Carbohydrates: Types and Functions

Biomolecules: Focus on Carbohydrates

Carbohydrates are one of the three primary macronutrients, alongside protein and fat, that supply energy to living organisms. These molecules are composed of carbon (C), hydrogen (H), and oxygen (O) atoms, with hydrogen and oxygen occurring at a 2:1 ratio. Carbohydrates play essential roles in the human body, including energy production, blood glucose and insulin metabolism, and cholesterol and triglyceride metabolism.

Carbohydrates are categorized into three types: monosaccharides, disaccharides, and polysaccharides.

Monosaccharides

Monosaccharides, also known as simple sugars, are the most basic units of carbohydrates. They contain three to seven carbon atoms and are typically composed of three to five hydroxyl groups (OH) and one carbonyl group (C=O). Examples of monosaccharides include glucose, galactose, and fructose.

Disaccharides

Disaccharides are formed when two monosaccharides are bonded together, eliminating a water molecule. Common examples of disaccharides include sucrose (glucose and fructose), lactose (glucose and galactose), and maltose (two glucose molecules).

Polysaccharides

Polysaccharides are long chains of monosaccharides connected through glycosidic bonds. They are further divided into storage polysaccharides and structural polysaccharides. Storage polysaccharides, like starch in plants and glycogen in animals, serve as energy reserves, while structural polysaccharides like cellulose, hemicellulose, and chitin provide structural support.

Complex Carbohydrates

Complex carbohydrates contain a large number of glucose molecules, providing a more gradual increase in blood sugar levels. Examples of complex carbohydrates include cellobiose, rutinose, amylose, cellulose, and dextrin, which are found in foods such as apples, broccoli, lentils, spinach, unrefined whole grains, and brown rice.

Fiber

Non-digestible complex carbohydrates, such as cellulose, hemicellulose, and pectin, are known as fiber. Fiber encourages healthy bacterial growth in the colon and acts as a bulking agent, easing defecation.

Carbohydrates are essential for maintaining proper bodily functions, such as energy production, blood glucose control, and immune system support. However, it is crucial to consume a balanced diet that includes a variety of carbohydrate sources to provide sustained energy and avoid nutrient deficiencies.