Energy, Chemical Reactions, and Enzymes in Organisms

Energy

Required for all cellular activities and functions.

Producers

Organisms that convert CO2 and water into sugars.

Photosynthesis

Process converting sunlight into chemical energy.

Consumers

Organisms that obtain energy by eating producers.

Metabolism

Total of all chemical reactions in cells.

Anabolic reactions

Build larger molecules from smaller ones.

Catabolic reactions

Break down large molecules into smaller ones.

Potential Energy

Stored energy with the potential to do work.

Kinetic Energy

Energy associated with movement and activity.

Chemical Bond Energy

Energy stored in chemical bonds of molecules.

First Law of Thermodynamics

Energy cannot be created or destroyed, only transformed.

Entropy

Measure of disorder in a system.

Second Law of Thermodynamics

Energy conversions are never 100% efficient.

Heat

Energy transfer that increases molecular motion.

Mechanical Energy

Energy used in muscle movement.

Energy Efficiency

Percentage of energy converted to useful work.

Cellular Respiration

Process of breaking down glucose for energy.

ATP

Energy currency of the cell.

Vesicles

Small membrane-bound sacs transporting materials.

Motor Proteins

Proteins that move vesicles within cells.

Immune Cells

Cells that patrol the body for pathogens.

Nerve Cells

Cells that transmit signals throughout the body.

Heart Cells

Cells that contract to pump blood.

Concentration Gradient

Difference in concentration across a membrane.

Electric Charge Imbalance

Difference in charge distribution across a membrane.

Ecological Pyramid

Representation of energy flow in ecosystems.

Energy Replenishment

Constant need for energy supply in organisms.

Gibb's Free Energy (G)

Usable energy for cellular reactions.

Entropy (S)

Unusable energy lost to disorder.

Enthalpy (H)

Total energy in a system.

ΔG

Change in usable energy for a reaction.

Endergonic Reactions

Require energy input, ΔG is positive.

Exergonic Reactions

Release energy, ΔG is negative.

Anabolic Reactions

Building processes, typically endergonic.

Catabolic Reactions

Breaking processes, typically exergonic.

ATP

Main energy currency of the cell.

ADP

Adenosine diphosphate, precursor to ATP.

Activation Energy (Ea)

Energy needed to initiate a reaction.

Transition State

Unstable state during a reaction.

Enzymes

Proteins that speed up biochemical reactions.

Enzyme-Substrate Complex

Temporary complex formed during enzyme action.

Active Site

Region where substrate binds on an enzyme.

Kinetic Energy

Energy of motion, needed for reactions.

Hydrolysis Reaction

Breaking bond to release energy.

Condensation Reactions

Reactions that build larger molecules.

Active Transport

Movement of molecules against a gradient.

Motor Proteins

Proteins that facilitate movement in cells.

Molecular Motion

Random movement of atoms and molecules.

Specificity of Enzymes

Enzymes bind only specific substrates.

Energy Coupling

Using energy from exergonic reactions for endergonic.

Caloric Measurement

Energy changes measured in calories or joules.

ΔH

Change in enthalpy during a reaction.

ΔS

Change in entropy during a reaction.

Temperature (T)

Factor affecting energy changes in reactions.

Energy Loss

Occurs in reactions with negative ΔG.

Enzyme

Biological catalyst speeding up chemical reactions.

Active Site

Region on enzyme where substrate binds.

Induced Fit

Enzyme shape change upon substrate binding.

Reaction Rate

Speed at which reactants convert to products.

Enzyme Occupancy

Maximum enzyme activity reached with substrate saturation.

Activation Energy (EA)

Energy barrier that must be overcome for reaction.

Inhibitors

Substances that decrease enzyme activity.

Reversible Inhibitors

Non-covalently bind to enzymes, allowing recovery.

Irreversible Inhibitors

Covalently bind, permanently disabling enzyme function.

Allosteric Regulators

Bind away from active site, altering enzyme shape.

Competitive Inhibitors

Compete with substrate for active site binding.

Noncompetitive Inhibitors

Bind elsewhere, changing enzyme shape and function.

Feedback Inhibition

Final product inhibits first enzyme in pathway.

Phosphorylation

Addition of phosphate group to activate enzymes.

Dephosphorylation

Removal of phosphate group to deactivate enzymes.

Optimal pH

pH level where enzyme activity is maximized.

Denaturation

Loss of enzyme structure, resulting in loss of function.

Temperature Effect

Higher temperatures increase reaction rates to a point.

DIPF

Irreversible inhibitor of acetylcholinesterase, a neurotoxin.

Sarin

Nerve gas that irreversibly inhibits acetylcholinesterase.

Malathion

Insecticide targeting insect enzymes specifically.

Methotrexate

Anti-cancer drug that competitively inhibits purine synthesis.

Enzyme Regulation

Control of enzyme activity through various mechanisms.

Metabolic Pathways

Series of enzyme-catalyzed reactions in cells.

Substrate Concentration

Amount of substrate available for enzyme activity.

Kinetic Energy

Energy of motion affecting reaction rates.

pH Measurement

Logarithmic scale measuring hydrogen ion concentration.

Amino Acid R-groups

Side chains affecting enzyme structure and function.

Cellular Control

Precise regulation of enzyme activity by cells.

Enzyme Shape

Determined by amino acid interactions, crucial for function.

Nerve Impulse

Signal transmission in neurons, requiring acetylcholinesterase.