The Basics of Biochemistry

There is an overall conundrum when it comes to high school science education. If you look at the way science is organized, physics forms the basic concepts that support chemistry, and chemistry is essential in understanding biology. Students, however, do not usually have the math skills necessary to tackle physics or even chemistry until later in their secondary education. This means that biology is usually taught before students have an understanding of basic chemical concepts. 

Because of this, biology teachers have a special challenge in introducing cellular processes. If we present biochemistry too simply, then students will have trouble understanding the processes involved in enzyme production, photosynthesis, cellular respiration, and other cell processes.  However, if we go into too much detail, we could risk spending most of the course on concepts that students will learn later in chemistry.

I solve this dilemma by teaching the most important chemical concepts and keeping them simple. If a student is interested in a more detailed understanding of chemistry, I allow them to work independently for extra credit, or appease them by promising them more detail when they take chemistry. I start with an introduction to atomic structure, covalent and ionic bonding.  Most students remember this from physical science coursework and we are able to move quickly. I spend more time on the structure and properties of water. The hydrogen bonds present in water give it many unique properties that make it valuable to life. Students complete a lab that highlights the cohesion, adhesion, solubility, and pH properties of water.

Next, we move on to carbon. As carbon-based life forms, it is important for students to understand the element’s bonding properties. We draw the atomic structure of carbon on an interactive whiteboard and show how the four electrons in carbon’s outermost orbital allow carbon to form four covalent bonds. This bonding structure makes carbon very versatile in the chains and ring shapes it can form. 

Once students understand carbon and water, they will be better able to learn about carbohydrates and lipids, which are composed of carbon, hydrogen, and oxygen. By adding nitrogen to the mix, we can then learn about proteins. Since previous knowledge of these organic macromolecules comes from food, I will often have students work in groups to present the chemical structure, bodily importance, and dietary sources of these compounds.  Then, students complete a lab testing for the macromolecules. This is often our first major lab of the course, so it is one that I use to practice lab safety and the scientific method. You can also incorporate the concepts of chemical reactions to help students explain how the reagents change into visible products during the lab.

Understanding just these basic chemical concepts gives my students enough knowledge to approach the challenges of cellular processes without bogging us down in excessive details. The lessons below will help you teach basic biochemistry as well.

Biochemistry Lesson Plans:

An Introduction to Four Groups of Biologically Important Compounds  

Students talk about the four biochemicals that are important biologically. In this lesson, students identify the four main groups of biochemicals, including carbohydrates, proteins, lipids and nucleic acids.

Detecting Compounds Made By Living Things?  

Students are able to study the groups of organic compounds as they tend to be found in nature. They discover that certain foods contain more than one organic compound. Students observe positive starch, sugar, protein, and fat tests. They develop scientific and technical skills by testing food samples.

Water Molecules And Hydrogen Bonding 

Students distinguish between polar and non-polar covalent bonds. They illustrate the three kinds of weak bonds using a drawing board and demonstrate how water molecules form hydrogen bonds. They draw a water molecule on a one-foot square drawing board.

Ionic or Covalent?  

Students explain the physical properties of substances based on the strength of molecular attractions. They describe the nature of ionic and covalent bonds and give examples of how they contribute to the formation of various types of compounds.