Chapter 7: Proteins

Question 1

structure of an amino acid

Answer 1

-central carbon
-nitrogen (H3)
-carboxylic acid
-side chain (R group)

Question 2

levels of structure

Answer 2

-primary (AA sequence)
-secondary (beta sheet, alpha helix)
-tertiary
-quaternary (more than 1 amino acid chain)

Question 3

what causes proteins to denature

Answer 3

-heat
-pH
-enzymes

Question 4

can we absorb denatured proteins

Answer 4

yes

Question 5

what structures are lost in denaturing

Answer 5

-all but primary

Question 6

what is sickle cell anemia

Answer 6

DNA mutation that codes for hemoglobin to become clumped (hydrophobic sides stick together, long cell not round)

Question 7

what is transamination

Answer 7

-transfer amino group to new (non-essential) AA
-(B6 removes nitrogen group from AA)

Question 8

deamination

Answer 8

-remove amino group
-excretion (in urea)

Question 9

complete vs incomplete proteins

Answer 9

complete (high levels of all essential AA)
-animal protein
-quinoa and soy
-complementary proteins

incomplete (deficient in at lest one essential AA)
-plant proteins

Question 10

Biological Value (BV)

Answer 10

ratio of N retained to N absorbed

Question 11

how to find N retained

Answer 11

N absorbed - N urea = N retained

Question 12

how to find N absorbed

Answer 12

N intake - N excreted = N absorbed

Question 13

what is the N in urea

Answer 13

the proteins that have been used, discarding the N through the urea

Question 14

what does BV measure

Answer 14

-quality: how efficiently body uses it

Question 15

what is Protein efficiency ratio (PER)

Answer 15

-measures how well a protein supports growth in young animals (usually RATS)
-FDA uses for labeling regulations for infant food

Question 16

nitrogen balance & mass

Answer 16

Negative nitrogen balance (losing mass)
-intake<losses

Nitrogen equilibrium
-Intake = losses

Positive nitrogen balance (gaining mass)
-intake>losses

Question 17

protein RDA

Answer 17

.8g/kg body weight

Question 18

how does pregnancy impact protein RDA

Answer 18

increased 25 g/d 2nd and 3rd trimester

Question 19

how do americans do with protein

Answer 19

get plenty

Question 20

what happens to excess protein (N & C)

Answer 20

the N is excreted, C skeletons used for energy

Question 21

functions of proteins

Answer 21

-energy
-glucose formation
-acid base balance
-structure
-immune function (cells)
-hormones & enzymes
-fluid balance

Question 22

how is protein digested

Answer 22

stomach
-HCl denatures protein
-pepsin breaks proteins into smaller pieces

small intestine
-chymotrypsin, trypsin, carboxypeptidase released and break things down more
-brush border enzymes (from microvilli) break things into AA

absorption
-intestinal cells absorb AA and small peptides
-large peptides are absorbed through endocytosis

Question 23

how much of the body’s energy is from proteins

Answer 23

only 5-10% bc it’s inefficient

Question 24

in prolonged exercise which AA are used for energy

Answer 24

-leucine
-isoleucine
-valine

bc they’re branched

Question 25

does the body break down protein for energy if not enough carbs

Answer 25

yes

Question 26

how do proteins regulate pH

Answer 26

they have charged side chains that can bind or release H

Question 27

what is hydrostatic pressure

Answer 27

blood pressure inside -> FLUID AND NUTRIENTS OUT (into the cells)

Question 28

what is osmotic pressure

Answer 28

albumin and globulins attract FLUID INTO blood

Question 29

what is Edema

Answer 29

insufficient protein -> low albumin in blood -> fluid out in tissue

Question 30

what is rabbit starvation

Answer 30

when getting lots of protein, but not enough other stuff

Question 31

types of protein deficiencies and their effects

Answer 31

kwashiorkor (no protein, yes food) -edema (stomach) marasmus (no protein, no food) -matchstick arms

Question 32

is vegetarian diet healthy

Answer 32

yes at any age if planned well

Question 33

types of food intolerances

Answer 33

-enzyme deficiencies (lactose) -chemical (MSG) -psychological (picky) -allergies (immune system)

Question 34

main food allergies

Answer 34

-peanut -tree nut -fish -shellfish -wheat -soy -milk -eggs