Chapter 8.txt

Coenzyme A bound to a twocarbon fragment from pyruvate, which it transfers to oxaloacetate for Krebs cycle.

[Gk. aer, air, + bios, life] Oxygen-requiring pathway of ATP formation in mitochondria: from glycolysis, to Krebs cycle and electron transport phosphorylation. Typical net energy yield: 36 ATP per glucose molecule.

An anaerobic ATPforming pathway using pyruvate and NADH from glycolysis. NADH transfers electrons to an intermediate, acetaldehyde, forming ethanol. Occurs in cytoplasm only. The net yield is 2 ATP from glycolysis; the steps remaining only regenerate NAD+.

[Gk. an, without, + aer, air] Of some bacteria and archaeans, ATP formation by way of a flow of electrons through transfer chains in the plasma membrane to a final electron acceptor that is not oxygen.

Adenosine triphosphate. A type of nucleotide that functions as the main energy carrier between reaction sites in cells. Consists of the base adenine, the five-carbon sugar ribose, and three phosphate groups.

A type of membrane-bound active transport protein that also catalyzes the formation of ATP.

An organic molecule that is a necessary participant in some enzymatic reactions; helps catalysis by donating or accepting electrons or functional groups; e.g., a vitamin, ATP, NAD+.

Final stage of aerobic respiration; electron flow through electron transfer chains in inner mitochondrial membrane sets up H+ concentration and electric gradients that drives ATP formation. Oxygen accepts electrons at the end of the chain.

Flavin adenine dinucleotide. A type of nucleotide coenzyme; transfers electrons and H+ from one reaction site to another.

Breakdown of glucose or another organic compound to two pyruvates. First stage of aerobic respiration, fermentation, or anaerobic electron transfer. Oxygen has no role in glycolysis, which takes place in the cytoplasm of all cells. Two NADH form. Net yield: 2 ATP per glucose molecule.

The second stage of aerobic respiration in which many coenzymes form as pyruvate from glycolysis is fully broken down to CO2 and H2O. Two ATP also form. Occurs only in mitochondria.

One of the anaerobic pathways of ATP formation. NADH from glycolysis donates hydrogen and electrons to pyruvate, converting it to three-carbon lactate, and regenerating NAD+. The net energy yield is 2 ATP (from glycolysis).

Double-membraned organelle of ATP formation; only site of the second and third stages of aerobic respiration.

Nicotinamide adenine dinucleotide. A nucleotide coenzyme; after it accepts electrons and H+, abbreviated as NADH.

A fourcarbon compound with roles in metabolism; e.g., the point of entry into the Krebs cycle.

Phosphoglyceraldehyde. During glycolysis, the intermediate that gives up electrons and hydrogen to form NADH. During turns of the Calvin�Benson cycle, two PGALs form one sugar; rearrangements of ten others regenerate a compound that is the entry point for the cycle.

Three-carbon compound that forms as an end product of glycolysis.

Direct, enzyme-mediated transfer of a phosphate group from a substrate to another molecule.