Lecture 8: Lipids

Question 1

What are the 4 main lipid families

Answer 1

Triacylglycerols/triglicerides
Glycerophospholilids
Sphingolipids
Isoprenoids

Question 2

Out of the 4, which are amphipathic

Answer 2

glyceophospholioida
Sphingolipids

Question 3

Why are isoprenoids diff fromm others

Answer 3

Doesn’t have a fatty acid chain as part of its component

Question 4

What is name given to carbon that is furthest from the carboxyl carbon in a fatty acid (the one at the end)

Answer 4

omega

Question 5

What type of double bond exists in natural monounsaturated FAs

Answer 5

cis double bond
Which introduces a kink in the chain

Question 6

How come tricylglycerols are neutral

Answer 6

no acid based properties cuz
All hydroxyls in the glycerol are fully esterified

Question 7

Triacylglyecerol structure

Answer 7

glycerol
3 fatty acids
Vry hydrophobic

Question 8

What is the more abundant memb lipid

Answer 8

glycerophospholipids

Question 9

What happens to the third hydroxyl group in glycerol in glycerophospholipid

Answer 9

Phosphate group gets esterified onto it
This group then gets further esterified to a polar group

Question 10

How is the fatty acid linked differently in a sphingolipid

Answer 10

is amide linked

Question 11

How many hydrophobic tails does sphingolipid have

Answer 11

2
1 fatty acid and then the other long thing

Question 12

Sphingosine with nothing extra

Answer 12

ceramide

Question 13

Sphingosine with phosphphocholine/ethanolamine attached

Answer 13

sphingomyelin
The most similar to a glycocerophospholipid

Question 14

Sphingosine with simple sugar attached

Answer 14

Cerebroside

Question 15

Sphingosine with complex oligosaccharide attached

Answer 15

ganglioside

Question 16

What is isoprenoids

Answer 16

All derived from isoprene
Which is a 5 carbon isoprene

Question 17

What is the shortest isoprenoid

Answer 17

C10
Essential oil components

Question 18

How many carbon is the vit E precursor

Answer 18

c20

Question 19

What is C30 isoprenoid

Answer 19

steroids

Question 20

Structure of steroids

Answer 20

4 ring system

Question 21

what is cholesterol a precursor to

Answer 21

steroid hormones e.g. Oestrogen
Bile acids- emulsify dietary fats

Question 22

What makes cholesterol so unflexible

Answer 22

Fused ring system

Question 23

How does cholesterol act as a buffer

Answer 23

increases fluidity at low temp
Decreases at low temp

Question 24

What is the distribution of sphingolipids and glycerophospholipids

Answer 24

Outer has more sphingolipid
Cystolic leaflet has more glycerophospholipids

Question 25

What types of lipid fluidity is there

Answer 25

lateral diffusion = v fast
transverse diffusion = very slow

Question 26

What are the 3 classes of memb proteins

Answer 26

• integral
• peripheral
• lipid anchored

Question 27

What 2 ways can memb proteins be interated into memb

Answer 27

memb spanning alpha helices
or
beta bsrrel fold - exterior is hydrophobic and interior usually filled with water

Question 28

what ways can peripheral memb proteins interact with the memb

Answer 28

charge-charge or hydrogen bonding
either with the integrated proteins or with the polar heads of memb lipids

Question 29

how can serine or cytosine be anchored into the lipid membrane

Answer 29

ester/thioester bond from the AA to a fatty acyl group

Question 30

what 3 types of bonds can be formed between AAs in proteins and the lipid memb (on cytosolic leaflet side)

Answer 30

• ester/thoiester
• amide
• thioether

Question 31

how can a protein be anchored onto glycosykohiskjarhgaerlg idek (GPI)

Answer 31

via its C-terminus
this is on outer leaflet of memb

Question 32

why are passive tranporters e.g. carriers/permeases slower than memb channels

Answer 32

cuz requires conformational change

Question 33

what are the 2 types of active transport

Answer 33

primary = direct source e.g. ATP, light, electron transport
secondary = ion conc. gradient