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LCRS - Neuroscience - Laz > The Molecules of Movement > Flashcards

Flashcards in The Molecules of Movement Deck (17)
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1
Q

What are the three types of molecular motor?

A

Linear
Oscillatory
Rotatory

2
Q

What is a molecular motor?

A

A protein assembly that converts chemical energy into mechanical energy.

3
Q

Give examples of protein rails that are used by linear motors.

A

Myosin uses actin. Kinesin and dynein use microtubules. Helicases and topoisomerases use DNA and RNA.

4
Q

Where are oscillatory motors found?

A

In cilia - they form cross-linked microtubule bundles called axonemes and are powered by dynein

5
Q

What are microtubules made up of?

A

Alpha and beta tubulin

6
Q

The microtubules are polarised. Which end is positive and which is negative?

A

Negative nucleus

Positive periphery

7
Q

What are the two motors that travel down these microtubules and which directions do they move in?

A

Kinesin - towards the positive

Dynein - towards the negative

8
Q

Give some features of F-actin.

A

It is inextensible, dual-stranded helix, and it is polar

9
Q

In which direction do myosin move along actin?

A

Move towards the positive end

10
Q

What does myosin consist of?

A

Two heavy chains and two light chains

11
Q

What type of myosin is found in a) muscle and b) brain?

A
Muscle = Myosin II
Brain = Myosin V
12
Q

What is the difference between myosin in muscle and myosin in the brain?

A

Myosin in the brain is processive - this means that the myosin is always in contact with the actin whereas in muscle the myosin can detach from the actin.

13
Q

What is the structure of myosin filaments?

A

Myosin filaments form anti-parallel dimers - so there is a region in the middle that doesn’t have any myosin heads and hence cannot form cross-bridges

14
Q

Describe the structure of kinesin.

A

Kinesin consists of two amino acid side chains.
The ends of the side chains have globular ATP binding heads
The heads interact with the microtubules and the tails hold the cargo

15
Q

Describe why kinesin is described as processive and myosin is not processive.
.

A

The kinesin is always in contact with the microtubule whereas the myosin an detach from the actin

16
Q

What is the largest of the three molecular motors?

A

DYNEIN

17
Q

Describe the structure of dynein.

A

Dynein consists of six tandemly linked AAA molecules within the head. They are MUCH BIGGER than kinesins.
NOTE: Dynein is an OSCILLATORY motor found in cilia