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NUTR2101 > Week 4 > Flashcards

Week 4 Flashcards

1
Q

What is the difference between essential and non-essential amino acids

A

Non-essential: Can be produced by the body via transamination of dietary amino acids at the required rate

Essential: Must be provided by the diet as the body is unable to produce these, or not a sufficient rate to meet demand
There are 8 essential amino acids for adults

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2
Q

What is amino acids are conditionally essential amino acid?

A

Tyrosine, histidine, Glutamine and arginine

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3
Q

What is amino acid Essentiality determined by?

A

Essentiality is determined on the basis of the inability of the human body to make the essential amino acids (EAA) because:

  1. Cells cannot make the carbon skeleton of EAA
  2. Cells lack the enzymes to attach the amine group to the carbon skeleton to form the EAA
  3. Cells cannot achieve the manufacture of EAA at a fast enough pace to meet requirements
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4
Q

When is gastrin produce?

A

in response to food exposure

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5
Q

what is the function of gastrin?

A

signals HCL production and pepsinogen secretions

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6
Q

What do secretin and CKK stimulate?

A

Secretin and CKK stimulate the pancreas to release proteases:
trypsin, chymotrypsin and carboxypeptidase into the duodenum

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7
Q

What digests short peptides into amino acids?

A

peptidases

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8
Q

What do proteases trypsin, chymotrypsin and carboxypeptidase, do?

A

These enzymes breakdown polypeptides into shorter peptides and into amino acids for absorption

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9
Q

Once absorbed, amino acids taken to liver via portal vein to constitute the amino acid pool for:

A

1) protein synthesis; or
2) for energy production after deamination; or
3) in gluconeogenesis after deamination

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10
Q

What is deamination?

A

when amino acids are to bec onverted to pyruvate, acetyl CoA, intermediates of the CAC, or to oxaloacetate for gluconeogenesis

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11
Q

What happens in deamination?

A
  1. Removal of the amine group from an amino acid (vitamin B6 is required)
  2. Amine group converted to ammonia
  3. Ammonia converted to urea in the urea cycle (in liver)
  4. Urea filtered in the kidney and excreted via urine
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12
Q

What do the Carbon skeleton of ketogenic amino acids form?

What does the product do

A

acetyl CoA: enter the CAC for energy production

fat production when in excess

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13
Q

What do Carbon skeleton of glucogenic amino acids forrm?

what does the product do?

A

Form pyruvate to fuel energy production or the oxaloacetate pool
– Enter the CAC to form various intermediates to fuel energy production
– Form oxaloacetate for gluconeogenesis pathway (in fasted state; in liver and kidney)

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14
Q

What is transamination? where does it occur?

A

when additional non-essential amino acids are required in the AA pool. Occurs principally in the liver

Transfer of an amine group from one AA to a carbon skeleton to form a new AA

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15
Q

What are the enzymes and cofactors required for transamination?

A

Enzymes and cofactors are required:
– Transaminases:
• Alanine aminotransferase (ALT)
• Aspartate aminotransferase (AST) – Vitamin B6

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16
Q

What are the two main phases of gene expression?

A

1- DNA transcription phase:
• DNA code copied and transferred from the nucleus to the cytosol via messenger RNA (mRNA)

2- mRNA translation phase:
• Amino acids (coming from the AA pool)are linked by peptide bonds to form proteins and have a physiological function

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17
Q

Define transcription

A

making a complementary copy of DNA = messenger RNA in nucleus

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18
Q

What does tRNA do?

A

tRNA’s present the adequate AA to the ribosome to be attached to the previous AA by peptide bond

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19
Q

What is a peptide bond?

A

Peptide bond = covalent bond between the carboxyl acid group of one amino acid and the amine group of another amino acid
(C-N)

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20
Q

Define the 4 protein structures?

primary, secondary, tertiary, quaternary

A

Primary: a simple sequence of amino acids in the chain

Secondary: the shape of the protein molecule caused by weak hydrogen bonding between C=O and N-H groups within the chain. E.g. alpha helix, beta-sheet

Tertiary: 3 D folding from the interaction between R- groups determining the overall shape and function of the protein

Quaternary: interactions between 2 or more polypeptide chains. The result is a protein classified as fibrous, globular or conjugated

21
Q

What are prosthetic groups in quaternary structures?

A

Inorganic substances may be incorporated into the
molecule

heme is the prosthetic group in hemoglobin. Allows for the binding of iron for oxygen transport (= hemoglobin function

22
Q

what happens due to denaturation of protein?

cause can cause it to occur?

A 
Altering the protein’s 3 dimensional structure
Acid alkaline (pH), heat, enzymes, HCl can modify the structure
23
Q

What are the 10 functions of proteins?

