L8 & 9, T4

Question 1

Difference b/n simple & complex triacylglycerols?

Answer 1

Simple: identical fatty acids, Complex: different

Question 2

Three Ss of Lipids

Answer 2

Storage, structure, signals

Question 3

How does an increase in C=C affect MP?

Answer 3

Lower MP as less tight packing means less E is needed to disrupt interactions and has less stable aggregates

Question 4

How does increase in C affect melting point?

Answer 4

Increases it and H2O solubility decreases

Question 5

C=C usually in cis or trans?

Answer 5

Cis

Question 6

C=C, expect 9,12,15 or 9,11

Answer 6

9,12,15

Question 7

When theres 2 or more double bonds (C=C), they are not usually ___

Answer 7

Conjugated

Question 8

Glycerol by itself is classified as a ____

Answer 8

Sugar

Question 9

Main sterol in animal tissues

Answer 9

Cholesterol which is amphipathic and has no fatty acid

Question 10

Sterols have _ fused carbon rings

Answer 10

4, ABC 6C, D 5C

Question 11

Sphingolipids do not always contain a ____ group but can also fall into a ___ grouping

Answer 11

Phosphate, glycolipid

Question 12

Head group of fatty acid

Answer 12

Carboxylic acid

Question 13

Head group of phospholipid

Answer 13

Phosphate group and alcohol group (choline)

Question 14

Cholesterol has a small polar head group and large rigid structure so they can form in neither __ nor __

Answer 14

micelle nor bilayer

Question 15

Which is more energetically favourable, bilayer or vesicle?

Answer 15

Vesicle as edges of bilayer would be exposed to aqueous environment (causing instability)

Question 16

Are bilayers formed spontaneously by phospholipids?

Answer 16

Yes

Question 17

Are the interaction in the fluid mosaic model covalent or non covalent?

Answer 17

Non covalent (allowing fluid, dynamic properties)

Question 18

Is distribution of proteins and lipids between the two membrane leaflets asymmetrical or symmetrical?

Answer 18

Asymmetrical

Question 19

Flexibility of phospholipid bilayer refers to

Answer 19

Their ability to change shape without losing their integrity and becoming leaky

Question 20

Which one is faster, lateral diffusion or transbilayer movement?

Answer 20

Lateral diffusion (1 micro metre per second)

Question 21

Flippase, Floppase, Scramblase

Answer 21

Towards inside, Towards outside, Scramble it in either direction

Question 22

Temp

Answer 22

Liquid-ordered, disordered state when > phys pH

Question 23

How can peripheral membrane proteins be released from membranes?

Answer 23

Disruption of ionic interaction and H-binding via high salt, change of pH (changes charge and break interactions), chelating agents (Remove Ca2+ that’s stabilising it)

Question 24

How can integral membrane proteins be released from membranes?

Answer 24

By disruption of hydrophobic interactions via detergents that maintain extracted proteins in solution by formation of mixed micelles including the protein

Question 25

On hydropathy index plot/graph, hydrophobic region and hydrophillic region is?

Answer 25

Hydrophobic is the upper half, hydrophillic is the lower half

Question 26

Precursor for steroid hormones

Answer 26

Cholesterol

Question 27

Examples of lipids as signals (3)

Answer 27

- Cholesterol-derived steroid hormones (cell to cell communication) - Phospholipid-derived second messengers (intracellular signal transduction) - Lipid (vitamin) - derived hormones (cell-to-cell communication)

Question 28

Examples of lipids as cofactors (5)

Answer 28

- Enzyme cofactors and light absorbing pigments - Lipids (vitamins) acting as oxidation-reducing cofactors - Electron carriers - Emulsifying agents in the gut - Hydrophobic anchors for membrane proteins

Question 29

Describe membrane rafts

Answer 29

Slightly thicker microdomains of the membrane that behave like a liquid-ordered RAFT in the SEA of liquid-disordered phospholipids. Lateral diffusion of components in and out of raft is possible.

Question 30

What is a better determinant of MP, saturated carbons or double bonds?

Answer 30

Saturated carbons