cellular resp

Cellular Respiration

The process by which cells convert glucose and oxygen into energy (ATP), carbon dioxide, and water.

Glycolysis

The first stage of cellular respiration that occurs in the cytoplasm, breaking down glucose into pyruvate.

Krebs Cycle (Citric Acid Cycle)

A metabolic pathway taking place in the mitochondria, producing ATP, NADH, and FADH2 from pyruvate.

Electron Transport Chain (ETC)

The final stage of cellular respiration located in the inner mitochondrial membrane that produces ATP through oxidative phosphorylation.

ATP (Adenosine Triphosphate)

The main energy currency of the cell produced during cellular respiration.

NADH

An electron carrier generated during glycolysis and the Krebs cycle that donates electrons to the electron transport chain.

FADH2

An electron carrier produced during the Krebs cycle that also donates electrons to the electron transport chain.

Pyruvate

A three-carbon compound produced from the breakdown of glucose during glycolysis.

Acetyl-CoA

A two-carbon molecule derived from pyruvate that enters the Krebs cycle.

Oxidative Phosphorylation

The process by which ATP is produced in the electron transport chain using the energy from electrons.

Proton Gradient

The concentration difference of protons across the inner mitochondrial membrane that drives ATP synthesis.

Aerobic Respiration

Cellular respiration that occurs in the presence of oxygen and produces a high yield of ATP.

Anaerobic Respiration

Cellular respiration that occurs without oxygen, leading to lower amounts of ATP being produced.

Energy Investment Phase

The phase in glycolysis where ATP is consumed to phosphorylate glucose and trap it inside the cell.

Energy Payoff Phase

The phase in glycolysis where ATP and NADH are produced from the conversion of pyruvate.

Citrate

A six-carbon molecule formed from Acetyl-CoA and oxaloacetate in the Krebs cycle.

Isocitrate

A rearranged form of citrate produced in the Krebs cycle prior to oxidative decarboxylation.

Alpha-Ketoglutarate

A five-carbon molecule produced from isocitrate in the Krebs cycle through oxidative decarboxylation.

Succinyl-CoA

A four-carbon molecule formed from alpha-ketoglutarate, releasing carbon dioxide in the Krebs cycle.

GTP (Guanosine Triphosphate)

An energy currency produced from succinyl-CoA in the Krebs cycle.

Fumarate

A four-carbon molecule produced from the oxidation of succinate in the Krebs cycle.

Malate

A four-carbon molecule formed from fumigate, which is then oxidized to regenerate oxaloacetate in the Krebs cycle.

NAD+

A coenzyme that acts as an electron acceptor in cellular respiration, being reduced to NADH.

FAD

A coenzyme similar to NAD+ that is reduced to FADH2 during the Krebs cycle.

Complex I

The first protein complex in the electron transport chain where NADH donates its electrons.

Complex II

The second protein complex in the electron transport chain where FADH2 donates its electrons.

Chemiosmosis

The movement of protons back into the mitochondrial matrix through ATP synthase to drive ATP production.

Electrochemical Gradient

The gradient established by the accumulation of protons in the intermembrane space during the electron transport chain.

Oxygen (O2)

The final electron acceptor in the electron transport chain which combines with electrons and protons to form water.

Cyanide

A poison that inhibits Complex IV of the electron transport chain, preventing ATP production.

Oligomycin

An inhibitor that blocks ATP synthase, disrupting ATP production during oxidative phosphorylation.

Glucose-6-Phosphate

A phosphorylated form of glucose that is trapped in the cell during the energy investment phase of glycolysis.

Fructose-1,6-Bisphosphate

An intermediate in glycolysis that is split into two three-carbon molecules.

Net Gain of ATP in Glycolysis

The overall production of 2 ATP molecules per glucose molecule during glycolysis.

Total ATP Production from Cellular Respiration

Approximately 30-32 ATP molecules are produced from one molecule of glucose through cellular respiration.

Waste Products of Krebs Cycle

Carbon dioxide is produced and released as a waste product during the Krebs cycle.

Protein Complexes in ETC

There are four main protein complexes (I, II, III, IV) involved in the electron transport chain.

Role of Protons in ATP Production

Protons contribute to the proton motive force necessary for ATP synthesis during chemiosmosis.

Inhibition of ETC

Certain substances can inhibit the electron transport chain, leading to reduced ATP production.

Importance of NADH and FADH2

These coenzymes are critical for ATP production as they donate electrons to the electron transport chain.

Function of ATP Synthase

A protein complex that synthesizes ATP from ADP and inorganic phosphate using the proton gradient.

Regeneration of Oxaloacetate

The process that occurs at the end of the Krebs cycle, allowing the cycle to continue.

Oxidative Decarboxylation

A chemical reaction in the Krebs cycle where a carbon atom is removed and NAD+ is reduced.

Fructose Metabolism

Fructose-1,6-bisphosphate is essential for the glycolysis pathway to continue.

Mitochondria

Organelles in eukaryotic cells where cellular respiration occurs, including the Krebs cycle and electron transport chain.