1. Proteins

2. 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.

3. 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.

4. 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.

5. 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

6. 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.