Midterm - Lipids

Question 1

are lipids soluble or insoluble in organic solvents

Answer 1

soluble

Question 2

how many different lipid species have been characterized

Answer 2

10,000

Question 3

what do lipids provide

Answer 3

energy
major component of cell and organelle membranes

Question 4

saturated lipids

Answer 4

max number of H atoms
single bonds

Question 5

unsaturated lipids

Answer 5

missing H atoms
double bonds
cis or trans configurations

Question 6

what are the 3 types of fatty acids

Answer 6

saturated
monounsaturated
polyunsaturated

Question 7

essential fatty acid

Answer 7

linoleum acid (produced in plants)

Question 8

why are these fatty acids essential

Answer 8

humans lack enzymes needed to insert double bonds beyond delta-9 position

Question 9

eicosanoids

Answer 9

metabolites of 20-carbon fatty acids

Question 10

what are eicosanoids produced by

Answer 10

most cells in the body

Question 11

characteristics of eicosanoids

Answer 11

hormone-like but function locally

Question 12

functions of eicosanoids

Answer 12

inflammation
platelet aggregation
blood pressure
implications for disease

Question 13

what is the main dietary lipid

Answer 13

triglycerides

Question 14

example of a major storage lipid

Answer 14

triglycerides

Question 15

what processes are triglycerides critical in

Answer 15

lipogenesis
lipolysis
transported in lipoproteins

Question 16

what are the 3 triglyceride structures

Answer 16

monoacylglycerol
diacylglycerol
triglyceride/triacylglycerol

Question 17

what determines the physicochemical properties

Answer 17

fatty acid composition

Question 18

are phospholipids or triglycerides more polar

Answer 18

phospholipids (hydrophilic phosphate head group)

Question 19

primary functions of phospholipids

Answer 19

components of membranes
source of active fatty acids (eicosanoid synthesis)
anchors membrane proteins
intracellular signalling

Question 20

what are sterols

Answer 20

steroid alcohols (monohydroxy)

Question 21

structural features of sterols

Answer 21

free or esterified with a fatty acid

Question 22

what are sources of cholesterol

Answer 22

meat, eggs, endogenous production

Question 23

primary functions of sterols

Answer 23

essential component of membranes

Question 24

what are sterols a precursor for

Answer 24

bile acid production
steroid sec hormone production
vitamin D synthesis

Question 25

what are digested lipids emulsified by

Answer 25

conjugated bile acids

Question 26

mixed micelles

Answer 26

small spherical complexes containing lipid digestion products plus bile salts

Question 27

what can mixed micelles access

Answer 27

spaces between microvilli in intesitne

Question 28

what are the 3 brush border enzymes in lipid absorption

Answer 28

pancreatic lipase cholesterol esterase phospholipase

Question 29

what is lipoprotein classification determined by

Answer 29

1.ratio of lipid-to-protein (affects density) 2. specific apolipoprotein content (affects receptor interactions)

Question 30

what do chylomicrons increase in

Answer 30

circulation after a meal - enter at a slow rate

Question 31

when do chylomicrons peak

Answer 31

30min to 3h after eating

Question 32

where is lipoprotein lipase located

Answer 32

surface of endothelial cells lining small blood vessels and capillaries

Question 33

what is LPL expressed by

Answer 33

adipose and muscle

Question 34

what is LPL activated by

Answer 34

ApoC in chylomicrons

Question 35

what does LPL hydrolyze

Answer 35

the TAG in chylomicrons into 2-MAG + 2 fatty acids

Question 36

when are chylomicrons referred to as a "chylomicron remnant)

Answer 36

when they become TAG depleted

Question 37

what happens to chylomicron remnants

Answer 37

they are removed from circulation through ApoE-mediated interactions with a receptor in the liver

Question 38

what percentage of blood cholesterol in LDL is in a fasting subject

Answer 38

60%

Question 39

what is VLDL

Answer 39

the main transporter of newly synthesized hepatic TAG

Question 40

what are the 3 fates of cholesterol in the liver

Answer 40

1. converted into bile acids to replenish bile acid pool 2. secreted "as is" directly with bile to be eliminated as faces 3. packaged into VLDL and sent around the body

Question 41

what does LDL do with cholesterol

Answer 41

delivers it for essential functions but can also deposit it in unwanted places

Question 42

what do higher HDL levels mean`

Answer 42

more cholesterol returning to liver

Question 43

where do lipids fit into gluconeogenesis

Answer 43

the glycerol backbone is glucogenic

Question 44

where do lipids fit into the Krebs cycle

Answer 44

fat oxidation via acetyl CoA

Question 45

what is the recommended caloric intake for men

Answer 45

2500kcal/day

Question 46

what is the recommended caloric intake for women

Answer 46

2000kcal/day

Question 47

what percentage should protein be of daily calories

Answer 47

10-35% (max of 218g)

Question 48

what percentage should carbohydrates be of daily calories

Answer 48

45-65% (max of 406g)

Question 49

what percentage should fats be of daily calories

Answer 49

20 - 35% (max of 97g)

Question 50

for people with high blood cholesterol, what does decreasing dietary cholesterol do

Answer 50

decreases LDL

Question 51

trans fats

Answer 51

unsaturated fatty acids with at least one double bond in the trans configuration

Question 52

what are the 2 kinds of trans fats

Answer 52

industrial and natural

Question 53

when are industrial trans fats produced

Answer 53

hydrogenation of vegetable oils

Question 54

what does partial hydrogenation result in

Answer 54

double bonds being converted from cis to trans

Question 55

what does complete hydrogenation result in

Answer 55

all double bonds becoming fully saturated

Question 56

what is the relationship between hydrogenation and saturation

Answer 56

increase in the amount of hydrogenation, increases the degree of saturation

Question 57

where are trans fats found naturally

Answer 57

ruminant fat

Question 58

what percentage of trans fat does milk contain

Answer 58

4-8%

Question 59

when are natural trans fats made

Answer 59

in the rumen through bacterial fermentation

Question 60

what are affects of a high intake of industrial trans fatty acids

Answer 60

increase in: LDL cholesterol, total cholesterol, inflammation decrease in: HDL cholesterol

Question 61

what are trans fats linked to

Answer 61

CVD risk