Cellular Respiration: Glycolysis to Electron Transport Chain

Cellular respiration

Catabolizes macromolecules to produce ATP.

ATP

Adenosine triphosphate, energy currency of cells.

ADP

Adenosine diphosphate, formed from ATP hydrolysis.

Catabolism

Breakdown of molecules to release energy.

Anabolism

Building larger molecules from smaller ones.

Aerobic respiration

Uses oxygen to convert food into ATP.

Anaerobic respiration

Occurs without oxygen, less efficient ATP production.

Calorie

Amount of heat to raise 1 liter of water by 1°C.

Proton gradient

Difference in proton concentration across a membrane.

Mitochondria

Cell organelles where aerobic respiration occurs.

Electron transport chain (ETC)

Series of proteins transferring electrons to produce ATP.

NAD+/NADH

Electron carrier, cycles between oxidized and reduced forms.

FAD/FADH2

Another electron carrier, involved in energy metabolism.

Citric Acid Cycle

Processes Acetyl CoA to produce ATP and electron carriers.

Glycolysis

First step of respiration, converts glucose to pyruvate.

Pyruvate oxidation

Converts pyruvate to Acetyl CoA, releasing CO2.

Krebs Cycle

Oxidizes Acetyl CoA, producing ATP and electron carriers.

Redox reactions

Reactions involving electron transfer between molecules.

Endergonic

Reactions that require energy input to proceed.

Exergonic

Reactions that release energy during the process.

Cytosol

Fluid-filled interior of the cell, excluding organelles.

Cristae

Folded inner membrane of mitochondria, increases surface area.

ATP synthase

Enzyme that synthesizes ATP using proton gradient.

Cofactors

Vitamins and minerals required for enzymatic reactions.

Electron Transport Chain (ETC)

Final step in cellular respiration producing ATP.

NADH

High-energy electron carrier donating electrons to ETC.

FADH2

Another electron carrier contributing to ATP production.

O2

Final electron acceptor forming H2O in ETC.

Pyruvate

3-carbon molecule produced from glucose in glycolysis.

Anaerobic

Process that does not require oxygen for glycolysis.

Energy Investment Phase

Initial phase of glycolysis consuming 2 ATP.

Energy Harvest Phase

Phase of glycolysis producing 4 ATP and 2 NADH.

Acetyl CoA

2-carbon molecule entering Krebs cycle after pyruvate oxidation.

Redox Reactions

Reactions involving oxidation and reduction of molecules.

Proton Gradient

Difference in H+ concentration driving ATP synthesis.

ATP Synthase

Enzyme synthesizing ATP using proton motive force.

Metabolic Water

Water produced as a waste product in ETC.

Inputs of Glycolysis

1 glucose, 2 ATP, 2 NAD+, 4 ADP.

Outputs of Glycolysis

4 ATP, 2 NADH, 2 pyruvate (net gain 2 ATP).

Inputs of Pyruvate Oxidation

2 pyruvate molecules entering mitochondrial matrix.

Outputs of Pyruvate Oxidation

2 NADH, 2 CO2, 2 Acetyl CoA.

Theoretical ATP Yield

Up to 36 ATP produced from 1 glucose.

Actual ATP Yield

Approximately 30 ATP produced per glucose.

Cellular Respiration

Process converting glucose into usable energy.

Cytoplasm

Location of glycolysis in the cell.

Mitochondrial Matrix

Location of pyruvate oxidation and Krebs cycle.

Waste Products

CO2 and H2O produced during cellular respiration.

ATP Transport

Energy currency used to move NADH.

Pyruvate Transport

Process of moving pyruvate into mitochondria.

H+ Ion Leakage

H+ ions bypass ATP synthase, reducing efficiency.

ATP Yield from Glucose

1 glucose yields approximately 30 ATP.

Energy Efficiency

Cellular respiration is 32-37% efficient.

Macromolecule Fuels

Proteins and lipids can fuel respiration pathways.

ETC Location

Electron Transport Chain occurs in inner mitochondrial membrane.

Oxidation and Reduction

Identify components oxidized or reduced in reactions.

Active Transport

Energy-dependent movement across membranes in ETC.

Facilitated Diffusion

Passive transport of molecules across membranes.

Fermentation Pathways

Allow cells to survive without oxygen.

Anaerobic Organisms

Organisms that do not require oxygen for survival.

NAD+ Regeneration

NAD+ is recycled from NADH during fermentation.

Lactic Acid Fermentation

Pyruvate converts to lactic acid, regenerating NAD+.

Ethanol Fermentation

Pyruvate converts to ethanol and CO2, regenerating NAD+.

Energy Transformation Efficiency

37% of glucose energy converted to ATP.

Glycolysis Efficiency

Glycolysis alone is only 2% efficient.

Fermentation as Last Resort

Used by organisms under oxygen-limited conditions.

Cellular Respiration Steps

Includes glycolysis, pyruvate oxidation, Krebs cycle, ETC.

Inputs and Outputs of Fermentation

Inputs: NADH, Outputs: NAD+, lactic acid or ethanol.