how many different amino acids are there?
20
proteins are made of strings of
amino acids
what groups make up an amino acid?
amino, acid, hydrogen, side
what is the amino group in an amino acid made of?
hydrogen and nitrogen
what part of the amino acid gives the aa its unique identity?
the side group
the three groups of amino acids
essential, nonessential, conditionally essential
amino acids are linked together by
peptide bonds
two amino acids are called a
dipeptide
three amino acids are called a
tripeptide
many amino acids linked together are called a
polypeptide
the reaction that occurs to join amino acids together, losing a water molecule is:
condensation
denaturation
the uncoiling of a protein
what can cause denaturation?
heat, pH, oxidation, agitation
the protein structure
a chain of amino acids linked by peptide bonds
the sequence of amino acids determines the protein's
shape
a protein's shape determines its
function
what is a peptide bond?
a bond between 2 amino acids formed when a carboxyl group (COOH-) of one amino acid joins an amino group (NH2) of another amine acid, releasing water in the process
complete protein
has all 20 amino acids present
incomplete protein
has some of the 20 amino acids missing
what part of the amino acid is measurable in the body/?
nitrogen
proteins are denatured in the stomach by
HCL
protein digestion in the stomach
pepsinogen and pepsin start to break polypeptides apart
pepsinogen
an inactive form of protein enzyme released in the presence of HCL
pepsin
an active form of an enzyme that cleaves the proteins into smaller polypeptides
protein digestion in the small intestine
enzymes from the pancreas and intestines (proteases and peptidases) complete digestion
protease
enzyme that hydrolyzes protein into short peptides called oligopeptides
oligopeptides
peptides made of 4-9 amino acids
peptidases
enzymes that split proteins into amino acids
what happens to the amino acids once peptidase breaks them down from proteins?
they can be absorbed into the bloodstream and brought to the liver
does the body handle broken down or whole proteins better?
whole
protein synthesis
mrna goes into a cell's nucleus, copies the dna, takes it out to a ribosome and waits for a trna to bring the correct assortment of amino acids to form the necessary protein
why does the sequence of amino acids matter?
sequence determines shape which then impacts function, so by changing the sequence you change the function
the 8 roles of protein
growth, enzymes, hormones, regulation of fluid balance, acid-base regulation, transport proteins, antibodies, source of energy and glucose
how do proteins regulate fluid balance?
plasma proteins attract water, they prevent edema
how do proteins regulate acid-base levels?
proteins act as buffers, accepting or donating H+ ions into the blood to keep blood at a certain pH
acidosis
proteins release H+
alkalosis
proteins accept H+
transport proteins act as ____ in cell membranes
pumps
protein turnover
proteins are constantly being broken down for use and regenerated
amino acid pool
the supply of aa available for protein synthesis
zero nitrogen balance
the amount of nitrogen consumed equals the amount excreted
positive nitrogen balance
the amount of nitrogen consumed is greater than the amount excreted
negative nitrogen balance
the amount of nitrogen consumed is less than the amount excreted
PEM stands for
protein energy malnutrition
PEm
inadequate calories and/or protein
two types of PEM
kwashiorkor, marasmus
kwashiorkor
severe dietary protein deficiency
marasmus
severe caloric deficiency
the health effects of too much protein
heart disease, osteoporosis, obesity, cancer
conditionally essential amino acids
nonessential amino acids that are made from essential amino acids; when the body doesn't get enough of the essential, it can't make the nonessential, making it conditionally essential
protein absorption
carriers transport amino acids into intestinal cells to be used for energy or to synthesize needed compounds before unused ones are transported to the the liver
high quality protein
dietary proteins containing all the essential amino acids in relatively the same amounts that human beings require
reference protein
a standard against which to measure the quality of other proteins
complementary proteins
two or more dietary proteins whose amino acid assortments complement each other in such a way that the essential amino acids missing from one are supplied by the other
signs of kwashiorkor
edema, muscle loss, skin rashes, hair changes, water and electrolyte imbalances
signs of marasmus
emaciation, lack of growth, loss of fat stores
what is the RDA for protein?
.8g/kg weight
what is the AMDR for protein?
10-35%