1.4 Proteins and Enzymes Flashcards
What bond is formed during the condensation of two amino acids?
A peptide bond forms between the carbon atom of one amino acid and the nitrogen atom of the other.
Describe the condensation of two amino acid monomers?
During condensation, the water molecule is formed by the combination of -OH from the carbonyl group of one amino acid with an -H from the amino group of another amino acid.
What is the primary structure?
The sequence of amino acids in a polypeptide chain
What is the secondary structure?
Polypeptide chain twists into a 3D shape (coils into an alpha-helix or folds into a beta-pleated sheet) due to hydrogen bonds between the amino acids.
What is the tertiary structure?
A complex, specific 3D structure maintained by different bonds.
1. Disulphide bridges - not easily broken
2. Ionic bonds - formed between any carboxyl and amino group not involved in peptide bond. Weaker than disulphide bonds and easily broken by changes in pH
3. hydrogen bonds - easily broken
What is the quaternary structure?
Multiple polypeptide chains link together. There could also be non-protein (prosthetic) groups associated with molecules
Describe the induced fit model of enzyme action
Model proposes that the active site of an enzyme forms as the substrate and enzyme interact. Basically, the enzyme is flexible and moulds itself around the substrate. As it changed shape, it adds strain to the substrate, which distorts particular bonds and consequently lowers the activation energy needed to break the bond.
