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Sport nutrition (EXCI 445) > Chapter 8- Proteins > Flashcards

Chapter 8- Proteins Flashcards

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Sports Trivia flashcards
1
Q

what is the proportion of proteins in body found in muscle ?

A

40%

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2
Q

what is the most widespread protein in the body?

A

actin and myosin (80-90%)

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3
Q

what are the three functions of proteins ?

A

structure, regulators of metabolism, energy

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4
Q

what are amino acids composed of , which elements ?

A

carbon, hydrogen, oxygen, nitrogen

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5
Q

how is it determined whether an aa is essential ?

A

you feed a diet w everything minus 1 aa. if the nitrogen balance becomes negative, the aa is considered essential/indispensable

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6
Q

what does aa lack limit ?

A

protein synthesis

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7
Q

what is the mnemonic for essential amino acids ?

A

PVT TIM HLL

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8
Q

what are the 9 essential aa ?

A

PVT TIM HLL
phenylalanine
valine
threonine

tryptophan
isoleucine
methionine

histidine
leucine
lysine

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9
Q

what are the 6 conditionally essential aa ?

A

CAT PGG
cysteine
arginine
tyrosine

proline
glutamine
glycine

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10
Q

what are proteins held with ?

A

peptide bonds

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11
Q

what chemical phenomenon leads to the formation of a peptide bond ?

A

condensation

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12
Q

what chemical process leads to the breakdown of peptide bonds ?

A

hydrolysis

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13
Q

how is aa transport executed simply put?

A

through transporters

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14
Q

what structure will a protein molecule have when put together ?

A

3D

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15
Q

what is another word for a high quality protein?

A

complete protein (all the essential aa)

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16
Q

which aa qualify as high quality protein ?

A

all of the essential aa

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17
Q

where are high quality protein usually derived from ?

A

animal protein

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18
Q

what are two non-animal sources of high quality protein?

A

quinoa and soy

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19
Q

what makes a protein low quality/incomplete ?

A

lacks one or more essential aa

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20
Q

what is the limiting aa?

A

the essential aa in short supply in the low quality protein

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21
Q

does a low quality protein necessarily mean that they are lacking an essential aa?

A

might have some but in small quantities

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22
Q

where in nature will you usually find low quality protein ?

A

plants

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23
Q

what are complementing proteins ?

A

incomplete proteins that, when put together, provide a full array of all essential aa

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24
Q

what are the 3 limiting aa in legumes ? what foods can complement well? 3 complementing meals ?

A

methionine, cysteine, tryptophan
complemented w grain and nuts/seeds

eg lentils and rice, beans and rice, hummus

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25
Q

what are the 3 limiting aa in grains ? what foods complement well?

A

lysine, isoleucine, threonine

legumes complement well
bread and peanut butter, barley and lentil soup

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26
Q

what are the 2 limiting aa in nuts ? what foods complement well?

A

lysine and isoleucine

just eat them w peanuts

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27
Q

what are the 3 limiting aa in vegetable? what 2 foods complement well?

A

lysine, methionine, cysteine

legumes and grains/nuts/seeds

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28
Q

what is protein energy malnutrition?

A

long term inadequate intake of protein, energy, or both, leading to wasting and infection

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29
Q

what is the percentage of ppl in world w PEM?

A

25%

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30
Q

in industrialized societies, what 3 ppl are at risk of PEM?

A

poor people
old people
hospital patients (AIDS, anorexia, cancer)

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31
Q

what is marasmus?

A

protein malnutrition due to inadequate energy intake

if untreated, body will not longer synthesize energy

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32
Q

what is kwashiorkor ?

A

protein malnutrition even if adequate energy intake, leads to edema and stomach swelling

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33
Q

when is the usual onset of kwashiorkor?

A

after breast feeding stops

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34
Q

what organs will be affected by too much protein intake ?

A

kidneys

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35
Q

what is the main risk w excessive protein diet ?

A

dehydration

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36
Q

what are 4 consequences of excess protein diet ?

A

dehydration (more urea)

fat deposition

calcium loss from bones (Ca2+ excreted in urine to treat its acidity)

risk of CVD due to increased fat especially if protein coming from high fat animal sources

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37
Q

what is the concentration gradient like for aa?

A

it is different for all aa

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38
Q

what are the aa transporters?

A

membrane bound proteins which recognize aa on shape and chemical properties
Na+ dependent or independent

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39
Q

what are the two inputs of AA?

A

intake and breakdown

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40
Q

does protein synthesis need a lot of energy?

A

yes !!!

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41
Q

what is the purpose of protein breakdown?

A

aa available for free aa pool

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42
Q

what are the three goals of protein breakdown?

