Chapter 8 Energy & Metabolism

Flashcards covering key concepts related to energy and metabolism including definitions of various processes and molecules involved.

Energy

The capacity to do work, expressed in units of work (KJ) or heat energy (kcal).

Metabolism

The total of all chemical reactions that occur within a living organism, divided into anabolism and catabolism.

Anabolism

Processes that build complex molecules from simpler ones.

Catabolism

Processes that break down complex molecules into simpler ones.

Dynamic equilibrium

A state where the concentrations of reactants and products remain constant as forward and reverse reaction rates are equal.

Exergonic reaction

A reaction that releases energy, where products have less free energy than reactants, and is thermodynamically favored.

Endergonic reaction

A reaction that absorbs energy and stores it in chemical bonds, where products have more free energy than reactants.

ATP (Adenosine Triphosphate)

A molecule that supplies energy to cells through hydrolysis, releasing approximately 30 kJ/mol.

Phosphate group transfer

A method of energy transfer in cellular reactions often involving the transfer of a phosphate group.

Redox reactions

Reactions involving the transfer of electrons where oxidation is the loss of electrons and reduction is the gain of electrons.

NAD+/NADH

Electron carriers involved in redox reactions, where NAD+ is the oxidized form and NADH is the reduced form.

Enzymes

Organic molecules that act as catalysts in chemical reactions, increasing reaction rates by lowering activation energy.

Activation energy

The energy required to break existing bonds of reactants in order for a chemical reaction to proceed.

Enzyme-substrate complex

A temporary complex formed when an enzyme binds to its substrate, facilitating the reaction.

Induced fit

A model describing how enzymes change shape to provide optimal fit for substrates.

Optimal conditions for enzyme activity

Specific temperature and pH ranges at which enzymes function efficiently.