Lydia Hernandez
Bio 156
Module 5

Cellular Respiration

Cellular Respiration is the process by which cells acquire energy by breaking down nutrient molecules produced by photo synthesizers. (Mc-Graw-Hill, 2014). Oxygen and carbon dioxide are what makes cellular respiration, without it, no animal, human or plants would breathe. Cellular respiration has four phases and that includes: glycolysis, citric acid cycle, preparatory reaction, and electron transport chain.
The first phase is glycolysis and it takes place outside of the mitochondria and during this phase it does require oxygen. During this phase, glucose is broke down to two molecules of pyruvate. During the breakdown it release enough energy to give a net gain of 2 Atp. Preparatory reaction and citric acid cycle follow next and occur in the mitochondria. The preparatory reaction happens in the matrix of the mitochondria. Carbon Dioxide is release and pyruvate is broken into a 2-carbon acetyl group. The citric acid cycle also takes place in the matrix. Oxidation occurs when two carbon dioxide molecules, three NADH molecules, and one FADH2 molecules are formed. This phase produces one ATP. The final phase is the electron transport chain that is located in the cristae in the mitochondria. FADH2 and NADH bring electrons to the transport chain. The electrons move down and energy is caught to form ATP. For every pair of electrons that enters by NADH, three ATP result and 2 ATP result by Fadh2. (Mc-Graw-Hill, 2014). As stated previously, cellular respiration is the process by which cells get energy by breaking down nutrients molecules. It is very vital in plant, animal and human life.

References
- Introductory Biology for Allied Health: A Laboratory Manual for BIO 156 ;. 2014.