the cytoplasm

Question 1

what % of our cells are water

Answer 1

70%

Question 2

what is cytosol

Answer 2

gel-like, semi-fluid substance that fills the interior of cells

Question 3

what does cytosol cover?

Answer 3

nucleus and ER

Question 4

what does the plasma membrane seperate?

Answer 4

prevents the free flow of molecules into/out of the cell
interior separated from the external environment

Question 5

what does cytosol contain?

Answer 5

200-400mg/ml protein

Question 6

what are the 2 cytosolic proteins

Answer 6

soluble globular proteins
Filamentous protein structures

Question 7

what does the filmaenotus protein make up

Answer 7

cytoskelton

Question 8

how can solable globualr proteins be removed

Answer 8

these can be removed by treatment with detergent.

Question 9

what are filmanetois proteins?

Answer 9

these remain after detergent treatment, and make up the Cytoskeleton

Question 10

describe cytoskeltal filamentous

Answer 10

long polymers of single monomeric proteins

Question 11

what do detergents do?

Answer 11

Detergents make cell membrane leaky

Question 12

what happens when detergents make the cell membrane leaky

Answer 12

whereupon soluble cytosolic proteins will leak out

Question 13

when detergents make the cell membrane leaky and cause cytoslic proteins leak what stays inside and why?

Answer 13

cytoskeletal proteins which are anchored to internal structures will not.

Question 14

what are the 3 types of cytoskeletal filaments

Answer 14

Actin filaments (microfilaments)
Intermediate filaments
Microtubules

Question 15

describe the cytosol protein filaments

Answer 15

filaments arranged into bundles, or in 3-D networks.

Question 16

what are the functions of protein filaments?

Answer 16

Establishing cell shape/providing mechanical strength
Determining intracellular location of organelles
Providing transport system linking different regions of the cell

Question 17

how are filametns held together

Answer 17

held in bundles/networks by cross-linking proteins

Question 18

what are the proteins that hold the filaments together

Answer 18

a actinin, fimbrin (bundles);
Filamin, spectrin, dystrophin (networks)

Question 19

bundles

Answer 19

a actinin, fimbrin (bundles);

Question 20

networks?

Answer 20

Filamin, spectrin, dystrophin (networks)

Question 21

what are b-catenin and ankyrin

Answer 21

Proteins embedded within plasma membrane that bind to cytoskeletal filaments

Question 22

in which way can the cytoskelton undergo changes?

Answer 22

Activation of white blood cells involves changes in the cytoskeleton

Question 23

what are the ends of endothelial cells

Answer 23

basolateral & apical ends; secretion occurs from apical end

Question 24

most cells are what?

Answer 24

polar and their ability to fulfill their functions requires that they have “different ends”

Question 25

cells with cytoskeltons can do what?

Answer 25

generate cell polarity

Question 26

what are some functions of actin?

Answer 26

Provides mechanical strength to the cell
Generates motion in motile cells
Generates motion in motile cells

Question 27

what do capping proteins do?

Answer 27

may either assemble filaments or promote dissaembly

Question 28

where are capping proteins found

Answer 28

end of actin filaments

Question 29

what do globaulr monmers of actin use?

Answer 29

energy of ATP to polymerize & form long thin helical fibres (F-actin

Question 30

when do intermidate filaments (IF) change?

Answer 30

change during large-scale events

Question 31

what do IFs provide?

Answer 31

long term structural framework within cells

Question 32

what do Intermediate Filament-Associated Proteins do?

Answer 32

bind IFs to each other in cross links, or bind IFs to other structures

Question 33

what does every IF monomer contain?

Answer 33

a-helical rod domain.

Question 34

wha is a dimer

Answer 34

when a helical rod coils around another helical rod forming like a rope

Question 35

how are tetramers formed?

Answer 35

when dimers pair up head to toe form tetramers

Question 36

what are microtubles

Answer 36

long straight, hollow cylinders

Question 37

how are microtubles built?

Answer 37

dimers of -tubulin and -tubulin.

Question 38

what are two types of microtubles

Answer 38

stable
unstable microtubles

Question 39

what is an unstable microtuble?

Answer 39

rapidly assembling /disassembling microtubules. eg. Centrosome

Question 40

what is an stable microtuble

Answer 40

supporting cell structure, movements of whole cell (eg. cilia, flagella).

Question 41

how does a postive end of a microtuble grow?

Answer 41

by polymerising tubulin dimers, and shrink at each end by releasing tubulin dimers

Question 42

what are depolymerization?

Answer 42

Positive end of microtubules grow by polymerising tubulin dimers, and shrink at each end by releasing tubulin dimers

Question 43

how are cilia and flagella specailed

Answer 43

provide locomotion for cells (e.g. sperm)
move fluid past cells (e.g., ciliated epithelial cells that line our air passages and move a film of mucus towards the throat).

Question 44

summarise the strcuture of flagella

Answer 44

a cylindrical array of 9 microtubules
2 single microtubules running upcentre of the bundle

Question 45

summarise why cells need skelton?

Answer 45

Proteins that carry out each individual function must be:
Transported from where they are made to the location(s) where they will carry out their function(s).

Question 46

what are 3 types of cytoskelton protein fibres.

Answer 46

actin/ microfilaments, intermediate filaments, tubulin/microtubules