Biology for Kids
What are carbohydrates?
When most people refer to carbohydrates they are talking about foods that are starchy (like bread, pasta, and rice) or are sugary (like candy, cookies, and cake). 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 being proteins, nucleic acids (DNA), and lipids (fats). Carbohydrates are made up of three elements: carbon, hydrogen, and oxygen.
What do they do?
Carbohydrates are important to the daily lives of living organisms. They store energy (starches), provide energy for cells (glucose), and provide structure to plants and some animals.
Types of Carbohydrates
Carbohydrates are sometimes referred to as saccharides. The different types of carbohydrates all have the word "saccharide" in them.
More about Complex Carbohydrates (Polysaccharides)
- Monosaccharides - Monosaccharides are the simplest form of carbohydrates. They include sugars such as glucose and fructose. Monosaccharides often taste sweet and dissolve in water. Glucose is a common carbohydrate found in plants and is the main product of photosynthesis.
- Disaccharides - Disaccharides are formed from two Monosaccharides. They are also known as sugars such as sucrose and lactose. Lactose is the 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 called complex carbohydrates.
There are four important types of complex carbohydrates:
What happens to left over carbohydrates?
- Starches - Starches are a way that many plants store energy. We can then eat starches and our bodies will use the energy.
- Glycogen - Animals use glycogen to store energy. It is stored in the liver and the muscles to be used when needed.
- Cellulose - Cellulose is used in plants as a structural molecule. It can't be digested by animals.
- Chitin - Chitin is used as a structural molecule in fungi and arthropods.
When you eat carbohydrates your body uses them for energy. However, if you eat more than your body needs, it will convert them into fat. Fat is the way that the body stores energy for later use. The body is trying to save up energy for a later time when you don't have any carbohydrates to eat.
Interesting Facts about Carbohydrates
- Most of the time, the hydrogen to oxygen atom ratio of a carbohydrate is 2 hydrogen atoms for every 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 between 2 and 3 percent of the average person's body mass.
- Some carbs help our bodies to absorb calcium.
- Many people try using a low carb diet to lose weight, but we all need some carbohydrates to survive.
- Carbohydrates help to insure that our cells get the energy they need to perform well.
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