Bio 1 Unit 2 Study Guide (comprehensive)

Amino Acid

Building blocks of proteins, consisting of an amino group, a carboxyl group, a hydrogen atom, and a variable R group.

Primary Structure

The sequence of amino acids in a polypeptide chain.

Secondary Structure

Local folded structures that form within a protein due to interactions between backbone atoms, typically resulting in α-helices and β-sheets.

Tertiary Structure

The overall three-dimensional shape of a single polypeptide chain, determined by interactions among various side chains (R groups).

Quaternary Structure

The complex formed by the assembly of multiple polypeptide chains into a single functional protein.

Denaturation

Process in which a protein loses its natural structure and function due to factors such as changes in pH, temperature, or salt concentration.

Enzyme

Biological macromolecules that act as catalysts, speeding up chemical reactions without being permanently altered in the process.

Activation Energy

The minimum energy required for a chemical reaction to occur.

Enzyme-Substrate Complex

Temporary complex formed when an enzyme binds to its substrate.

Competitive Inhibition

Situation where a molecule similar to the substrate competes with the substrate for binding to the active site of an enzyme.

Non-Competitive Inhibition

Inhibition where the inhibitor binds to an enzyme at a site other than the active site, altering the enzyme's shape and function.

Allosteric Site

A specific site on an enzyme where an inhibitor or activator can bind, causing a change in the enzyme's shape and function.

Allosteric Activator

A molecule that binds to an allosteric site on an enzyme and increases its activity.

Catabolism

The metabolic process that breaks down molecules into smaller units, releasing energy.

Anabolism

The metabolic process that builds larger molecules from smaller units, requiring energy.

Induced Fit

A model of enzyme action that suggests that the binding of a substrate induces a change in the enzyme's shape to facilitate the reaction.

Types of Interactions that Make Up Each Level of Protein Structure

Primary structure is determined by peptide bonds, secondary by hydrogen bonds, tertiary by various interactions (hydrogen, ionic, hydrophobic, and disulfide bonds), and quaternary structure by the interactions among multiple polypeptide chains.

Disulfide Bond

A covalent bond formed between the sulfur atoms of two cysteine residues, contributing to protein stability.