IB Biology: Proteins

Proteins

Biomolecules composed of amino acid chains.

Amino Acids

Building blocks of proteins with variable side chains.

Alpha Carbon

Central carbon atom in amino acids.

Peptide Bond

Covalent bond between amino acids' amine and carboxyl groups.

Polypeptides

Chains of amino acids linked by peptide bonds.

Essential Amino Acids

Cannot be synthesized by the body, must be ingested.

Non-Essential Amino Acids

Can be synthesized by the body from other amino acids.

Conditional Amino Acids

Required during specific conditions like illness or pregnancy.

Protein Deficiency Malnutrition

Health issues from lack of essential amino acids.

Hydrolysis Reactions

Breakdown of polypeptides into amino acids using water.

Primary Structure

Sequence of amino acids in a polypeptide chain.

Secondary Structure

Folding patterns like alpha helices and beta sheets.

Alpha Helices

Coiled structure formed by hydrogen bonds in proteins.

Beta-Pleated Sheets

Staggered strand conformation in protein folding.

Tertiary Structure

Three-dimensional shape of a protein determined by side chains.

Quaternary Structure

Complex of multiple polypeptide chains or prosthetic groups.

Denaturation

Loss of protein structure and function due to stress.

Hydrophobic Properties

Non-polar amino acids cluster inside globular proteins.

Hydrophilic Properties

Polar amino acids interact with water, influencing protein function.

Integral Proteins

Proteins embedded in cell membranes with hydrophobic regions.

Chemical Diversity

Variety in amino acid side chains affects protein function.

Protein Functions

Roles include structure, hormones, immunity, transport, and enzymes.

Hydrogen Bonds

Weak bonds stabilizing protein structures like secondary and tertiary.

Ionic Bonds

Attractions between charged side chains affecting protein shape.

Disulfide Bridges

Covalent bonds between cysteine residues stabilizing protein structure.

Zwitterions

Amino acids with both positive and negative charges.

Optimal pH

pH level at which a protein functions best.

Thermal Energy

High temperatures disrupt hydrogen bonds in proteins.