Introduction to Biotechnology

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What Is Biotechnology?

Biotechnology is the use of technology to study, change, or use living organisms to solve problems or make products.

While the term may sound modern, the practice dates back thousands of years. The first forms of biotechnology were used when humans began domesticating plants and animals.

Ancient farmers saved seeds from plants that produced the best fruit or bred animals that were easiest to manage. That’s biotechnology: choosing traits in living things and passing them on.

Modern biotechnology takes this to a whole new level. Instead of just breeding organisms with desirable traits, scientists can now change DNA directly—cutting, copying, and moving genes to make crops resistant to pests, create bacteria that produce medicine, or even glow in the dark.

Penicillin and the Power of Microorganisms

In 1928, a scientist named Alexander Fleming discovered something strange. Mold had accidentally grown on a petri dish, and it killed the bacteria around it.

This mold, Penicillium, became the source of the world’s first antibiotic: penicillin. But isolating and producing it in large amounts required the tools of biotechnology.

This discovery saved millions of lives and paved the way for using microbes to create medicines.

Griffith’s Discovery: Transformation

Also in 1928, British scientist Frederick Griffith made a surprising discovery while working with two strains of bacteria called Pneumococcus.

One strain had a protective outer capsule and was deadly to mice.

The other lacked this capsule and was harmless.

Here’s what Griffith did.

1. He injected mice with the deadly strain → the mice died.

2. He injected mice with the harmless strain → the mice survived.

3. He killed the deadly bacteria with heat, then injected them → the mice survived.

4. Then came the twist: he mixed the dead deadly bacteria with live harmless ones → the mice died.

When Griffith examined the dead mice, he found live bacteria with the deadly capsule. Somehow, the dead bacteria had passed a “transformation factor” to the harmless ones, making them deadly.

He didn’t know it at the time, but he had discovered that genetic information can be transferred between organisms—a major foundation of modern biotechnology.

Gene Splicing and Genetic Engineering

Griffith’s experiment showed that genetic material could move from one cell to another. About 40 years later, scientists Stanley Cohen and Herbert Boyer figured out how to do that on purpose.

They developed genetic engineering, a method for cutting and pasting DNA. Here's how it works.

1. Choose a gene of interest. For example, a gene from frog DNA that makes a specific protein.

2. Cut the DNA using restriction enzymes. These are like molecular scissors.

One common enzyme, EcoRI, cuts DNA at a specific sequence: GAATTC, leaving sticky ends that are perfect for connecting to other DNA pieces.

3. Open a plasmid. A plasmid is a circular piece of DNA found in bacteria. Scientists use restriction enzymes to cut open the plasmid in just the right spot.

4. Paste the gene into the plasmid. Another enzyme, DNA ligase, acts like glue to seal the new gene into the plasmid.

5. Insert the new plasmid into bacteria. Scientists use heat and cold to cause bacterial cell walls to open up, allowing the plasmid to slip inside.

6. Grow the modified bacteria. Only bacteria with the new gene survive on special antibiotic plates, because the plasmid also carries a resistance gene.

7. Check which bacteria have the right gene. Scientists can separate out the ones that took up the gene by using gel electrophoresis—a process that sorts DNA by size using electricity.

These techniques allow scientists to clone genes, produce insulin, create pest-resistant crops, and more. This is the heart of modern biotechnology.

From Corn to Cloning

Biotechnology has come a long way from selective breeding. Today, it includes the following.

Genetic modification of plants to resist pests and diseases.

Medical treatments, such as synthetic insulin for diabetes.

Gene therapy to treat genetic disorders.

Cloning and stem cell research.

Environmental clean-up using genetically engineered bacteria.

And it all started with a few moldy dishes, a pair of molecular scissors, and a surprising mouse experiment.

Ready to Dig Deeper?

Next, you’ll explore how gene splicing and restriction enzymes make modern biotechnology possible—and see it in action.

Keep going in the Got It? section.