Microbiology

Microbiology Study Guide

The process required to form ATP molecules is much more complex, and is referred to as chemiosmosis . In this process, a steep proton gradient is created by pumping a large number of protons between the areas bound by the membrane. In the case of prokaryotic cells, this area is the space in the cell membrane, while in eukaryotic cells, this area is the mitochondria membranes. Once the pumping of the protons is done, they build up gradually and reach a larger amount. After this, they move in reverse direction and start to travel back across the membranes. During this process energy is released, which is used to form ATP by initiating the fusion between ADP with phosphate ions. The energy generated during this fusion is trapped in the high energy bond of the ATP and thus, they become capable of performing the work of a cell. Photosynthetic vs. Chemosynthetic Metabolism Photosynthesis is the process by which the microorganisms, like cyanobacteria, extract and trap the solar energy and store it in the form of chemical bonds in the molecules of carbohydrates. Glucose is the major carbohydrate that is developed during the process of photosynthesis. It should further be noted that many other organisms, which are non-photosynthetic like fungi, bacteria, and protozoa, do not support photosynthesis and hence, in order to perform their metabolic activities, must rely on the carbohydrates derived from the environment. Cellular Respiration The process by which organisms derive their energy from carbohydrates is known as cellular respiration. Organisms grasp the carbohydrates in their cytoplasm and then energy is released by breaking down carbohydrates. The energy is stored in the ATP molecules by combing the ADP with the phosphate ions. In this process, the waste product is extracted in the form of carbon dioxide. Carbon dioxide is used to form new carbohydrates by the photosynthesizing cells. Oxygen is needed as the main ingredient for the acceptance of the electrons in the aerobic process of cellular respiration. The process of cellular respiration involves four sub-divisions: glycolysis, Krebs Cycle, electron transport system, and chemiosmosis. In the first phase, glylcolysis, pyruvic acid molecules are formed by breaking down the glucose molecules. In the second phase of the Krebs Cycle, high energy compounds like NADH are produced by breaking down and utilizing the energy of the pyruvic acid. The third phase is the electron transport system in which the coenzymes and cytochromes carry the electrons and energy in the electrons is released. The final phase is chemiosmosis in which the released energy is used to pump the protons that yield the energy for the synthesis of the ATP.

©2018

Achieve

Page 28

of 132