The Importance Of Cell Respiration

Task 4 ii) Cell respiration is considered as controlled burning. This is when cells that are not related to photosynthesis obtain their energy by oxidizing food molecules such as carbohydrates into carbon dioxide. ATP is formed when the energy difference between the food molecules and the carbon dioxide are used.

There are three steps to cell respiration. Glycolysis, the Krebs cycle and respiratory electron transport system.

Glycolysis is a succession of chemical reactions which are taken place within the cytosol of the cell. The whole process is enzyme controlled. The cytosol is the aqueous part of the cytoplasm in a cell.

Glycolysis is an anaerobic respiration. The first step involves the breakdown of glucose. Phosphate groups are added to the glucose to make it a six carbon ring sugar phosphate. For this to happen, 2 ATP are required, this energizes the glucose. The glucose is now more reactive and so this six carbon sugar phosphate is then broken down, forming two, 3 carbon phosphates. From these two phosphates, the hydrogen is taken away and given to the 2 NADS, which are reduced. The two phosphates which are called Triose phosphates, have now been converted to Pyruvate, and produced 2 molecules of ATP.

4 ATP have come out of glycolysis, but 2 ATP as an overall net gain, along with 2 NADH + H+.

(HallyHosting, n.d)

The next stage of glycolysis occurs in thecytoplasm of the mitochondria. This is called the link reaction, also known as oxidative carboxylation. Oxygen is required in this stage so is an aerobic respiration and completes the conversion of pyruvate.

The 2 pyruvic acid molecules, or also known as pyruvate, enter into the mitochondria, where the hydrogen and carbon dioxide become removed from them creating t...

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...oup to be added to ADP. This then forms ATP. NADH + H is an electron carrier. It gives an electron to the chain, specifically to the first protein. This protein, which is the NADH-Q reductase, is then ultimately reduced. It then oxidizes by the next protein along getting reduced. This carries on along the chain until all proteins are reduced and oxidized. When this has happened, all the electrons gathered reduce the terminal electron acceptor. This is oxygen. The oxygen that is reduced produces water. The step by step reduction of all the proteins, produces energy gradually. Protons are transported through the membrane this way.

Overall, once glycolysis and cellular respiration have occurred, 36 ATP have been produced and the glucose has been oxidized completely. Each step of the process occurs by the control of enzymes, making it a controlled burning process.