Protein (Exam 2) Flashcards

1
Q

Dietary proteins are polymers of ______.

A

amino acids

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2
Q

The amino acids of dietary proteins contain at least one ______ group and at least one _____ group.

A

carboxyl
amino

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3
Q

___ (number) different _ amino acids are commonly found in proteins.

A

20
L-amino acids

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4
Q

Amino acids differ from each other in the structure of ______.

A

side chains (R group)

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5
Q

_____ is a structurally exceptional amino acid not bound to dietary protein.

A

taurine

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6
Q

Taurine has an acidic group that is a ____ rather than carboxylic acid which is located on __ rather than __ carbon.

A

sulfonic
beta
alpha

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7
Q

__ to __ amino acids are nutritionally essential, varying by species.

A

9-11

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8
Q

3 reasons for needing nutritionally essential amino acids

A
  1. metabolites + synthesis of proteins
  2. carbon skeletons (carnitine)
  3. nitrogen + sulfur
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9
Q

(T/F) Half of amino acids in dietary proteins are classified as nutritionally essentially.

A

True

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10
Q

What makes an amino acid “essential”?

A

cannot be synthesized by animal OR not synthesized at sufficient rate

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11
Q

Arginine is essential in ______ but not in other species.

A

dogs/cats

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12
Q

Arginine is conditionally essential in _____ & during _____.

A

neonates
disease

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13
Q

Which amino acid is essential in cats and other “strict” carnivores?

A

taurine

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14
Q

Taurine is conditionally essential in ____ and ____.

A

neonates + adult dogs

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15
Q

Why is taurine conditionally essential in adult dogs? When is it necessary?

A

during dietary deficits

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16
Q

Two dietary deficiencies in which taurine is necessary/essential for dogs?

A
  1. low cysteine + methionine
  2. unexplained dietary interactions
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17
Q

(T/F) Using non-essential amino acids in the diet can increase the dietary need for essential amino acids.

A

False - can reduce need for some essential nutrients

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18
Q

What do “non-essential” amino acids provide which is essential for life?

A

provide amino nitrogen for protein synthesis

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19
Q

Non-protein and non-amino acid sources of nitrogen are used for low-cost substitution for protein in what kind of animals?

A

ruminants

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20
Q

To an extend, _______ make amino acids and protein from non-protein nitrogen sources.

A

rumen microbes

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21
Q

What are 2 common non-protein nitrogen sources?

A

ammonium salts
urea

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22
Q

3 limitations to using ammonium salts as a non-protein nitrogen source.

A
  1. forms ammonia
  2. acidifying
  3. excreted as urea
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23
Q

(T/F) Urea is a prominent source of non-protein in a horse’s diet.

A

False - toxic to horses!

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24
Q

2 limitations of urea as a non-protein nitrogen source

A
  1. produces ammonia
  2. toxic to horses
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25
Q

Nutritional value or “quality” of dietary protein varies with its amino acid ______ and _____.

A

composition
bioavailability

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26
Q

List the 4 methods to evaluate protein quality

A
  1. Protein Efficiency Ratio (PER)
  2. Net Protein Utilization (NPU)
  3. Biological Value (BC)
  4. Chemical Score
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27
Q

What is the “first-limiting” amino acid percentage that is a method used to evaluate protein quality?

A

chemical score

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28
Q

(T/F) Crude protein of proximate analysis measures nitrogen content but does not indicate protein content or quality.

A

True

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29
Q

Plant proteins are (higher/lower) quality than animal proteins.

A

lower

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30
Q

Which amino acid is the first-limiting amino acid in cereals like corn, wheat, and rice?

A

lysine

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31
Q

Which 2 amino acids are first-limiting amino acids in meats and legumes?

A

methionine
cysteine

32
Q

Which amino acid is the first limiting amino acid in collagen (gelatin) and also the second limiting amino acid of corn behind lysine?

A

tryptophan

33
Q

The bioavailability of amino acids in protein is influenced by what 3 things?

A
  1. poor solubility
  2. anti-proteolytic factors
  3. heat treatment
34
Q

What 3 things have poor solubility of amino acids, and therefore low bioavailability?

A
  1. collagen
  2. keratin
  3. zein
35
Q

Give an example of an anti-proteolytic factor that decreases amino acid bioavailability

A

anti-trypsins of soybeans

36
Q

Which two amino acid have crosslinks during heat treatment that can make them less bioavailable/digestable?

A

lysine
cysteine

37
Q

Heat treatment can interfere with amino acid availability by oxidation of amino acid __-groups and isomerization of amino acids from __ to __ forms.

