Compare Glycolysis, Kreb's Cycle, and Electron Transport Chain - Essay Example

Glycolysis is the process in which carbohydrates are broken by in the body in order to release energy and occurs in both aerobic and anaerobic respiration. Glycolysis has three main functions:1. Glycolysis generates high-energy molecules such as Adenosine Triphosphate (ATP) and the reduced form of Nicotinamide adenine dinucleotide (NADH). 2. The production of Pyruvate for use in the Krebs cycle stage of aerobic respiration.3. The production of intermediate compounds, which are removed at various steps in the process for other cellular purposes.

During aerobic glycolysis when glucose is converted to Pyruvate, one mole of glucose is converted to two moles of Pyruvate with production of two moles each of ATP and NADH, as shown below;Glucose + 2 ADP + 2 NAD+ + 2 Pi -----> 2 Pyruvate + 2 ATP + 2 NADH + 2 H+ .The Kreb's cycle is also known as the citric acid cycle, or the tricarboxylic acid cycle (TCA cycle) consists of enzyme-catalyzed chemical reactions that are of importance in all aerobic living cells. In eukaryotes, the Krebs cycle occurs in the matrix (fluid portion) of the mitochondrion.

The Pyruvate produced during glycolysis enters the mitochondria leading to the removal of one carbon while the other two-carbon fragment joins a coenzyme A. The main functions of the Kreb's cycle include;1. The transfer of H+ and electrons to Nicotinamide adenine dinucleotide (NAD) and Flavine adenine dinucleotide, to produce NADH+ and FADH2 respectively.2. The production of two moles of ATP by substrate-level Phosphorylation.3. The recycling of most of the molecules to conserve oxaloacetate for the continuous processing of acetyl-CoA.

The majority of the energy conserved during catabolism reactions occurs near the end of the metabolic series of reactions in the Electron transport chain. During the electron transport chain, fast electrons are transported to meet up with oxygen. The electron transport chain takes place in eight or more steps, it starts when an organic intermediate from the Krebs cycle reacts with the coenzyme NAD+. The other seven steps in the electron chain involves the passing along of 2H+ ions and electrons to react with oxygen, the formation of 3 ATP molecules, and the regeneration of coenzymes as oxidizing agents.

In summary, the reaction may be written as: a) MH2 + NAD+ ---> NADH + H+ + M + energyb) ADP + P + energy ---> ATP + H2Oc) MH2 + NAD+ -----> NADH + H+ + M: + energywhere M = any metabolite.The overall electron chain transport reaction is: 2 H+ + 2 e+ + 1/2 O2 ---> H2O + energy.Summary of Stages.GlycolysisKreb's CycleElectron Transport ChainNumber of ATP molecules produced 2 moles of Pyruvate, 2 moles of ATP and 2 moles of NADH2 moles of ATP3 moles of ATPSite of activityCytosol in all living cellsMitochondrion of living cellsMitochondrial Inner membraneEnergy Energy is needed to run the processEnergy is neededEnergy is needed