cytoskeleton

Question 1

cytoskeleton

Answer 1

protein filaments in eukaryotic cells

Question 2

primary filament systems comprising the cytoskeleton

Answer 2

microtubules
microfilaments (actin filaments)
intermediate filaments

Question 3

cytoskeletal works to

Answer 3

create internal architecture to give the cell its shape

accessory proteins link cytoskeleton to one another the plasmalemma and or membranes of intracellular organelles

Question 4

function of cytoskeleton (filaments and tubules)

Answer 4

structural support

intracellular movement and transport

cell locomotion

chromosome seperation

muscle contraction (specialized cells)

Question 5

3 major cytoskeleton filaments are

Answer 5

actin filaments (microfilaments)

microtubules

intermediate filaments

Question 6

Actin (microfilaments)

Answer 6

thin filament 6-8nm in diameter

distributed in 3D network throughout cytoplasm

important in maintaining cell shape

facilitate cell changes during movement
ex. wound contration during healing

Question 7

what forms actin filaments

Answer 7

smaller g-actin subunits

g-actin = small globular protein monomer that polmerizes to form protofilaments

2 protofilaments twist together to form a double helix = F-actin

these combine to make larger actin filaments

Question 8

terminal web

Answer 8

a support meshwork formed by actin and filamin

prevents cells from deformation

Question 9

microvilli and stereocilia

Answer 9

increase surface area of cell

core of actin filaments that anchor to the terminal web of the cell

Question 10

Myosin

Answer 10

thick filament - 15 nm

motor protein

long rod shaped with globular heads

myosin heads form cross bridges between adjacent filaments

Question 11

Intermediate Filaments

Answer 11

8-10 nm or 10-15 nm (how it is on the slides)

primarily structural

heterogenous group / makeup varies between cells

generally form large filaments that bind with intracellular structures

useful in tumor id

Question 12

cytokeratin

Answer 12

characteristic of all epithelial cells

forms tonofibrils in epidermis of skin

Intermediate filaments

Question 13

vimentin

Answer 13

intermediate filament found in mesodermal cells of mesenchymal origin

included endothelial cells muscle and neuroectodermal cells

Question 14

desmin

Answer 14

intermediate filament unique to muscle cells

mesodermal origin

Question 15

neurofilament proteins

Answer 15

present in nerve cells

Question 16

GFAP (glial fibrillary acidic protein)

Answer 16

found in glial support cells of nervous system

astrocytes

Question 17

Lamin

Answer 17

forms layer on inside of nuclear membrane

Question 18

Epidermolysis bullosa simplex disorder

Answer 18

giant blisters caused by mechanical stress

disrupts binding of basal epidermal cells - no attachment -> cannot resist friction

mutation in intermediate filament genes cytokeratins 5 &15

Question 19

cytokeratins role in disease diagnosis

Answer 19

primary intermediate filaments

can stain for a variety of cytokeratins that can be used to confirm if a tumor is of epithelial origin or is a carcinoma

Question 20

Immmunohistochemistry staining

Answer 20

can be use to confirm tissue type

desmin/muscle

neurofilaments/nervous

Question 21

microtubules

Answer 21

24nm

composed of 2 types of globular protein -> alpha and beta tubulin

arranged in coiled spiral pattern and polymerize to form hollow tubes

involved in cell movement maintenance of cell shape and intracellular transport

Question 22

microtubules and intracellular movement

Answer 22

movement occurs through the addition or subtraction of tublin subunits from microtubules

capping proteins stabilizes the growing end of the tubules

motor proteins (dynein and kinesin) attach to microtubules to organelles

Question 23

Kinesin

Answer 23

moves things away from cell body

Question 24

dynein

Answer 24

takes things back toward cell body

Question 25

Microtubules are found in

Answer 25

cilia and flagella

centrioles (used for cell division)

basal bodies of cilia

mitotic spindles

Question 26

Axoneme

Answer 26

9 pairs of microtubules -> peripheral doublets contain dynein arms arragned in a circle with a central doublet

Question 27

radial spokes

Answer 27

in an axoneme it connects the central double to the peripheral doublets

Question 28

nexin

Answer 28

in axoneme connects peripheral doublets to each other

Question 29

Centrioles

Answer 29

located in the centrosome near the nucleus

function in cell division

each centrioles consists of 9 triplets of microtubules arranged in a cylinder

nucleation center for microtubules