A

R
L
D

38
Q

(T/F) Protein digestabilities are similar across species for highly digestible proteins.

A

True

39
Q

Poorly digestible proteins have (higher/lower) digestibility in cats than in dogs.

A

lower

40
Q

Dietary protein requirement depends on the profile of ______.

A

amino acids

41
Q

If an animal is eating the optimal proportions, this will reduce the _____ requirement.

A

protein

42
Q

Low protein is used in therapeutic diets for what 2 diseases?

A

kidney + liver disease

43
Q

Protein requirement (increases/decreases) when energy intake (increases/decreases).

A

increases
decreases

44
Q

What is needed to use dietary protein in synthetic processes?

A

energy

45
Q

(T/F) If you decrease your energy intake, the dietary protein will be used more for energy production.

A

True

46
Q

Protein concentration (increases/decreases) in weight-loss diets.

A

increases

47
Q

Why is amount of protein increased in weight-loss diets?

A

protein preserves muscle while body fat is lost

48
Q

Why is amount of protein increased in weight-loss diets?

A

protein preserves muscle while losing body fat

49
Q

Protein requirement (increases/decreases) with age.

A

increases

50
Q

Why does protein requirement increase with age?

A

lowered energy intake + metabolism differences

51
Q

(T/F) Proteins levels are high in omnivore and herbivore diets.

A

False - variable

52
Q

In omnivores and herbivores, ______ can be changed in response to protein content in the diet.

A

protein metabolism

53
Q

(T/F) Carnivores conserve protein well when given a low protein diet.

A

False - do not conserve well!

54
Q

What two things may occur when diets are more than 50% protein?

A

decreased food intake
weight gain

55
Q

Which amino acid is potentially toxic and has a narrow optimum?

A

methionine

56
Q

What 3 things can cause protein & amino acid deficiency?

A
  1. no protein in diet
  2. lack of complete protein
  3. imbalance of energy with protein
57
Q

Term for protein deficiency without severe restriction of energy

A

kwashiorkor

58
Q

Term for protein deficiency with severe restriction of energy (starvation)

A

marasmus

59
Q

List a few non-specific physical signs of protein deficiency

A

decreased muscle mass
weight loss
poor coat
ascites

60
Q

List a few non-specific clinical laboratory findings that may indicate protein deficiency

A

anemia
hypoalbuminemia
low blood urea (BUN)

61
Q

3 specific types of single amino acid deficiencies

A
  1. taurine deficiency
  2. phenylalanine deficiency
  3. histidine + methionine deficiencies
62
Q

What specific amino deficiency is associated with the following signs:

dilated cardiomyopathy, central retinal degeneration (cats), poor growth & reproduction

A

taurine

63
Q

What specific amino acid deficiency is associated with the following sign:

black hair turns reddish Brown in dogs & cats

A

phenylalanine

64
Q

Which 2 amino acid deficiencies are associated with cataracts?

A

histidine + methionine

65
Q

_______ is a major site for catabolism of most amino acids except leucine, isoleucine, and valine.

A

liver

66
Q

Because leucine, isoleucine, and valine are not catabolized in the liver, they are termed the “_______ amino acids”.

A

branched-chain

67
Q

The first-step catabolism of branched-chain amin acids occurs where?

A

muscle, kidney, other non-liver tissues

68
Q

______ amino acids are higher than branched-chain amino acids in liver disease.

A

aromatic amino acids

69
Q

Which two amino acids are considered “aromatic”?

A

phenylalanine + tyrosine

70
Q

In liver failure, there is a reduced ability to detoxify what compound?

A

ammonia

71
Q

Restriction of ______ may prolong life in moderate to severe kidney failure.

A

dietary protein

72
Q

What percent of nephrons are functional when kidney insufficiency is detected?

A

25-33

73
Q

In kidney insufficiency, restriction of protein may reduce what 2 things?

A

reduce damage of nephrons
reduce excretion of nitrogen waste

74
Q

How does protein restriction reduce damage of nephrons? (2 ways)

A
  1. reduces nephron hyper-perfusion
  2. reduce glomerular pressure
75
Q

2 methods to assess if a diet is high, moderate, or low in protein

A
  1. estimate protein dry matter percent
  2. estimate protein metabolizable energy percent
76
Q

When comparing protein percentages with the averages of commercially available diets, dogs have an average of ___ to __% dry matter (and ME) while cats have an average of __ to __% dry matter (and ME).

A

20-25
30-35

77
Q

Proteins content of commercial dog & cat diets are usually much (lower/higher) than NRC adequate & AAFCO minimum recommendations. Why?

A

higher

protein is a major positive palatant to dogs/cats