proteins Flashcards
kcals/g of protein
4
functions
build tissue
regulate body
energy (non-optimal)
how do proteins regulate body functions
hormones and enzymes for metabolism and digestion
exerts osmotic pressure on cells
pH balance
antibodies
transports fats
whats the blood pH
7.35-7.45
4 things attached to the carbon
amino group, carboxyl group, side chain, H
what bond join amino acids together
peptide bond
classification of proteins
indispensable/essential
dispensable/nonessential
conditionally indispensable
complete proteins
incomplete proteins
complementary proteins
what are indispensable/essential proteins
body cannot make enough so necessary in diet
amino acids that are essential
methionine, tryptophan, phenylalanine, leucine + more
what are dispensable/nonessential
proteins
Can be made in body from other amino acids
amino acids that are nonessential
cysteine, glutamic acid, aspartic acid, glutamine, histidine, tyrosine, proline, serine, more
what are conditionally indispensable proteins
Normally dispensable but sometimes needed in diet
what are complete proteins
contain all the essential
amino acids
bioavailable (ability for body to absorb and use)
sources of complete protein
meats, fish, poultry, eggs milk, cheese
animal proteins
what are incomplete proteins
do not contain all of the essential amino acids
cannot be used singularly to build muscle
sources of incomplete protein
animal: gelatin
corn, peanuts, peas, beans, grains, nuts, seeds
mainly plants
what are complementary proteins
incomplete proteins that when combined provide all ten essential amino acids
examples of complementary proteins
corn and beans
bread and PB
macaroni and cheese
cereal and milk
other sources of proteins
dairy/eggs for lacto-ovo and lacto-vegetarians
albumin - egg whites
gluten - wheat
casein - milk
why are vegetarian diets good
lower risk of obesity, diabetes, cancer, good for treatment of renal disease (less demand on kidneys)
how much protein is digested
92%
state the different locations of protein digestion and explain
mouth: chewing/mastication
stomach: HCl
small intestine
use of HCl in stomach
turn enzymes into inactive forms (pepsinogen in proteins to pepsin)
unfold protein making it more accessible to pepsin
3 ENZYMES IN small intestine that break down proteins
trypsin, carboxypeptidase, chymotrypsin
describe digestion in small intestine
trypsinogen (pancreas) is activated by an enzyme (enterokinase) that makes it active into trypsin.
this trypsin activates chymotrypsinogen into chymotrypsin and procarboxypeptidase into carboxypeptidase
what is deamination and when does it happen
When amino acids are broken down, the nitrogen-containing amine group is stripped off.
what does deamination produce
ammonia -> liver -> urea -> excreted in kidneys
remaining parts changed to energy can become another amino acid.
Rate of deamination depends on
metabolic activity and available supply of amino acids
Tissue turnover meaning
continuous reshaping of protein balance in body
amount of protein a person needs depends on
age, size, sex, physical/emotional situation
recommended protein intake
0.8g protein/kg of body weight
what are some examples of different protein needs in the body
bad digestion, surgery, severe burns, infections, emotional trauma
what is nitrogen balance
when nitrogen intake equals nitrogen excreted
positive nitrogen balance occurs when
nitrogen intake exceeds outgo
pregnant, new muscles forming or reforming after physical trauma
Negative nitrogen balance occurs when
more nitrogen lost than taken in
starvation, burns, injury, fever
% of kcal
10-35%
what does long-term high protein cause
colon cancer
high calcium excretion (deplete calcium in bones -> osteoporosis)
< demand on liver/kidneys because need to excrete excess urea
In children, long time of negative nitrogen balance can cause
retardation
fatal
protein supplements purpose and properties
bulking, finger nails, weight loss, etc.
NOT to build muscles (only diet and exercise can help with that)
not as bioavailable as High-quality protein
protein deficiency signs
muscle wasting -> thin arms and legs
albumin (protein in blood plasma) will go down causing edema and swollen appearance
depressed
protein deficiency usually neglected in what group
children, elderly, poor, or incapacitated
PEM meaning
lack protein and energy-rich foods
2 diseases affecting children are
Marasmus
Kwashiorkor
Marasmus meaning and signs
severe wasting caused by lack of protein and all nutrients or faulty absorption
emancipated but no edema
skin is wrinkled, hair is dull
Kwashiorkor
extreme and sudden lack of protein
fat accumulates in liver
edema (swelling), painful lesions, change in pigmentation
high mortality
those that survive protein deficiency still face permanent…
mental retardation
only plant source of complete proteins
quinoa
what age does body protein reach the adult level of 18% of body weight
4
