Cellular Respiration & Photosynthesis Case

Cellular respiration is a redox reaction in the mitochondria. There is a transfer of electrons. These electrons release energy which is then used to synthesize ATP. The loss of electrons is called oxidation, while the gain of electrons is called reduction. There are three stages of cellular respiration; glycolysis, the citric acid cycle, and oxidative phosphorylation. Glycolysis is known as the “splitting of sugar.” Glycolysis is the breakdown of glucose into two pyruvate, each has three carbons. Glycolysis occurs in the cystol. The energy invested would be 2 ATP and the energy pay off would be 4 ATP + 2 NADH. The citric acid cycle is the breakdown of glucose of glucose further. In the presence of oxygen, the citric acid cycle generates 1 ATP, 3 NADH and 1 FADH. Oxidative phosphorylation accounts for most of the ATP synthesized. Chemiosmosis couples electron transport to ATP synthesis.

Cellular respiration has catabolic pathways, such as fermentation and aerobic respiration. Fermentation is the partial degradation of sugars without use of oxygen. Meanwhile in aerobic respiration, oxygen is consumed as a reactant along with organic fuel. Chemiosmosis is where energy is stored in the form of a hydrogen ion gradient across a membrane is used to derive cellular work such as synthesis of ATP. In short terms, it is the flow of H+ ions across a membrane.

There are two different types of fermentation, one is alcohol fermentation and the other is lactic fermentation. Alcohol fermentation is when the pyruvate is converted from ethanol in two steps. The first is carbon dioxide is released from pyruvate to form a two carbon acetaldehyde. The second is that same acetaldehyde is reduced by NADH to ethanol. This regenerates the NAD+ for glycolysis. Lactic fermentation is when the pyruvate is reduced directly by NADH to form lactate as an end product with no release of carbon dioxide.

Photosynthesis is in some ways similar to cellular respiration and in other ways different. Photosynthesis mainly happens with the autotrophs, the “self-feeders” or in other words, they sustain themselves without eating anything derived from another living being. The site of photosynthesis is in the chloroplasts of the leaves. t is mainly found in the mesophyll cells, which is the interior of a leaf. Mesophyll cells have about thirty to forty chloroplasts each. Similar to cellular respiration, photosynthesis has a cycle, this is called the Calvin Cycle. The Calvin cycle uses chemical energy to make organic molecules out of food.

Water is absorbed into the roots and then delivered to the leaves via veins. The plants also use the veins to export sugar to the roots and other parts of the plant that do not undergo photosynthesis. Photosynthesis is also a redox reaction, just like cellular respiration. In this case, photosynthesis reverses the direction of electron flow. In this process, water is split and electrons are transferred