Chapter 6: Energy, Enzymes, and Metabolism

These flashcards cover key concepts related to energy, enzymes, and metabolism as outlined in Chapter 6.

Catalyst

An agent that speeds up the rate of a chemical reaction without being consumed during the reaction.

Enzymes

Protein catalysts in living cells that speed up reactions.

Activation Energy (EA)

The initial input of energy required for a chemical reaction to occur.

Active Site

The location where the reaction takes place on an enzyme.

Substrate

The reactant that binds to the active site of an enzyme, forming an enzyme-substrate complex.

Specificity

The high degree of selectivity of an enzyme's active site for its substrate, often described by the "lock and key" model.

Induced Fit

The conformational change in an enzyme and substrate upon binding.

Michaelis Constant (Km)

The substrate concentration at which the reaction velocity is half maximal.

Competitive Inhibition

Occurs when an inhibitor binds to the active site of an enzyme.

Noncompetitive Inhibition

Occurs when an inhibitor binds to an allosteric site on an enzyme.

Metabolism

The sum of all chemical reactions that occur within a living organism.

Catabolic Reactions

Reactions that result in the breakdown of complex molecules, releasing energy (exergonic).

Anabolic Reactions

Reactions that synthesize complex molecules, requiring energy input (endergonic).

Redox Reactions

Reactions that involve the transfer of electrons, including oxidation and reduction.

Oxidation

The removal of electrons from organic molecules or atoms.

Reduction

The addition of electrons to an organic molecule or atom.

Feedback Inhibition

A form of biochemical regulation where the product of a pathway inhibits an early step in that pathway.

Half-Life

The time required for 50% of a molecule to be broken down and recycled.

Autophagy

The process of recycling worn out organelles using an autophagosome.

Proteasomes

Large complexes that break down proteins using protease enzymes.

Ubiquitin

A small protein that tags unwanted proteins for degradation by the proteasome.