Krebs Cycle and Glycolysis: Steps and Enzymes

Posted by on Jan 8, 2025 in Biochemistry | 0 comments

Krebs Cycle (Citric Acid Cycle)

Step 1: Formation of Citrate

  • Substrate: Acetyl CoA
  • Enzyme: Citrate synthase
  • Cofactor: None
  • Product: Citrate

Step 2: Isomerization of Citrate

  • Substrate: Citrate
  • Enzyme: Aconitase
  • Cofactor: None
  • Product: Isocitrate

Step 3: Oxidative Decarboxylation of Isocitrate

  • Substrate: Isocitrate
  • Enzyme: Isocitrate dehydrogenase
  • Cofactor: NAD+
  • Product: Alpha-ketoglutarate, NADH, CO2

Step 4: Oxidative Decarboxylation of Alpha-ketoglutarate

  • Substrate: Alpha-ketoglutarate
  • Enzyme: Alpha-ketoglutarate
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TCA Cycle: A Key Metabolic Pathway in Cellular Respiration

Posted by on Jan 8, 2025 in Biochemistry | 0 comments

The Tricarboxylic Acid (TCA) Cycle

The Tricarboxylic Acid (TCA) cycle, also known as the citric acid cycle or Krebs cycle, is a central metabolic pathway that plays a crucial role in the aerobic respiration of eukaryotic cells and many bacteria. It is named after Sir Hans Krebs, who elucidated its key features in the 1930s and 1940s. The TCA cycle takes place in the mitochondria of eukaryotic cells and the cytoplasm of prokaryotic cells.

Detailed Description of the TCA Cycle

  1. Acetyl-CoA Entry:
    • The TCA
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Cellular Respiration: Glycolysis, Krebs Cycle, and More

Posted by on Jan 6, 2025 in Biochemistry | 0 comments

Glycolysis

Glycolysis (ATP Expenditure)

  1. Phosphorylation: Glucose + ATP – (Hexokinase) -> ADP + Glucose-6-Phosphate
  2. Glucose-6-Phosphate <- (Phosphohexose Isomerase) -> Fructose-6-Phosphate
  3. Phosphorylation: Fructose-6-Phosphate + ATP – (Phosphofructokinase-1) -> Fructose-1,6-Bisphosphate + ADP
  4. Fructose-1,6-Bisphosphate <- (Aldolase) -> Glyceraldehyde-3-Phosphate + Dihydroxyacetone Phosphate
  5. Dihydroxyacetone Phosphate <- (Triose Phosphate Isomerase) -> Glyceraldehyde-3-Phosphate

Energy

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