`alpha`-Maltose consists of

Options

A. one `alpha-D` -glucopyranose unit and one `beta-D`-glucopyranose unit by 1,2-glycosidic linkage
B. two `alpha-D`-glucopyranose unit with 1,2-glycosidic linkage
C. two `beta-D`- glucopyranose units with 1,4-glycosidic linkage
D. two `alpha-D-glucopyranose units with 1,4-glycosidic linkage

Explanation

To determine the composition of alpha-maltose, we can break down the information provided in the video transcript and supplement it with some additional knowledge about carbohydrates.

### Step 1: Understand the Composition of Alpha-Maltose
Alpha-maltose is a disaccharide, which means it is composed of two monosaccharide units. In the case of alpha-maltose, these units are both glucose molecules.

### Step 2: Identify the Monosaccharide Units
The two glucose units in alpha-maltose are:
- One unit is in the alpha-D-glucopyranose form.
- The other unit is in the beta-D-glucopyranose form.

### Step 3: Glycosidic Linkage
The two glucose units are linked together by a glycosidic bond. In alpha-maltose, this bond is specifically an α(1→4) glycosidic linkage, which means that the first carbon of the alpha-D-glucopyranose unit is linked to the fourth carbon of the beta-D-glucopyranose unit.

### Step 4: Structure of Alpha-Maltose
The structure of alpha-maltose can be represented as:
- One α-D-glucopyranose unit connected to one β-D-glucopyranose unit through an α(1→4) glycosidic bond.

### Final Answer
Alpha-maltose consists of:
- 1 α-D-glucopyranose unit
- 1 β-D-glucopyranose unit
- 1 α(1→4) glycosidic linkage