Ap Bio Unit 3: Cellular Energetics

Enzyme

A biological catalyst that speeds up the rate of biochemical reactions by lowering the activation energy required for the reaction to proceed

Enzyme-mediated reactions

Any reaction involving an enzyme, from steps of a mechanism to the overall mechanism that occurs with the help of enzymes to increase the reaction rate and efficiency

Active site

A physical location on the enzyme where the reactants (substrates) go to bind, facilitating the chemical reaction

Lock-and-key model

A model explaining the specific interactions between enzymes and substrates based on shape compatibility

Activation energy (Ea)

The amount of energy needed for a chemical reaction to take place

Transition state

The moment in a reaction with the highest amount of free energy before the reaction continues

Denaturation

The process where a protein loses its function due to changes in its environment, such as temperature or pH

Optimal conditions

Specific environmental conditions that allow enzymes to work at their fastest rate

Inhibitor

A molecule that, when attached to an enzyme, makes the active site inaccessible to its specific substrate

Competitive inhibitor

A type of inhibitor that directly competes with the substrate for the active site

Noncompetitive inhibitor

An inhibitor that binds to an allosteric site, changing the enzyme's shape and function without blocking the active site

Bioenergetics

The flow of energy specific to living organisms

Chemical pathway

A series of chemical reactions where the product of one reaction serves as the reactant for the next

Metabolism

The sum of all chemical reactions within an organism

Favorable / spontaneous reaction

A reaction that occurs with a net release of free energy, indicated by G < 0

Unfavorable / nonspontaneous reaction

A reaction that requires an input of energy to occur, indicated by G > 0

Energy coupling

The process of linking a favorable reaction with an unfavorable reaction to help the unfavorable reaction proceed

Photosynthesis

The chemical pathway where sugar molecules (Glucose) are synthesized using Carbon Dioxide, Water, and light energy

Calvin cycle

The light-independent reactions in photosynthesis that convert CO2 into glucose, using ATP and NADPH

Cellular respiration

The chemical pathway that allows for the release of chemical energy from organic molecules to produce ATP

Aerobic respiration

Cellular respiration that occurs in the presence of Oxygen

Anaerobic respiration

Cellular respiration that occurs without Oxygen

Glycolysis

The first step in cellular respiration where glucose is broken down into pyruvate

Fermentation

The process of converting pyruvate into lactic acid or ethanol to produce ATP without Oxygen