Human Nutrition: Proteins

polypeptides

10 or more groups

RDA for protein

10-15% of total calories, .8g protein per kg of healthy body weight ex: 70kgX.8g protein = 56 g protein per day

how many nonessential amino acids?

11

dipeptides

2 groups

how many amino acids are used to make protein?

20 different amino acids

tripeptides

3 groups

oligopeptides

4-9 groups

how many essential amino acids?

9

pepsin

active form

denaturation

alteration of a protein's three-dimensional structure, because of treatment by heat, enzymes, acid, alkaline solutions, agitation

building blocks of protein

amino acids

conditionally essential amino acid

amino acids made from essential amino acids if insufficient amounts are eaten

body makes proteins from?

amino acids we obtain from food

5 contributors of protein in us

beef, poultry, milk, white bread, & cheese - animal protein is 70% of our protein intake

limiting amino acid

body will only be able to make proteins if it has enough amino acids - importance of variety and balance!

functions of proteins

building blocks of body components, fluid balance and maintenance, acid/base balance, building blocks of hormones and enzymes, immune function, forming glucose, energy yielding, contributing to satiety

essential amino acids

cannot be made by humans in sufficient amount or at all, must be included in diet

protein synthesis: gene is expressed when?

cell makes protein

proteins linked together by?

chemical bonds called peptide bonds

protein synthesis: amino acids added one at a time as

code is "read" on ribosome (w/ aid of transfer RNA (tRNA)

protein digestion

cooking is useful in aiding digestion

DNA will not leave nucleus

copy made

egg to fried egg

denaturation from heat which results in alteration of the proteins 3-dimensional structure

dietary protein: low-quality (incomplete)

dietary proteins that are low in or lack one or more essential amino acid

dietary protein: high quality (complete)

dietary proteins that contain ample amounts of all nine essential amino acids

protein turnover

during any day, an adult makes and degrades about 250 grams of protein

protein synthesis: the protein synthesis steps require:

energy

limiting amino acid

essential amino acid in lowest concentration in food or diet relative to body needs

why people become vegetarians

ethics, religion, economics, health - can still meet nutritional needs as a vegetarian. Good for disease prevention, increases plant proteins in your diet

protein americans 2020

fat free and low fat milk products, variety of protein foods, increase amount and variety of seafood, replace protein foods high in solid fats

stomach and protein

gastrin hormone stimulates release of HCI and ultimately pepsin (enzyme to break down protein)

gluten sensitivity - celiac disease

gluten is protein found in certain grains, wheat, rye, barley - it is the incomplete breakdown in the small intestine

positive protein balance

growth, pregnancy, recovery stage after illness, injury, athletic training

protein equilibrium

healthy adult meeting nutrient needs, notably protein and calorie needs

health related to plant proteins

heart healthy, cancer-fighting, bone health, glucose control, soy and menopausal symptoms

plant sources

high fiber, limited saturated fat, contains no cholesterol

food protein allergies

immune system mistakes food protein for harmful invader, 8 protein foods account for 90% of food-related allergies (soy, peanuts, tree nuts, wheat, milk, eggs, fish and shellfish) reactions range from mild intolerance to fatal, introducing allergenic foods early in life may prevent allergies

pepsinogen

inactive form

proenzyme

inactive form of an enzyme - activated by HCI low PH in stomach - cleaves protein to smaller polypeptides

negative protein balance

inadequate protein intake, inadequate protein intake, fevers, burns, infections, increased protein loss

high protein diet

increased urine, can put strain on kidney, may increase calcium loss in urine

protein's final shape determines:

it's function in the body

order of amino acids in a protein determines:

it's ultimate shape, therefor order is very important

protein foods

legumes, beans, peas, peanuts, nuts and seeds - all contribute to protein, vitamin, fiber in meal

branched chain amino acids

leucine, isoleucine and valine (used by muscles for energy needs) - proteins from milk for strength training athletes

animal proteins

normally contain all 9 essential amino acids

amino acid supplements

not considered safe

plant proteins in grains

often low in one or more of the nine essential amino acids

most proteins are?

polypeptides 50-2000 groups

functions of protein

regulates and maintains body functions and provides essential form of nitrogen(in the form of amino acids)

hemoglobin abnormal sequence:

sickle cell anemia

protein digestion

small intestine peptide bonds broken down - small peptides and amino acids remain

protein-calorie malnutrition

somewhat rare in developed countries - examples kwashiorkor marginal calories insufficient protein, marasmus starvation of insufficient protein and calories

protein synthesis: copies of codes

transferred to the cytoplasm and ribosome (via mRNA)

complementary proteins

two food protein sources that make up for each other's inadequate supply of specific essential amino acids, together they yield a sufficient amount of all nine, so they provide high-quality (complete) protein when eaten together

protein absorption

what is being absorbed? small peptides and single amino acids