Protein Flashcards

1
Q

What are proteins made up of?

A

made from strands of amino acids
composed of carbon, hydrogen, oxygen, and nitrogen atoms; some
amino acids also contain sulphur atoms

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2
Q

What makes proteins different than carb and lipid-carbon, hydrogen, and O2?

A

Protein contains nitrogen atoms

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3
Q

What is each amino acid made up of?

A

amine (-NH2, containing nitrogen) and carboxylic
acid (-COOH) functional groups, a hydrogen atom and a distinctive side group,
all linked to the same central carbon atom

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4
Q

How many amino acids are there?

A

20

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5
Q

How many essential amino acids are there?

A

9
1. Histidine
2. Isoleucine
3.Leucine
4. Lysine
5. Methionine
6. Phenylalanine
7. Threonine
8. Tryptophan
9. Valine

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6
Q

How many non-essential amino acids are there?

A

11
1. Alanine
2. Arginine
3. Asparaginee
4. Aspartic acid
5. Cysteine
6. Glutamic acid
7. Glutamine
8. Glycine
9. Proline
10. Serine
11. Tyrosine

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7
Q

What is transamination

A

– transfer the amine (NH2) group from one amino acid to another molecule (keto acid, amino acid without an amine group) to make a
new amino acid and a new keto acid

  • Occurs in the liver
    -Converts essential to non-essential
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8
Q

What is conditionally essential?

A

an amino acid that is normally nonessential
but must be supplied by the diet in special circumstances when the need for it becomes greater than the body’s ability to produce it

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9
Q

How are proteins made?

A

link amino acids to form peptides

  • condensation reaction to form a peptide bond (release of water)
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10
Q

What is a dipeptide?

A

two amino acids bonded together

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11
Q

What is a tripeptide?

A

three amino acids bonded together

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12
Q

Polypeptide

A

10 or more amino acids bonded together

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13
Q

How many amino acids long are proteins?

A

30-300

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14
Q

Protein synthesis

A
  1. makes messenger RNA or mRNA
  2. mRNA moves out of nucleus to cytosol
  3. Ribosomes attach to mRNA strand
  4. Ribosomes decipher code and line up transfer
    RNA (tRNA) accordingly
  5. tRNA helps decode a messenger RNA (mRNA)
    sequence into a protein
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15
Q

What does transcription mean?

A

is the process by which the
information in a strand of DNA is copied into
a new molecule of messenger RNA (mRNA)

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16
Q

What is translation during protein synthesis?

A

which is a process that
synthesizes a protein from an mRNA molecule

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17
Q

How many sequencing errors are there?

A
  1. Genetic error
  2. copying error
  3. reading error
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18
Q

What is synthesis limiting?

A

improper combination and quantity of essential (limiting) amino acids – incomplete or low quality protein source

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19
Q

What is limiting amino acids?

A

is an essential amino acid that is present in
dietary protein in the shortest supply relative to the amount needed for protein synthesis in the body

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20
Q

How many different kinds of protein are there?

A

10,000 - 50,000

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21
Q

What is denaturation?

A

-Loss function
-Destroy all structure except primary

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22
Q

Digestion of protein in the mouth

A

-chewing protein foods and mix them
with saliva to be shallowed

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23
Q

what is HCI?

A

Hydrochloric acid : denatures proteins

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24
Q

What is pepsin?

A

activated by HCL and cleaves proteins into smaller polypeptides

25
Q

What breaks down polypeptides?

A

Pancreatic protease and intestinal protease that break it down into dipeptides and amino acids

26
Q

What is the primary site of amino acid absorption into the blood

A

Small intestine

27
Q

How are amino acids transported directly to the liver?

A

portal vein: used to makes proteins or broken down to produce glucose

28
Q

What is competitive inhibition?

A

consumption of too much of one amino acid (supplementation) may inhibit absorption of another

29
Q

What is incomplete protein?