A
  1. DNA expresses enzymes
  2. helps give rigid structure and assist in contractions
  3. transport of nutrients
  4. hormones and neurotransmitters
  5. keeps acid base balance
  6. DNA production and formation
  7. helps in immune function, antibodies
  8. helps keep fluid balance
  9. forms glucose
  10. provides energy
24
Q

How do proteins help keep fluid balance?

A

fluid is forced into the interstitial space by blood pressure generated by the pumping action of the heart
fluid is drawn into the bloodstream by the proteins as blood pressure declines in the capillary bed

25
Q

Define incomplete protein

A

Doesn’t contain all essential amino acids

usually plant proteins

26
Q

define complete protein?

A

contains all essential amino acids

usually animal proteins

27
Q

How do you measure protein quality?

A
  1. biological value (BV) of protein
  2. Protein effeciency ratio (PER)
  3. Chemical Score (CS)
  4. protein digestability corrected amino acid score (PDCAAS)
28
Q

What is biological value?

A

How efficiently the protein from a food is converted to body tissue protein. If all 8 (9) AA are present, the body can use this protein more efficiently

29
Q

How is biological value determined?

A 
Nitrogen retained (g) / Nitrogen absorbed (g) x 100
Measure takes into account urinary % and fecal nitrogen excretion
30
Q

What is the difference between high and low biological value?

A

High BV = Foods that provide amino acids in amounts consistent with body’s needs (e.g. similar AA profile). The body will retain much of the absorbed nitrogen, especially if consumption does not exceed requirement

Low BV = Foods that provide the amino acids in amounts not consistent with body’s needs (e.g. different AA profile). The body will not retain all of the nitrogen absorbed.

31
Q

What is there protein effeciency ratio?

A

Compares weight gain of a laboratory animal consuming a tested protein with the weight gain of an animal consuming a protein of reference

32
Q

How is protein effeciency ration calculated?

A

PER= Weight gain (g) /protein consumed

33
Q

How is chemical score calculated?

A

mg of limiting amino acid in 1 gram of the test food
divided by
mg of that amino acid in 1 gram of the reference food

34
Q

How is protein digestibility corrected amino acid score (PDCAAS) calculated?

A

PDCAAS= chemical score x digestability

35
Q

How is protein digestability determined?

A

Protein digestibility = amount of amino acids absorbed. This is the amino acid profile able to support growth and maintenance

36
Q

What is a “limiting” amino acids?

A

The “limiting” amino acids are the essential AA missing in the profile of a protein food

37
Q

What is “the” limiting amino acid?

A

Limits the amount of protein a body can make

38
Q

What is are Complementary” proteins

A

the protein foods that can be combined to supply all limiting AA’s

39
Q

What is the aim of the NRV’s?

A

Maintaining sustenance and preventing deficiencies in the population

40
Q

what is the AMDR for protein?

A

15-25%

41
Q

what is gluten?

A

general term to describe a variety of proteins found in wheat, barley, rye, oats.

42
Q

Gluten proteins are made of 2 groups of proteins: what are they?

A

glutelins (glutenin in wheat) and prolamines (gliadin in wheat)

43
Q

What is Coeliac disease

A

Coeliac disease is an auto-immune gluten allergy disease

44
Q

What happens to the body in coeliac disease?

A

the villi become inflammed and merge together decreasing the surface area

45
Q

What is the difference between Kwashiorkor and Marasmus protein health concerns

A

Kwashiorkor
protein malnutrition specifically
Minimal amounts of protein intake but
moderate energy deficit

Marasmus
Protein + energy malnutrition
Minimal amounts of energy, protein and micronutrients intake

46
Q

What happens when a protein is eaten that someone is allergic to?

A

Proteins (allergens) in food cause hypersensitivity reactions and trigger an immune response:

Stimulate white blood cells to produce antibodies, mostly immunoglobulin E (IgE)

47
Q

Anaphylaxis is a life-threatening condition: what happens to the body when this occurs?

A
  • Decreased blood pressure
  • Respiratory distress
  • Death with out medical treatment
48
Q

What are the advantages of a high protein diet?

A
  • Greater thermic effect post prandial=increased EE: good for weight balance or weight loss programs
  • Appetite control
  • Advantage im sparing muscle mass loss with ageing (sarcopenia)
  • Advantage in mental well being: precursors of neurotransmitters
49
Q

What are the disadvantages to a high protein diet?

A
  • over burden on the kidneys
  • increase urinary bone calcium loss
  • may relpace other food groups with meat and loose good vitamins and minerals

NUTR2101 (14 decks)

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