NADPH

Definition

NADPH, or Nicotinamide adenine dinucleotide phosphate, is a reduced coenzyme that serves as a crucial electron carrier in cellular processes. It plays a significant role in the synthesis of carbohydrates and fatty acids, as well as in the defense against oxidative stress. In photosynthesis, NADPH is generated during the light-dependent reactions and is essential for driving the Calvin cycle.

5 Must Know Facts For Your Next Test

1. NADPH is produced in the chloroplasts during the light-dependent reactions of photosynthesis, specifically through the electron transport chain.
2. This coenzyme provides reducing power by donating electrons during the Calvin cycle, which is essential for synthesizing glucose from carbon dioxide.
3. NADPH also helps protect plant cells from oxidative damage by participating in the regeneration of antioxidants.
4. In addition to its role in photosynthesis, NADPH is involved in various anabolic reactions, including lipid synthesis and nucleotide metabolism.
5. The balance between NADPH and NADP+ is crucial for maintaining cellular redox state and regulating metabolic pathways.

Review Questions

• How does NADPH function within the process of photosynthesis and why is it important for the Calvin cycle?
  • NADPH functions as a crucial electron donor during the Calvin cycle, allowing for the conversion of carbon dioxide into glucose. It is generated in the light-dependent reactions when electrons are transferred through the electron transport chain. The energy and reducing power provided by NADPH are vital for driving the synthesis of carbohydrates, making it an essential component for plant metabolism and growth.
• Evaluate the role of NADPH in protecting plant cells from oxidative stress and its importance in metabolic pathways.
  • NADPH plays a significant role in safeguarding plant cells against oxidative stress by supplying reducing power needed for antioxidant regeneration. This is particularly important during periods of environmental stress, where reactive oxygen species can accumulate and cause damage. Additionally, NADPH is critical for various anabolic pathways, such as fatty acid and nucleotide synthesis, illustrating its multifaceted role in plant metabolism.
• Assess how disruptions in NADPH production could impact photosynthesis and overall plant health.
  • Disruptions in NADPH production can severely impact photosynthesis by limiting the availability of reducing power necessary for the Calvin cycle. If plants cannot synthesize sufficient NADPH, they will struggle to convert carbon dioxide into sugars, resulting in reduced growth and biomass accumulation. Furthermore, compromised NADPH levels can hinder antioxidant defenses, making plants more susceptible to oxidative damage from environmental stresses, ultimately affecting their survival and productivity.

Related terms

Chlorophyll: The green pigment in plants that captures light energy for photosynthesis.

ATP: A molecule that serves as the primary energy currency of the cell, produced alongside NADPH during photosynthesis.

RuBisCO: An enzyme that catalyzes the first step of carbon fixation in the Calvin cycle, utilizing CO2 and ribulose bisphosphate.