How to teach high school biology at home

High school biology at home takes about 150 to 180 hours across a year, needs a microscope and a dissection kit but little else, and is one of the easier sciences to teach well at home. The conceptual difficulty is concentrated in a handful of invisible processes, and those are where a homeschooling family should put their effort.

Biology is often the first science a homeschooling family takes seriously, because it arrives in ninth or tenth grade and because it is the one most likely to end up on a college application. It also has the useful property that most of its content can be learned at a kitchen table.

What a full year covers

A credible high school biology course covers roughly these units, in roughly this order:

1. The chemistry of life. Water, pH, carbon, the four macromolecule families. Short, and routinely rushed, which causes problems later.
2. Cells. Structure, membranes, transport, the organelles and what they do.
3. Energy. Photosynthesis and cellular respiration. The hardest unit in the course.
4. Cell division and genetics. Mitosis, meiosis, Mendelian inheritance, pedigrees.
5. Molecular genetics. DNA structure, replication, transcription, translation, mutation.
6. Evolution. Natural selection, evidence, speciation, population genetics.
7. Ecology. Energy flow, cycles, populations, ecosystems.
8. Human body systems. Often taught, and the unit most safely trimmed if time runs short.

If you are aiming at an AP exam, work from the published AP Biology course framework rather than a general textbook's table of contents; the framework specifies depth as well as topics, which is where homeschool courses usually diverge from what the exam asks.

Where it actually gets hard

Three units cause nearly all the trouble, and they share a property: nothing is visible.

Photosynthesis and respiration. Students can recite the equations and have no model of what is happening. The electron transport chain in particular is a sequence of events at a scale nobody can picture, taught through diagrams that look like plumbing.

Protein synthesis. Transcription and translation involve three molecules that all sound alike, moving through steps in a fixed order, in two different compartments.

Meiosis, specifically versus mitosis. Students confuse them endlessly, because the pictures look similar and the differences are in counts and timing rather than in appearance.

The common factor: these are processes, and a process cannot be understood from a static picture of it. The thing that works is making the student reproduce the sequence from memory, out loud or on paper, and catching the step where it breaks down. Which step they get wrong is diagnostic. "I don't understand respiration" is not; "they put the proton gradient on the wrong side of the membrane" is.

Labs without a school lab

You need less than you think. A workable home setup:

• A compound microscope reaching 400x, with prepared slides
• A dissection kit with a few preserved specimens
• Kitchen chemistry: iodine, hydrogen peroxide, vinegar, bicarbonate, food colouring
• Pond water, leaves, onions, and whatever is in the garden

That equipment supports osmosis experiments, enzyme experiments with liver and peroxide, cell observation, pond ecology, chromatography of leaf pigments, germination studies, and a dissection or two. Thirty hours of documented lab work is readily achievable.

The write-up is what makes it count. Question, hypothesis, method, data, analysis, conclusion, every time, dated. A lab log that reads like an actual record is the difference between a lab science credit and a claim of one.

A realistic weekly rhythm

That is about four and a half hours a week, 36 weeks, plus lab time. Friday is the part families skip and the part that determines how much is left by June. Testing yourself beats rereading by a wide margin on anything you need weeks later, a result established by Roediger and Karpicke in 2006 and confirmed in the 2013 Dunlosky review of study techniques.

Eight labs that work at home

A documented lab log is what turns a biology course into a lab science credit. These eight cover most of the curriculum's observational requirements with equipment that costs little.

1. Osmosis in potato strips. Mass change in salt solutions of different strengths. Produces real quantitative data and a graph, which is what examiners want to see.
2. Enzyme activity with liver and hydrogen peroxide. Catalase breaking down peroxide, varied by temperature or pH. The classic rate experiment.
3. Onion cells and cheek cells under the microscope. Plant against animal cell structure, drawn to scale with magnification stated.
4. Mitosis in a prepared root tip slide. Count the proportion of cells in each phase. Connects a static picture to a process, which is the hardest step in the unit.
5. Leaf pigment chromatography. Separate chlorophylls and carotenoids with a strip of filter paper and nail polish remover.
6. Pond water survey. Identify what is there, estimate abundance, discuss the food web.
7. Germination under varied conditions. Light, water, temperature. Slow, cheap, and good for experimental design and controls.
8. A dissection. A preserved specimen with a proper diagram and labels, or a virtual equivalent written up the same way.

Each write-up: question, hypothesis, method, data, analysis, conclusion, dated. Thirty hours of this is a defensible lab component.

Where students actually lose marks

In order of how often it happens:

Describing when asked to explain. "The rate increases as temperature rises" describes a graph. The question wanted the because.

Vocabulary without models. Knowing that ATP is the energy currency, and being unable to say where it is made or what makes it.

Mitosis and meiosis conflated. Study them against each other, on a small number of axes, not one after the other.

No causal chain. Biology answers are chains: this happens, which causes this, which means that. A student who gives the first and last links loses the middle marks.

Ignoring the data provided. A question with a graph expects the graph quoted in the answer.

A 36-week outline

That is about 150 hours of instruction plus lab time, which supports a full lab science credit.

Making it count

For a transcript, keep a course description naming the text and topics, the lab log, and samples of graded work.

For an AP exam, you must arrange a seat. Homeschooled students take AP exams at a school willing to host them, and the arrangements start in the autumn, not the spring. The College Board's AP Services for Students can help locate a participating school. We cover the process in detail here.

For a college that wants a lab science, the lab log is the evidence. A biology course with no documented practical work is read as a reading course with a science name on it.

Where TruLearn fits

TruLearn teaches AP Biology and an introductory college biology version of the same material. It is voice-first: it explains a concept out loud, draws the diagram as it describes it, then asks your child to explain the idea back in their own words and grades that against a rubric a person wrote. For the three hard units above, that matters: it catches the specific step a student has wrong rather than reporting a score on the unit.

What it does not do: labs. The microscope, the specimens and the write-ups remain yours, and there is no parent dashboard yet.

See how a session works, or read about the explain-back method.