FLUID MOSAIC MODEL

Question 1

tell me about the cell membrane

Answer 1

plasma membrane bilayer surrounds cells and forms a boundary between cytoplasm and environment
controls entry and exit of minerals from mitochondria/chloroplast
isolates organelles
internal transport system (ER)
isolate enzymes
provide surfaces for biochemical reactions
allows change of shape to the cell

Question 2

tell me about the bilayer

Answer 2

hydrophobic tail - attracted to fat and points to the centre of the membrane
hydrophilic head - attracted to water
inner phospholipid layer - head points to intracellular cytoplasm
outer phospholipid layer- head interacts with extracellular solution

Question 3

what does fluid mosaic model mean

Answer 3

fluid - molecules move around
mosaic - protein floating among phospholipids

Question 4

function of plasma membrane

Answer 4

allows lipid soluble substances to enter and leave the cell
prevents water soluble substances from entering and leaving the cell
makes the membrane flexible

Question 5

cholestrol

Answer 5

strength to membrane
hydrophobic - prevents water and ion loss from cell
binds to tails - restricts their movement and doesnt make them fully rigid
ensures fluidity of membrane is reduced at higher temp

Question 6

how are proteins in the membrane embedded

Answer 6

intrinsic - span the bilayer (carrier/membrane bound enzymes/channel)
extrinsic - doesnt span the bilayer / partially embedded / provide mechanical support

Question 7

membrane protein functions

Answer 7

structural support
channels e.g. Na - K
allows for active transport across the membrane
form recognition sites to identify proteins needed for immune response
adhere cells
receptors for molecules

Question 8

what is a channel protein

Answer 8

forms tubes that fill with water so water soluble ions can diffuse

Question 9

what are carrier proteins

Answer 9

bind with larger molecules e.g. glucose/aas and change shape to transport them to the other side

Question 10

what are glycoproteins

Answer 10

carbohydrates attached to extrinsic protein molecule
type of extrinsic protein
cell surface receptor for hormones and neurotransmitters
recognition sites

Question 11

what are glycolipids

Answer 11

carbohydrate covalently bonded with a lipid
external carbohydrate
cell, surface receptor for specific chemicals e.g. blood group recognition proteins
attach cells to eachother to form tissues