Unit 3: Cellular Energetics (copy)

Bioenergetics

The study of how cells accomplish energy transfer and transformation.

First Law of Thermodynamics

Energy cannot be created or destroyed, only transferred from one form to another.

Second Law of Thermodynamics

Energy transfer leads to less organization in the universe, tending toward disorder (entropy).

Exergonic Reactions

Reactions where the products have less energy than the reactants.

Endergonic Reactions

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

Catalyst

A substance that speeds up a reaction without being consumed in the process.

Enzyme

A biological catalyst that lowers activation energy and facilitates reactions.

Activation Energy

The minimum energy required to initiate a chemical reaction.

Enzyme Specificity

The concept that each enzyme catalyzes only one specific type of reaction.

Substrates

The target molecules that enzymes act upon in a biochemical reaction.

Active Site

A special region on the enzyme where the substrate binds to form an enzyme-substrate complex.

Induced-fit model

The mechanism where an enzyme changes shape to fit the substrate more effectively.

Cofactors

Additional non-protein molecules required by some enzymes to assist in catalyzing reactions.

Denatured Enzyme

An enzyme that has lost its functional shape due to extremes in temperature or pH.

Saturation Point

The substrate concentration point at which all enzyme active sites are occupied.

Competitive Inhibition

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

Allosteric Sites

Specific sites on an enzyme that allow molecules to bind and modulate enzyme activity.

ATP (Adenosine Triphosphate)

The primary energy carrier in cells that provides energy for cellular processes.

Cellular Respiration

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

Photosynthesis

The process by which light energy is converted into chemical energy, forming glucose from CO2 and H2O.

Calvin-Benson Cycle

The light-independent reactions of photosynthesis that convert CO2 into carbohydrates.

Glycolysis

The first stage of cellular respiration that breaks down glucose into pyruvic acid.

Krebs Cycle

A series of reactions in the mitochondria that produce ATP, NADH, and FADH2 from acetyl-CoA.

Oxidative Phosphorylation

The final stage of cellular respiration where ATP is produced using the electron transport chain and chemiosmosis.

Chemiosmosis

The process of ATP production driven by the movement of hydrogen ions across a membrane.

Fermentation

The anaerobic process by which glucose is partially broken down, yielding a small amount of ATP without oxygen.