Topic 5 - Cellular Respiration

Catabolic Pathway

Pathway in metabolism aimed at breaking down complex molecules to release energy.

Aerobic Respiration Equation

C6H12O6 + 6 O2 ——> 6CO2 + 6 H2O + ATP + heat

Exergonic Reaction

A reaction that releases energy, such as aerobic respiration.

Final Electron Acceptor in Electron Transport Chain

Oxygen (O2)

Anaerobic Respiration

Respiration occurring without oxygen where an inorganic molecule other than O2 accepts electrons.

Fermentation

Metabolic process without O2 that does not involve an electron transport chain.

Redox Reactions

Reduction-oxidation reactions involving the transfer of electrons.

Oxidation

The loss of electrons (OIL: Oxidation Is Loss).

Reduction

The gain of electrons (RIG: Reduction Is Gain).

Reducing Agent

The substance that donates electrons in a redox reaction.

Oxidizing Agent

The substance that accepts electrons in a redox reaction.

NAD+

Nicotinamide adenine dinucleotide, an electron acceptor in metabolic reactions.

NADH

The reduced form of NAD+, carries electrons and H+ to the electron transport chain.

Glycolysis

The metabolic pathway that converts glucose into pyruvate, producing ATP and NADH.

Substrate-Level Phosphorylation

The direct production of ATP by transferring a phosphate group to ADP from a substrate.

Pyruvate Oxidation

Conversion of pyruvate into Acetyl-CoA, producing NADH and CO2.

Citric Acid Cycle

A metabolic pathway that completes the breakdown of glucose, producing ATP, NADH, and FADH2.

ATP Production

A major goal of cellular respiration, primarily achieved during oxidative phosphorylation.

Oxidative Phosphorylation

The process of ATP production that uses the electron transport chain and chemiosmosis.

Energy Payoff Phase

Part of glycolysis where ATP is produced through substrate-level phosphorylation.

De-carboxylation in Pyruvate Oxidation

The removal of a carboxyl group from pyruvate to release CO2.

Electron Transport Chain

Series of proteins that transfers electrons and pumps H+ ions to create a gradient.

H+ Gradient

A difference in H+ concentration across a membrane used to drive ATP synthesis.

ATP Synthase

Enzyme that produces ATP using the energy from the H+ gradient.

Chemiosmosis

Process of using the energy of an electrochemical gradient to produce ATP.

Efficiency of Respiration

Ratio of energy captured as ATP to the total energy released from glucose oxidation.

Starch and Glycogen

Polysaccharides that can be broken down into glucose for energy.

Amino Acids

Building blocks of proteins derived from the breakdown of proteins in metabolism.

Fats in Metabolism

Converted to glycerol and fatty acids that can enter metabolic pathways.

Anabolic Pathways

Metabolic pathways that build complex molecules from simpler ones.

Feedback Mechanisms

Regulatory mechanisms that control metabolic pathways, such as inhibition of enzymes.

Phosphofructokinase

Key regulatory enzyme in glycolysis, affected by energy levels in the cell.

Anaerobic Respiration Key Difference

Uses an electron acceptor other than O2, such as sulfate.

Regeneration of NAD+

Essential function of fermentation to allow glycolysis to continue.

Microbial Fermentation

Process used in food production, such as brewing and cheese-making.

Neurodegenerative Disorders

Conditions potentially caused by defects in protein complex assembly in cellular respiration.

Proton-Motive Force

The energy derived from an H+ gradient used by ATP synthase to produce ATP.

ATP Yield from Glucose

Typically between 30 to 32 molecules of ATP produced per glucose in cellular respiration.

C3 and C2 Compounds

Intermediate molecules formed during glycolysis and citric acid cycle.

Citric Acid Cycle Products

Produces CO2, NADH, FADH2, and ATP from each acetyl-CoA.

Enzyme Complexes in Electron Transport Chain

Multiprotein structures (Complexes I-IV) involved in electron transport.

Redox Reactions in Respiration

Couples electron transfer with H+ transfer to produce energy.

Glucose to Pyruvate Step

First step in cellular respiration where glucose is converted to two pyruvate molecules.

