Enzymes: Catalysts in Action

Flashcards about Enzymes

Enzyme

A protein that speeds up chemical reactions.

Activation Energy

Energy needed to start a chemical reaction.

Exergonic Reaction

A reaction that releases energy.

Specificity (Enzymes)

Enzymes work only on specific substrates (e.g., one enzyme digests sucrose, not lactose).

Active Site

The location on an enzyme where the substrate binds.

Lock and Key Model

The substrate fits perfectly into the enzyme's active site.

Induced Fit Model

The enzyme changes shape to better fit the substrate.

Competitive Inhibitor

A molecule that blocks the active site, preventing substrate binding.

Noncompetitive (Allosteric) Inhibitor

A molecule that binds to another site, changing the enzyme's shape and reducing activity.

Allosteric Activator

A molecule that increases enzyme activity by improving the active site.

Feedback Inhibition

When the final product inhibits the first enzyme in the pathway.

Optimum Temperature (Enzymes)

The temperature at which an enzyme works best (usually around 37°C for human enzymes).

Optimum pH (Enzymes)

The pH at which an enzyme works best (varies by enzyme, e.g., pepsin pH 1.5, trypsin pH 8).

Extremophiles

Organisms with enzymes that work in extreme conditions (e.g., high heat, extreme pH, salt).

Enzyme vs. Receptor

Enzymes catalyze reactions; receptors trigger cell responses.

Enzyme Nomenclature

Enzyme names often end in '-ase' (e.g., catalase); exceptions exist (e.g., pepsin).

Enzyme Reusability

Enzymes can be reused because they don't change during reactions.

Clinical Relevance of Enzymes

Enzymes are targets for drugs and diagnostic tools (e.g., penicillin, CPK enzyme, ACE inhibitors).