Flashcards in Chapter Six - Protein Deck (51)
What is Protein? (3)
1. Component of every living cell
2. Made of amino acids
3. Every amino acid contains nitrogen (proteins are about 16% nitrogen by weight)
Calculation for protein intake
Nitrogen intake (g) X 6.25 = protein intake (g)
What is an amino group?
True or False: all amino acids have the same side chain.
False, the side chain is unique to each amino acid.
What is the side chain for glycine?
What is the side chain for methionine?
CH2 - CH2 - S - CH3
What is the side chain for phenylalanine?
CH2 - ring structure
What is PKU?
Phenylketonuria, people with this cannot normally metabolize phenylalanine and it accumulates in the body and results in damage to the CNS. Phenylalanine is found in aspartame and nutrasweet.
What does phenylalanine break down to in normal metabolism?
What does phenylalanine break down to in people with PKU?
What are the essential amino acids?
Methionine, phenylalanine, isoleucine, leucine, lysine, histidine, threonine, tryptophan, valine.
What reaction causes a peptide bond?
Dehydration reaction (takes water out).
What is the primary structure of a protein?
The linear sequence of amino acids.
What is the secondary structure of a protein?
Shapes within parts of the protein. (Helical, beta pleated sheet, linear)
What is the tertiary structure of a protein?
Final 3D structure of the protein, determined by the amino acid sequence of the protein.
What is critical to the function of a protein?
The protein's shape, altering the amino acid sequence can change the protein function dramatically.
How many amino acid chains are in insulin?
Two amino acid chains. There are only 3 amino acids that make the difference between the insulin of a pig, human, and cow.
What is denaturation?
Changing the shape of the protein by altering the bonds of the protein through heat or chemicals, making the protein change shape and loose its function.
What does a change in a single amino acid in the hemoglobin protein result in?
Sickle cell anemia.
What foods provide most of our protein?
Cereal products, dairy products, meats.
What proteins help regulate body processes?
Some hormones (e.g. insulin), enzymes (e.g. lipase, amylase, trypsin), neurotransmitters (e.g. serotonin).
What proteins help with growth and repair of tissues?
Muscle proteins (collagen, actin and myosin [muscle contraction and relaxation]).
What is normal turnover?
The breakdown and replacement of all body tissues/organs.
What proteins help with immune defence?
What proteins help with transportation?
Hemoglobin (oxygen), transferrin (blood transport protein for iron).
Where does most of protein digestion start?
The stomach, with hydrochloric acid denaturing proteins. Pepsin is an active enzyme that breaks apart proteins into peptide.
What pre-enzymes come from the pancreas?
Trypsinogen and chymotrypsinogen.
What active enzymes come from the small intestine?
Intestinal enterokinase, which activates trypsinogen.
What does Trypsin do?
Activates various intestinal pre-peptidases and chymotrypsinogen, and works together with chymotrypsin to cleave peptides into smaller peptides.