Chapter 7: Proteins Flashcards
structure of an amino acid
-central carbon
-nitrogen (H3)
-carboxylic acid
-side chain (R group)
levels of structure
-primary (AA sequence)
-secondary (beta sheet, alpha helix)
-tertiary
-quaternary (more than 1 amino acid chain)
what causes proteins to denature
-heat
-pH
-enzymes
can we absorb denatured proteins
yes
what structures are lost in denaturing
-all but primary
what is sickle cell anemia
DNA mutation that codes for hemoglobin to become clumped (hydrophobic sides stick together, long cell not round)
what is transamination
-transfer amino group to new (non-essential) AA
-(B6 removes nitrogen group from AA)
deamination
-remove amino group
-excretion (in urea)
complete vs incomplete proteins
complete (high levels of all essential AA)
-animal protein
-quinoa and soy
-complementary proteins
incomplete (deficient in at lest one essential AA)
-plant proteins
Biological Value (BV)
ratio of N retained to N absorbed
how to find N retained
N absorbed - N urea = N retained
how to find N absorbed
N intake - N excreted = N absorbed
what is the N in urea
the proteins that have been used, discarding the N through the urea
what does BV measure
-quality: how efficiently body uses it
what is Protein efficiency ratio (PER)
-measures how well a protein supports growth in young animals (usually RATS)
-FDA uses for labeling regulations for infant food
nitrogen balance & mass
Negative nitrogen balance (losing mass)
-intake<losses
Nitrogen equilibrium
-Intake = losses
Positive nitrogen balance (gaining mass)
-intake>losses
protein RDA
.8g/kg body weight
how does pregnancy impact protein RDA
increased 25 g/d 2nd and 3rd trimester
how do americans do with protein
get plenty
what happens to excess protein (N & C)
the N is excreted, C skeletons used for energy
functions of proteins
-energy
-glucose formation
-acid base balance
-structure
-immune function (cells)
-hormones & enzymes
-fluid balance
how is protein digested
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
how much of the body’s energy is from proteins
only 5-10% bc it’s inefficient
in prolonged exercise which AA are used for energy
-leucine
-isoleucine
-valine
bc they’re branched
does the body break down protein for energy if not enough carbs
yes
how do proteins regulate pH
they have charged side chains that can bind or release H
what is hydrostatic pressure
blood pressure inside -> FLUID AND NUTRIENTS OUT (into the cells)
what is osmotic pressure
albumin and globulins attract FLUID INTO blood
what is Edema
insufficient protein -> low albumin in blood -> fluid out in tissue
what is rabbit starvation
when getting lots of protein, but not enough other stuff
types of protein deficiencies and their effects
kwashiorkor (no protein, yes food)
-edema (stomach)
marasmus (no protein, no food)
-matchstick arms
is vegetarian diet healthy
yes at any age if planned well
types of food intolerances
-enzyme deficiencies (lactose)
-chemical (MSG)
-psychological (picky)
-allergies (immune system)
main food allergies
-peanut
-tree nut
-fish
-shellfish
-wheat
-soy
-milk
-eggs
