Krebs Cycle, Citric Acid Cycle, or Tricarboxylic Acid Cycle (TCA)
The TCA cycle, is a series of chemical reactions that are used by all aerobic organisms to generate energy. The cycle takes in acetyl-CoA, a molecule that is produced from the breakdown of glucose, and produces carbon dioxide, NADH, FADH2, and ATP.
Krebs cycle
The compounds that are involved in the Krebs cycle are often named as acids or "ates". This is because they contain carboxyl groups, which are functional groups that consist of a carbon atom bonded to two oxygen atoms. The carboxyl group can lose a hydrogen atom to form a negatively charged carboxylate ion, which is what gives acids their sour taste.
In the Krebs cycle, some of the compounds are shown as acids, while others are shown as "ates". This is because the oxidation state of the carbon atom in the carboxyl group can vary. In some compounds, the carbon atom has a higher oxidation state and is therefore shown as an acid. In other compounds, the carbon atom has a lower oxidation state and is therefore shown as an "ate".
For example, the compound oxaloacetate is shown as an "ate" because the carbon atom in the carboxyl group has a lower oxidation state of +3. The compound citrate is shown as an acid because the carbon atom in the carboxyl group has a higher oxidation state of +5.
The use of acids and "ates" to name the compounds in the Krebs cycle can be confusing, but it is important to remember that the oxidation state of the carbon atom in the carboxyl group determines whether the compound is shown as an acid or an "ate".
Here is a table of some of the compounds in the Krebs cycle and their oxidation states:
Compound | Oxidation State of Carbon Atom in Carboxyl Group |
---|---|
Oxaloacetate | +3 |
Citrate | +5 |
Isocitrate | +4 |
α-Ketoglutarate | +3 |
Succinyl-CoA | +4 |
Succinate | +3 |
Fumarate | +2 |
Malate | +3 |
Oxaloacetate | +3 |
As you can see, the oxidation state of the carbon atom in the carboxyl group increases as the compound progresses through the Krebs cycle. This is because the carbon atom is oxidized, which means that it loses electrons. The loss of electrons releases energy, which is used to produce ATP.
Krebs Cycle - Enzymes
