ANSC 3400- Quiz 4: Lipids

What is the main difference in the composition of fatty acids that make up animal fats and plant fats?

Animal fats contains more saturated fatty acids

Why are fatty acids a good source of energy for cells?

Fatty acids are highly reduced

What is the type of bond that forms between the hydroxyl group of glycerol and the carboxyl group of a fatty acid to form fat?

Ester Bond

What is an example of a monounsaturated fatty acid?

Oleic Acid

What are lecithin and cephalin?

Phospholipids

What lipid is a precursor of bile acids and steroid hormones?

Cholesterol

Where do fatty acids undergo β-oxidation in cells?

Mitochondrial matrix

What is another name for volatile fatty acids?

Short-chain fatty acids

How many carbons do long-chain fatty acids contain?

More than 12

What property of fat is true?

Contain more energy per gram than either carbohydrates or proteins

How many carbons do short-chain fatty acids contain?

Less than 6

What is the main difference in the composition of fatty acids that make up pork fat and beef fat?

Pork fat contains less saturated fatty acids than beef fat

Why are rumen microbes not able to oxidize long-chain fatty acids effectively to make ATP?

Rumen is an anaerobic environment

Which of the following does not contribute to the emulsification of fat?

Chylomicron

What is the rate-limiting step in β-oxidation?

Transfer of fatty acid from coenzyme A to carnitine in the intermembrane space of the mitochondria

What is an example of an essential fatty acid?

α-Linolenic acid

Where are bile salts reabsorbed in the small intestine following fat digestion?

Ileum

What molecule helps long-chain fatty acids enter the mitochondrial matrix before they can undergo β-oxidation?

Carnitine

How many NADH and FADH2 are produced per round of beta oxidation (not including the NADH and FADH2 from the subsequent oxidation of acetyl-CoA)?

1 NADH, 1 FADH2

What is one way that rumen microbes avoid the negative effects of dietary unsaturated fatty acids in ruminants?

Convert them to saturated fatty acids

What is the main role of lingual lipase and gastric lipase during fat digestion?

Starts emulsification of fat droplets

Why is it important to avoid feeding high fat diets to ruminant animals?

High fat diets depress feed intake and cellulose fermentation in the rumen

What role does the large intestine have in fat digestion in either non-ruminant or ruminant animals?

Minimal fat digestion in the large intestine

What anatomical part of the small intestine villi transports chylomicrons away from the small intestine and toward other parts of the animal?

Lacteal

What two molecules are linked to bile acids to form bile salts?

Glycine and Taurine

What molecule complements bile to help emulsify dietary fat and form mixed micelles during fat digestion in ruminants?

Microbial phospholipids

What is not a product of fat digestion in the small intestine?

Bile salt

Where does fat emulsification mainly occur in poultry?

Gizzard

What happens to short-chain fatty acids once they are absorbed by enterocytes in the small intestine?

Short-chain fatty acids can bypass lymphatic circulation and enter blood directly

What is the most important property of bile salts that helps them emulsify fat in the diet?

Bile salts are amphipathic

What happens to long-chain fatty acids once they are absorbed by enterocytes in the small intestine?

Long-chain fatty acids must be esterified onto a glycerol backbone

Stearic acid

18:0

Oleic acid

18:1n9

Palmitic acid

16:0

Acetic acid

2:0

Butyric acid

4:0

α-Linolenic acid

18:3n3

Linoleic acid

18:2n6

Docosahexaenoic acid

22:6n3

Albumin

Transports fatty acids from adipose tissue to other tissues

Chylomicron

Transports re-esterified fats from small intestine to other tissues in dogs

Portomicron

Transports re-esterified fats from small intestine to other tissues in poultry

Very-low-density lipoprotein

Transports fats from the liver to other tissues

Mixed micelle

Aggregate of bile salts, phospholipids, fatty acids, and other lipids that are absorbed into enterocytes

Carnitine palmitoyltransferase I

Transports fatty acyl-CoA from cytosol to the mitochondrial intermembrane space

Carnitine palmitoyltransferase II

Transports acylcarnitine from the mitochondrial intermembrane space to the mitochondrial matrix

Fatty acyl-CoA synthetase

Activates fatty acids with coenzyme A

Acyl-CoA dehydrogenase

Oxidizes carbon-carbon single bond to carbon-carbon double bond; reduces FAD to FADH2

β-hydroxyacyl-CoA dehydrogenase

Oxidizes hydroxyl group to carbonyl group; reduces NAD+ to NADH

β-ketoacyl-CoA thiolase

Produces acetyl-CoA and a shortened fatty acyl-CoA