Nutrition and Macromolecules

From our perspective as consumers in a food chain, we must ingest all the nutrients we require. These essential nutrients(definition:Nutrients that an organism can only get from their environment.)  are found in a variety of different foods that are part of a balanced diet. Our body can convert these essential nutrients into other important biological molecules. The most important nutrients for us are carbohydrates(definition:A type of neutral compound made of carbon, hydrogen, and oxygen mostly formed by green plants and is a major class of animal foods.). They are found in almost every food we eat and without them we would quickly run out of energy. Various foods have distinct flavours and textures because they contain different types of carbohydrates.

The carbohydrate content of 10 different food items is shown below. Drag the name of each food item (not the picture of each food item) and drop it on the sweetness scale according to your taste experience. 

Long Description

How all biological molecules are used by cells and the body depends on the structure of those molecules. The functional groups that make up different biological molecules are related to the types of intermolecular forces of attraction(definition:An interaction between two molecules that can either be attractive or repulsive.) that are made between those molecules. Also, the shape and size of the molecule is important. 

There are four main types of nutrients that we require in large amounts. For this reason they are called macronutrients(definition:A chemical element or substance that is essential in relatively large amounts to the growth and health of a living organism.). They are also unique among other nutrients because they are made of smaller molecules, called monomers(definition:Small chemical molecules that can be connected together to make larger molecules.), put together to make larger ones, called polymers(definition:A chemical molecule made from many smaller monomer molecules.).

 How does understanding change?

Making analogies are a good way to see if you understand a concept. For example, polymers are like toy blocks that connect together because they’re made of repeating “monomer” blocks.

Describe another analogy for monomers and polymers. A good analogy uses familiar ideas or concepts.

Join The Discussion

Monomers and polymers of carbohydrates each have different uses. This video will give you a taste of what’s to come next.

Uses of Carbohydrates

There is a wide variety of different carbohydrates so it’s sometimes difficult to describe them as a group with similar characteristics. However, as you have seen, all carbohydrates share a similar chemical composition: molecules composed of carbon, hydrogen and oxygen. The name carbohydrate also reminds us of this composition: when we say something is hydrated we understand that it is full of water.  That makes carbohydrates molecules with a simple formula of CH₂O, or any other number of those three atoms in a similar ratio: 1 C : 2 H : 1 O.

At the end of this Activity you will explain how the structure of different carbohydrates is related to their function. So let’s first explore some of the different uses of carbohydrates in cells. Look specifically for which carbohydrate molecules are used for different purposes.

Structures of Carbohydrates

 Quiz

Check your understanding of the structures of carbohydrates. Visit the Dallas Learning Cloud, scroll down the page to the Functional Groups of Carbohydrates title, then click on the Launch Activity bar.

 

 

In some cases, the carbon, hydrogen and oxygen can be arranged differently with the same number of atoms.

Notice that each of these carbohydrates has the same number of each element. They can all be summarized as C₆H₁₂O₆. However, the way the functional groups are organized is different. We describe these three carbohydrates as isomers. (definition:Chemical molecules made from the same number of each type of element but those elements are arranged differently.) Because they have different structures they have different properties.

 Modeling Carbohydrates

Using the CheMagic Virtual Molecular Model Kit, build the following four monosaccharides.

Take a screenshot of each molecule.

Compare the structure of two of these monosaccharides in a Venn diagram . Just like for other graphic organizers, the comparison should: 

• be meaningful;
• be well-organized and easy-to-follow;
• show your understanding of the vocabulary.

Submit Your Work

Chitin

The exoskeleton of arthropods is composed of a polysaccharide called chitin. For these animals, their exoskeleton has to be rigid to provide protection yet flexible enough to allow for the animal to grow.  

 Why is shape important in Biology?

Chitin is also used in a variety of different applications. Try searching to see how chitin is used in industry, society or agriculture. Explain how the use is related to the structure of the polysaccharide. 

Join The Discussion

One of the important functions of carbohydrates we have not discussed so far is cell-to-cell communication. Because there is a large possible structural variation in monosaccharides, this allows for specific recognition between cells. For example, human red blood cells come in different “blood types” depending on which oligosaccharide antigen they have on the exterior of the red blood cell membrane. 

 Why is shape important in Biology?

Explore the Biomolecules: Carbohydrates interactive below to see how different oligosaccharides (definition:A carbohydrate made of up to 20 monosaccharides joined together.) change the blood type of red blood cells. Blood cells that don’t have the same oligosaccharide antigen are detected by the immune system and destroyed.

After your exploration, answer the following question.

Shape 5. Why is it important to know what blood type antigen is on red blood cells when someone receives blood after a surgery?

Go To Portfolio

Now, let’s start by connecting some important ideas and words about carbohydrates.

 Connect 2

Choose any two words in the table below, then connect them with a complete idea.  Repeat this process three times in total.

monomer	disaccharide	glucose
cell wall	energy	structure
glycosidic bond	isomer	cell-to-cell communication

For example: if the two words are ribosome and protein, then you could write:  Ribosomes are connected to proteins because the ribosomes are the protein builders in the cell. Ribosomes are made of two parts or subunits. The larger of the 2 parts is where the ribosome can add on an amino acid to the growing protein chain. 

Join The Discussion