A

– does not contain all nine
essential amino acids
– considered “low quality”
– plant sources (e.g. legumes)

30
Q

What is complete protein?

A

– contains all nine essential
amino acids
– considered “high quality”
– animal sources (e.g. egg) and
soy (e.g. tofu, soy milk)

31
Q

What are the two factors that determine protein quality or completeness?

A
  1. Amount of essential amino acids
  2. Protein digestibility
32
Q

What percentage of animal foods are digestible?

A

90-99% highly digestible

33
Q

What percentage of soy food are digestible?

A

> 90% highly digestible

34
Q

What percentage or other plant foods are digestible?

A

70-90% less digestible

35
Q

What are PDCAAS?

A

Protein digestibility-corrected amino acid score

-amino acid score (based on amount of essential amino acids) X protein digestibility

36
Q

What is PDCAAS used for?

A

The method is based on comparison of the concentration of the first limiting essential amino acid in the test protein with the concentration of that amino acid in a reference (scoring) pattern

37
Q

What is DIAAS?

A

Digestible indispensable amino acid score

Protein quality method

DIAAS determines amino acid digestibility, at the end of the small intestine (ileum, ileal digestibility), while PDCAAS determines amino acid digestibility based on total tract digestibility

provides a more accurate measure of the amounts of amino acids absorbed by the body and the protein’s contribution to human amino acid and nitrogen requirements

38
Q

What has greater DIAAS values than plant proteins?

A

meat and milk

39
Q

What is mutual supplementation?

A

– obtain complete amino acid requirements from two or more incomplete protein sources

40
Q

What are complementary proteins?

A
  • two or more proteins whose amino acids complement each other
  • essential amino acids missing from one are supplied by another
41
Q

What provides plenty of isoleucine and lysine but is short in methionine and tryptophan?

A

legumes

grains have the opposite strengths and weaknesses making them a perfect match for legumes

42
Q

Acid-base balance for proteins

A

help maintain the acid-base balance of body fluids by acting as buffers

43
Q

Protein turnover

A

Within each cell of the body, proteins are continually being made and broken down

44
Q

What percentage of available amino acids are stripped of their nitrogen and used for energy?

A

25%

45
Q

What is nitrogen balance?

A

Nitrogen intake from protein in food balances with nitrogen excretion via urine

46
Q

What is positive nitrogen status?

A
  • Body synthesizes more than it degrades
  • Growing children, pregnant women, and other life stages
47
Q

What is negative nitrogen status?

A
  • Occurs in the starving, and people who have severe burns, injuries,
    infections, or fever
48
Q

How much protein should we eat?

A

AMDR for adults = 10-35% /day

(0.8 g/kg body weight)

49
Q

People who require more protein include:

A

– infants and children – 0.95-1.5 g/kg/day

– adolescents – 0.85-0.95 g/kg/day

– pregnant or lactating women – 1.1 g/kg/day

– vegetarians – 0.9-1 g/kg/day

– athletes – 1.2-1.7 g/kg/day

50
Q

Too much protein can cause what?

A

-high cholesterol and heart disease
- Bone loss
-Kidney disease

51
Q

what is semivegitarian?

A

Vegetables, nuts, grains, legumes, sometimes seafood, poultry, eggs
and dairy

52
Q

What is pescovegetarian?

A

veg, nuts, grain, legumes, , eggs, dairy, seafood

excludes poultry

53
Q

What is laco-ovo

A

veg, nuts, grain, legumes, poultry, eggs, dairy

no seafood

54
Q

What is lactovegetarian

A

veg, nuts, grains, legumes, poultry, dairy, seafood

excludes eggs

55
Q

What is Ovovegetarian

A

veg, nuts, grains, legues, poultry, seafood, eggs

excludes dairy

56
Q

What is the only complete plant source of protein?

A

Tofu

57
Q

What is an example of complementary protein sources?

A

beans or lentils with rice

58
Q
A