Glycolysis & Fermentation

Metabolism

The complete set of chemical reactions in a cell that transform molecules and transfer energy

Catabolism

Breakdown of macromolecules that releases energy

Anabolism

Synthesis of macromolecules that requires energy

Cellular respiration

Catabolic process that breaks down glucose to produce ATP

Overall purpose of cellular respiration

Convert energy stored in glucose into ATP

Oxidation-reduction (redox) reactions

Chemical reactions involving transfer of electrons

Oxidation

Loss of electrons

Reduction

Gain of electrons

Oxidizing agent

Molecule that accepts electrons and becomes reduced

Reducing agent

Molecule that donates electrons and becomes oxidized

Role of oxygen in cellular respiration

Final electron acceptor

Role of glucose in cellular respiration

Electron donor

ATP

Energy currency of the cell

Phosphorylation

Addition of a phosphate group to a molecule

Substrate-level phosphorylation

ATP formation by enzyme-catalyzed transfer of phosphate

Oxidative phosphorylation

ATP production using electron transport chain

Electron carriers

Molecules that transfer electrons between reactions

NAD+

Electron carrier that accepts electrons and becomes NADH

NADH

Reduced form of NAD+ carrying electrons

FAD

Electron carrier that accepts electrons to form FADH2

FADH2

Reduced form of FAD carrying electrons

Four stages of cellular respiration

Glycolysis, pyruvate oxidation, citric acid cycle, oxidative phosphorylation

Location of glycolysis

Cytoplasm

Location of pyruvate oxidation

Mitochondria

Location of citric acid cycle

Mitochondria

Location of oxidative phosphorylation

Mitochondrial inner membrane

Glycolysis

First stage of cellular respiration that breaks glucose into pyruvate

Reactant of glycolysis

Glucose

Products of glycolysis

Two pyruvate molecules

ATP investment phase

First stage of glycolysis requiring ATP input

Cleavage phase

Stage where glucose splits into two molecules

Energy payoff phase

Stage producing ATP and NADH

Net ATP produced in glycolysis

2 ATP

NADH produced in glycolysis

2 NADH

Pyruvate

Three-carbon molecule produced during glycolysis

Fermentation

Alternative energy pathway used when oxygen is absent

Purpose of fermentation

Regenerate NAD+ for glycolysis

Ethanol fermentation

Conversion of glucose to ethanol without oxygen

Where ethanol fermentation occurs

Plants and fungi

Products of ethanol fermentation

Ethanol and carbon dioxide

Lactic acid fermentation

Conversion of glucose to lactic acid without oxygen

Where lactic acid fermentation occurs

Animals and bacteria

Product of lactic acid fermentation

Lactic acid

Why NAD+ recycling is important

Allows glycolysis to continue

Why carbohydrates are good energy sources

Bonds contain high potential energy

Examples of fermentation in food

Bread, cheese, soy sauce, alcohol

Mitochondria

Organelle responsible for most ATP production

Mitochondrial inner membrane

Highly folded membrane increasing surface area

Why mitochondrial inner membrane is folded

Increase space for energy-producing protein