The Basics of Carbs
Have you noticed the carbohydrate food group on the food pyramid lately? I think it's still on the bottom and I think it's still the biggest...but I'm not too sure. Although, I think they haven't changed that food pyramid much. Obvious to all, carbohydrates are the most important types of food that we should be taking in. The reason is quite simple. Carbohydrates are our energy source. They help us stay alive!
You probably noticed the "carbo" in carbohydrates. You may have also guessed correctly that "carbo" comes from the word carbon. This shows that carbohydrates have carbon in them. In fact, the basis of carbohydrates are carbons joined together in rings. The picture below shows glucose (a 5-carbon sugar). The carbons are typically not shown but are located at the corners of the hexagon (just like where the O is in the top right corner). The molecular formula for the glucose depicted is C6H12O6. The genearl formula for all carbohydrates is CH2O.
Some of the sugars that we eat are disaccharides. That is, they contain two ("di") molecules of sugar linked together. For example, sucrose (table sugar) has glucose linked with fructose. Lactose (the sugar in milk) has glucose linked with galactose. The links between the monosaccharide sugar molecules is called a glycosidic linkage. When we eat these sugars, they are digested by the process of hydrolysis. In hydrolysis, water reacts with the di- or polysaccharide molecules and breakes the glycosidic linkage. Thus, monosaccharides are formed.
Glucose is the most abundant sugar and is used as an energy source by most organisms including us humans. When we eat sugars, we digest complex sugars into single units of glucose by hydrolysis. These glucose molecules are further oxidized in our cells. The oxidation converts the stroed energy in glucose into a form that can be readily used. In humans, the glucose is stored as glycogen. In plants, it is stored as starch.