While the question "What is full of NADH2?" is somewhat ambiguous, we can interpret it in a few ways, focusing on where NADH (which can also be represented as NADH + H+, and sometimes loosely as NADH2 for simplification) is produced or highly concentrated.
Here are the likely interpretations and their respective answers:
1. Cellular Locations/Processes with High NADH Production:
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Mitochondria: Specifically, the mitochondrial matrix is full of NADH during cellular respiration. The Krebs Cycle (also known as the Citric Acid Cycle or Tricarboxylic Acid Cycle) occurs in the mitochondrial matrix and generates a significant amount of NADH.
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Cytosol: While the mitochondria are the primary site for NADH production, glycolysis, which occurs in the cytosol, also generates NADH. Therefore, we can consider the cytosol to be abundant in NADH also.
2. Understanding NADH's Role:
NADH (Nicotinamide Adenine Dinucleotide + Hydrogen) is a crucial electron carrier in cellular respiration. It carries high-energy electrons from the breakdown of glucose and other fuel molecules to the electron transport chain (ETC) in the inner mitochondrial membrane.
3. Importance of NADH:
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Energy Production: NADH is vital for ATP production via oxidative phosphorylation in the ETC. The electrons it carries are used to pump protons across the inner mitochondrial membrane, creating an electrochemical gradient that drives ATP synthase.
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Redox Reactions: NADH participates in numerous redox (reduction-oxidation) reactions within the cell, serving as a reducing agent.
4. Analogy:
Think of NADH as a loaded truck carrying valuable cargo (electrons) to a power plant (ETC). The power plant then uses these electrons to generate electricity (ATP).
In summary, while NADH itself is a molecule and doesn't contain anything, the question most likely refers to cellular locations or processes where NADH is abundant, such as the mitochondrial matrix and cytosol during cellular respiration. These are environments where NADH is actively generated and utilized in energy production.
