Mechanism first: how I teach molecular biology

Open a biology textbook and you will find thousands of terms. Many students try to memorize them. It rarely works, and it is not how scientists think.

Memorization fails for a simple reason. Without a structure to hang them on, terms are just words, and they disappear soon after the exam. Scientists remember the names of proteins and pathways because they understand what those parts do and why they are there. The vocabulary follows the understanding, not the other way around.

Start with the why

Before naming the parts, I explain the problem the cell is solving. How does a cell copy three billion letters of DNA without losing its place? Once the problem is clear, the machinery makes sense, and the names stick.

Take DNA replication. If you start with a list of enzymes, it feels arbitrary. If you start with the problem, the list writes itself. The double helix has to be opened, so something must unwind it. The strands must not snap back together, so something must hold them apart. A new strand needs a starting point, and the copy needs to be checked for errors. Each of those needs corresponds to a protein. Students who see it this way can often predict what the next part does before I tell them.

Draw it

I ask students to redraw every mechanism without looking. If you can draw it, you understand it. If you can’t, you know exactly where to look.

If you can draw it, you understand it.

Drawing forces you to make decisions that reading lets you avoid. Which molecule comes first? Where does it bind? What changes afterward? Gaps that are invisible on a page become obvious on a blank sheet. It is also a habit that carries into research, where sketching a mechanism is often the fastest way to see whether an idea holds together.

Make it free

I put full courses on YouTube because good explanations should not be locked behind a tuition fee. Students review at their own pace, and people far outside the classroom use them too.

Recorded lectures also change how class time can be used. If students can watch an explanation as many times as they need, time together can go to questions, problems and discussion, which is where most of the real learning happens.

My perspective

I think biology has a reputation for being a memorization subject because of how it is often taught, not because of what it is. At its core, molecular biology is a set of solutions to physical and chemical problems. When students see it that way, it becomes something they can reason through rather than something they have to recall.

That matters beyond the exam. Research constantly presents systems nobody has described yet. The students who do well are not the ones who memorized the most, but the ones who can look at something unfamiliar and ask what problem it solves.

The goal is not to know more terms. It is to be able to reason about a system you have never seen before.