The Cytoskeleton

Question 0

Name five functions of the cytoskeleton

Answer 0

1. Provide structure and support
2. Intracellular transport
3. Hold organelles in place
4. Generate force for cell movement
5. Helps in cell division

Question 1

What is the difference between dynein and kinesin motors?

Answer 1

Kinesins move toward +end of Microtubules (to cell membrane)

Dyneins move toward -end of Microtubules (toward centriole)

Question 2

What bonds are not present in Microtubules?

Answer 2

Covalent bonds

Question 3

What bonds and/or forces will be present in cytoskeletal fibre assembly?

Answer 3

Ionic bonds
Hydrogen bonds
van der Waals forces

Question 4

What is the energy source and binding site in tubular subunits?

Answer 4

GTP

Question 5

What is the energy source of micro filaments?

Answer 5

ATP

Question 6

Do micro filaments have polarity?

Answer 6

Yes

Question 7

Do intermediate filaments have polarity? Why?

Answer 7

The a-helical monomer and the b-helical are coiled together anti parallel, giving a neutral charge

Question 8

Which of the cytoskeletal fibres requires no energy to assemble?

Answer 8

Intermediate filaments

Question 9

What can be carried in the vesicles by motor proteins? (5)

Answer 9

Organelles, proteins, enzymes, neurotransmitters, and pigments

Question 10

How are motor proteins powered?

Answer 10

ATP

Question 11

In the flagella, what linker protein holds the doublets together? It allows the Microtubules that have slid over to pull back

Answer 11

Nexin

Question 12

What motor protein allows Microtubules to slide over each other in the flagella and cilia?

Answer 12

Dynein

Question 13

How many double Microtubules surround the middle two in a flagellum or cillum?

Answer 13

9

Question 14

What does the ECM primarily consist of?

Answer 14

Things secreted by the cell

Question 15

What is an important component of the ECM, of which collagen is a member?

Answer 15

Glycoproteins

Question 16

What are some of the functions of the ECM?

Answer 16

Can form complex structures outside the cell
Cell adhesion
Embryonic development

Question 17

Why is collagen valued?

Answer 17

Because of its great tensile strength and elasticity

Question 18

What determines the consistency of the ECM?

Answer 18

The amount of proteoglycan layers and the number of linkages it has with polysaccharide molecules

Question 19

When will the consistency of the ECM be jelly like?

Answer 19

High amounts of linkages between proteoglycans and the polysaccharides because those trap lotsa water

Question 20

What glycoprotein is responsible for anchoring the ECM to the cell?

Answer 20

Fibronectin

Question 21

How does Fibronectin anchor the ECM to the cell?

Answer 21

One end acts as a barbed hook that anchors in the ECM, and the other side threads through membrane proteins called integrins. It then binds to micro filaments on the other side.

Question 22

How do the integrins determine how well the ECM holds to the cell?

Answer 22

By how many there are

Question 23

What are Matrix Metallo - Proteins?

Answer 23

These guys produce and degrade the ECM allowing the cell to move

Question 24

Where are intermediate filaments found?

Answer 24

Form cage around the nucleus and are underneath the plasma membrane

Question 25

Which of the Tubulin dimers has its active site covered?

Answer 25

Alpha

Question 26

What is a single row of heterodimers assembled in a single row called?

Answer 26

Protofilament

Question 27

What are the Microtubules that attach to the chromosomes and pull them apart?

Answer 27

Kinetocore Microtubules

Question 28

What is the finger like projection at the end of a neuron called?

Answer 28

Filopodium

Question 29

What is the web like portion at the end of a neuron called?

Answer 29

Lamellipodia