Protein - Nutrition Ch 6

AMDR for protein

10-35%

energy potential in protein

4 kcal/g

ideal use for protein

to build

amino acids

building blocks of protein

total number of amino acids

20

number of indispensable acids

9

indispensable acid

essential

number of dispensable acids

11

dispensable acid

non-essential

conditionally indispensable

at time when the body can’t make a particular acid

dipeptide

2 amino acids

oligopeptide

4-10 amino acids

polypeptide

>10 amino acids

protein (peptide)

>50 amino acids

r-group

give the acid an identity

amino group

contains the nitrogen in the structure

denaturation

destabilization of the protein shape

collagen

most abundant protein in mammals

keratin

dense, forms hair and nails

motor proteins

turn energy into work

antibodies

blood proteins that attack viruses

enzymes

speed up chemical reactions

buffer

pick up extra hydrogen ions in acidic environment, donate to alkaline

acidosis

low blood pH

alkalosis

high blood pH

cellular transport

channels, pumps, carriers

albumin + globulin

balance water

edema

fluid leaking into surrounding tissues

hormones

chemical messengers

deamination

removal of nitrogen, reduces amino acid to carbon skeleton

carbs and lipids

are protein sparing

proteases

protein-digesting enzymes

proenzymes

inactive enzymes

stomach

beginning site of protein digestion

HCl

denatures protein in the stomach

pepsin

begins breaking down denatured protein

small intestine

where most protein digestion occurs

intestinal cells

absorb small peptides

proteins that enter bloodstream as amino acids

99%

celiac

GI tract cannot digest the protein gluten

cystic fibrosis

mucus prevents digestive enzyme from reaching small intestine, blocking absorption

CCK

signals satiety and hunger

CCK release

released when lipid and protein enter stomach

when a dispensable amino acid is missing from the pool

the cell will make or get from the liver

when an indispensable amino acid is missing from the pool

the body will break down it’s own protein

when an indispensable amino acid is not available

protein synthesis halts

protein turnover

constant recycling of protein, reason so little protein is needed

protein in intestine in liver

have 50% of turnover due to quick degradation and re-synthesis

ammonia

toxic, made from unstable nitrogen

unstable nitrogen

leftover from deamination

healthy adult

equal nitrogen balance in urea

too much protein

positive nitrogen balance

too little protein

negative nitrogen balance

protein RDA

0.8 g/kg bw

complete protiens

provide all indispensable amino acids

incomplete proteins

low in one or more indispensable amino acids

good protein source

provides all indispensable amino acids, provides enough of them, is easy to digest

protein hydrolysates

broken down peptides, used as thickener/stabilizers

protein-energy malnutrition (PEM)

correlated with poverty, insufficient food intake, poor quality food

Kwashiorkor

sufficient carbs, low protein

edema in stomach and feet

Marasmus

inadequate protein, energy, and nutrients

muscle/tissue wasting

kidney strain

caused by too much protein

osteoporosis

high calcium loss caused by high protein excretion