Microbiology Study Guide Unit 2

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Define metabolism:
The sum of all biological chemical reactions inside a cell or organism Differences in catabolism and anabolism:
Catabolism is an enzyme-regulated chemical reaction that releases energy. Complex organic compounds such as glucose, amino acids, glycerol and fatty acids are broken down into simpler ones. The energy of catabolic reactions is used to drive the anabolic reactions. Anabolism is also enzyme regulated but requires energy for taking the simpler broken down components from the catabolism phase and building them into complex molecules such as starch, proteins and lipids What is the role of ATP?

ATP is the driving force for catabolic and anabolic reactions. ATP stores energy that is produced from the catabolic reactions which is later released to drive the anabolic reaction and other cellular work. ATP is stored energy in cells (phosphate groups held together by high energy reacting bonds) ATP is required for synthesis and some of the energy is given off as heat What are enzymes and their components?

Enzymes are biological catalysts (substances that speed up a chemical reaction without themselves being permanently altered) Components:
Apoenzyme is the protein portion of an enzyme. Inactive by themselves, must be activated by cofactors Cofactor- non protein portion (IE: ions of iron, zinc, magnesium and calcium) ****If the cofactor is an organic molecule, it is called a coenzyme Holoenzyme- The apoenzyme+cofactor forms the holoenzyme. It is the active enzyme. If you remove the cofactor, the apoenzyme will not function. **Cofactors may assist the enzyme by accepting atoms removed from the substrate or by donating atoms required by the substrate. (Substrate=the specific substance that an enzyme will act on) **The crucial function of enzymes is to speed up biochemical reactions at temperatures that are compatible with the normal functioning of the cell. What are metabolic pathways?

The sequence of enzyme catalyzed chemical reactions within a cell. What is the Kreb’s cycle?
A pathway that converts two-carbon compounds to CO2, transferring electrons to NAD+ and other carriers; also called tricarboxylic acid (TCA) cycle or citric acid cycle A series of biochemical reactions in which a large amount of potential chemical energy stored in acetyl CoA is released step by step. In the cycle, a series of oxidations and reductions transfer that potential energy in the form of electrons to electron carrier coenzymes (mostly NAD+). The pyruvic acid derivatives are oxidized and the coenzymes are produced. Kreb’s cycle is for lipid catabolism. Glycerol is converted into dihydroxyacetone phosphate (DHAP) and catabolized via glycolysis and the Kreb’s cycle. Fatty acids undergo beta-oxidation, in which carbon fragments are spit off two at a time to form acetyl CoA which is catabolized by Kreb’s cycle. What is glycolysis?

**Glycolysis creates to ATP molecules
The main pathway for oxidation of glucose to pyruvic acid:
Glycolysis is usually the first stage in carbohydrate catabolism. This occurs from the oxidation of glucose to pyruvic acid. Most microorganisms use this pathway and it occurs in most living cells. The term “glycolysis” means the splitting of sugar. The sugars are oxidized, release energy and then their atoms are rearranged to form 2 molecules of pyruvic acid. **Glycolysis does not require oxygen! Explanation of cellular respiration:

Cellular respiration takes place after the glucose is broken down in pyruvic acid which is then channeled into the next step of either fermentation or cellular respiration. Cellular respiration is defined as the ATP-generating process in which most molecules are oxidized and the final electron acceptor is (almost always) an inorganic molecule. **operates via an electron transport chain * Aerobic respiration the final electron acceptor is O2

* Anaerobic respiration the final electron acceptor is an inorganic molecule other than O2 What is an electron transport...
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