carbohydrate- monosaccharides and disaccharides

What are the primary components and typical ratio of carbohydrates?

Carbohydrates are composed of C, H, and O, typically in the ratio (CH2O)n.

List the main functions of carbohydrates.

Carbohydrate functions include energy storage, serving as structural components, and facilitating cell-cell recognition.

Define monosaccharides and describe their common forms.

Monosaccharides are the smallest carbohydrate unit, usually containing 3–7 carbons. They can exist in either linear or ring (cyclic) forms in solution.

How are monosaccharides classified by their carbon number? Provide examples for each.

Monosaccharides are classified by carbon number:

1. Hexoses (6C):
   • Glucose (primary energy source)
   • Fructose (fruit sugar, a ketose)
   • Galactose
   • Mannose
2. Pentoses (5C):
   • Ribose (found in RNA)
   • Deoxyribose (found in DNA)
   • Xylose
   • Arabinose

What are the two main types of monosaccharides based on their functional groups? Provide an example for each.

The two main types are:

1. Aldoses: Contain an aldehyde group (e.g., glucose).
2. Ketoses: Contain a ketone group (e.g., fructose).

How are disaccharides formed, and what type of bond connects their monosaccharide units?

Disaccharides are formed by dehydration synthesis (a condensation reaction) between two monosaccharides. The bond formed is a glycosidic linkage, which is a C-O-C bridge.

Provide examples of common disaccharides, their constituent monosaccharides, and the type of glycosidic linkage.

Examples of disaccharides include:

• Maltose: composed of glucose + glucose (connected by an \alpha-1,4 linkage).
• Lactose: composed of glucose + galactose (connected by a \beta-1,4 linkage).
• Sucrose: composed of glucose + fructose (connected by an \alpha-1,2 linkage).

Why is the type of glycosidic linkage in disaccharides biologically significant for humans?

The linkage type is biologically significant because:

• Humans can break \alpha linkages (found in starch, maltose, sucrose).
• Humans cannot break \beta linkages in cellulose (which acts as dietary fiber).
• Lactose intolerance is the inability to hydrolyze the \beta-1,4 bond of lactose.

Give an example of a monosaccharide that is a ketose.

Fructose is an example of a monosaccharide that is a ketose.

What is the primary energy source in the body among the hexoses?

Glucose is the primary energy source among the hexoses.