Select the correct statement

Options

A. For exergonic reactions `Delta`G gt 0
B. ATP undergoes a three step hydrolysis
C. Conversion of ATP to ADP is highly endergonic reaction
D. Dark reactions do not proceed even on being coupled with hydrolysis of ATP

Answer

To solve the question, we need to evaluate each statement regarding biochemical processes and the properties of ATP. Here’s the step-by-step breakdown:

### Step 1: Evaluate the First Statement
- **Statement**: For exergonic reactions, ΔG is greater than zero.
- **Analysis**: Exergonic reactions are characterized by a negative change in Gibbs free energy (ΔG < 0). Therefore, this statement is incorrect.

### Step 2: Evaluate the Second Statement
- **Statement**: ATP undergoes a three-step hydrolysis.
- **Analysis**: ATP hydrolysis typically occurs in two main steps: ATP → ADP + Pi (inorganic phosphate) and then ADP can further hydrolyze to AMP (adenosine monophosphate) + Pi. However, the primary hydrolysis reaction is considered to be a two-step process. Thus, this statement is also incorrect.

### Step 3: Evaluate the Third Statement
- **Statement**: Conversion of ATP to ADP is a highly endergonic reaction.
- **Analysis**: The conversion of ATP to ADP is actually an exergonic reaction, releasing energy that can be used for cellular work. Therefore, this statement is incorrect. However, if we consider the context of energy transfer, the energy released can be used to drive endergonic processes, but the reaction itself is not endergonic.

### Step 4: Evaluate the Fourth Statement
- **Statement**: Dark reactions do not proceed even on being coupled with hydrolysis of ATP.
- **Analysis**: Dark reactions (Calvin cycle) can indeed proceed when coupled with ATP hydrolysis, as ATP provides the necessary energy for these reactions. Thus, this statement is also incorrect.

### Conclusion
After evaluating all four statements, we find that:
- Statement 1: Incorrect
- Statement 2: Incorrect
- Statement 3: Incorrect
- Statement 4: Incorrect

However, the video transcript indicates that the third statement is considered true in the context of energy absorption for work, which may need clarification.

### Final Answer
The correct statement is: **None of the statements are correct based on standard definitions. However, if considering the context of energy usage, the third statement may be considered in a different light.**

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