AP Biology: Enzymes and Photosynthesis

These flashcards cover key vocabulary and concepts related to enzymes, photosynthesis, and cellular respiration from biology.

Enzyme

A macromolecule that acts as a biological catalyst to speed up chemical reactions.

Active site

The region of an enzyme where substrate molecules bind and undergo a chemical reaction.

Substrate

The reactant on which an enzyme acts.

Induced fit model

The mechanism by which an enzyme changes shape to enhance the fit for the substrate.

Activation energy

The minimum energy required for a chemical reaction to occur.

Gibbs free energy (ΔG)

The energy available to do work in a reaction; it can be used to predict whether a reaction will occur spontaneously.

Competitive inhibitor

A substance that competes with a substrate for binding to the active site of an enzyme.

Noncompetitive inhibitor

A substance that binds to an enzyme at a site other than the active site, reducing its activity.

Photosynthesis

The process by which green plants and some other organisms use sunlight to synthesize foods with the help of chlorophyll.

Calvin Cycle

A cycle of biochemical reactions in photosynthesis that produces glucose from carbon dioxide.

Light-dependent reactions

The first stage of photosynthesis where sunlight is captured and converted to ATP and NADPH.

NADPH

A high-energy electron carrier produced in the light-dependent reactions of photosynthesis.

Reversible denaturation

A process in which an enzyme denatures but can regain its function under favorable conditions.

Krebs cycle

A series of enzymatic reactions that produce ATP and release carbon dioxide from glucose breakdown.

Electron transport chain

A series of protein complexes that transfer electrons to create a proton gradient for ATP synthesis.

Chemiosmosis

The process of using a proton gradient to drive ATP synthesis.

Photolysis

The process of splitting water molecules using light energy during photosynthesis.

Cyclic electron flow

A pathway of electron transport in photosynthesis that produces ATP without NADPH.

Biofilm

A community of microorganisms on a surface, often encased within a protective matrix.

Fermentation

An anaerobic process that allows glycolysis to continue by regenerating NAD+.

Glycolysis

The first step of cellular respiration that breaks down glucose into pyruvate, producing ATP and NADH.

ATP synthase

An enzyme that catalyzes the synthesis of ATP from ADP and inorganic phosphate.

Cyanobacteria

Photosynthetic bacteria that are believed to be the first organisms to produce oxygen through photosynthesis.

Endosymbiotic theory

A theory that explains how eukaryotic cells may have evolved from prokaryotic cells through symbiosis.

Entropy

A measure of disorder in a system, described in the second law of thermodynamics.

Exergonic reaction

A reaction that releases energy; characterized by a negative delta G.

Endergonic reaction

A reaction that requires energy input; characterized by a positive delta G.

Biological catalyst

A substance that increases the rate of a chemical reaction in a biological context without being consumed.

Proton gradient

A difference in proton concentration across a membrane, used in ATP synthesis.

Allosteric site

A site on an enzyme where molecules can bind and regulate the enzyme's activity.

Chemical gradient

A difference in concentration of substances across a space, driving diffusion.

Polar molecule

A molecule with an uneven distribution of electrons, leading to partial positive and negative charges.

Hydrogen ion concentration

The amount of hydrogen ions in a solution, which influences pH.

Oxygen generation

The process by which oxygen is produced, primarily through photosynthesis.

Alkaline environment

An environment with a pH greater than 7, which can affect enzyme activity.

Prokaryotic

Single-celled organisms without a nucleus, such as bacteria.

Eukaryotic

Organisms whose cells contain a nucleus and organelles.

Cellular respiration

The metabolic process by which cells convert glucose and oxygen into energy, carbon dioxide, and water.

Metabolic pathway

A series of chemical reactions in a cell that build up or break down substances.

Photosystem

A protein-pigment complex in the thylakoid membrane responsible for capturing light energy.

Carbon fixation

The process of converting inorganic carbon (CO2) into organic compounds in photosynthesis.