Chapter 8 Exam 2 Study guide

Metabolism

All chemical reactions and physical workings occurring within a cell.

Anabolism

Energy-requiring process that builds complex molecules from simpler molecules; biosynthesis.

Catabolism

Process that breaks down complex molecules into simpler molecules and releases energy.

Enzyme

Biological catalyst that speeds up chemical reactions without being consumed.

Catalyst

Substance that increases the rate of a chemical reaction without being permanently changed.

Characteristics of Enzymes

Protein nature, substrate specificity, extreme efficiency, environmental sensitivity, reversibility, regulation, inhibition, and activation.

Active Site

Specific region on an enzyme where the substrate binds and the reaction occurs.

Substrate

Reactant molecule upon which an enzyme acts.

Factors Affecting Enzyme Function

Temperature, pH, substrate concentration, enzyme concentration, inhibitors, activators, and denaturation.

Denaturation

Loss of an enzyme's three-dimensional shape and function due to environmental changes such as heat or pH.

Exoenzyme

Enzyme produced inside a cell and secreted outside to perform its function.

Endoenzyme

Enzyme that functions within the cell that produced it.

Constitutive Enzyme

Enzyme produced continuously regardless of environmental conditions.

Regulated Enzyme

Enzyme whose production or activity is controlled according to cellular needs.

Exergonic Reaction

Chemical reaction that releases energy.

Endergonic Reaction

Chemical reaction that requires an input of energy.

Relationship of Exergonic Reactions to Metabolism

Typically associated with catabolic pathways that release energy.

Relationship of Endergonic Reactions to Metabolism

Typically associated with anabolic pathways that require energy.

Aerobic Respiration

Process of producing ATP from glucose using oxygen as the final electron acceptor.

Major Stages of Aerobic Respiration

Glycolysis, Pyruvate Oxidation, Krebs Cycle, Electron Transport Chain (ETC), and Oxidative Phosphorylation.

Glycolysis Beginning Product

Glucose.

Glycolysis Ending Products

2 Pyruvate, 2 ATP (net), and 2 NADH.

ATP Yield of Glycolysis

2 ATP (net).

Pyruvate Oxidation Beginning Product

2 Pyruvate.

Pyruvate Oxidation Ending Products

2 Acetyl-CoA, 2 NADH, and 2 CO₂.

ATP Yield of Pyruvate Oxidation

0 ATP.

Krebs Cycle Beginning Product

2 Acetyl-CoA.

Krebs Cycle Ending Products

4 CO₂, 2 ATP, 6 NADH, and 2 FADH₂.

ATP Yield of Krebs Cycle

2 ATP.

Electron Transport Chain Beginning Products

NADH, FADH₂, oxygen, and electrons.

Electron Transport Chain Ending Products

Water and approximately 25–34 ATP.

ATP Yield of Electron Transport Chain

Approximately 25–34 ATP.

Total ATP Yield of Aerobic Respiration

Approximately 29–38 ATP per glucose molecule.

Aerobic Respiration Requires

Oxygen.

Aerobic Respiration End Products

ATP, carbon dioxide, and water.

Anaerobic Respiration

Respiration that occurs without oxygen and uses an alternative final electron acceptor.

Difference Between Aerobic and Anaerobic Respiration

Aerobic uses oxygen and produces more ATP; anaerobic does not use oxygen and produces less ATP.

Fermentation

An anaerobic process that converts glucose into acids, gases, or alcohols while regenerating NAD⁺.

Purpose of Fermentation

Regenerates NAD⁺ so glycolysis can continue in the absence of oxygen.

Lactic Acid Fermentation

Fermentation that converts pyruvate into lactic acid.

Ethanol Fermentation

Fermentation that converts pyruvate into ethanol and carbon dioxide.

Acetic Acid Fermentation

Fermentation that produces acetic acid (vinegar).

ATP Yield of Fermentation

2 ATP per glucose molecule.

Amphibolism

Metabolic pathways that function in both catabolism and anabolism.

Photosynthesis

Process by which light energy is converted into chemical energy.

Two Main Parts of Photosynthesis

Light-dependent reactions and light-independent reactions (Calvin Cycle).

Light-Dependent Reactions

Use light energy to produce ATP and NADPH.

Calvin Cycle

Uses ATP and NADPH to fix carbon dioxide into sugars.

Final Product of Photosynthesis

Glucose.

Overall Photosynthesis Equation

6CO₂ + 6H₂O + Light → C₆H₁₂O₆ + 6O₂