There are certain experiments that should be in every biology teacher’s repertoire. These experiments illustrate important concepts of modern biology as they help students develop critical thinking and scientific method. These experiments go beyond demonstrating fundamental principles in life sciences to showing the societal importance of biology. These experiments show students how biological science changes the world. These individual biology experiments are on Modern Biology’s list of the top biology experiments of all time.
How We Chose Our Top Experiments
We didn’t choose the topics for your experiment kits randomly, and our products are experiments, not demonstrations. We specifically selected experiments that not only tie into important social issues, but that also are backed up in the literature of science education and that have real-world relevance to students.
EXP-102: Genetics and Sickle Cell Anemia
Consider our experiment on sickle cell anemia, for example. Students use electrophoresis to test for variants of the sickle cell gene in real blood samples from the students themselves.
This one experiment can be used to teach concepts of genetics, physiology, biochemistry, and evolution. It can be used to teach about the relationships of genotype and phenotype, about balanced polymorphisms, and about developmental gene regulation, cooperative binding, and protein polymerization. But it also can be used to teach the social context of biological science so students gain an accurate understanding of allele frequency and distribution, and the importance of understanding this concept for people in the real world. And by helping students explore three genotypes in their own blood, this experiment reinforces the concept that there is no single “right answer” in experimental biology, especially in the study of DNA.
Mastering the tools of electrophoresis is the way your students can make DNA real.
IND-24: An Introduction to Electrophoresis and Multiple Follow-Up Experiments
Gel electrophoresis is an indispensable laboratory method for separating and analyzing large molecules, typically proteins, DNA, and RNA. Clinical chemists use electrophoresis to separate proteins by size and charge, and molecular biologists use it to separate samples of fragments of DNA and RNA by length. And biology teachers use electrophoresis to tie together numerous disparate concepts in biology with multiple vivid laboratory experiences.
Consider how you might approach this topic:
First you might get your students to explain why the technique is called gel electrophoresis. You’d review the properties of the agarose gel you will be using in the lab and the “opposites attract, likes repel” nature of the electrophoresis pan.
Then you could use these concepts to explain the helical configuration of DNA, how the DNA helix does not consist just of the four bases adenosine (A), guanine (G), cytosine (C), and thymine (T), but also of billions of phosphate groups, each with a tiny negative electrical charge. The presence of phosphate groups gives DNA its helical shape.
You’d review how the sample being analyzed is placed in wells made with a comb at the negatively charged side of the tray. Since opposite charges attract, the larger fragments of DNA or RNA or the larger proteins will travel toward the anode. However, not all fragments move at the same rate. The smaller fragments move more easily through the sticky gel and move closer to the anode, while the larger fragments are more resistant to the gel and fall behind.
You could encourage your students to take a look at the gel through a microscope, you see a mesh-like structure. The size of the pores in the gel is nearly constant throughout the gel. When different-sized fragments are exposed to an electrical charge across the gel, the smaller fragments escape the pores faster and the larger fragments take longer to move through the pores.
It isn’t enough just to place the sheet of gel in the well, add the protein sample, and turn on the power. DNA, RNA, and other proteins are colorless. It is impossible to see them without a dye. A color loading dye is added to the DNA, RNA, or protein sample before it is put onto the gel.
And it is also necessary to add a buffer to the gel before beginning the analysis to get better conduction of electricity through the seaweed gel. This teaches your students that instrumentation isn’t magical. It requires thoughtful inputs.
The loading dye moves just a little faster than the DNA with which it is mixed. It arrives at the anode when the DNA is almost at the anode. This tells us when to turn off the power supply. If the electrical charge on the gel were applied indefinitely, eventually all the fragments would gather at the anode. This would just move the sample from one end of the gel to the other. That’s the reason the charge is applied only long enough for the fragments to separate in lines across the gel.
Even after all of this, it is not possible to see the DNA molecules yet, because they are colorless. The next step involves adding a chemical called ethidium bromide to the surface of the gel. Ethidium bromide binds to DNA molecules so that when they are exposed to ultraviolet light, they create orange-colored bands that are easy to see.
How do we know the size of the fragments on the gel? The bands on the gel are compared with a standard chart known as a DNA ladder. This gives us the size of the fragment. Finally, we can cut out each fragment from the gel, separately, in a process called elution. Elution is done in such a way that the individual fragments of DNA can be used for further downstream processing, such as genome sequencing.
Your students get an opportunity to see DNA.
What do your students get from these experiments? Obviously, they gain mastery over a technique they will use over and over in their academic careers. More importantly, they will have a tangible experience of observing DNA, making it real to them. Modern Biology Inc. sells the electrophoresis packs your students need to begin their learning experience with gel electrophoresis.
IND-17: A Rapid Immunological Method to Study Evolution
Chances are that all of your students can identify gross morphological differences between a cow, a horse, a sheep, a goat, and a chicken. But do they really have an understanding of how, say, the immune systems of these common animals are different on an antigenic level?
In IND-17: A Rapid Immunological Method to Study Evolution, students develop hypotheses about the degree of differences between the immune systems of these common animals. Then they dot small amounts of serum from each species and incubate it on nitrocellulose against bovine antibodies. Purple dots in the nitrocellulose after incubation indicate the intensity of the antibody reaction and the degree of difference between each pair of species.
Modern Biology Inc. also reinforces the one common concept that unites the field of biology, evolution. Students cannot proceed with further study of biology without understanding the core concepts of evolution, such as cell theory, germ theory, and energetics We give students the laboratory experience that illustrates A Molecular Approach to the Study of Genetics and Evolution that your students can complete in a single lab session.
Get Interesting and Creative Biology Experiments for Your Students
Modern Biology takes the drudgery out of preparing meaningful lab experiences. We provide all the supplies you need for each experiment for every student (although we’ll assume your lab has some basic equipment used for every experiment). We will provide you with a teacher guide and a handout you can copy for your students.
Modern Biology empowers you to integrate scientific method into what is too often a descriptive course. We take care of your ordering and inventory tasks for over 20 hours of laboratory instruction, and we price our products to fit public school budgets.
Over 500,000 students learn biology with the help of Modern Biology Inc. products every year. We want to show you why thousands of teachers trust Modern Biology Inc.