7.2 Microfiliments I

Question 1

What is the general structure of an actin monomer?

Answer 1

Actin is small, globular.

When not polymerized, actin is in the form of a monomeric, globular “G-actin”

Question 2

Actin polymers resemble a _____.

Answer 2

twisted filament.

When assembled, actin is known as “F-actin”

Question 3

Mlb, MreB and ParM

Answer 3

Prokaryotes contain these proteins that resemble actin and may be evolutionary actin precursors

Question 4

Mutation in Mlb alters the bacterial _______ .

Answer 4

Shape

Question 5

Actin assembly is energy dependent and requires ______ .

Answer 5

Bound ATP

Question 6

Actin exhibits _____ assembly of monomers.

Answer 6

Polarized

Question 7

Actin assembly occurs preferentially at the ___ end.

Answer 7

+ end

Question 8

Can actin filaments exhibit treadmilling?

Answer 8

yes

Question 9

Profilin and Thymosin

Answer 9

Regulation of actin assembly. They are actin sequestering proteins.

Question 10

Actin related protein (ARP2/3) nucleates branched actin meshwork assembly in the ______.

Answer 10

Lamellae structure

Question 11

Actin is severed by _____ .

Answer 11

Gelsolin

Question 12

Actin disassembly is promoted by the protein ______ .

Answer 12

Cofilin

Question 13

Actin capping proteins stabilize…

Answer 13

The + filament ends so that growth only occurs at the - end