To determine the relationship between the two structures of D-glucopyranose, we need to analyze the structures of alpha-D-glucopyranose and beta-D-glucopyranose. Here’s the step-by-step solution:
### Step 1: Draw the Structure of Alpha-D-Glucopyranose
1. **Identify the six-membered ring structure**: D-glucopyranose is a cyclic form of glucose that contains a six-membered ring.
2. **Label the carbons**: Start numbering the carbons in the ring from the anomeric carbon (C1) to C6.
3. **Place the hydroxyl (OH) and hydrogen (H) groups**:
- At C1, the OH group is positioned downwards.
- At C2, the OH is upwards, and H is downwards.
- At C3, the OH is downwards, and H is upwards.
- At C4, the OH is upwards, and H is downwards.
- At C5, the CH2OH group is upwards.
4. **Final structure**: The final structure shows the CH2OH and OH groups on the same side (cis), which defines it as alpha-D-glucopyranose.
### Step 2: Draw the Structure of Beta-D-Glucopyranose
1. **Similar six-membered ring structure**: Again, we start with the cyclic form of glucose.
2. **Label the carbons**: Number the carbons in the same way as before.
3. **Place the hydroxyl (OH) and hydrogen (H) groups**:
- At C1, the OH group is positioned upwards.
- At C2, the OH is upwards, and H is downwards.
- At C3, the OH is downwards, and H is upwards.
- At C4, the OH is upwards, and H is downwards.
- At C5, the CH2OH group is upwards.
4. **Final structure**: The final structure shows the CH2OH and OH groups on opposite sides (trans), which defines it as beta-D-glucopyranose.
### Step 3: Identify the Relationship Between the Two Structures
- The only difference between alpha-D-glucopyranose and beta-D-glucopyranose is the orientation of the hydroxyl group at the anomeric carbon (C1).
- In alpha-D-glucopyranose, the OH group at C1 is down, while in beta-D-glucopyranose, the OH group at C1 is up.
- This difference in configuration at the anomeric carbon indicates that these two forms are anomers.
### Conclusion
The two structures of D-glucopyranose are **anomers**.
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