT disassembly

Question 22

What often gets anchored at the centrosome ?

what are MT dynamics confined to in certain cases?

Answer 22

• minus ends of MTs are often anchored at the centrosome;
• MT dynamics are confined to plus ends.

Question 23

What is treadmilling

Answer 23

What’s Produced from simultaneous assembly and disassembly of MTs

Question 24

What type of cells does treadmilling occur in?

Answer 24

Living cells

Question 25

WHat does the alpha and beta tubulin do to GTP

Answer 25

Each bind to one GTP molecule

Question 26

WHat do growing MTshave at their plus ends versus shrinking MTs at their - ends?

Answer 26

Growing MTs have **GTP** Shrinking have **GDP**