lecture 5- membrane proteins

Question 1

membrane proteins used for

Answer 1

•transport •intracellular junction- holds membrane together •receptors •cell-cell recognition •attachment to the cytoskeleton and extracellular matrix

Question 2

2 main functions

Answer 2

•transport of molecules across membranes •transduction of signals across membranes

Question 3

peripheral/ extrinsic proteins

Answer 3

•on the outside of the cell- dont permeate through •they have H bonds and oletostatic •these are POLAR interactions can be disrupted by adding salt or changing the pH

Question 4

intergral/ intrinsic Proteins

Answer 4

•interact with the hydrocarbon chain of membrane lipids that san the lipid bilayer. can only be released b agents that compete for these non-polar interactions

Question 5

glycoproteins

Answer 5

proteins with attached carbohydrate (sugar) group. same sugars occur in both membrane glycoproteins and glycolipids. sugar on the outside of the cell is called sugar coating

Question 6

glycocalyx

Answer 6

carbohydrates of glycoproteins and glycolipids occurs on the outer surface of plasma membranes which gives it the sugar coating

Question 7

function of glycoproteins

Answer 7

•cell-cell recognition •cell adhesion •binding specific substrate

Question 8

membrane proteins

Answer 8

•carbohydrate containing lipid and protein molecules are also important in cell-cell recognition

Question 9

structure of membranes

Answer 9

•phospholipids suspended in water- bilayer

Question 10

membrane fluidity

Answer 10

•controlled by fatty aids and cholesterol •the more the unsaturation o fatty acyl chain the more fluid •increasing the amount of cholesterol makes the membrane less fluid

Question 11

features of membrane

Answer 11

•1:4 or 4:1 lipid to proteins •membrane lipids are hydrophilic or hydrophobic form bilayers and barriers •separates cell content from enviro •recognition and response •cell adhesion