Chapter 7: Cellular Respiration Study Guide

Cellular Respiration

The process by which cells extract energy from glucose to produce ATP.

Significance of Cellular Respiration

Essential for powering cellular activities.

Cellular Respiration Equation

C6H12O6 + 6O2 → 6CO2 + 6H2O + ATP.

Oxidation

Loss of electrons.

Connection of Oxidation to Cellular Respiration

Glucose is oxidized during cellular respiration.

Reduction

Gain of electrons.

Connection of Reduction to Cellular Respiration

Oxygen is reduced to water.

Electron Carriers

Molecules that transport electrons during redox reactions.

Significance of Electron Carriers

Carry high-energy electrons to the electron transport chain (ETC).

NAD+

An electron carrier that accepts electrons and becomes NADH.

FAD

An electron carrier that becomes FADH₂ after gaining electrons.

Glycolysis

The first step in cellular respiration occurring in the cytoplasm.

Products of Glycolysis

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

Significance of Glycolysis

First step, no oxygen required.

Pyruvate Oxidation

Process converting pyruvate to Acetyl-CoA, CO₂, and NADH.

Location of Pyruvate Oxidation

Mitochondrial matrix.

Citric Acid Cycle

Also known as the Krebs Cycle, occurring in the mitochondrial matrix.

Products per Glucose in Citric Acid Cycle

6 NADH, 2 FADH₂, 2 ATP, 4 CO₂.

Function of Citric Acid Cycle

Regenerates oxaloacetate and feeds electrons to ETC.

Oxidative Phosphorylation

Major ATP production site in cellular respiration.

Location of Oxidative Phosphorylation

Inner mitochondrial membrane.

Steps of Oxidative Phosphorylation

Consists of Electron Transport Chain + Chemiosmosis.

Substrate-Level Phosphorylation

Direct transfer of phosphate to ADP.

Occurs In Substrate-Level Phosphorylation

Glycolysis and Citric Acid Cycle.

Chemiosmosis

H+ ions flow through ATP synthase to generate ATP.

Connection Between Chemiosmosis and Proton Gradient

Uses the proton gradient from ETC.

ATP Synthase

Enzyme that synthesizes ATP as protons flow through.

ETC

Series of protein complexes transferring electrons.

Final Electron Acceptor in ETC

O₂, forming H₂O.

Fermentation

Anaerobic process that does not require oxygen.

Lactic Acid Fermentation

Conversion of pyruvate into lactate, occurs in muscles.

Alcohol Fermentation

Conversion of pyruvate into ethanol and CO₂, occurs in yeast.

NAD+ Regeneration in Fermentation

Regenerates NAD+ for glycolysis to continue.

Aerobic Respiration

Uses oxygen; high ATP yield (~32-34 ATP).

Anaerobic Respiration

Occurs without oxygen; low ATP yield (2 ATP).

Lipids in Metabolism

Broken down into glycerol and fatty acids for energy.

ATP Yield of Lipids

Higher than glucose per molecule.

Proteins in Metabolism

Broken down into amino acids and enter glycolysis or citric acid cycle.

Deamination

Removal of nitrogen from amino acids before metabolism.

Carbohydrates in Metabolism

Primary fuel; broken down into glucose for glycolysis.

Conclusion of Energy Flow in Respiration

Redox reactions fuel electron carriers which drive the ETC.

Proton Gradient

Generated by the ETC and powers chemiosmosis to produce ATP.

Common Entry Point for Food Molecules

Glycolysis is the entry point for various food molecules.

Fate of Pyruvate

Depends on oxygen availability; either becomes acetyl-CoA or lactate/ethanol.

ATP Yield Variance

Based on the respiration pathway used.