TCA Cycle Overview

TCA Cycle Overview

The TCA (Tricarboxylic Acid) cycle, also known as the citric acid cycle or Krebs cycle, is a series of chemical reactions that occur within the mitochondria of cells. It is a crucial step in cellular respiration, as it generates energy for the cell by converting acetyl-CoA into carbon dioxide and coenzyme A.

Steps of the TCA Cycle

1. Acetyl-CoA: The cycle begins with the conversion of acetyl-CoA, a product of fatty acid breakdown and glycolysis, into citrate.
2. Citrate: Citrate is converted into isocitrate through the enzyme aconitase.
3. Isocitrate: Isocitrate is converted into α-ketoglutarate through the enzyme isocitrate dehydrogenase, producing NADH and CO2.
4. α-Ketoglutarate: α-Ketoglutarate is converted into succinyl-CoA through the enzyme α-ketoglutarate dehydrogenase, producing NADH and CO2.
5. Succinyl-CoA: Succinyl-CoA is converted into succinate through the enzyme succinyl-CoA synthetase, producing ATP and CoA.
6. Succinate: Succinate is converted into fumarate through the enzyme succinate dehydrogenase, producing FADH2.
7. Fumarate: Fumarate is converted into malate through the enzyme fumarase.
8. Malate: Malate is converted into oxaloacetate through the enzyme malate dehydrogenase, producing NADH.
9. Oxaloacetate: Oxaloacetate is converted back into citrate, completing the cycle.

Products of the TCA Cycle

• ATP: 2 ATP molecules are produced per glucose molecule
• NADH: 6 NADH molecules are produced per glucose molecule
• FADH2: 2 FADH2 molecules are produced per glucose molecule
• CO2: Carbon dioxide is produced as a byproduct

Importance of the TCA Cycle

• Energy production: The TCA cycle produces energy for the cell through the generation of ATP, NADH, and FADH2.
• Intermediary metabolism: The TCA cycle plays a central role in intermediary metabolism, connecting glycolysis, fatty acid breakdown, and the electron transport chain.
• Regulation of cellular metabolism: The TCA cycle is regulated by various enzymes and feedback mechanisms to ensure proper cellular metabolism.

TCA Cycle Overview

• The TCA cycle is a series of chemical reactions that occur within the mitochondria of cells.
• It generates energy for the cell by converting acetyl-CoA into carbon dioxide and coenzyme A.

Steps of the TCA Cycle

• The cycle begins with the conversion of acetyl-CoA into citrate.
• Citrate is converted into isocitrate through the enzyme aconitase.
• Isocitrate is converted into α-ketoglutarate, producing NADH and CO2.
• α-Ketoglutarate is converted into succinyl-CoA, producing NADH and CO2.
• Succinyl-CoA is converted into succinate, producing ATP and CoA.
• Succinate is converted into fumarate, producing FADH2.
• Fumarate is converted into malate.
• Malate is converted into oxaloacetate, producing NADH.
• Oxaloacetate is converted back into citrate, completing the cycle.

Products of the TCA Cycle

• 2 ATP molecules are produced per glucose molecule.
• 6 NADH molecules are produced per glucose molecule.
• 2 FADH2 molecules are produced per glucose molecule.
• Carbon dioxide is produced as a byproduct.

Importance of the TCA Cycle

• The TCA cycle produces energy for the cell through the generation of ATP, NADH, and FADH2.
• It plays a central role in intermediary metabolism, connecting glycolysis, fatty acid breakdown, and the electron transport chain.
• The TCA cycle is regulated by various enzymes and feedback mechanisms to ensure proper cellular metabolism.

Laminar Flow of Blood in Vessels

• Blood flowing at a steady rate through a long smooth vessel forms streamlines, with each layer maintaining a consistent distance from the vessel wall.
• In laminar flow, the centralmost portion of the blood remains in the center of the vessel.
• Laminar flow is characterized by a smooth, continuous, and organized flow of blood.
• This type of flow is in contrast to turbulent flow, where blood flows in all directions and continually mixes in the vessel.