unit 3 for bio

Bioenergetics

The study of how cells accomplish energy transformations.

First Law of Thermodynamics

Energy cannot be created or destroyed; it must be harvested from somewhere.

Second Law of Thermodynamics

Energy transfer leads to less organization; the universe tends toward disorder (entropy).

Exergonic Reaction

A reaction where the products have less energy than the reactants.

Endergonic Reaction

Reactions that require an input of energy; products have more energy than the reactants.

Enzyme

A biological catalyst that speeds up reactions by lowering activation energy.

Enzyme Specificity

The property that each enzyme catalyzes only one kind of reaction.

Substrate

Targeted molecules in enzymatic reactions.

Active site

The region on an enzyme where substrates bind and reactions occur.

Enzyme-Substrate Complex

The temporary complex formed when an enzyme binds with its substrate.

Induced-fit model

The change in enzyme shape to better fit the substrate.

Cofactor

A factor that assists enzymes, can be organic molecules (coenzymes) or inorganic molecules.

Denatured Enzyme

An enzyme that has lost its functional shape due to high temperature or incorrect pH.

Saturation Point

The concentration of substrate where all enzyme active sites are filled.

Competitive Inhibition

A type of enzyme regulation where an inhibitor competes with the substrate for the active site.

Allosteric Inhibition

A type of enzyme regulation where the inhibitor binds to an allosteric site, altering enzyme function.

ATP (Adenosine Triphosphate)

The energy currency of the cell, produced through cellular processes.

Cellular Respiration

The process by which cells break down glucose to produce ATP.

Glycolysis

The first stage of cellular respiration, where glucose is split into two pyruvic acid molecules.

Krebs Cycle

A stage of aerobic respiration where acetyl-CoA is processed to produce ATP, NADH, and FADH2.

Oxidative Phosphorylation

The final stage of cellular respiration, involving the electron transport chain and chemiosmosis.

Fermentation

An anaerobic process that allows glycolysis to continue in the absence of oxygen.

Facultative Anaerobes

Organisms that can perform both aerobic and anaerobic respiration.

Light-dependent reactions

Stage of photosynthesis that converts light energy into chemical energy, producing ATP and NADPH.

Calvin Cycle

The light-independent reactions of photosynthesis that use ATP and NADPH to synthesize sugars.

Photolysis

A process of splitting water molecules into hydrogen and oxygen using light energy.

Carbon Fixation

The initial carbon dioxide fixation process in the Calvin cycle, forming a 3-carbon compound.

RuBisCO

An enzyme in the Calvin cycle that catalyzes the carboxylation of RuBP.

Catabolic Pathways

Metabolic pathways that release stored energy by breaking down complex molecules.

Anabolic Pathways

Metabolic pathways that consume energy to build complicated molecules from simpler ones.

Electron Transport Chain (Photosynthesis)

A series of proteins embedded in the thylakoid membrane that facilitates the transfer of electrons during photosynthesis.

Chemiosmosis

The synthesis of ATP coupled to electron transport and proton movement across a membrane.