Calorimetry in Respiration Studies

Method used to measure the energy output of catabolic reactions.

Cellular Respiration

The process of converting biochemical energy from nutrients into ATP.

Cellular Respiration Stages

Includes glycolysis, pyruvate oxidation, citric acid cycle, and oxidative phosphorylation.

Glycolysis

The catabolic pathway that converts glucose into pyruvate.

Pyruvate

The product of glycolysis that can be oxidized to acetyl CoA.

Citric Acid Cycle

A series of chemical reactions used by all aerobic organisms to generate energy through the oxidation of acetyl CoA.

Electron Transport Chain

A series of protein complexes in the inner mitochondrial membrane that transfer electrons and pump protons to generate ATP.

Aerobic Respiration

The most efficient catabolic pathway that uses oxygen to produce energy.

Exergonic Reaction

A chemical reaction that releases energy, indicating a negative delta G.

ATP Production

The ultimate goal of catabolic pathways, providing energy for cellular work.

Decarboxylation

The removal of carbon dioxide from a molecule, as seen in the conversion of pyruvate to acetyl CoA.

Acetyl CoA

The product of pyruvate oxidation that enters the citric acid cycle.

Krebs Cycle

Another name for the citric acid cycle, named after Hans Krebs.

Proton Gradient

A difference in proton concentration across a membrane that drives ATP synthesis.

Chemiosmosis

The process of using a proton gradient to synthesize ATP.

ATP Synthase

An enzyme that produces ATP from ADP and inorganic phosphate using the proton gradient.

Oxidative Phosphorylation

The production of ATP using energy derived from the electron transport chain.

Substrate-Level Phosphorylation

The direct synthesis of ATP from ADP using a phosphate group during glycolysis and the citric acid cycle.

Organic Molecules

Molecules that contain carbon and are utilized as fuel in cellular respiration.

Catabolism

The metabolic process where large molecules are broken down into smaller units, releasing energy.

OIL RIG

A mnemonic for remembering that oxidation is loss and reduction is gain of electrons.

Reducing Agent

A substance that loses electrons and is oxidized in a redox reaction.

Oxidizing Agent

A substance that gains electrons and is reduced in a redox reaction.

Cyanobacteria

Photosynthetic bacteria capable of generating oxygen and organic molecules.

Photosynthetic Bacteria

Bacteria that can conduct photosynthesis to produce organic compounds.

Glycogen

A stored form of glucose, primarily used for energy by animals.

Starch

A carbohydrate that is a major source of glucose for animals.

Beta Oxidation

The process of breaking down fatty acids to produce acetyl CoA.

Lactic Acid Fermentation

The process where pyruvate is converted directly to lactate without CO2 release.

Alcoholic Fermentation

The process where pyruvate is converted to ethanol and CO2 is released.

Glycerol

A component of fats that can be converted into a glycolytic intermediate.

Fatty Acids

Components of fats that can be broken down for energy via beta oxidation.

Oxaloacetate

A four-carbon molecule that combines with acetyl CoA in the citric acid cycle.

NADH and FADH2

Electron carriers that transfer electrons to the electron transport chain.

Mitochondria

Organelles where aerobic respiration occurs, including glycolysis, citric acid cycle, and electron transport chain.

ATP

The primary energy carrier in cells, produced during respiration.

Heat Energy

Energy lost during metabolic processes, often in the form of heat.

Eukaryotes

Organisms whose cells contain a nucleus, including animals, plants, fungi, and protists.

Prokaryotes

Organisms whose cells lack a nucleus, where respiration can still occur without mitochondria.

Dehydrogenase

An enzyme that catalyzes the removal of hydrogen from a substrate.

Acetate

The product formed during the conversion of acetyl CoA back into the cycle.

Energy Flow

The movement of energy through an ecosystem, primarily from the sun to living organisms.

Chemical Recycling

The continuous cycling of chemicals through living organisms and the environment.

GTP

A potential energy carrier like ATP, used in protein synthesis.

Krebs Cycle Products

From one acetyl CoA, we generate ATP, NADH, FADH2, and CO2.