Chapter 8

Question 1

Shorter fatty acids had (higher/lower) melting point

Answer 1

Lower

Question 2

Saturated fatty acid examples

Answer 2

No DB

Palmitate and Stearate

Question 3

Which glycophospholipids have H-bonding head groups?

Answer 3

All except phosphatidylcholine

Question 4

Why are archaeal lipids more stable than glycerophospholipids?

Answer 4

Acyl attached by ether linkage (not ester)

Question 5

Why do antibiotics decrease vitamin K?

Answer 5

50% made by bacteria

Question 6

Melting points of fatty acids

Answer 6

Double bonds: more important
More DB = low mp

Length: shorter = lower mp

Question 7

Animal fatty acids are solids because they are

Answer 7

Longer, more saturated

Question 8

Does cholesterol promote crystallization or fluidity?

Answer 8

Neither

Decreases fluidity (movement of acyl)

Decreases crystallization (preventing close packing of groups)

Question 9

Why can steroids be intracellular proteins?

Answer 9

They are nonpolar and pass through the bilateral

Question 10

Why do glycerosphingolipids pack loosely?

Answer 10

They have larger head groups.

Question 11

Are lipid rafts more or less fluid than the membrane? Why?

Answer 11

Less fluid

Why? –>

1. Presence of cholesterol
2. Saturated acyl chains

Question 12

Locations of glycerophospholipids (Hint: based on head groups)

Answer 12

Ethanolamine and serine: Inner leaflet
Choline- outer leaflet
Glycerol- both leaflets

Question 13

What phospholipases cleave what stuff?

Answer 13

A1/A2: Acyl Chains
C: phosphate derivative
D: Polar Group

Question 14

Fatty Acids

Answer 14

not free in cell, too disruptive
form micelles
Even numbered C chains

Question 15

Triglycerides

Functions structure

Answer 15

Storage for fuel
Hormone signaling

Glycerol + 3 fatty acyl chains
Ester bond
Adipose Tissue globules

Question 16

Glycerophospholipids

Answer 16

Glycerol + 2 fatty acyl chains +
1x phosphate derivative (head group)

Ester bond

Question 17

Sphingolipids:

Answer 17

Backbone of serine and palmitate

Amide Bond - attaches 2nd fatty acyl group to serine nitrogen

Question 18

Sphingomyelins head groups

Answer 18

phosphocholine or phosphoethanolamine

Question 19

Glycolipids head groups

Answer 19

Cerebroside- monosaccharide

Ganglioside- oligosaccharide head group

Question 20

In a glycerophospholipids, ____esterified at position 1 and 2, ___ at position 3

Answer 20

Acyl groups

Phosphate

Question 21

How do omega 3:6 ratio for inflammation work?

Answer 21

Compete for enzymes that convert fatty acids to signaling molecules.

Question 22

Archaeal membrane differences:

Answer 22

Glycerol has opposite chirality
Acyl chains on C2 and C3
Tails are branched, not straight
Hydrocarbon tails attached by ETHER bond, not ester. (harder to degrade)

Question 23

Name some isoprenoids

Answer 23

Ubiquinone
Cholesterol
tails of archaeal membrane lipids
Vitamins

Question 24

Waxes

Answer 24

Protect plants from water loss

Alcohol + Fatty acids

Question 25

Vitamin A

Answer 25

Vision- too little = blind, too much= birth defects From beta-carotene Retinol oxidized to retinal, aldehyde with is light receptor in the eye

Question 26

Vitamin D

Answer 26

Too little: Rickets (stunt growth, deformed bones) Too much: Abnormal calcification of tissues D2- plants D3- cholesterol UV light by liver and kidneys Calcium deposits in bones and teeth

Question 27

Vitamin E

Answer 27

Alpha-tocopherol ``` Hydrophobic molecule in cell membranes Immune function (antioxidant) ``` Deficiency: membrane damage

Question 28

Vitamin K

Answer 28

1/2 by intestinal bacteria, rest from green plants carboxylation of glutamate residues in proteins involved in BLOOD CLOTTING. Poor coagulation: prevents Glu carboxylation, inhibits normal protein function, excessive bleeding

Question 29

What CAN make the bilayer?

Answer 29

Glycerophospholipids | Sphingolipids

Question 30

Why can't these make the bilayer: Fatty acids Triacylglycerols Pure Cholesterol

Answer 30

Fatty acids? Form spheres Tri? no, almost completely NP Cholesterol? no, only single polar hydroxyl group

Question 31

Rafts

Answer 31

Near Crystalline Tight Cholesterol and Spingolipids Important for signaling: can anchor proteins

Question 32

What causes lipid asymmetry?

Answer 32

Orientation of lipid synthesizing enzymes in ER.

Question 33

Alpha Helix

Answer 33

20 to transverse hydrophobic in middle, larger chains Charged residues: where it's exposed to solvent

Question 34

Beta barrel

Answer 34

interior hydrophilic, exterior phobic side chains in beta sheet point alternately to each face, so some point to interior, others to bilayer → thus, can’t predict form primary sequence Some large ones have central water whole Smallest are about 8 strands

Question 35

The alpha helix and beta barrel are subtypes of

Answer 35

integral membrane proteins

Question 36

Where do most lipid-linked proteins face?

Answer 36

interior

Question 37

The one weird long named lipid linked protein thing.

Answer 37

almost always face external surface of cell, found in sphingolipid- cholesterol rafts C-terminus attached to sugar chain lipid-carbohydrate group (attach phosphotal and oxitial groups)

Question 38

Getting those pesky proteins out the membrane: How to

Answer 38

Peripheral: Easy, some salt Integral: detergent, destroy the whole membrane lipid-linked: salt usually works

Question 39

Do membrane proteins move?

Answer 39

laterally only

Question 40

Do membrane proteins diffuse freely?

Answer 40

No, interactions with cytoskeletal elements