A

degrade potentially damaged proteins to prevent a decline in their function

give energy when aa become either acetyl coa or TCA intermediates and are oxidized

synthesis of other compounds, eg NT, hormones, peptides and proteins

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43
Q

amino acids can be converted into which 3 energy sources ?

A

glucose, ketones, and fat

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44
Q

what is transamination?

A

a reversible reaction in which amino group is transferred to a keto-acid, resulting in formation of different aa

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45
Q

when you transaminate glutamate, you get…

A

a-ketoglutarate

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46
Q

what is oxidative deamination?

A

amino group removed from aa to form free ammonia (NH3)

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47
Q

what happens to the free ammonia after oxidative deamination ?

A

excreted as urea, or transferred to alpha-ketoglutarate to make glutamate and then glutamine

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48
Q

which aa can undergo transamination with glutamate ?

A 
leucine
valine
isoleucine
alanine
aspartate
glutamine

(LIVAAG)

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49
Q

what are the most abundant aa in muscle ?

A

glutamate and glutamine

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50
Q

what are the only essential aa that can undergo transamination?

A

branched chain amino acids

leucine, isoleucine, and valine

51
Q

what is the main limiting factor in transamination?

A

processes sometimes take place in different tissues, and aa have to be transported by circulation

52
Q

out of 20, how many aa are significantly oxidized by muscle ?

A

6

53
Q

what are the 6 aa that are significantly oxidized by muscle ?

A

isoleucine
leucine
valine

aspartate
glutamate
asparagine

54
Q

how does synthesis of essential aa work ?

A

it doesnt bc we cant synthesize it

55
Q

how does synthesis of non essential aa work ?

A

glutamate donates nitrogen in transamination to give to carbon skeleton of keto acid (from TCA, or a non-essential or essential aa), so it becomes amino acid

56
Q

why is synthesis of aa by transamination rarely limited ?

A

ample availability of substrates (NH3 and carbon skeletons)

57
Q

why is synthesis of aa from other aa limited ?

A

limited dietary supply

58
Q

what two aa are special cases in aa synthesis, especially dependent on adequate aa intake ?

A

cysteine and tyrosine: they are synthesized from essential aa

59
Q

how does protein turnover depend on function?

A

regulatory or signalling: minutes, hours, days

structures: days, weeks, months

60
Q

why is it that you don’t have to eat large amount of protein?

A

protein turnover is magic

61
Q

in a normal diet, the intake of protein provides only _____% of amino acids entering amino acid pool

A

25%

62
Q

what organs are involved in protein turnover ?

A

gut, kidneys, liver

also a bit of muscle

63
Q

what is creatine synthesized from ? (3)

A

arginine, glycine, methionine

64
Q

what is glutathione (antioxidant) synthesized from? (3)

A

cysteine, taurine, glutamine

65
Q

what are NT synthesized from? (3)

A

glutamate
tyrosine
tryptophan

66
Q

what are purines synthesized from? (3)

A

aspartate, glutamine, glycine

67
Q

what are pyrimidines synthesized from? (2)

A

aspartate and glutamine

68
Q

what is histamine synthesized from

A

histidine

69
Q

what is carnitine synthesized from

A

lysine

70
Q

what are choline and serine synthesized from

A

methionine

71
Q

what are T3, T4, epinephrine synthesized from

A

tyrosine

72
Q

tryptophan is the precursor of what

A

serotonin

73
Q

protein synthesis- what % blood proteins, viscera, and muscle ?

A

20% blood, 50% viscera, 30% muscle

74
Q

what is urea concentration in urine an indicator of ?

A

whole body protein breakdown

75
Q

what is nitrogen balance an indicator of?

A

protein diet, since protein is our only diet source of nitrogen

76
Q

when calculating nitrogen balance in exercise, what precaution must we take ?

A

measure sweat

77
Q

what is positive nitrogen balance ?

A

when N intake > excretion

78
Q

what is negative nitrogen balance

A

when N excretion > intake

79
Q

what are disadvantages of nitrogen balance measures ?

A

time consuming, trained staff, underestimate nitrogen excretion (doesnt usually measure sweat or feces) and doesn’t give insight on metabolic pathways

80
Q

what is 3-methylhistidine excretion?

A

measure of contractile protein breakdown, found in urine

however, diet with meat and fish can confound the results

81
Q

how can one measure net uptake and release of aa by tissue ?

A

AV-difference

82
Q

what are labeled tracers?

A

follow aa in body

83
Q

what are the 2 arguments saying that exercise increases protein requirement ?

A

amino acids may be oxidized during exercise

increased protein synthesis needed to repair damage and form training adaptations

84
Q

what are the answers to arguments saying exercise increases protein requirement bc aa used in metabolism?

A

even if aa oxidized, contribute less than 5% to metabolism.

also, oxidized aa not derived from muscle !

