Chapter 03: Energy, Chemical Reactions and Cellular Respiration Flashcards

A set of vocabulary flashcards covering the key terms of energy, enzyme kinetics, and cellular respiration based on the Chapter 03 lecture notes.

Energy

The capacity to do work.

Potential energy

The energy of position or stored energy.

Kinetic energy

The energy of motion.

ATP

The “energy currency” of cells formed through the breakdown of glucose.

Metabolism

All biochemical reactions in living organisms.

Chemical reactions

Processes that occur when chemical bonds in existing molecular structures are broken.

Reactants

Substances present prior to the start of a chemical reaction, written on the left side of a chemical equation.

Products

Substances formed by a chemical reaction, written on the right side of a chemical equation.

Reaction rate

A measure of how quickly a chemical reaction takes place.

Activation energy ($E_a$)

The energy required to break existing chemical bonds; it is a primary factor determining reaction rate.

Enzymes

Biologically active catalysts that accelerate chemical reactions by decreasing the activation energy.

Active site

A unique 3-dimensional structure in the protein chain of an enzyme where a substrate binds.

Enzyme-substrate complex

The temporary structure formed when a substrate binds to the active site of an enzyme.

Induced fit model

A mechanism where an enzyme changes shape slightly when a substrate enters the active site, resulting in an even closer fit.

Optimal temperature

The temperature at which human enzymes function best, usually $40^{\circ}\text{C}$ ($104^{\circ}\text{F}$).

Optimal pH

The pH range, typically between $6$ and $8$, where most enzymes function best.

Denaturation

The loss of an enzyme's 3-dimensional shape and function due to severe increases in temperature or significant changes in pH.

Competitive inhibitor

An inhibitor that resembles the substrate and competes for occupation of the enzyme's active site.

Noncompetitive inhibitors

Also called allosteric inhibitors; these bind to a site other than the active site (allosteric site) and induce a conformational change in the enzyme.

Cellular respiration

A multistep metabolic pathway where organic molecules like glucose are disassembled by enzymes to transfer energy to ADP and $P_i$ to form ATP.

Oxidized

The state of an organic molecule that has given up its energy by releasing high energy electrons.

Glycolysis

The first stage of cellular respiration, which can occur with or without $O_2$.

Four stages of cellular respiration

Glycolysis, Intermediate stage, Citric acid cycle, and Electron Transport System.