membrane structure

Question 1

give 2 ways in which bronchial epithelium is specialised to its function

Answer 1

ciliated epithelial cells which beat mucus out of lungs
goblet cells which secrete mucus to trap pathogens and debris

Question 2

what is the role of cholesterol

Answer 2

-adds strength
-hydrophobic so prevents water loss
-holds tails together so less movement
-increases membrane fluidity

Question 3

phospholipid structure

Answer 3

phosphate group
2 fatty acid tails
a molecule of glycerol

Question 4

role of phospholipids in the cell membrane

Answer 4

-hydrophobic interior only lipid soluble substances can get through
-water soluble substances cant get through
-make membrane flexible and self sealing

Question 5

what is the bilayer a result of

Answer 5

the hydrophillic and hydrophobic components of phospholipids

Question 6

role of cholesterol in cell membranes

Answer 6

-holds tails together preventing movement
-adds strength
-hydrophobic so prevents water loss
-increases membrane fluidity (constantly moving around)

Question 7

glycoprotein role in PLB

Answer 7

cell-cell signalling, antigen receptor

Question 8

glycolipid role in PLB

Answer 8

cell-cell signalling & antigen receptor again

Question 9

what did the davidson danelli cell membrane model show

Answer 9

phospholipid bilayer (light region) with 2 thick layers of protein surrounding it (dark region)

Question 10

problems with davidson danelli model

Answer 10

unclear how proteins would move through
no fluidity
membrane proteins are largely hydrophobic so unlikely to be positioned by phosphate heads

Answer 11

protein recap
quaternary=diff polypeptide chains
tertiary= peptide bonds hydrogen bonds disulphide bridges and hydrophobic interactions with non polsr r groups
secondary between amine groups and carboxyl
tertiary between R groups

Question 12

which molecules cant permeate cell membranes

Answer 12

-large
-charged (polar molecules)
-same charge as protein channels so repelled

Question 13

what does the fluid mosaic model mean

Answer 13

components constantly moving around
mosaic=multiple components-proteins floating in membrane

Question 14

what experiments showed fluid mosaic phospholipid bilayer was right not

Answer 14

freeze fracture imaging
(split frozen cells apart allowing sight of individual cells and sea of proteins in phospolipid bilayer)

Question 15

which monomers make up glycogen

Answer 15

only alpha glucose