Looks like no one added any tags here yet for you.
functions of proteins
structural materials like muscle/bone/skin/nails, growth, maintenance, repair, energy at 4kcal, critical functions like enzymes/hormones/antibodies/fluid balance/ acid base balance/ transporters/ blood clotting
healthy non growing adult
0.8 grams of protein per kg of body weight
athletes
1.2-1.7g/kg
elderly
1.0-1.2g/kg
adequate energy
with enough kcal you do not use much protein for energy and can instead keep the protein for all the functions it is needed for
protein AMDR
10-35%
find AMDR
Multiply 2400kcal or amount eaten by each percentage
find RDA for 154 lb adult
154/2.2kg= 70kg then 70kg times 0.8g= 56g
find 12% of 2400kcal and grams
2400 times .12= 288kcal then 288/4g= 72g
structure of amino acid
Consists of central carbon atom, amino group with nitrogen, acid group, hydrogen, variable side chain
side chain
where amino acids differ
peptide bonds
amino acids are joined by these
essential amino acids
9, can’t be made by the body
nonessential amino acids
11, can be made by the body
step 1 transcription
DNA undwinds
step 2 transcription
info from DNA is transcribed into messenger RNA or mRNA
step 3 transcription
mRNA carries info into cytoplasm where protein synthesis occurs
step 1 translation
mRNA interacts with ribosomes that read mRNA and translates it into an amino acid sequence to assemble a protein
step 2 translation
tRNA molecules carry specific amino acids to ribosomes
step 3 translation
ribosomes direct tRNA matching mRNA to proper position to be added
step 4 translation
Empty tRNA carrying previous amino acid moves out of the way so TRNA carrying next amino acid moves into position and process continues
step 5 translation
newly formed protein chain detaches from ribosomes and translation is done
step 6 translation
peptide bonds are formed
amino acids and translation
most are used to make working proteins in the body like enzymes or muscle cells
amino acids and translation
what gets made is controlled by your DNA which codes for protein
amino acids and translation
when a protein gets made then it is said that the gene has been ‘expressed’
3 dimensional
long chains of amino acids won’t work unless they are folded
protein folding
after translation amino acids fold into a 3 dimensional shape
protein folding
shape determines protein’s function
protein folding
proteins must retain shape to function properly
protein denaturation
Caused by heat, light, change in pH, alcohol, or motion and is most common in cooking/digestion, protein can no longer perform its functions
step 1 protein denaturation
HCl in stomach denatures protein making it lose its shape
step 2 protein denaturation
Pepsin then binds to protein and breaks protein into shorter strands
protein digestion in mouth
mechanical digestion like chewing
protein digestion in stomach
pepsin breaks down denatured proteins into large peptide fragments, acidic juices like HCl denature the protein
step 1 protein digestion in SI
Polypeptides are broken down into pancreatic proteases in small fragments
step 2 protein digestion in SI
Continues at brush border by proteases anchored to microvilli on surface of mucosal cells
step 3 protein digestion in SI
Individual acids or peptides are absorbed by mucosal cells of SI assisted by transport proteins
step 4 protein digestion in SI
Dipeptides and tripeptides are broken down to single acids and leave cel through transport proteins to enter bloodstream
protein turnover
we don’t store amino acids like we have a store of carbs and a store of fats but instead each cell maintains an amino acid pool that is in constant flux
amino acid pool
comes from protein intake and is a small supply of amino acids present in blood cells used for protein synthesis
protein turnover
once in the amino acid pool these amino acids can be used to make more proteins, make ATP, make glucose or make fatty acids for storage
amino acid
used to make protein or energy
amino acid
use for energy or glucose or fat
deamination
nitrogen is removed and incorporated into urea in liver and then excreted as urine, leaves CHO available to be used in energy pathways, results in dehydration
high protein diet
results in dehydration due to loss of nitrogen through urine
nitrogen lost in body
urine, feces, sweat, skin, hair, nails
zero equilibrium
nitrogen in= nitrogen out
positive equilibrium
more nitrogen in, building muscle, kids, pregnancy
negative equilibrium
more nitrogen out, old, sedentary, losing weight, trauma or burn patients
athletes and protein
don’t actually need more protein but benefit from optimal protein intake for performance advantage
adults over 65 and protein
Reduces loss of lean body mass, improves functionality, reduces risk of diability and health, combine with resistance training
8 grams
1 ounce of lean meat
8 grams
1-1.5 ounces of fish
8 grams
1 jumbo egg
8 grams
½ to 2/3 cup of legumes
8 grams
¼ to 1/3 cup of nuts
8 grams
1 cup of cooked grains
8 grams
1 cup of milk
8 grams
1 ounce of cheese
protein quality
determined by digestibility and amino acid composition
digestibility
how well a protein is digested, complete proteins are more digestible
amino acid composition
does it contain essential proteins
limiting amino acid
If there is not enough of an amino acid to make a particular protein, then that amino acid is the limiting one
complete or high quality protein
all animal proteins and soy, have all the essential amino acids and in the right amounts
incomplete or low quality protein
ll other plant proteins, are low or lacking in one or more of the essential a.a.
complementary proteins
combining 2 incomplete proteins to make a complete protein
made from soy foods
soy milk, tofu, tempeh, natto, edamame
soy protein isolates
very processed, protein bars and shakes
my plate soy
soy milk is only non milk allowed
plant estrogen
in soy foods, lowers breast cancer risk by mimicing estrogen
malnutrition and protein
low protein diets significantly affect countries malnutrition but not the US
high protein diets
High in saturated fats, cholesterol and sodium but low in fiber, phytochemicals, certain vitamins and minerals
paleo and carnivore
low fiber, removes food groups, encourages healthy foods
mediterranean diet
Rich in fruits, veggies, nuts, olive oil, and whole grains and low in processed and red meats, dairy products, sweets
minimally processed foods
reudce risk of heart problems and heart related deaths
vegan
no animal foods
lactoovovegetarian
eggs and dairy
lactovegetarian
dairy
pescatarian
fish
quasi vegetarian
poultry and fish
flexitarian
limited meat, poultry, and fish
semi vegetarian
pescatarian, Quasi vegetarian, flexitarian
plant food
More fiber, vitamin C/E, folate, magnesium, potassium, antioxidants, phytochemicals
plant food
less omega 3, B12, calcium, iron, protein
cancer and diet
diet contributes to 20% of cancers
reduce risk of cancer
stay active, limit red and processed meat, limit salt and alcohol, eat plant based foods
step 1 cancer
initiation or cell mutation
step 2 cancer
promotion or enhance growth
step 3 cancer
tumor progression or cells mutate and expand quickly
step 4 cancer
malignancy or invade surrounding tissue or spread/metastisize to other parts of body
phytochemicals
not nutrients but prevent cancer from starting or spreading
polyphenols
one category of phytochemicals we mainly eat
phytochemicals
provide color, aroma and flavor
increase phytochemicals
eat a rainbow or variety of foods
vegan diet concerns
low protein, zinc, vitamin D and B12, omega 3 and iodine
complement proteins
mix of grain and legume like rice and beans or peanut butter and bread
heme iron
much more bioavailable from animal foods
bioavailability
amount of a nutrient that is absorbed and used by the body
vitamin C
enhances absorption of iron