lipids

Question 1

simple lipids

Answer 1

consist primarily of triacylglycerols
major storage form of fat in adiopocytes

contain one glycerol and three fatty acid chains

longer fatty acid chains contain less water-soluble molecules

Question 2

what are the three lipid groups

Answer 2

simple (neutral fats)
- a simple lipid is a fatty acid ester of different alcohols and carriers no other substance

compound
- compound lipid are esters of fatty acids with alcohol and possess additional groups. An example compound is a phospholipid

derived
- are the substances derived from simple and compound lipids by hydrolysis. cholesterol steroids, terpens and carotenoids

Question 3

what are saturated fatty acids

Answer 3

carbon binds to the maximum number of hydrogens

no double bond; fatty acid chains fit close together

occur primarily in animal products and some plants (beef, lamb, pork, egg yolk)

Question 4

what are unsaturated fatty acids

Answer 4

monounsaturated contain one double bond
polyunsaturated contain two or more double bonds
linolenic acid is an example of an essential fatty acid

Question 5

triacylglycerol formation (esterification)

Answer 5

fatty acid substrate attaches to coenzyme A to form fatty acyl-CoA which then transfers to glycerol
in

in subsequent reactions two more fatyy acyl-CoAs link to single glycerol backbone to form the composite triacylglycerol molecule

Question 6

triacylglycerol synthesis increases following a meal for two reasons

Answer 6

food absorption increases blood levels of fatty acids and glucose

relatively high levels of circulating insulin facilitate triacylglycerol synthesis

Question 7

mobilization of fatty acids via lipolysis predominates under four conditions

Answer 7

low-to-moderate-intensity physical activity

low-calorie dieting or fasting

cold stress

prolonged exercise that depletes glycogen reserves

Question 8

average person in US consumes about 15% of total calories as

Answer 8

saturated fatty acids

the equivalent of about 23 kg yearly

Question 9

daily recommended lipid intake

Answer 9

20% of total calories from lipids replace high fat foods with fruits vegetables whole grains fish poultry and lean meat

20-35% of total daily kcal

Question 10

what are trans fatty acids

Answer 10

derived from partial hydrogenation of unsaturated corn soybean or sunflower oil

Question 11

what are health concerns of trans fatty acids

Answer 11

increases harmful low density lipoprotein cholesterol

decreases beneficial high density lipoprotein cholesterol

Question 12

what are compound lipids

Answer 12

triacylglycerol components combined with other chemicals

represent 10% of the lipids in the body

Question 13

what are phospholipids

Answer 13

compound lipid

fatty acid joined to a phosphate group and nitrogen containing molecule

Question 14

what are the four main functions of phospholipids

Answer 14

interact with water and lipid to modulate fluid movement across cell membranes

maintain structural cell integrity

play important role in blood clotting

provide structural integrity to the insulating sheath surrounding nerve fibers

Question 15

what are glycolipids

Answer 15

fatty acids bound with carbohydrate and N2

Question 16

what are lipoproteins

Answer 16

protein molecule joined with a triacylglycerol or phospholipid

Question 17

what are the four types of lipoproteins

Answer 17

chylomirons = transport vitamins A,D,E,K
HDL = good cholesterol
VLDL = transport TAGS to muscle and adopoise tissue
LDL = bad cholesterol

Question 18

what are derived lipids

Answer 18

derived lipids are the substances derived from simple and compound lipids by hydrolysis

Question 19

what is cholesterol

Answer 19

exists only in animal tissue

does not contain fatty acids but shares some of lipids physical and chemical characteristics

high cholesterol diets can increase risk of coronary heart disease and atherosclerosis

Question 20

what are the major functions of lipids

Answer 20

energy source and reserve 
protect vital organs
thermal insulation 
vitamin carrier
hunger suppressor

Question 21

lipid activation

Answer 21

catacholamines

• epinephrine
• norepinephrine

glucagon

growth hormone

cyclic AMP
- cAMP

Question 22

____speeds up lipolysis & fatty acid activation

Answer 22

exercise

epinephrine increase with exercise

Question 23

triglycerides are catabolised by lipolysis in ___ of adipocytes; a hormone sensitive lipase (HSL) yielding ___ fatty acids and ___

Answer 23

cytosol

3 fatty acids

glycerol

Question 24

once a triglyceride is catabolised by lipolysis the fatty acids produced can then __

Answer 24

1) re-esterify

2) enter blood and bind with albumin for transport

Question 25

____ is not re-used after lipolysis so chemists can measure it as a marker of lipolysis

Answer 25

glycerol

Question 26

what is the RER

Answer 26

respiratory exchange ratio
the ratio between the amount of carbon dioxide produced in metabolism and oxygen used to create energy from lipid and CHO fuel sources in the body

Question 27

are RER and RQ the same

Answer 27

no but they are often used interchangeable but differ in how they are applied

Question 28

fat dynamics during light-moderate intensity exercise

Answer 28

fatty acids provide predominant energy source in light intensity exercise

energy derives from equal amounts of carbohydrates and lipid in moderate intensity exercise

Question 29

fat dynamics during high intensity exercise

Answer 29

energy derives from carbohydrate, primarily muscle glycogen