Ch. 9, Cellular Resp and Fermentation

ATP

Adenosine triphosphate, the main energy currency of cells.

ADP

Adenosine diphosphate, formed when ATP loses a phosphate.

Oxidation

The loss of electrons from a substance during a chemical reaction.

Reduction

The gain of electrons by a substance in a chemical reaction.

Glycolysis

The process of breaking down glucose into pyruvate, generating energy.

Citric Acid Cycle

A metabolic cycle that breaks down Acetyl CoA to produce ATP and electron carriers.

Oxidative Phosphorylation

The process in cellular respiration that generates ATP using the electron transport chain and chemiosmosis.

NAD+

Nicotinamide adenine dinucleotide, the oxidized form that acts as an electron carrier.

NADH

The reduced form of NAD+, carrying electrons and energy.

Fermentation

A metabolic process that produces energy in the absence of oxygen.

Lactic Acid Fermentation

A type of fermentation that converts pyruvate into lactate.

Alcohol Fermentation

A type of fermentation that converts pyruvate into ethanol and carbon dioxide.

Oxidizing Agent

A substance that gains electrons in a redox reaction.

Reducing Agent

A substance that loses electrons in a redox reaction.

Substrate-level Phosphorylation

A process of generating ATP by directly transferring a phosphate group to ADP.

Proton gradient

A difference in proton concentration across a membrane, used to drive ATP synthesis.

Chemiosmosis

The movement of ions across a membrane to generate ATP through ATP synthase.

Electron Transport Chain

A series of protein complexes that transfer electrons and pump protons.

Pyruvate Oxidation

The conversion of pyruvate to Acetyl CoA, linking glycolysis to the citric acid cycle.

Acetyl CoA

Acetyl coenzyme A, the entry molecule for the citric acid cycle.

Glucose

A simple sugar that is the primary energy source for cells.

ATP Synthase

An enzyme that uses the proton gradient to synthesize ATP.

Heat energy

Energy released as a byproduct of cellular respiration.

Feedback Inhibition

A regulatory mechanism where the end product inhibits an earlier step.

Electrochemical gradient

A gradient that generates voltage across a membrane due to ion concentration differences.

Oxaloacetate

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

FADH2

Flavin adenine dinucleotide, reduced form that carries electrons.

Metabolic pathways

Series of chemical reactions in a cell that lead to a product.

Coupled reactions

Reactions where the energy from one reaction drives another.

High-energy covalent bonds

Bonds that store significant amounts of energy, found in organic molecules.

Endergonic reactions

Reactions that require energy input to proceed.

Exergonic reactions

Reactions that release energy.

Caloric input

Energy intake from food sources.

Pyruvate dehydrogenase complex

An enzyme complex that catalyzes the conversion of pyruvate to Acetyl CoA.

Hydrogen ions (H+)

Positively charged ions contributing to the proton gradient.

Energy investment phase

The initial phase of glycolysis where ATP is used.

Energy payoff phase

The phase of glycolysis where ATP is generated.

Krebs Cycle

Another name for the Citric Acid Cycle.

Reducing power

The capacity of a substance to donate electrons.

Calvin Cycle

Process in photosynthesis that uses ATP and NADPH to convert CO2 to glucose.

End products of glycolysis

Two molecules of pyruvate, four ATP, and two NADH.

3 ATP

The total ATP produced by one turn of the citric acid cycle.

32 ATP

Total ATP yield from one molecule of glucose during cellular respiration.

Oxygen's role in respiration

Final electron acceptor in the electron transport chain.

Heat generation

The release of energy during respiration, often as heat.

Metabolic fuel

Substances that organisms use to produce energy.

Fermentation products

End products of anaerobic metabolism, like ethanol or lactate.

ATP generation mechanisms

Includes substrate-level phosphorylation and oxidative phosphorylation.

Invariant ratio of NADH

The empirical relationship between NADH and ATP production.

Inner mitochondrial membrane

Site of the electron transport chain.

Mitochondrial matrix

The space within the inner membrane of mitochondria.

