Carbohydrate Biochemistry Fundamentals

Carbohydrate Biochemistry

Carbohydrates are one of the three macronutrients in the human diet, along with protein and fat. These molecules contain carbon, hydrogen, and oxygen atoms. Carbohydrates play an important role in the human body. They act as an energy source, help control blood glucose and insulin metabolism, participate in cholesterol and triglyceride metabolism, and help with fermentation. The digestive tract begins to break down carbohydrates into glucose, which is used for energy upon consumption. Any extra glucose in the bloodstream is stored in the liver and muscle tissue until further energy is needed.

Structures

Monosaccharides

The most basic, fundamental unit of a carbohydrate is the monosaccharide. These are simple sugars with the general chemical structure of C6H12O6. Examples include glucose, galactose, and fructose.

Disaccharides

Compound sugars containing two monosaccharides with the elimination of a water molecule have the general chemical structure C12H22O11. Examples include sucrose and lactose.

Oligosaccharides

These polymers contain three to ten monosaccharides. Examples include maltodextrins and raffinose.

Polysaccharides

Polymers containing long chains of monosaccharides connected through glycosidic bonds are called polysaccharides. Examples include amylose and cellulose.

Types

Simple Carbohydrates

Simple carbohydrates, also known as simple sugars, are composed of one or two sugars (monosaccharides or disaccharides) and have a simple chemical structure. These are easily utilized for energy, causing a rapid rise in blood sugar and insulin secretion from the pancreas.

Complex Carbohydrates

Complex carbohydrates, also known as complex sugars, contain three or more sugars (oligosaccharides or polysaccharides) bonded together in a more complex chemical structure. These are used for energy storage and structural purposes in cells.

Glycolysis

Glycolysis is the process by which glucose is broken down into pyruvate, which can then be used for energy production. This process occurs in the cytoplasm of the cell and does not require oxygen. It consists of two stages: the preparation phase and the energy-producing phase.

Carbohydrate Metabolism

Carbohydrates are used for energy production in the body through a process called cellular respiration. When glucose is consumed, it enters the bloodstream and is transported to the liver, where it can be either used for energy production or stored as glycogen. Glycogen is a large, branched polysaccharide of glucose that is stored in the liver and muscles as an energy reserve.

Gluconeogenesis

Gluconeogenesis is the process by which the body produces glucose from non-carbohydrate sources, such as amino acids and glycerol. This process occurs in the liver and kidneys and is regulated by hormones such as glucagon and insulin.

Glycogen

Glycogen is a large, branched polysaccharide of glucose that is stored in the liver and muscles as an energy reserve. It is synthesized from glucose 6-phosphate and is hydrolyzed to release glucose 6-phosphate, which can enter glycolysis for energy production.