Second Half I F24: Lecture Slides 1 - 19

Question 1

What are lipids defined by?

Answer 1

Their hydrophobicity (not by their chemical structure)

Question 2

What do we use to dissolve lipids?

Answer 2

Organic Solvents

Question 3

What is the organic solvent we use to dissolve lipids?

Answer 3

Typically a 2:1 mixture of Chloroform and Methanol

Question 4

What are triglycerides?

Answer 4

Fats and Oils

Question 5

What are the functions fo triglycerides?

Answer 5

Energy storage (use when needed)

Question 6

What are the functions of phospholipids and sterols?

Answer 6

Structural elements of biological membranes

Question 7

What are the functions of steroid hormones and prostaglandins?

Answer 7

Signal Transduction (cell-cell communication)

Question 8

What is Coenzyme Q?

Answer 8

A mitochondrial electron transport chain

Question 9

What is the function of coenzymes?

Answer 9

Enzyme cofactors

Question 10

What are Vitamins A, D, E and K?

Answer 10

Lipids

Question 11

What is the function of carotene?

Answer 11

Light-absorbing Pigment

Question 12

What are glycolipids?

Answer 12

Contain both sugar and lipid portions and are important constants of cell membranes

Question 13

What are the human blood types?

Answer 13

(O,A,B) are defied by the glycolipids displayed on the outer surfaces of blood cells.

Question 14

What are lipoproteins?

Answer 14

VLDL, HDL, LDL (defined by density, transport blood in lipids)

Plasma lipoproteins that are associated with cardiovascular health and disease.

Question 15

What are there three types of lipids we’re looking at?

Answer 15

1.) Fatty Acids

2.) Triacylglycerides

3.) Phosphoglycerides

Question 16

What are fatty acids?

Answer 16

• Building blocks of many complex lipids
• Central Intermediates in Metabolism but not freely found in the environment or in cells (always conjugated)

Question 17

What are Triglcyerides?

Answer 17

A storage fat

Question 18

What are phosphoglycerides?

Answer 18

The major lipids in membranes

Question 19

What are the characteristics of Fatty Acids?

Answer 19

They are a carboxylic acid with hydrocarbons ranging from 4-36 carbons

Question 20

What are saturated fatty acids?

Answer 20

No double bonds between carbons in the chain (all single bonds)

Question 21

What are unsaturated fatty acids?

Answer 21

Fatty Acids with one or more double bonds

Question 22

When labelling fatty acids, which carbon is number 1 assigned to?

Answer 22

The carboxyl carbon is C-1

Question 23

What are features of commonly occurring fatty acids?

Answer 23

• Have an even number of carbon atoms
• Are unbranched

Question 24

What configuration are the double bonds in a fatty acid found in?

Answer 24

Cis transformation, which introduces a kink in the chain.

Question 25

What are the double bonds in polyunsaturated fatty acids (PUFA)?

Answer 25

Methylene Bridged, not conjugated.

Question 26

What are PUFA separated by?

Answer 26

By a methylene carbon and therefore the bond pattern is double-single-single-double (not conjugated)

Question 27

What fatty acid would not be an important constituent in human nerve cells?

Answer 27

An odd number of carbons

Question 28

What are the Five Commonly Occurring Saturated Fatty Acids Trivial Name and the number of Carbons?

Answer 28

12 Laurate 14 Myristate 16 Palmitate 18 Stearate 20 Arachidate "Let My Pal Stay Around"

Question 29

What can the process of partial hydrogenation of unsaturated fatty acids do?

Answer 29

It is used in manufacturing margarine and similar products to isomerize double bonds, generating trans fats

Question 30

What does a Trans double bond allow a fatty acid to do?

Answer 30

Adopt an extended conformation, which can have serious negative effects on cardiovascular health.

Question 31

What is partial hydrogenation?

Answer 31

Take double bonds and add hydrogens

Question 32

What does the saturated chains extended conformation cause?

Answer 32

Them to pack in a fairly orderly way (causing extensive favourable interactions)

Question 33

For saturated fatty acids what happens as the chain length increases?

Answer 33

Melting Point Increases and Solubility Decreases

Question 34

How do unsaturated fatty acids pack and why?

Answer 34

Less regularly due to the kink caused by the cis double bond, lowering the number of favourable interactions.

Question 35

What is the melting point of unsaturated fatty acids?

Answer 35

Drastically lower as less thermal energy is required to disrupt ordered packing and the fluidy of the membrane depends on this.

Question 36

Why can trans fatty acids pack more regularly than cis forms?

Answer 36

Due to their extended nature, trans form shows a higher melting point.

Question 37

What is the melting point of the saturated fatty acid Stearic Acid?

Answer 37

+70 degrees celsius

Question 38

What is the melting point of the unsaturated fatty acid Linoleic Acid?

Answer 38

-5 degrees celsius

Question 39

What do carboxylic acids form when combined with alcohols?

Answer 39

Esters

Question 40

What do carboxylic acids form when combined with acids?

Answer 40

Acid Anhydrides

Question 41

What are majority of fatty acids in biological systems found in?

Answer 41

The form of triacyglycerols

Question 42

How are triaglycerols formed by?

Answer 42

Linking three fatty acids to a glycerol molecule through ester linkages.

Question 43

What are TAGs the major constituent of?

Answer 43

Bulk fats and oils, including the human body's depot fat.

Question 44

What are some characteristics of triacylglcdyeride?

Answer 44

Highly hydrophobic as the polar carboxylic acids of the fatty acids are tied up as (less polar esters)

Question 45

What does the melting point of TAGs depend on?

Answer 45

The length and degree of saturation of their fatty acid constitutes

Question 46

Will you be asked to draw a triacylglyceride?

Answer 46

Yes.

Question 47

What is a simple TAG

Answer 47

Same fatty acid in all three positions

Question 48

What is a mixed TAG

Answer 48

2 or 3 different fatty acids

Question 49

What is the MP and Unsaturation of a Solid TAG?

Answer 49

M.P increases Unsaturation decreases

Question 50

What is the MP and Unsaturation of a liquid TAG?

Answer 50

MP decreases Unsaturation Increases