MCAT BIO CH. 3 Flashcards
What are the components of an amino acid structure?
- Alpha amino group
- Variable R-group
- Alpha-carboxyl group
- Tetrahedral alpha-carbon
Draw the amino acid structure?
Page 41 in Biology MCAT
What do all twenty amino acids share?
Same nitrogen-carbon-carbon backbone
What is the unique feature of each amino acid?
Side chain (variable R-group)
What are the two common types of covalent bonds between amino acids in proteins?
The peptide bonds and disulfide bridges
What do peptide bonds link?
Link amino acids together into polypeptide chains (with a nitrogen)
What do disulfide bridges link?
Between cysteine R-groups
What is a residue based on amino acids?
Amino acid a part of a polypeptide chain
What is the first end and the last end of polypeptide chains?
The amino terminus is the first end made during polypeptide synthesis, and the carboxyl terminus is made last
What terminal residue is always written first?
The amino-terminal residue is also always written first
What is proteolysis?
Hydrolysis of a protein by another protein
What is a proteolytic enzyme? What’s another word for it?
Protein that cuts during proteolysis, protease
What bond do proteolytic enzyme cleave?
Specific means of cleaving peptide bonds
What is the important concept of denaturation based on what it involves?
It involves the disruption of a protein’s shape without breaking peptide bonds
What can proteins be denatured by?
Extreme pH, extreme temperatures or tonicity
What is the primary structure of a protein?
Sequence of amino acids
What is the secondary structure of a protein?
Folding of a polypeptide chain into shapes stabilized y hydrogen bonds between backbone NH and CO
What are the two common motifs of secondary structure?
alpha-helix and beta pleated sheets
What are the two types of beta pleated sheets?
parallel b-pleated sheets, anti-parallel b-pleated sheets
What is the tertiary structure of a protein?
Interactions between amino acid residues located more distantly from each other in the polypeptide chain
What drives the folding to form tertiary structures?
Interactions between the R-groups and with water solvent
How does water affect the tertiary structures of proteins?
- Hydrophobic R-groups tend to fold in the interior away from water
- Hydrophilic R groups tend to be exposed to water not he surface
What does the forces drive for the proteins to form into their what..?
Lowest energy conformation
What is disulfide bridge considered? 1o, 2o or 3o
3o