Biosynthetic reactions

Reactions involved in the synthesis of complex molecules.

Respiratory control

Regulation of the rate of cellular respiration based on ATP levels.

Electron carriers

Molecules like NADH and FADH2 that transfer electrons.

NADH utilization

Represents stored energy to synthesize ATP.

Proton motive force

The force generated by the movement of protons across a membrane.

Organic molecules

Molecules containing carbon that serve as energy sources.

Metabolite by-products

Waste products produced during metabolism.

Pyruvate fate

Can be converted into acetyl CoA, lactate, or ethanol depending on oxygen availability.

ATP yield variability

Variances in ATP production depending on metabolic conditions.

Cellular energy production

The processes by which cells generate ATP from food sources.

Fermentative pathways

Pathways used to generate energy in the absence of oxygen.

Glucose catabolism

The breakdown of glucose in metabolic processes.

Emphasis on anaerobic pathways

Mobile alternative pathways for energy in absence of oxygen.

Role of ATP in cellular processes

Serves as an energy source for biochemical reactions.

Energy expenditure

Energy consumed by cellular processes, influenced by ATP availability.

Aerobic vs Anaerobic respiration

Comparison of energy production in the presence vs absence of oxygen.

Mitochondrial function in respiration

Involves conversion of pyruvate and electron transport.

Role of NAD+ in metabolism

Acts as an oxidizing agent, accepting electrons.

ATP production efficiency

Measure of how effectively cells produce ATP from nutrients.

Rate of respiration regulation

Controlled by substrates and end products, primarily ATP.

Electron sharing in covalent bonds

The redistribution of electrons during redox reactions.

Enzyme specificity

Each enzyme catalyzes a specific reaction based on molecular structure.

Feedback regulation of enzymes

Control mechanism that adjusts metabolic pathways based on resource availability.

Nutrient catabolism

Breakdown of nutrients to release energy.

Energy investment vs payoff in glycolysis

Differentiates between initial ATP usage and subsequently generated ATP.

Chemiosmotic ATP synthesis

Production of ATP due to proton flow through ATP synthase.

ATP balance equation

Net gain of ATP through various metabolic pathways.

Metabolic interfaces

Sites of interactions between different metabolic pathways.

Complexity of metabolic regulation

Interdependency of various pathways for overall energy homeostasis.

Cellular respiration as a dynamic process

Ongoing metabolic reactions continuously adapting to cellular needs.

Contributors to metabolic pathways

Substances that participate in the series of reactions in metabolism.

Biochemical conversion

Transformations that molecules undergo during a chemical process.

Energy coupling mechanism

Combines exergonic and endergonic reactions to drive metabolism.

Cyclic nature of the citric acid cycle

Reiteration of metabolic pathway returning to the initial molecule.

Key enzymes in glycolysis

Hexokinase, phosphofructokinase, and pyruvate kinase.

High energy yield mechanisms

Processes that maximize ATP production from substrate breakdown.

Substrates of the citric acid cycle

Acetyl CoA and oxaloacetate reactants in the cycle.

Electron transport sequence

Orders of events in electron transfer across mitochondrial membranes.

Chemical feeding in mitochondria

Utilization of metabolites leading to ATP generation.

Cofactors in metabolic reactions

Molecules assisting enzymes in catalyzing reactions.

Dynamic ATP concentrations

Variability of ATP amounts during rest and active states in cells.

Carbon atoms in glucose breakdown

Release of carbon dioxide during aerobic respiration.

Rate-limiting steps in respiration

The slowest step that determines the speed of a metabolic pathway.

End products of fermentation

Ethanol or lactate produced during anaerobic processes.

Role of carbon in metabolic reactions

Carbon-containing molecules drive energy transformations in respiration.

Response to high energy demands

Increase in metabolic rate and ATP production in active states.

Importance of pyruvate in energy production

Crucial intermediate linking glycolysis to other pathways.

Living systems and energy needs

The constant requirement for energy to maintain life.

Complex mixture of biochemical pathways

Interconnected metabolic routes ensuring energy production and usage.