Biological membranes

Question 1

how do cis double bonds effect the melting point

Answer 1

they lower the melting point

Question 2

length effect on melting point

Answer 2

longer melt at high temps.
shorter melt at lower temps.

Question 3

unsaturation effect on melting point

Answer 3

saturated = melt at high temp
unsaturated = melts at lower temps.

Question 4

does length or saturation effect m.p. more?

Answer 4

saturation

Question 4

membrane lipids (3)

Answer 4

glycerophospholipids, sphingolipids, cholesterol

Question 5

ordered gel phase

Answer 5

acyl chains pack together in van der waal contact, in gel like soild sate

Question 5

components of bilayers

Answer 5

acyl chain, polar head group.

Question 6

disordered gel phase

Answer 6

above trans temp the acyl chains move freely and rapidly

Question 7

transtion temp

Answer 7

depends on acyl-chain unsaturation and length, when the ordered sate becomes disordered

Question 8

cold tempatures (effect on membrane)

Answer 8

unsaturated and shorter

Question 9

hot tempatures (effect on membrane)

Answer 9

saturated and longer

Question 10

high tempatures (cholesterol)

Answer 10

decreases disorder of acyl chains, increases rigidity

Question 11

cholesterols effect on membrane fluidity

Answer 11

rigid and planar -limits movment increases van der waal interactions of acyl chains

Question 12

low tempatures (cholersterol)

Answer 12

prevents close packing between acyl chains

Question 13

lipid movement

Answer 13

lateral, not transvese

Question 14

simple diffusion rates depend on what ?

Answer 14

size of moelcule, conc, gradient, lipid solubility

Question 15

size of molecule (simple diffusion)

Answer 15

smaller moves faster

Question 16

conc. gradient (simple diffusion)

Answer 16

larger gradient increases rate

Question 17

lipid solublity (simple diffusion)

Answer 17

greater solublity increases diffusion rate

Question 18

free energy (delta G) negative

Answer 18

passive transport, spontanous

Question 19

free energy (delta G) positive

Answer 19

active transport, energy must be provided for reaction to occur

Question 20

porins and ion channels

Answer 20

passive

Question 21

proins

Answer 21

trimers, non-selective, water-filled pore in the centre of b-barrel (mostly B-sheets)

Question 22

ion channels

Answer 22

channel is formed between subunits, highly selective

Question 23

channel selctivity

Answer 23

depends on the size of the pore and the properties of the side chains/function groups found there

Question 24

transporter and transport proteins

Answer 24

transporter proteins change conformation transport don't

Question 25

Transporter (carrier) proteins

Answer 25

DON'T have membrane spanning pores, change form open on one side to the other, selective, passive or active

Question 26

carrier proteins kinetic curve

Answer 26

hyperbolic

Question 27

types of transporter (carrier) proteins

Answer 27

uniport, symport, antiport.

Question 28

uniport

Answer 28

one being transported

Question 29

symport

Answer 29

two being transported in the same direction

Question 30

antiport

Answer 30

two being transported in opposite directions

Question 31

primary active transporters

Answer 31

typically uses ATP as source of free energy, (delta Greaction less then 0)

Question 32

secondary active transporters

Answer 32

uses ion gradient as a source of free energy, (delta GTion less then zero)

Question 33

Na+, K+, ATPase

Answer 33

primary active transporter, the two conc gradient generated across the cell memb. are sued as the source of energy for many seondary active transport processes

Question 34

Na+ glucose transporter

Answer 34

Na+ transport provides the energy for glucose import