NADPH

Definition

NADPH, or nicotinamide adenine dinucleotide phosphate, is a coenzyme that plays a critical role in anabolic reactions and biosynthetic pathways by acting as a reducing agent. It is essential for the synthesis of fatty acids and nucleic acids, providing the necessary electrons and protons needed for these processes. NADPH is primarily generated in the pentose phosphate pathway and during light reactions of photosynthesis, linking energy metabolism with biosynthetic processes.

5 Must Know Facts For Your Next Test

1. NADPH is vital for fatty acid synthesis and the production of cholesterol, providing the reducing power needed for these anabolic processes.
2. In photosynthesis, NADPH is generated during the light-dependent reactions and is used in the Calvin cycle to convert carbon dioxide into glucose.
3. The pentose phosphate pathway not only produces NADPH but also generates ribose-5-phosphate for nucleotide synthesis, illustrating its importance in both energy and biosynthesis.
4. NADPH helps maintain the redox state of cells by providing reducing equivalents that protect against oxidative stress.
5. It serves as a key player in detoxification processes by participating in the reduction of oxidized glutathione, which protects cells from reactive oxygen species.

Review Questions

• How does NADPH function as a reducing agent in biosynthetic pathways?
  • NADPH functions as a reducing agent by donating electrons and protons in various anabolic reactions. This electron donation is crucial for processes such as fatty acid synthesis and nucleotide production, where it helps convert substrates into more complex molecules. The ability of NADPH to provide these reducing equivalents makes it essential for building cellular components and supporting growth.
• Discuss the role of NADPH in photosynthesis and how it connects to energy metabolism.
  • In photosynthesis, NADPH is produced during the light-dependent reactions when light energy is converted into chemical energy. This NADPH is then utilized in the Calvin cycle to help convert carbon dioxide into glucose. This connection between light reactions and the Calvin cycle illustrates how NADPH serves as a bridge between energy metabolism and anabolic processes, enabling plants to produce organic compounds from inorganic materials.
• Evaluate the importance of NADPH in maintaining cellular health and function amidst oxidative stress.
  • NADPH plays a critical role in maintaining cellular health by providing reducing power to combat oxidative stress. It is involved in regenerating reduced glutathione, a key antioxidant that helps neutralize reactive oxygen species. By participating in detoxification processes and supporting redox balance within cells, NADPH ensures that metabolic functions can proceed without disruption from oxidative damage, highlighting its importance for overall cellular integrity.

Related terms

NADH: NADH, or nicotinamide adenine dinucleotide, is a coenzyme similar to NADPH but mainly involved in catabolic reactions, carrying electrons to the electron transport chain for ATP production.

Pentose Phosphate Pathway: The pentose phosphate pathway is a metabolic pathway that generates NADPH and ribose-5-phosphate from glucose-6-phosphate, playing a crucial role in cellular metabolism.

Anabolism: Anabolism refers to the metabolic pathways that construct molecules from smaller units, using energy often derived from ATP and NADPH for biosynthesis.