DNA (deoxyribonucleic acid in full) is the hereditary material present in most living things responsible for function and development. There are two types of DNA: autosomal DNA and mitochondrial DNA. The offspring acquires the autosomal or nuclear DNA is from their parents. Each parent, male and female, contributes 23 chromosomes, which add up to 46 chromosomes. The mitochondrial DNA (mtDNA) is inherited from the maternal side and is present in the mitochondria.
The properties of DNA include:
- DNA has a phosphate molecule and a sugar or deoxyribose molecule.
- DNA has four nitrogenous bases units, namely adenine (A), guanine (G), cytosine (C), and thymine (T).
- The chemical bases are attached to the sugar and phosphate molecules, forming nucleotides with a double helix structure.
Based on the properties of DNA, here are the best DNA experiments for high school science classes:
Materials required for this experiment include:
- 80ml calf thymus DNA,
- Denatured alcohol,
- Ice chips,
- Eight glass vials,
- Eight glass rods,
- Boiling water bath,
- 16 glass test tubes,
- 1ml DNAse1,
- 10 small pipets, and
- 10 large pipettes.
The object of the project is to determine the effects of DNAse 1 and denaturing the DNA structure. The isolated DNA in a test tube is a stiff molecule, but its fibers precipitate when adding alcohol. Precipitation allows the DNA to be spooled onto a glass rod, making it enough for the students to work in pairs. Students should investigate, observe, and record the effects of breaking DNA into smaller pieces using enzyme DNAse.
Building Your Own Tool for Identifying DNA
Building your tool for identifying DNA is another exciting experiment involving DNA and its properties. The students will create a gel electrophoresis chamber to compare the molecules in food-coloring dye. The instructions will direct students on how different pieces of DNA, RNA, or proteins behave when exposed to gel electrophoresis.
The required material includes 9-volt batteries, plastic foam, stainless steel wire, baking soda, Agarose gel, and food color. The aim is to determine how many macromolecules are in the dye or which dye goes through the gel fastest by placing the gel and food color in the chamber. Following this procedure, students can build their tools for identifying DNA.
Your DNA is 99.9% identical to another human being who is not even related to and almost identical to chimpanzees. However, they are a tiny aspect of the DNA that gives each person unique fingerprints.
This experiment allows students to test the uniqueness of their fingerprints by creating DNA sequences and using an online random sequence generator or another online program to make fingerprints of each piece of DNA created. Comparison between the designed pieces and DNA sequences will determine if they are similar or unique.
Genetically modified foods are those that their DNA has been manipulated to give them new traits like resistance to drought or pests. However, the alterations interfere with taste and crop nutrition.
Many countries have implemented laws on labeling GMO foods, but you can find out for yourself if the food is not marked. To conduct this experiment, students need GM Food and Amplification Kit and a laboratory with equipment that can carry out PCR (polymerase chain reaction) and gel electrophoresis.
The requirements to conduct this simple experiment include fruits, water, clear dish soap, salt, toothpicks, plastic bags, clear glasses, and ice-cold rubbing alcohol about 70%. First, the students should place a third of the fruit in a bag and smash it into pulp.
Then they should mix the pulp with dish soap, water, and salt to break down the fruit cell wall. Stir the mixture and let it sit for about fifteen minutes. Next, filter the solution and mix alcohol. Students should notice stringy white strands, and they can remove them with toothpicks. Following this procedure, students should be able to extract fruit DNA.
Wolbachia is a species of bacteria that can form confusing mitochondrial patterns by influencing the mitochondria barcodes. The use of Wolbachia will help students understand their diversity when preparing a specimen for DNA analysis. In addition, students will need to understand the DNA extraction techniques of these endosymbiotic bacteria living within 20% of insect species. The extracted DNA is placed in a PCR machine, which amplifies the DNA millions of times, making it easy to detect and study.
DNA profiling is a technique commonly used in forensic science to investigate and compare criminal suspects’ DNA profiles to the DNA evidence collected at the crime site. This experiment will use a DNA Gel Electrophoresis kit, whereby they cut the DNA using restriction enzymes. Then, the available DNA fragments are separated electrophoretically using Agarose gel. Students should learn how to handle, prepare, and interpret the results of the investigation.
Transforming Bacteria to Make Colored Pigments
First, the students need to select the gene of bacteria they intend to produce, create a sequenced DNA and a promoter to help express the correct time and levels. Next is getting the engineered DNA into the bacteria, and one way to do that is by bacteria transformation. Bacteria transformation is a process by which bacteria can take up foreign DNA from the environment. During this experiment, students should explore some questions like; how bacteria transformation occurs, how efficient it is, and whether its efficiency changes when you use different bacteria.
Identifying Building Blocks of Life
This experiment aims to give students a hypothetical DNA sequence present in a protein or part of an enzyme. With the aid of the Universal Genetic Code, students can determine the amino acid sequence coded for by the DNA. They will then predict the shape of the enzyme and use Lego blocks to represent different shapes. Later on, they will mix the enzyme mixed with a substrate, and observe whether the substrate affects the enzyme’s structure. This experiment will help the students understand the effects of mutation of the DNA sequence based on the interaction between the enzyme and the substrate.
Expression cloning is a technique employed in DNA cloning to generate a library of clones using one protein. Students can investigate expression cloning and how it is used in the biotechnology industry using kits meant for high school classes. Using kits with plasmids and bacterial cells is also crucial for the transformation. Here are two possibilities:
- Glow-in-the-dark transformation kit has supplies required to make bacteria clone green fluorescent protein but has fewer combinations for students to explore.
- Bio Builder What a Colorful World Kit allows students to explore different pigments produced by bacteria during expression cloning.