lecture 2

Question 1

what is 2 phase system?

Answer 1

Monomers of lipids are in solution together with their micells

Question 2

Gibbs free energy of micelle formation

Answer 2

Difference in standard chemical potentials of lipid monomers in the micelle and monomers in solution

Question 3

what is CMC

Answer 3

the maximum concentration of lipid monomers coexisting with their micelle form

Question 4

How can CMC be determined

Answer 4

tracking surface tension, osmotic pressure, conductivity and other colligative properties

Question 5

packing paremeter bigger than 1?

Answer 5

Inverted cone

Question 6

Packing parameter less than one

Answer 6

cone pointing downwards

Question 7

What does the main phase transition temperature of membrane phospholipids depend on?

Answer 7

The nature of the polar head groups + the length of the hydrophobic chain. the degree of unsaturation of lipid tails.
sometimes,
it is affected by the pH and the presence of ions

Question 8

……Rotation……packing

…….packing……rotation

Answer 8

more, less

less, more

Question 9

Cholesterol can induce the coexistance of ….

Answer 9

Liquid ordered and liquid disordered states

Question 10

what happens if the solubility of cholesterol in membranes is exceeded

Answer 10

Cholesterol forms crystals

Question 11

What is GPI-anchor

Answer 11

Is glycosylphosphatidylinositol used to anchor certain peripheral proteins

Question 12

How is GPI-anchored released?

Answer 12

Released by the use of phospholipase C

Question 13

certain ways to remove integral proteins from the membrane

Answer 13

Detergents

Question 14

Proteins with intrinsic curvature can help with what?

examples?

Answer 14

helping bending membranes for endocytosis and exocytosis. BAR proteins at the membrane surface

Question 15

How are integral proteins held in membranes

Answer 15

Through hydrophobic interactions with the surrounding lipids

Question 16

…% to ….% of all proteins are integral membrane proteins

Answer 16

10 -20

Question 17

The length of the unbroken sequence of integral membrane proteins

Answer 17

20

Question 18

Hydrophobicity? negative and positivty?

Answer 18

hydrophillic, hydrophobic

Question 19

Indole ring is found in which amino acid?

Answer 19

tryptophan

Question 20

Which residues in membrane proteins cluster at the water lipid interface ?

Answer 20

tryptophan + tyrosin

Question 21

which secondary structures are present in membrane pores?

Answer 21

alpha-helices

Question 22

which are larger alpha-helical pores or B-barrels

Answer 22

B-barrels

Question 23

Pressures arising from lateral diffusion

Answer 23

Positive (repulsions between head groups)
positive (repulsion between the hydrophobic side chains)
negative (interface between water and the hydrophobic part of the lipid. (interfacial tension).