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The Importance of Complex Carbohydrates

Carbohydrates can be linked into super long and complicated structures. These are known as polysaccharides.

Polysaccharides have many functions, including energy storage and structural support. Important examples of this macromolecule include cellulose, chitin, glycogen, and starch.

Providing Structure

Cellulose and chitin are examples of structural polysaccharides.

Plants use long chains of glucose to create cellulose, which is a rigid structure that makes up a plant's body. Animals that eat plants have digestive enzymes which allow them to use the energy that is stored in cellulose molecules. Humans do not have these enzymes, which is why we can't eat grass.

Chitin is another type of carbohydrate used to make strong structures. You can find it in fungal cell walls. You've also probably seen it in the hard exoskeletons of insects, crabs, and shrimp. Chitin helps protect the soft bodies of these animals.

Providing Energy

Large energy storage molecules are called starches. Plants store energy in a bunch of different kinds of starches. Plant starches usually need to be processed in some way for humans and other animals to eat them.

The starch in potatoes needs to be boiled or baked for us to enjoy. Similarly, the starch in grains needs to be ground up and baked into bread for us to eat.

Animals store energy in a starch called glycogen. Glycogen is stored in muscle cells and in the liver where it can be easily broken down into glucose. It is then used in the process of cellular respiration.

How Are Polysaccharides Formed?

Polysaccharides are highly branched compounds. They are made of many simple sugars linked together by glycosidic bonds. This is a type of bond that connects carbohydrates. Once the sugar chains are connected, hydrogen bonds make sure the chains stay in place. Because there is a large number of these hydrogen bonds, the resulting structure is extremely strong.

What Is a Simple Sugar?

Simple sugars are also called monosaccharides. The prefix mono- means "one" and saccharide means sugar. They are like building blocks that can combine to make more complex sugars. What they make depends on the type of monosaccharide used. Three common ones are glucose, fructose, and galactose. Two of these single sugars can combine in different ways to make a disaccharide (di- meaning "two"). Examples of disaccharides are lactose, sucrose, and maltose. When many simple sugars combine into long chains, they make polysaccharides such as starch and glycogen (poly- meaning "many").

Breaking Down Glycogen

Polysaccharides are sometimes referred to as complex carbohydrates. They are macromolecules formed from monosaccharide units. Monosaccharides are sugar molecules in their simplest form, such as glucose molecules. Carbohydrates are so common because glucose is the most abundant organic molecule on Earth.

Animals use a storage polysaccharide called glycogen (sometimes called animal starch) to store excess sugar. If your blood sugar ever gets too low, glycogen will be broken down into glucose units for more energy.

Plants use a sugar called cellulose. This type of structural polysaccharide makes up tough but flexible fibers found in the cell walls of plants. Cellulose provides the plant with stability. Large amounts of it are present in wood and paper. Plants can also store excess sugars in the form of starch.

$$\color{#8925AE}{\text{Vocabulary Review:}}$$

$\color{#8925AE}{\text{Monomer}}$ : Any molecule that can react with other molecules of the same or different makeup to form a chain, or polymer

$\color{#8925AE}{\text{Polymer}}$ : A chain of monomers (repeating units) made of a specific type of compound

$\color{#8925AE}{\text{Macromolecule}}$ : A polymer that has a large (macro) molecular mass. There are four main types in organisms: carbohydrates, proteins, lipids, and nucleic acids

$\color{#8925AE}{\text{Monosaccharide}}$ : The most basic types of sugars, called simple sugars

$\color{#8925AE}{\text{Polysaccharide}}$ : A polymer of simple sugars. Things like starch and glycogen

$\color{#8925AE}{\text{Carbohydrate}}$ : A polymer of sugars or starch monomers

(Video) Complex Carbohydrates

by Whats Up Dude

This video describes several types of complex sugars and how we break them down in our bodies.

Complex sugars, also called polysaccharides, are made of many subunits called monosaccharides. The most common types of this important macromolecule include starch and cellulose.

Starch is a source of energy for many organisms, including humans. It can be broken down into simpler sugar molecules that are then used by the body.

Cellulose has a similar structure, but it cannot be completely broken down by the human body. Instead, it serves as a form of fiber. It helps the body get rid of waste, excess sugar, and cholesterol.