Cytoskeleton

Question 1

What are the components of the cytoskeleton? AIM

Answer 1

1. actin microfilaments 2. intermediate filaments 3. microtubules

Question 2

What is the cytoskeleton?

Answer 2

proteins that provide shape to the cell

Question 3

What are the functions of the cytoskeleton?

Answer 3

1. transportation of vesicles 2. motility e.g. sperm 3. structure 4. anchoring organelles

Question 4

What movements do the cytoskeleton aid in?

Answer 4

1. movement of cell organelles 2. movement of cell

Question 5

Actin Filaments

Answer 5

thin and flexible - 7 nm

Question 6

Structure of actin filaments?

Answer 6

each filament is a twisted chain of identical globular actin molecules

Question 7

Funtions of actin filaments?

Answer 7

1. in contractile ring 2. pull cell into various shapes

Question 8

Name actin dependent motor proteins?

Answer 8

myosin-I

Question 9

How do motor proteins generate movement?

Answer 9

use ATP hydrolysis

Question 10

What is DMD?

Answer 10

Duchenne Muscular Dystrophy - failure of the protein dystrophin to hold the actin microfilaments inside the muscle cells to their attachment points on the membrane so when the cells move, they rip their membranes apart and die and then the muscle cells swell and burst as fluid enters through the torn membranes.

Question 11

What makes up the contractile ring of mitosis?

Answer 11

actin + myosin

Question 12

Intermediate Filaments

Answer 12

provide great tensile strength, tough and durable - 10 nm in diameter

Question 13

Structure of intermediate filaments?

Answer 13

long strands of fibrous proteins twisted together to provide tensile strength

Question 14

Location of intermediate filaments?

Answer 14

1. tight junctions 2. in cytoplasm surrounding nucleus and extending out into the cytoplasm 3. within nucleus as part of nuclear lamina that supports nuclear envelope

Question 15

Types of intermediate filaments?

Answer 15

1. keratin 2. vimentin 3. neurofilaments 4. nuclear lamins

Question 16

What is EBS?

Answer 16

Epidemolysis bulosa simplex - mutations in the basal cell layer of epidermis, this disrupts the normal network of keratin filaments in the cell making the individual sensitive to mechanical injury

Question 17

Name accessory protein of IF?

Answer 17

plectin

Question 18

Microtubules

Answer 18

make up the axons of nerves

Question 19

Structure of microtubules?

Answer 19

long hollow tubule made of tubulin subunits

Question 20

How do they move?

Answer 20

disassemble and reassemble to various locations in the cell

Question 21

Where do they grow from?

Answer 21

centrosome

Question 22

Funtctions of microtubule?

Answer 22

1. pull apart chromatids during anaphase of mitosis 2. transport vesicles around the cell 3. keep organelles in place

Question 23

Role is cell division?

Answer 23

1. pull apart chromatids during anaphase of mitosis

Question 24

Microtubules form the core of?

Answer 24

cilia and flagella

Question 25

Functions of centrosome?

Answer 25

make the microtubules of the mitotic spindle 1. controls how many microtubules are formed 2. controls orientation of microtubules 3. controls location of microtubules

Question 26

Accessory proteins?

Answer 26

dynein