CellularRespiration

Cellular Respiration

The process by which living cells obtain energy from organic molecules, primarily glucose.

Photosynthesis

The process by which plants and other autotrophic organisms convert sunlight into chemical energy, producing glucose and oxygen.

Catabolic pathways

Metabolic pathways that break down molecules into smaller units, releasing energy.

Fermentation

A metabolic process that partially breaks down sugars in the absence of oxygen.

Mitochondria

Organelles in eukaryotic cells where most of the processes of cellular respiration occur.

Glycolysis

The anaerobic process that breaks down glucose into two pyruvate molecules, producing a small amount of ATP.

Citric Acid Cycle

Also known as Krebs cycle; it further oxidizes pyruvate into CO2 while generating ATP and electron carriers.

Oxidative Phosphorylation

The final stage of cellular respiration where ATP is produced using the electron transport chain and chemiosmosis.

Redox reactions

Reactions involving the transfer of electrons, resulting in the oxidation of one molecule and the reduction of another.

ATP synthase

An enzyme that produces ATP from ADP and inorganic phosphate during chemiosmosis.

Obligate anaerobes

Organisms that cannot survive in the presence of oxygen.

Facultative anaerobes

Organisms that can survive using either fermentation or respiration depending on the presence of oxygen.

NAD+

A coenzyme that acts as an electron carrier in cellular respiration.

Chemiosmosis

The process of using a proton gradient to generate ATP in the mitochondria.

Lactic acid fermentation

A type of anaerobic respiration where pyruvate is reduced to lactate, occurring in human muscle cells when O2 is scarce.

Alcohol fermentation

A type of anaerobic respiration performed by yeast where pyruvate is converted into ethanol and CO2.

Proton-motive force

The potential energy stored in the form of a proton gradient across a membrane.

Efficiency of Cellular Respiration

The total energy yield from cellular respiration is about 30-38 ATP per glucose molecule, with the rest lost as heat.