The Nutritional Value of Fats and Proteins Flashcards Preview

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Flashcards in The Nutritional Value of Fats and Proteins Deck (40):
1

What is the body's premium reserve fuel?

Fats

2

What are the functions of protein?

structural dietary component and energy source

3

What is the key structural material of the diet?

protein

4

Protein is used to form

all structural components (eg collagen) and enzymes for metabolism

5

What are the general steps of protein digestion?

denaturing of dietary protein, rendering it to amino acids, transport them via multiple gut transporters

6

What are the implications of branched chain amino acids on performance?

eg valine, leucine, and isoleucine - transaminate in muscles but have no proven role as performance-enhancing

7

How much protein is made and broken down by the body per day?

300g

8

How much of our amino acids are recycled under normal conditions?

2/3rds

9

Broken down amino acids are used for

carbon sources for fuel

10

Amino acids make non-protein products such as

neurotransmitters

11

What is the major waste product to remove excess nitrogen?

urea (some ammonia can be passed direct from kidneys)

12

Breakdown of proteins in fasting fuels

formation of glucose and ketone bodies to maintain brain and RBCs

13

Acetyl-coA is never metabolised to

pyruvate; ie C from fat never becomes C in glucose

14

Fatty acids are metabolised to and from

Acetyl-coA

15

Why can't the brain use fats for energy?

long-chain fatty acids cannot cross the BBB

16

Fat cells produce what hormones?

leptin and adiponectin to tell the brain how much fat is stored

17

Hormone sensitive lipase

triacylglycerol lipase: converts TAGs to FFAs and glycerol

18

What is the role of carnitine?

Carries fatty acids from fatty acyl-coA across the mitochondrial membrane into the matrix - this is a rate limiting step of beta oxidation

19

What is the role of malonyl-coA?

it is a precursor of fat synthesis and inhibits high energy and blocks the carnitine acytltransferase from transferring fatty acyl-coA into the mitochondrial matrix for beta oxidation (ie fat is being made so don't break it down)

20

Fats are made in the

cytosol

21

Fats are broken down in

mitochondria

22

Beta oxidation of palmitate produces what yield of ATP via acetyl-coA in Krebs?

106 ATP/palmitate

23

What is the role of citrate?

exits from mitochondria into cytosol to generate acetyl-coA

24

Palmitate is synthesized by

polymerization of acetyl-coA (formed by citrate) by fatty acid synthase

25

Ketone bodies are made by

liver mitochondria to fuel other organs in starvation

26

Ketone bodies are a mixture of

acetoacetate, B-hydroxybutyrate, and acetone (breath only)

27

Ketone body production follows the same pathway as

cholesterol synthesis up to HMG-CoA, but cholesterol is only made in cytosol by HMG-CoA reductase

28

Cholesterol is only made in

cytosol

29

NADH generated in beta oxidation is used

to generate B-hydroxybutyrate from acetoacetate for energy

30

Ketoacidosis

metabolic acidosis due to high concentrations of ketone bodies as a result of failure to produce insulin - unregulated levels of ketone bodies and blood glucose

31

Ketosis

metabolic state where energy supply is ketone bodies (eg starvation) and insulin and blood glucose are low

32

What happens when glycogen stores are depleted (eg starvation)?

protein is broken down to amino acids for gluconeogenesis; after 3-4 days more and more ketone bodies are produced; glucose is maintained by gluconeogenesis from proteins and glycerol from TAG metabolism to FFAs

33

Omega fatty acids in fish oils are

eicosapentaenoic (6) acid and docosahexaenoic (3) acid (essential fatty acids)

34

What are the beneficial effects of omega 3 fatty acids?

inhibit production of leukotrienes (inflammation) and thromboxanes (platelet aggregation, thrombosis); promote production of prostacyclins (antithrombotic)

35

What is the dietary requirement for protein?

0.6-0.8g/kg body weight

36

What is pellagra?

disease of the 4 D's - photosensitive dermatitis, diarrhea, dementia, death; caused by niacin deficiency (eg corn diet with no tryptophan, precursor to niacin)

37

Transamination

transfers an amino group from an amino acid to a ketone producing a new amino acid and a keto acid

38

What is the function of the alanine cycle?

alanine is produced by muscle to carry nitrogen from muscle protein breakdown to the liver where it is transaminated to make urea; the carbon is recycled as glucose

39

Gout is caused by

uric acid crystals and resulting inflammation

40

Gout can be treated with

allopurinol, a xanthine oxidase inhibitor; NSAIDs, and corticosteroids to treat the inflammation