85
Q

what are the answers to arguments saying exercise increases protein requirement bc increased protein synthesis needed to repair tissues?

A

training causes a protein sparing effect

86
Q

what is the research discussing increase in aa oxidation in acute exercise ?

A

usually based on leucine oxidation, BUT leucine oxidation is diff from other proteins, overestimates protein oxidation

87
Q

what is the research discussing increase in protein degradation in exercise ?

A

resistance exercise may accelerate protein turnover (synthesis and degradation) BUT nitrogen balance studies found no diff or more positive balance after exercise

88
Q

what is the argument for increasing or maintaining protein for endurance athletes ?

A

endurance increases protein oxidation but also it works to spare protein interestingly, less breakdown.. and also no trouble meeting increased needs

89
Q

for resistance athletes, does training increase rate of leucine oxidation

A

no (unlike endurance)

90
Q

for resistance athletes, what justifies need for increased aa in diet ?

A

aa as precursors for proteins synthesized

91
Q

if there is an increased need, what are the recommendations for protein?

A
  1. 2-1.4/1.8 g/kg BW endurance

1. 6-1.7 g/kg BW strength athletes

92
Q

most uni students eat how much protein?

A

1-1.5 g/kg BW

93
Q

what is the relationship between protein and energy intake? what does this mean

A

linear relationship so supplementation not needed

94
Q

which athletes at risk of PEM?

A

those who eat not a lot

eg wrestlers, gymnasts

95
Q

are vegetarian athletes at risk of PEM ?

A

nah

96
Q

what type of exercise increases protein synthesis

A

both strength and endurance !!!

97
Q

how does strength training increase protein synthesis

A

hypertrophy, muscle mass, mitochondria MASS

myofibrillar protein synthesis

98
Q

how does endurance training increase protein synthesis

A

increase mitochondrial DENSITY, no mass increase

mitochondrial protein synthesis

99
Q

what are the 4 factors that affect protein synthesis after exercise protein intake ?

A

coingestion
amount
timing
type

100
Q

how does co-ingestion impact protein synthesis in post workout meal

A

measured phenylalanine uptake
control CHO diet, AA diet, mix diet
mixed diet had significantly more uptake and synthesis: carb intake creates favorable encironment

101
Q

what did IV studies show when it comes to protein synthesis after exercise ?

A

more aa available for synthesis

however IV study can’t be applied bc neglects liver, which normally extracts 20-90% aa after gut absorption

102
Q

explain research concerning timing of protein food after exercise

A

Tipton et al: 6g EAA + 35g CHO
before and after acute resistance bout
uptake and synthesis greater when nutrients ingested before

then, replicated study w 20g whey protein, and found no difference in aa uptake

103
Q

does it really matter if you eat protein 1h or 3h before ?

A

nah

104
Q

what protein is fast to be absorbed ?

A

whey

105
Q

what protein is slow to be absorbed?

A

casein

106
Q

milk protein is composed of what and what ?

A

80% casein, 20% whey

107
Q

why is casein slow ?

A

clots in stomach, slowing gastric emptying

108
Q

how does milk protein compare to soy when it comes to protein synthesis and muscle mass ?

A

milk better

109
Q

what do ppl claim is the benefit of free AA?

A

improve exercise performance, hormone release, immune function

110
Q

do free AA help as supplements ?

A

no benefit

111
Q

what is the downside of free AA supplements ?

A

toxic or lead to deficiencies in other AA

112
Q

can free AA increase GH?

A

injection maybe, orally no

113
Q

how is glutamine made ?

A

from glutamate (Krebs) by glutamine synthetase

114
Q

what is the most abundant AA in plasma and muscle ?

A

glutamine

115
Q

what is the biggest danger for healthy ppl w high protein intake ?

A

it comes at the cost of carb intake

116
Q

do glutamine supplements help ?

A

no

117
Q

what are the three BCAA ?

A

valine, leucine, isoleucine

118
Q

BCAA constitute what % of muscle protein

A

33%

119
Q

what serves as nitrogen source for glutamine synthesis

A

BCAA

120
Q

what is the central fatigue hypothesis ? how would BCAA help ?

A

FA mobilized from fat used as fuel, meaning tryptophan can’t bind to albumin. more free Trp (fTrp) means there is an increase in fTrp:BCAA ratio, increased fTrp transport in BBB, converted to serotonin, local increase of that NT

serotonin brings fatigue
therefore BCAA would prevent that from happening bc BCAA counter fatigue, reduce transport of fTrp to brain

121
Q

does BCAA intake change time to fatigue according to research?

A

no !

122
Q

is BCAA good for muscle soreness ?

A

yes but not function

123
Q

what is considered excess protein intake ?

A

3g/kg BW

124
Q

does tryptophan help release GH?

A

no

Sport nutrition (EXCI 445) (17 decks)

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