Energy metabolism

• The central molecule used as an energy source is glucose (CH₁₂O6). ATP stores the energy. And it's distribution occurs to the various energy-consuming parts of the cell.

Cellular respiration

• Process in which the release of energy from glucose ensues with the consumption of oxygen gas. C6H1206 + 6CO2 - 6C02 + 6H20 + 38 ATPs

Glycolysis

• The partial breakdown of the glucose occurs in the cytosol and does not depend on oxygen gas.

• It results in two molecules of pyruvate and the release of ATP

Krebs Cycle

• The Krebs Cycle is a series of anabolic and catabolic reactions. It Completes the oxidation of pyruvate gradually.

• Water and carbonic gas are the residues of this step. These have the objective of producing energy for the cells, being one of the three steps in the process of cellular respiration.

• In eukaryotic cells, the cycle happens in the mitochondrial matrix, whereas in prokaryotic organisms, this step occurs in the cytoplasm.

• It occurs only under aerobic conditions in the mitochondrial matrix.

Respiratory cell

• Electrons end up being removed by releasing energy and a proton (H") gradient across the mitochondria's inner membrane (mitochondrial crest);

• To convert ADP into ATP, we use the energy from this gradient.

• It occurs only under aerobic conditions because the final electron receptor of this chain is oxygen gas, which receives electrons and H' ions, forming water.

Fermentation

• This process leads to broken glucose without consuming oxygen gas from the environment.

• It has a lower energy yield; glucose is not completely broken down and oxidized, and the products still have stored energy.

Lactic fermentation: the final residue is lactic acid, carried out by lactobacilli. And we use them in the production of yogurt and curds.

• Muscle cells perform lactic fermentation when there is not enough oxygen.

Alcoholic fermentation: the final residues are ethyl alcohol and carbon dioxide.

• Yeast is responsible for this fermentation.

• We use them as ferments. And during the production of alcoholic beverages (beer and wine).

Photosynthesis

• This process consists of the transformation of carbonic ace and water molecules to sugars; With the use of light energy.

• 6CO₂+ 6H₂O CH12O6+ 60₂

• The oxygen gas atoms come from H₂O molecules, not CO2 molecules.

• Photochemical stage (light phase): light energy is absorbed by chlorophyll and stored in ATP molecules; light also promotes the transformation of water into hydrogen and oxygen gas.

• Chemical stage (dark phase): In carbon fixation, we use the ATP and hydrogen produced in the previous phase. It is also called the pentose cycle or Calvin-Benson cycle.

Chemo-synthesis

• Chemo-synthesis is a process that occurs from the oxidation of inorganic substances in places lacking sunlight. And autotrophic bacteria accomplish it.

• Thus, with energy obtained through chemical reactions between the compounds present in the environment, it's possible to produce organic matter.

• This process consists of the transformation of carbon dioxide and water molecules into sugars, with no use of light energy.

• Certain bacteria carry out this process to fix carbon, using the energy released in the oxidation of inorganic substances (ammonia, sulfur, ferrous salts, etc.). Some chemo-synthesizing bacteria participate in the nitrogen cycle.