To determine the correct chemical equation that shows the relationship between ADP and ATP, we need to understand the basic biochemistry behind the conversion between these two molecules.
1. Understanding ADP and ATP:
- ADP (Adenosine Diphosphate): This molecule consists of an adenosine molecule attached to two phosphate groups.
- ATP (Adenosine Triphosphate): This molecule contains an adenosine molecule attached to three phosphate groups. ATP is known as the energy currency of the cell.
2. Conversion Process:
- The conversion from ADP to ATP involves the addition of a phosphate group (Pi). The process of adding a phosphate group to ADP to form ATP is called phosphorylation.
- Specifically, the reaction can be represented as:
[tex]\[
\text{ADP} + \text{P}_{\text{i}} \rightarrow \text{ATP}
\][/tex]
- This reaction captures energy within the new bond formed in ATP.
3. Analyzing the Options:
- Option A: [tex]\(\text{ATP} + \text{P} \rightarrow \text{ADP}\)[/tex]
- This implies ATP is breaking down to ADP by losing a phosphate group, which is incorrect as it represents de-phosphorylation.
- Option B: [tex]\(\text{ADP} + \text{P} \rightarrow \text{ATP}\)[/tex]
- This correctly shows the addition of a phosphate group to ADP to form ATP, matching our understanding of phosphorylation.
- Option C: [tex]\(\text{ADP} + H^{+} \rightarrow \text{ATP}\)[/tex]
- This suggests that a proton (H+) is added to ADP to form ATP, which is not biochemically accurate for this process.
- Option D: [tex]\(\text{ATP} + H^{+} \rightarrow \text{ADP}\)[/tex]
- This implies ATP is breaking down into ADP with the release of a proton (H+), which is also not correct for showing the direct conversion to ATP.
4. Selecting the Correct Answer:
- Based on the biochemical understanding of the conversion process, the correct equation that shows the relationship between ADP and ATP is:
[tex]\[
\text{ADP} + \text{P} \rightarrow \text{ATP}
\][/tex]
- This matches Option B.
Thus, the correct answer is B. ADP + P → ATP.
