model of cell membranes

Question 1

what is the name of the cell membrane model

Answer 1

fluid - mosaic model

Question 2

what are cell membranes mainly made of?

Answer 2

phospholipids and proteins

Question 3

what part of membrane is hydrophobic

Answer 3

fatty acid tails

Question 4

what part of membrane is hydrophilic

Answer 4

phosphate head

Question 5

what can polar molecules interact with

Answer 5

other polar molecules such as water

Question 6

what can phospholipids form

Answer 6

bilayers

Question 7

which way does the inner layer of hydrophilic heads point

Answer 7

points towards the cell

interacts with the water in the cytoplasm

Question 8

which way does the outer layer of hydrophilic heads point

Answer 8

outwards

interacts with water surrounding the cell

Question 9

what does the phopshoplipid bit of the membrane allow?

Answer 9

lipid soluble molecules across but not water soluble molecules

Question 10

defenition of the fluid mosaic model

Answer 10

proteins are studded through a phospholipid bilayer

movement of molecules within the bilayer is fluid

Question 11

what are the 2 different types of proteins

Answer 11

intrinsic
extrinsic

Question 12

what does intrinsic proteins span?

Answer 12

across both layers of the bilayer

Question 13

what does extrinsic proteins span?

Answer 13

are on either surface of the bilayer

Question 14

what does extrinsic proteins do?

Answer 14

structural support
identifying cells
hormone receptors

Question 15

what does intrinsic proteins include

Answer 15

transport proteins

Question 16

what do transport proteins do

Answer 16

uses active / passive transport to move molecules and ions across the cell membrane

Question 17

whats the fluid bit of the fluid mosaic model

Answer 17

individual phospholipid mols can move within a layer relative to one another

Question 18

whats the mosaic bit of the fluid mosaic model

Answer 18

proteins embedded in bilayer vary in shape and size and in their distribution among the phospholipids

Question 19

what does plant and animal cell membranes contain

Answer 19

glycoproteins, glycolipids and sterols

Question 20

what is the sterol in animal cell membranes

Answer 20

cholesterol

Question 21

where does cholesterol occur

Answer 21

between phospholipid molecules

Question 22

what does cholesterol do

Answer 22

makes membrane more stable at high temperatures and more fluid at low temps

Question 23

what makes membrane more stable at high temperatures and more fluid at low temps in plant cells

Answer 23

sterols

Question 24

what is the glycocalyx

Answer 24

carbohydrate layer around an animal cell

Question 25

roles of glycocalyx

Answer 25

hormone recptors cell to cell recognition cell to cell adhesion

Question 26

diffuseability of small molecules

Answer 26

move between phospholipid mols and diffuse across membrane

Question 27

example of small molecules

Answer 27

oxygen and carbon dioxide

Question 28

example of lipid soluble molecule

Answer 28

vitamin A

Question 29

example of water soluble molecule

Answer 29

glucose polar molecules

Question 30

diffuseability of lipid soluble substances

Answer 30

dissolve in phospholipid and diffuse across membrane

Question 31

why can lipid soluble substances move through cell membrane easier than water soluble substances

Answer 31

phospholipid layer is hydrophobic so lipid - soluble molecules move throuh the cell membrane easier

Question 32

what can water soluble substances not diffuse through

Answer 32

phospholipids

Question 33

what must water soluble substances pass through

Answer 33

intrinsic protein moleulces which form water filled channels across membrane

Question 34

as a result of the intrinsic proteins what happens to cell surface membrane permability

Answer 34

selectively permable to water