Proteins & Enzymes 1 Flashcards
Define covalent bonds.
Atoms share one or more pairs of electrons so that the outer shells are filled.
Define polar covalent bond.
Results when electrons are drawn to one nucleus more than to the other, because one atom has more electronegativity.
Define ionic bonds.
When one atom is so electronegative that it removes an electron from another atom to form an ionic bond.
Define isomers.
Molecules with the same chemical formula but atoms are arranged differently.
Define structural isomers.
Differ in how their atoms are joined together.
Define optical isomers.
Occur when a carbon atom has four different atoms or groups of atoms attached to it.
What are the four macromolecules present in living things?
- Proteins
- Nucleic acids
- Carbohydrates
- Lipids.
Name the functions of proteins.
- Enzymes
- Signalling
- Carriers/transporters
- Storage
- Structural
- Glue for cells to stick together.
- Hormones
- Receptor proteins.
Define polypeptide chain.
Single unbranched chain of amino acids.
Are amino acids acids or bases?
Possess carboxyl and amino groups so function as both.
How does a disulfide bridge form and what is its purpose?
When the terminal SH group of cysteine reacts with another cysteine side chain. Important in protein folding.
Describe the primary structure of a protein?
The sequence of amino acids.
Describe the secondary structure of a protein.
a helix - right handed cool resulting from hydrogen bonding between N-H groups on one amino acid and C=O groups on another.
B pleated sheet - two or more polypeptide chains are aligned; hydrogen bonds form between the chains.
Describe the tertiary structure of a protein.
Bending and folding results in a macromolecule with specific three dimensional shape.
What R-groups determine the tertiary structure?
- Disulfide bridges
- Hydrogen bonds
- Aggregation of hydrophobic side chains
- van der Waals forces
- Ionic bonds.
