Week 4 - Protein Flashcards
What are essential amino acids?
amino acids that cannot be synthesized and must be consumed in the diet
What are nonessential amino acids?
amino acids that can be made from others in the body
How many essential amino acids are there?
9
What are BCAAs?
branch-chain amino acids - leucine, isoleucine, and vailne
what is the primary protein structure?
a sequence of amino acids that forms one or more polypeptide chains
what is the secondary protein structure?
the coiling or folding of its polypeptide chains as a result of hydrogen bonding between amino acid chains
What is tertiary protein structure?
a folded three-dimensional shape caused by weak interactions between side groups
What is the quaternary protein structure?
the final 3d structure formed by all the polypeptide chains making up the protein
how is protein broken down in the mouth?
by mechanical digestion (chewing), no enzymes
How is protein digested in the stomach?
hydrochloric acid unfolds protein into long polypeptide chains
How do the pancreas and small intestine contribute to protein digestion?
they contribute enzymes that break polypeptide chains into free amino acids and smaller chains
How and where are amino acids absorbed?
they are absorbed by enterocytes that line the small intestine, then sent to the liver and released into circulation
What are the three fates for absorbed amino acids?
- incorporated into body protein or used to make other nitrogen compounds
- be oxidized for energy (deamination)
- contribute to the body’s glucose, ketone, and lipid pool
how is protein synthesized?
- transcription - DNA is split and copied to mRNA which is a recipe for protein
- translation - mRNA recipe is read to make a polypeptide chain or peptide
What happens if the body is missing a non-essential amino acid during synthesis?
the body will make it or obtain from the pool of amino acids in the liver via bloodstream
What happens if the body is missing an essential amino acid during synthesis?
synthesis will stop and the incomplete protein will be tagged for break down - amino acids will be recycled to the liver pool
What is kwashiorkor caused by
a lack of protein in the diet
what are the effects of kwashiorkor?
change in skin hair color texture, fatigue, diarrhea, loss of muscle, failure to grow,
edema (swelling) of the ankles, feet, and belly
damaged immune system, etc
what is phenylketonuria?
a rare inherited disorder that causes the amino acid phenylalanine to build up in the body
how can phenylketonuria be treated?
a carefully monitored low protein diet, or dietary supplements without phenylalanine
what are the effects of phenylketonuria?
cognitive damage and intellectual disabilities
What is the protein RDA for adults?
0.8g/kg
What percent of daily energy intake should be made up of protein?
10-35%
