Cell membranes

Question 1

What does membranes being fluid mean?

Answer 1

lipids and proteins can diffuse rapidly

Question 2

What is hydrophobic property of fatty acid?

Answer 2

Saturated or unsaturated carbon chain

Question 3

What are membrane lipids?

Answer 3

phospholipid
glycolipids
cholesterol

Question 4

What is phospholipid made of

Answer 4

2 fatty acid + glycerol + phosphate + alcohol

Question 5

Where is ester bond in PPL?

Answer 5

between phosphate and alcohol

Question 6

What is polar head?

Answer 6

outside since it is hydrophillic

Question 7

What are lipid bilayers held together by?

Answer 7

non covalent hydrophobic interactions

Question 8

What does hydrophobic fatty acid chains mean?

Answer 8

lipids close and form compartments

lipid bilayers are self sealing

Question 9

What are integral membrane proteins ?

Answer 9

transverse the bilayer

Question 10

What are Peripheral membrane proteins?

Answer 10

bind to outer surfaces of integral proteins

Question 11

What does bacteriorhodopsin consist of?

Answer 11

alpha helices, amino acids in helices are non polar

Question 12

What is Bacterial porin consist of?

Answer 12

anti parallel beta strands bonded via H bonds

Question 13

what is bacterial porin?

Answer 13

outer membrane protein for pores or channels

Question 14

what is bacteriorhodopsin ?

Answer 14

proton pump

Question 15

What is the enzyme Prostaglandin H2 synthase held in the membrane by?

Answer 15

alpha helices with hydrophobic side chains

Question 16

What does table of free energy change for amino acids being transferred from hydrophobic to aqueous show?

Answer 16

amino acids more negative value= in aqueous environment

Question 17

how wide is hydrophobic core of membrane?

Answer 17

30A

Question 18

What does fluid mosaic model of PPL bilayer allow?

Answer 18

Lateral movement

Question 19

What is transverse diffusion?

Answer 19

from one membrane surface to the other

Question 20

What controls membrane fluidity?

Answer 20

• double bonds and length of fatty acid chain

- cholesterol content

Question 21

What do unsaturated fatty acids have?

Answer 21

kink by double bond

Question 22

What can prokaryotes have?

Answer 22

Either 1 or 2 membranes

Question 23

What does Low density lipoprotein carry?

Answer 23

Cholesterol

Question 24

How is cholesterol released into a cell?

Answer 24

receptor mediated endocytosis

Question 25

What is the enzyme called Na+/K+ ATPase?

Answer 25

hydrolyse ATP to actively transport Na out and K+ into cells

Question 26

What is the enzyme called Ca 2+ATPase?

Answer 26

Ca2+ pump of sarcoplasmic reticulum in muscle cells

Question 27

What does Ca2+ pump have?

Answer 27

spanning alpha helices and 3 domains

Question 28

What do P-type ATPases do?

Answer 28

Transport lipid across membrane

Question 29

What do flippases do?

Answer 29

Flip phospholipids and maintain membrane assymetry

Question 30

What are ATP-binding cassette transporters?

Answer 30

membrane protein that can cause drug resistance

Question 31

What do MDR proteins show?

Answer 31

4 DOMAINS

• 2 membrane binding
• 2 ATP binding cassettes

Question 32

What are histidine permeases?

Answer 32

proteins that transport molecules into a cell

Question 33

What are secondary transporters?

Answer 33

Anti porters

symporters

Question 34

What are anti porters?

Answer 34

use electro-chem gradient of Na to pump Ca out of cell

Question 35

What are Symporters?

Answer 35

Same direction, glucose into cells powered by Na entry too