Proteins

Protein Functions: Enzymes Defensive Proteins catalytic molecules that speed up reactions. Defensive Proteins Antibodies -recognize and respond Hormonal and Regulatory Proteins Insulin – control physiological processes Receptor Proteins Receive and respond to molecular signals.

Protein Functions: Storage Proteins Structural Proteins Store amino acids for later use. Structural Proteins Collagen – provide physical stability and enable movement. Transport Proteins Hemoglobin -Carry Substances within the organisms Genetic Regulatory Proteins Transcription factors –regulate when, how, and to what extent a gene is expressed.

Amino Acids Monomers that make up proteins. Contain 2 functional groups. Amino group and carboxyl group Identified by its ‘R’ group Hundreds of Amino Acids in Nature, but on 20 Amino Acids occur extensively in the proteins of all organisms.

20 Amino Acids 5 amino acids 7 amino acids Electronically charged side chains Hydrophilic attract oppositely charged ion. Polar side change Tend to form hydrogen bonds with water Hydrophilic 7 amino acids Side chains are nonpolar hydrocarbons Hydrophobic

Glycine Proline Cysteine Side Chain Side chain consists of a single H atom Small enough to fit into tight corners in the interior of a protein molecules. Proline Modified amino group that lacks of a H atom. Forms a covalent bond with the Hydrocarbon chain. Results in a ring structure Limits both its hydrogen-bonding ability and its ability to rotate. Used to stabilize bonds and loops in proteins. Cysteine Side Chain Has a terminal –SH group Can react with another cysteine side chain to form a covalent bond Disulfage bridge (disulfide bond) -S-S- Determines how a protein molecules fold.