Nutrition Chapter 7

Question 1

What is the structure of an amino acid?

Answer 1

an amino group, an acid group, a hydrogen, a side chain (different for each amino acid)

Question 2

What are the 9 essential amino acids?

Answer 2

histidine, isoleucine, leucine, lysine, methionine, phenylalanine, threonine, tryptophan, valine

Question 3

What is an essential amino acid?

Answer 3

amino acids that must be obtained from food because the body can’t make them

Question 4

What is transamination?

Answer 4

transfer of an amino group from 1 amino acid to a carbon skeleton to form a new amino acid

Question 5

What is deamination?

Answer 5

cleaving off an amino group, amino group joins urea, carbon skeleton used for other things

Question 6

How are protein synthesized?

Answer 6

amino acids are linked together through a peptide bond (condensation reaction)
amino group of one AA attaches to the acid group of another AA

Question 7

How does protein synthesis happen?

Answer 7

occurs in the ribosomes
transcription - mRNA formed from DNA
translation - mRNA used to synthesis polypeptide chains

Question 8

How are proteins organized?

Answer 8

primary, secondary, tertiary, quaternary structure

folding determines the overall shape and therefore function of the protein.

Question 9

How is protein denatured?

Answer 9

exposure to acid, base, heat, enzymes (pepsin in the stomach)

Question 10

What is BV?

Answer 10

biological value, measure of how efficiently the absorbed food protein in converted to tissue protein
nitrogen retained/nitrogen absorbed = bv

Question 11

What is PER?

Answer 11

protein efficiency ration, measure of food protein quality
weight gain (g)/protein consumed = PER

Question 12

What is CS?

Answer 12

chemical score

mg of limiting AA per g of protein/mg of limiting AA per g protein of an “ideal” protein

Question 13

What is PDCAAS?

Answer 13

protein digestibility corrected amino acid score
most widely used measure of quality
CS x digestibility

Question 14

What is protein quality evaluation?

Answer 14

ability of a protein to support body growth and maintenance

only applies when amount consumed is less than or equal to the body’s needs

Question 15

What is the recommended intake of protein?

Answer 15

8-10% of kcal
enough to maintain nitrogen balance
replace what is lost
RDA for adults = .8g / kg body weight (56 g for men and 46 g for women - avg. weight)

Question 16

What happens to excess protein?

Answer 16

it can’t be stored as protein, carbon skeletons used for energy or stored as fat

Question 17

How is protein digested in the stomach?

Answer 17

HCl denatures the protein, the enzyme pepsin uses hydrolysis reactions to start breaking the long polypeptide chains into shorter chains

Question 18

What is pepsin?

Answer 18

pepsin is an enzyme that is stored as pepsinogen in the cells of the stomach, its release is controlled by the hormone gastrin

Question 19

How is protein digested in the SI?

Answer 19

walls of the SI release the hormones secretin and CCK, this stimulates the pancreas to release proteases that digest the chains into individual AAs or short chains, peptidases break down short chains

Question 20

How is protein absorbed?

Answer 20

active transport, travel to the liver via the portal vein where they join the amino acid pool

Question 21

What are the functions of protein?

Answer 21

produce vital body structures
maintain fluid balance
provide energy
contribute to immune function
transport nutrients
maintain pH
synthesize hormones, enzymes and neurotransmitters
form glucose

Question 22

What is PEM?

Answer 22

protein energy malnutrition

usually occurs as marasmus or kwashiorkor

Question 23

What is kwashiorkor?

Answer 23

acute development, usually when a new child is born and the older one no longer gets nursed or an underlying disease or infection
causes edema, fatty liver, growth impairment, moderate weight loss

Question 24

What is marasmus?

Answer 24

develops slowly, severe deficiency of energy

causes severe weight loss, wasting and stunting

Question 25

What problems can high protein diets cause?

Answer 25

kidney stress (mostly with underlying kidney issues)
lots of cured meats can increase cancer risks
lots of animal sources can limit plant foods and provide a lot of sat. fat and chol.
calcium loss