What are Carbohydrates? | Types, Definition, Structure, Function & Facts

What are Carbohydrates?

When most people talk about carbs, they’re talking about starchy foods (like bread, pasta, and rice) or sugary foods (like candy, cookies, and cakes). In science, when we talk about carbohydrates, we are talking about specific types of molecules.

Carbohydrates are one of the four major groups of organic molecules; the other three are proteins, nucleic acids (DNA) and lipids (fats). Carbohydrates are made up of three elements: carbon, hydrogen, and oxygen.

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What are they doing?

Carbohydrates are very important for the daily life of living organisms. They store energy (starch), provide energy for cells (glucose) and are the structure of plants and some animals.

Types of Carbohydrates

Carbohydrates are sometimes called saccharides. Different types of carbohydrates all contain the word “saccharide“.

Monosaccharides – Monosaccharides are the simplest form of carbohydrates. These include sugars such as glucose and fructose. Monosaccharides are usually sweet and soluble in water. Glucose is a common carbohydrate found in plants and is the main product of photosynthesis.

Disaccharide – Disaccharide is formed from two monosaccharides. They are also known as sugars such as sucrose and lactose. Lactose is a carbohydrate found in milk.

Oligosaccharides – Oligosaccharides are formed from a small number (usually three to six) of monosaccharides.

Polysaccharides – Polysaccharides are long carbohydrate molecules. They are often referred to as complex carbohydrates.

About Complex Carbohydrates (Polysaccharides)

There are four important complex carbohydrates:

Starch – Starch is a way for many plants to store energy. Then we can eat the starch and our body will use the energy.

Glycogen – Animals use glycogen to store energy. It is stored in the liver and muscles for use when needed.

Cellulose – Cellulose is used in plants as a structural molecule. It cannot be digested by animals.

Chitin – Chitin is used as a structural molecule in fungi and arthropods.

What happens to the remaining Carbohydrates?

When you eat carbohydrates, your body uses them for energy. However, if you eat more than you need, your body will convert them to fat. Fat is the body’s way of storing energy for later use. Your body is trying to save energy for later when you don’t have carbs to eat.

Interesting facts about Carbohydrates

Most of the time, the ratio of hydrogen to oxygen atoms in carbohydrates is 2 hydrogen atoms to 1 oxygen atom. This is the same ratio as in water (H2O).

The word “saccharide” comes from the Greek word “sakkharon” which means “sugar“.

Carbohydrates make up 2-3% of the average person’s body mass. Some carbohydrates help our body absorb calcium.

Many people try low-carb diets to lose weight, but we all need carbs to survive.

Carbohydrates help ensure that our cells receive the energy they need to function properly.