Cellular Respiration

Cell respiration is a series of oxidative reactions by which cells gradually release energy from glucose and transfer it to molecules of ATP (adenosine triphosphate).
Energy stored in ATP is immediately available for cellular activities such as contracting muscles, passing an impulse along a nerve, or pumping ions by active transport.
The equation for the complete aerobic respiration of one molecule of glucose:
C6H12O6 + 6O2 → 6CO2 + 6H2O + energy
Glucose combines with oxygen to produce energy (ATP) plus the waste products (carbon dioxide and water).

ATP- adenosine triphosphate
ATP is the special high-energy molecule that stores energy for immediate use in the cell. It consists of adenosine (nucleotide adenine and ribose) and three phosphates.

ADP- adenosine diphosphate
The removal of one phosphate group from ATP results in the formation of a more stable and lower energy molecule. Energy is released as ATP converts to ADP. Energy is absorbed to add a phosphate to produce ATP.

Structure of the mitochondrion-
The mitochondrion is enclosed by two membranes (outer membrane and inner cristae membrane which is folded). The inner membrane divides the mitochondria into two internal compartments (the outer compartment and the matrix). The Krebs cycle takes place in the matrix. The electron transport chain takes place in the cristae membrane.

Cell respiration-
Cell respiration has two phases (anaerobic and aerobic). If oxygen is not present (anaerobic), glycolysis is followed by alcohol fermentation or lactic acid fermentation. If oxygen is present (aerobic), glycolysis is followed by the Krebs cycle, the electron transport chain, and chemiosmosis.

Anaerobic respiration- (when oxygen is not present)
Anaerobic respiration or fermentation consists of the process known as glycolysis plus alcohol fermentation or lactic acid fermentation. Anaerobic respiration originated billions of years ago when there was no free oxygen in...