Chapter 7: Cellular Respiration

Oxidation

A chemical reaction where electrons and hydrogen are lost from a substance and oxygen is gained.

Reduction

A chemical reaction where electrons and hydrogen are gained from a substance and oxygen is lost.

Electron carriers

Proteins arranged in chains on a membrane which transfer high energy electrons to a lower energy state

Phosphorylation

The metabolic process of adding a phosphate group onto an organic molecule resulting in a higher energetic state.

Glycolysis

Anaerobic first step in respiration, in which a molecule of glucose is broken into two molecules of pyruvate in the cytoplasm.

Decarboxylation

The loss of a carboxyl group from an organic molecule as carbon dioxide

Acetyl group

A two-carbon group (-COCH3) made by decarboxylation of pyruvate by oxidation

Link reaction

The decarboxylation of glucose that occurs in the mitochondrion between glycolysis and the Krebs cycle that produces acetyl coenzyme A/Acetyl CoA.

Co-enzyme

A small molecule (not a protein but sometimes a vitamin) essential for the activity of some enzymes

Acetyl CoA

The molecule which brings the 2C acetyl group into the matrix of the mitochondrion.

Citrate

A six carbon molecule formed in the Krebs cycle by the joining of an group from Acetyl CoA with an oxaloacetate.

Krebs cycle

The second anaerobic stage of cellular respiration occurs when citrate is oxidized by dehydrogenation. This results in reduced hydrogen carriers and carbon dioxide production for a small gain in ATP.

Hydrogen carrier molecules

NAD and FAD coenzymes that carry H+ and e- to electron transport chain

Cristae

In-foldings of the inner membrane of a mitochondrion that houses the electron transport chain proteins and ATP synthase

Proton gradient

The difference in hydrogen ion concentration occurs on either side of a membrane - for example, the inner membrane of the mitochondrion

Proton pumping

Process whereby energy released from high-energy electrons passing along the electron transport chain (e.t.c.) is used to move protons into inter-membrane space against the concentration gradient.

Intermembrane space

Low volume space between the inner and outer mitochondrial membranes.

Chemiosmosis

Process by which H+ passively flows from inter-membrane to matrix through ATP synthase which leads to the creation of ATP.

ATP synthase

A complex of membrane-bound proteins in the inner membrane of mitochondrion which has a proton channel and an enzyme which phosphorylates ADP generating ATP

Oxidative phosphorylation

The process in which ATP is formed (by the phosphorylation of ADP) as a result of the transfer of electrons from NADH or FADH2 to O2 by a series of electron carriers.

NADH

The reduced form of (NAD+) - a hydrogen carrier which results in the production of 3 ATP by chemiosmosis.

FADH2

The reduced form of FADH, - a hydrogen carrier that results in the production of 2 ATP by chemiosmosis.

Final electron acceptor

Oxygen combines with H+ to form water (H2O)

Electron tomography

3D model buildup using Transmission Electron Microscopy data that enables scientists to view the dynamic nature of mitochondrial membranes.