What is essentially the difference between `alpha`-glucose and `beta`-glucose ? What is meant by pyranose structure of glucose ?

Explanation

### Step-by-Step Solution

1. **Understanding Alpha and Beta Glucose**:
- Alpha-glucose and beta-glucose are two cyclic hemiacetal forms of glucose. The essential difference between them lies in the position of the hydroxyl group (-OH) attached to the first carbon (C1) in the cyclic structure.

2. **Structure of Alpha-Glucose**:
- In alpha-glucose, when the glucose molecule is in its open-chain form, the hydroxyl group at C1 is positioned on the right side. When it cyclizes, this hydroxyl group remains on the same side as the CH2OH group at C5, which is at the bottom of the ring structure.

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