How to study for a general biology exam

A general biology exam tests three different things, and they need different kinds of practice. First there's vocabulary, a lot of it: organelles, enzymes, stages, molecules. Then there are processes, where order and location matter: glycolysis, mitosis, transcription. And there's a small amount of math: pH, Punnett ratios, probability, map distances. Most students study all three the same way, by rereading slides, and that works badly for all three.

1. Treat vocabulary as the foundation, and start it early

Intro biology has more new terms per week than most foreign language courses. You can't reason about the light reactions if "thylakoid", "stroma" and "photosystem" still need looking up. So the first job each week is getting the terms into long-term memory, before the lectures that build on them.

What works:

• Make or use flashcards that ask for the term from the definition and the definition from the term.
• Review a little every day rather than a lot the night before. Spacing reviews out beats massing them for anything you need to remember longer than a few days. What spaced repetition actually does covers why.
• Go after the confusable pairs directly: stroma vs stoma, chromatin vs chromatid vs chromosome, fermentation vs anaerobic respiration, codominance vs incomplete dominance, leading vs lagging strand. Exams love these because they catch students who half-know both.

2. Quiz processes in order, with locations

Process questions ask what comes next, where it happens, what goes in and what comes out. Rereading a diagram feels productive but doesn't practice any of that. Instead:

• Close the book and write the sequence from memory: the phases of mitosis (prophase, prometaphase, metaphase, anaphase, telophase in OpenStax), the path of a secreted protein through the endomembrane system, or the electron path through the mitochondrial chain.
• For every stage, attach a location and an input and output. Glycolysis: cytoplasm, glucose in, 2 pyruvate, net 2 ATP and 2 NADH out. The citric acid cycle: mitochondrial matrix, 2 turns per glucose.
• Compare parallel processes side by side. Mitosis vs meiosis and respiration vs photosynthesis make up a big share of the "which statement is true" questions. Cellular respiration vs photosynthesis, side by side is a worked example of that kind of comparison.

The main technique is retrieval: pulling the answer out of memory rather than looking at it. It feels harder than rereading, and that difficulty is what makes it work. The testing effect explains the research.

3. Practice the math until the setup is automatic

The math in General Biology I is simple arithmetic, but exams give you little time, so the setup has to be automatic. The main types:

• pH. pH = -log[H+]. Each pH unit is a factor of 10, so pH 4 has 10^3 = 1,000 times more H+ than pH 7.
• Punnett squares and probability. Aa x Aa gives a 3:1 phenotype ratio and AaBb x AaBb gives 9:3:3:1. For more genes, use the product rule instead of drawing the grid: the chance of aabb from two AaBb parents is 1/4 x 1/4 = 1/16. Punnett squares: monohybrid and dihybrid crosses walks through each type, and the Punnett square calculator checks your answers.
• Map distances. Recombination frequency = recombinant offspring / total offspring, and 1 percent = 1 map unit. With 50 recombinants out of 1,000 offspring, 50 / 1,000 = 5 percent, so the genes are 5 map units apart.
• ATP bookkeeping. Know the per-stage yields: 2 ATP from glycolysis, 2 from the citric acid cycle, and most of the rest from oxidative phosphorylation. Know which total your textbook uses. Modern texts say about 30 to 32 per glucose; older ones say 36 to 38.

Do the problems on paper without notes, then check. If you got it wrong, redo it the next day, not just once more right away.

4. Space the unit, then mix it

A typical intro biology exam covers three or four textbook chapters. A workable plan for the two weeks before one:

• Every day: 15 to 20 minutes of flashcard review for everything covered so far, not just the newest chapter.
• Twice a week: one sequence written from memory and one short problem set.
• Final week: mixed practice. Shuffle questions from all the chapters together so you have to recognize what kind of question each one is. Interleaving vs blocking explains why mixed practice beats doing one chapter at a time.
• Night before: a light review of the cards you've been missing, then sleep.

For the final, the timeline changes. Material from week 2 needs to survive to week 15, which only works if it keeps coming back for review all semester. Studying for a cumulative final vs a unit test covers how to plan for that.

5. Use the textbook's structure

Most general biology courses follow the OpenStax Biology 2e chapter order or something close to it: chemistry of life, cells, membranes, energy, respiration, photosynthesis, signaling, cell division, genetics, DNA, gene expression and biotechnology. Knowing the order helps, because later chapters assume the earlier ones. Gene regulation makes no sense without transcription, and meiosis questions assume you have mitosis down. If one unit is shaky, fix it before the next one builds on it. What's in General Biology I lists all 16 units in teaching order.

Common mistakes

• Highlighting instead of quizzing. It feels like progress but tests nothing.
• Learning the diagram, not the question. Exams describe the process in words and ask about one step. Practice answering from a verbal description.
• Skipping the "why". "Why does FADH2 produce less ATP than NADH?" (its electrons enter the chain after complex I, skipping one proton pump) is the kind of question that separates an A from a B.
• Cramming the math. Punnett and probability questions are the easiest points on the exam if you have practiced them, and the easiest to lose under time pressure if you haven't.

If you're taking the second semester next, how to study for General Biology 2 covers the changes: less chemistry, more classification and physiology. If you're taking chemistry alongside biology, how to study for a general chemistry exam splits recall from problem-solving the same way this plan does.

Encodr's free General Biology I course has 1,390 cards in the textbook's order, scheduled with spaced repetition.