Choose the correct molecule for glucose.

Options

A.
B.
C.
D.

Answer

To choose the correct molecule for glucose, we need to understand the structure of glucose and its two forms: alpha-D-glucose and beta-D-glucose. Here’s the step-by-step solution:

### Step 1: Understand the Structure of Glucose
Glucose is a simple sugar (monosaccharide) that exists in two cyclic forms: alpha-D-glucose and beta-D-glucose. Both forms are structural isomers of each other.

### Step 2: Draw the Structures
1. **Alpha-D-Glucose**:
- In alpha-D-glucose, the hydroxyl group (-OH) on the first carbon (C1) is positioned below the plane of the ring.
- The structure can be represented as:
```
CH2OH
|
H---C1---OH
|
HO--C2---H
|
H---C3---OH
|
H---C4---OH
|
C5
```

2. **Beta-D-Glucose**:
- In beta-D-glucose, the hydroxyl group (-OH) on the first carbon (C1) is positioned above the plane of the ring.
- The structure can be represented as:
```
CH2OH
|
OH--C1---H
|
H---C2---H
|
H---C3---OH
|
H---C4---OH
|
C5
```

### Step 3: Compare with Given Options
Now, compare the drawn structures with the provided options. Look for the arrangement of the hydroxyl and hydrogen groups on the first carbon.

### Step 4: Identify the Correct Option
After comparing the structures, identify which option corresponds to either alpha-D-glucose or beta-D-glucose. According to the explanation, option A corresponds to the correct structure of glucose.

### Conclusion
Hence, the correct answer is **option A**.

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