Importance of Coenzymes in Cellular Respiration

Introduction

• Focus on coenzymes in cellular respiration, based on the OCR A-level biology specification.
• Importance: Vital for respiration processes, both aerobic and anaerobic.

Coenzymes in Respiration

NAD (Nicotinamide adenine dinucleotide)

• Known for accepting hydrogen atoms and electrons to become reduced NAD.
• Used in:
  • Glycolysis
  • Link reaction
  • Krebs cycle
• NAD is involved in both aerobic and anaerobic pathways.
• Plays a role in oxidative phosphorylation (aerobic respiration).

Coenzyme A

• Role: Carries acetate (ethanoic) groups from pyruvate in the link reaction to the Krebs cycle.
• Cycle:
  • Drops off acetate in Krebs cycle.
  • Returns to link reaction to collect more acetate.

FAD (Flavin adenine dinucleotide)

• Accepts hydrogen atoms and electrons to become reduced FAD.
• Used exclusively in the Krebs cycle.
• Only involved in aerobic respiration.

Final Notes

• Coenzymes are essential for both aerobic and anaerobic respiration.
• Exam Tips:
  • Avoid using vague terms like "it," "they," "amount," and "size".
  • Use precise scientific terminology to maximize marks.
• Summary: Coenzymes are crucial for respiration processes at various stages and must be understood in detail.