Chapter 3.2 - Proteins

Biomolecules

Most structurally and functionally diverse group involved in almost everything in biology.

Functions of Proteins

Enzymes, structure (keratin, collagen), carriers & transport, receptors & binding, contraction (actin & myosin), signaling (hormones).

Monomer

Amino acid, the basic building block of proteins.

Polymers

Polypeptide chain, formed by linking amino acids.

Peptide Bond

The bond that holds amino acids together in a protein.

3-D Shape

Proteins form large and complex molecules with a unique folded and twisted structure.

Amino Acid Structure

Central carbon, amino group, carboxyl group, and variable R group.

R Group

The variable group in amino acids that gives them unique chemical properties.

Nonpolar Amino Acids

Amino acids with nonpolar and hydrophobic side chains.

Polar Amino Acids

Amino acids with polar or charged (positive or negative) and hydrophilic side chains.

Dehydration Synthesis

The process that creates peptide bonds by linking NH2 of one amino acid to COOH of another, removing H2O.

N-terminal

The beginning of a polypeptide chain, characterized by the NH2 group.

C-terminal

The end of a polypeptide chain, characterized by the COOH group.

Primary Structure

The order of amino acids in a chain, determined by DNA.

Sickle Cell Anemia

A condition caused by a slight change in the amino acid sequence affecting protein structure and function.

Secondary Structure

Local folding of the polypeptide, caused by hydrogen bonding, includes alpha helix and beta pleated sheet.

Tertiary Structure

Global folding of the protein determined by interactions between R groups.

Quaternary Structure

The structure formed when more than one polypeptide chain joins together.

Chaperonin Proteins

Proteins that guide proper folding of other proteins by providing isolated space.

Denaturation

The process of unfolding a protein, disrupting its 3D structure due to changes in pH, temperature, or salt concentration.