Carbohydrates

Carbohydrates are a large group of organic compounds occurring in foods and living tissues, including sugars, starch, and cellulose. They contain hydrogen and oxygen in the same ratio as water (2:1) and typically can be broken down to release energy in the animal body. These compounds are one of the major families of biomolecules, along with amino acids, fats, and nucleic acids.

Types of Carbohydrates

Carbohydrates, also known as saccharides, are divided into several categories based on their structure and complexity:

Monosaccharides

Monosaccharides are the simplest form of carbohydrates and cannot be hydrolyzed to a simpler compound. They serve as the building blocks for more complex carbohydrates. Common examples include glucose, fructose, and galactose.

Disaccharides

Disaccharides consist of two monosaccharide molecules. They are soluble in water and include sucrose, lactose, and maltose.

Oligosaccharides

Oligosaccharides consist of 3-10 monosaccharides. They play various roles in cell recognition and signaling.

Polysaccharides

Polysaccharides are large molecules made up of numerous monosaccharides linked together. They serve as energy storage (e.g., starch and glycogen) or structural components (e.g., cellulose in plants).

Functions of Carbohydrates

Carbohydrates perform several vital functions in living organisms:

Energy Provision: They are a primary source of energy for cellular respiration. During digestion, carbohydrates are broken down into glucose, which is utilized by cells to produce ATP, the energy currency of the cell.
Storage: In animals, excess glucose is stored as glycogen in the liver and muscles, while in plants, it is stored as starch.
Structural Role: Carbohydrates like cellulose provide structural integrity to plant cells, forming a major component of the plant cell wall.
Biological Recognition: They play crucial roles in cell recognition and signaling processes, which are vital for immune system responses and cellular functions.

Carbohydrate Metabolism

Carbohydrate metabolism involves the chemical processes responsible for the synthesis and breakdown of carbohydrates in living organisms. It is central to many essential metabolic pathways:

Glycolysis: The process of breaking down glucose to produce energy.
Gluconeogenesis: The synthesis of glucose from non-carbohydrate precursors.
Glycogenesis: The formation of glycogen from glucose.
Glycogenolysis: The breakdown of glycogen to release glucose.

Dietary Considerations

Carbohydrate Counting and Low-Carbohydrate Diets are strategies for managing carbohydrate intake for various health reasons, such as controlling blood sugar levels in diabetes or supporting weight loss.

Carbohydrate Loading is a strategy used by athletes to maximize the storage of glycogen in the muscles and liver.

Carbohydrate Intolerance, such as lactose intolerance, is the inability to digest specific carbohydrates due to the lack or dysfunction of certain enzymes.