LIFE SCIENCE

Detailed explanation-1: -Sources. The most common naturally occurring monosaccharides are d-glucose, d-mannose, d-fructose, and d-galactose among the hexoses and d-xylose and l-arabinose among the pentoses.

Detailed explanation-2: -This indicated that most natural carbohydrates have a D configuration. For example, glucose one of the most common and important carbohydrates also used extensively for the initial studies, was found to exist naturally as a D isomer.

Detailed explanation-3: –If the carbohydrate has the hydroxyl group at the last chiral carbon towards the right side, it is denoted by the letter D and if the hydroxyl group at the last chiral carbon lies towards the left side, it is denoted by the letter L.

Detailed explanation-4: -Most carbs occur naturally in plant-based foods, such as grains. Food manufacturers also add carbs to processed foods in the form of starch or added sugar. Common sources of naturally occurring carbohydrates include: Fruits.

Detailed explanation-5: -Almost all sugars found in nature are D-sugar. Like R and S, D and L indicate the configuration of an asymmetric carbon, but they do not indicate whether the compound rotates polarized light to the right or to the left. For example, D-glyceraldehyde is dextrorotatory, whereas D-lactic acid is levorotatory.