Module 8

Question 1

Fatty Acids

Answer 1

Hydrocarbon tails with Carboxylic head
Differ in length and degree of saturation
Usually even number of C’s (12-24)

Question 2

Saturated

Answer 2

No double bonds

Question 3

Unsaturated

Answer 3

One double Bond

Question 4

Polyunsaturated

Answer 4

Multiple Double bonds

Question 5

Double bonds are usually in

Answer 5

Cis Configuration

Question 6

Double bonds are separated by

Answer 6

Methylene Group

Question 7

Fatty Acid Structure

Answer 7

Hydrocarbon tails of fatty acids associate through hydrophobic and Can Der Waals Interactions
Longer chains have stronger associations than short chains
Saturated chains have stronger associations than unsaturated

Question 8

Longer they are

Answer 8

The more they are likely to make a solid structure

Question 9

Double bonds

Answer 9

Lower melting points

Question 10

Fats and Oils as Energy Storage Molecules

Answer 10

Lipids represent critical energy storage molecules for plants and animals

Question 11

Triacylglycerols

Answer 11

Fatty acids required for energy
Storage lipids in animals and plants
Simple Triacylglycerols have the same 3 fatty acids at each position, complex triacylglycerols have different fatty acids
Ester linkage removes the polar carboxyl group to make a more hydrophobic molecule

Question 12

longer chains

Answer 12

Solid (Saturated)

Question 13

more double bonds

Answer 13

Liquid

Question 14

Why are fats good at storage

Answer 14

Low oxidation state
Low hydration State

Question 15

Low oxidation state

Answer 15

Less oxygenated fuels burn more efficeintly; triacylglycerols have lower oxygenation state than carbohydrates

Question 16

Low hydration state

Answer 16

lipids are hydrophobic with limited interaction with water providing a more compact dehydrated energy storage form

Question 17

Saponification

Answer 17

Treatment of fat with a strong base breaks the ester linkages to release free fatty acids
The amphipathic properties of free fatty acids make them effective in solubilization of hydrophobic substances

Question 18

Waxes

Answer 18

Esters of long chain fatty acids and long chain alcohols
Waxes are very insoluble and have high melting temps (60-100 degrees)
They are widely distributed in nature as protective waterproof coatings on leaves, fruits, animal skin and feathers

Question 19

Glycerophospholipids

Answer 19

Most Abundant lipids in membranes
Glycerol backbone with a phosphate at the C 3 position
The phosphate group is the point of attachment for a variety of polar head groups

Question 20

Head groups

Answer 20

All groups are polar
Different head groups have different functions

Question 21

Galctolipipds and Sulfolipids

Answer 21

Phosphate availability is often limiting to plants
Plants use sugar and sulphate polar head groups
Plants often use Galactiolipids
One or two Galactose groups linked to C3 of diacylglycerol

Question 22

Sphingolipids

Answer 22

long chain amino alcohol
Single fatty acid linked by amide bond to form ceramide
Structurally ceramide is similar to diacylglycerol

Question 23

Sphingomyclins

Answer 23

Phosphocholine

Question 24

Cerebrosides

Answer 24

Glycosphingolipid
Single sugar unit

Question 25

Gangliosides

Answer 25

Glycosphingolipids
Multiple sugar units

Question 26

Unique Membrane lipids

Answer 26

Ester linkages
Branchponts within the hydrocarbon tails Mmembrane spanning hydrocarbon tails composed of a single molecule

Question 27

Steroids

Answer 27

Sterols are structural membrane lipids
Sterols contain 4 fused ring steroid nucleus
Ring system is rigid and planar
Sterols also serve as precursors for many biologically active products, for example testosterone

Question 28

Cholesterol

Answer 28

Cholesterol serves a number of critical biological functions such as mediating membrane fluidity
Also serves as a precursor of steroid hormones and bile salts

Question 29

Active roles of Lipids

Answer 29

Intercellular signalling molecules
Harmones
Enzyme Co factors
Pigments
Vitamins

Question 30

Phosphatidylinositols Act as Intracellular Signal

Answer 30

Is on the membrane surface
Activation of Phospholipase C is response to an extracellular signal triggers the cleavage of head group to produce inositol 1,4,5 triphosphate with increases Ca2+
Both Ca2+ and diacylglycerol activate specific intracellular pathways and processes

Question 31

Eicosnoids

Answer 31

Paracrine harmones (Act on cells near point of productions)
Derivatives of C20 polyunsaturated fatty acids (Arachidonic acid)
Three classes of Eicosanoids

Question 32

Prostaglandins

Answer 32

Constriction of blood vessels

Question 33

Leukotrienes

Answer 33

Smooth Muscle Contraction

Question 34

Steroid Harmones

Answer 34

Hydrophobic oxidized sterol derivatives
Carrier through blood stream by carrier proteins
Pass through plasma membrane to bind receptors in the nucleus
Alter patterns of gene expression and metabolism

Question 35

Lipid Vitamins

Answer 35

A,D,E,K
All contain rings and long, aliphatic side chains
All are highly Hydrophobic
Lipid Vitamins differ widely in their functions

Question 36

Vitamin D

Answer 36

Regulates Ca2+ uptake and deposition
Vitamin D can be obtained from the deer or produced endogenously
Endogenous production occurs in a series of reactions, one of which requires UV light
Insufficient Vitamin D is associated with skeletal defects (Rickets)
Excessive Vitamin D can cause calcification of soft tissues

Question 37

Vitamin A

Answer 37

Obtained from liver, egg yolks and milk products
Vit A exists in 3 forms: Alcohol(retinol), aldehyde and retinoid acid
Retinal aldehyde is a light sensitive compound d with a role in vision

Question 38

Vitamin E

Answer 38

A reducing reagent that savings oxygen free radicals
May prevent damage of fatty acids in membranes
Often used as an addictive in cosmetics
Deficiencyt causes scaly skin, muscular weakness and sterility

Question 39

Vitamin K

Answer 39

Required for synthesis of blood coagulation proteins