AP Biology

Self-paced lessons — an introduction plus 126 lessons · 2125 ideas · 1262 questions. Work through at your own rate; each part ends with a check you must pass to move on.

Whole-unit review copies

Each tab opens one scrollable page with every lesson, practice set and test of that unit in course order, answer keys marked and FRQ models shown (reviewers only; students never see this view). Status as of 2026-09-28 13:30 SAST.

Unit 1Unit 2Unit 3Unit 4Unit 5Unit 6Unit 7Unit 8
UnitTopics and where they standFixes: done, queued
Unit 1 · Chemistry of Life1.1–1.6 LiveDan's review corrections applied (25 Sept). Two one-word fixes still queued for the next release (L11 'small RNA' → 'short RNA').
Unit 2 · Cells2.1–2.10 LiveAccuracy corrections of 25 Sept applied; three re-cut videos submitted the same day.
Unit 3 · Cellular Energetics3.1–3.5 LiveColleague's correction list of 28 Sept (30 corrections, 24 figure notes) queued for the round before the next release; not yet applied.
Unit 4 · Cell Communication and Cell Cycle4.1–4.6 LiveOne one-word fix queued (L09B 'reporter gene').
Unit 5 · Heredity5.1–5.5 Live22 video slots to move one step below the check they answer — queued for the next release. Video scripts for the whole unit delivered to the producer (28 Sept).
Unit 6 · Gene Expression and Regulation6.1–6.4 Live · 6.5 Finished, awaiting release · 6.6 Finished, awaiting release (lessons finished; topic test in review) · 6.7 In review · 6.8 Being writtenThis review copy shows 6.1–6.6. 6.7 and 6.8 are added when they close.
Unit 7 · Natural Selection7.1–7.9 Live · 7.10–7.12 Not startedThis review copy shows 7.1–7.9.
Unit 8 · Ecology8.1–8.4 Live · 8.5 Finished, awaiting release · 8.6–8.7 Not startedThis review copy shows 8.1–8.5.
Live Live on the site and reviewed (two independent blind readers agreed every answer key).   Finished, awaiting release Finished and reviewed; published at the next release, reachable now only through this review copy.   In review Written; going through the review chain (accuracy pass, question review, blind reads, adjudication).   Being written Lessons being written now.   Not started Blueprint approved; lessons not yet written.

Introduction · Life at every scale

  1. What biology studies, and at what scales11 ideas · 3 parts · 2 questions
  2. Zooming in on a living thing: cells, molecules and atoms28 ideas · 5 parts · 8 questions
  3. Zooming out from one organism: populations, communities and ecosystems19 ideas · 4 parts · 8 questions
  4. The four questions AP Biology asks at every level26 ideas · 4 parts · 7 questions

Unit 1 · Chemistry of Life

Topic 1.1 · Structure of Water and Hydrogen Bonding

  1. Bonds and partial charges27 ideas · 6 questions
  2. The hydrogen bond22 ideas · 10 questions
  3. Water sticks to itself and to other things20 ideas · 15 questions
  4. Slow to warm16 ideas · 6 questions
  5. Cooling by evaporation22 ideas · 7 questions
  6. Why ice floats13 ideas · 5 questions

How AP Biology asks you questions

  1. Four options, one answer14 ideas · 4 questions
  2. What the verb is asking for: Describe, Explain, Predict28 ideas · 10 questions
  3. What the verb is asking for: Justify, Identify, Represent26 ideas · 8 questions
  4. How a point is earned29 ideas · 8 questions
  5. A free-response question, step by step13 ideas · 2 questions
  6. What the verb is asking for: Make a claim, Support a claim, Evaluate, Determine57 ideas · 25 questions

Topic 1.1 · Structure of Water and Hydrogen Bonding (continued)

  1. Practice questions10 multiple choice · 2 free response
  2. End-of-topic test: Structure of Water and Hydrogen Bonding18 multiple choice · 2 free response

Topic 1.3 · Introduction to Biological Macromolecules

  1. Chains: build and break22 ideas · 7 questions
  2. Counting the water28 ideas · 17 questions
  3. Practice questions9 multiple choice · 2 free response
  4. End-of-topic test: Introduction to Biological Macromolecules18 multiple choice · 2 free response

Topic 1.4 · Carbohydrates

  1. One sugar, many chains20 ideas · 8 questions
  2. Starch, glycogen and cellulose16 ideas · 6 questions
  3. Practice questions9 multiple choice · 2 free response
  4. End-of-topic test: Carbohydrates18 multiple choice · 2 free response

Topic 1.5 · Lipids

  1. Why oil and water don't mix25 ideas · 8 questions
  2. Butter or olive oil30 ideas · 17 questions
  3. Where the energy in a food store comes out16 ideas · 5 questions
  4. Building a fat10 ideas · 3 questions
  5. Steroids and hormones13 ideas · 7 questions
  6. The membrane around every cell26 ideas · 5 questions
  7. Cholesterol, cold water and the membrane24 ideas · 5 questions
  8. Practice questions10 multiple choice · 2 free response
  9. End-of-topic test: Lipids18 multiple choice · 2 free response

Topic 1.7 · Proteins: Structure and Function

  1. Inside one amino acid28 ideas · 6 questions
  2. From amino acids to a chain22 ideas · 7 questions
  3. Coils and sheets in the chain12 ideas · 3 questions
  4. What the R groups do10 ideas · 4 questions
  5. Why the nonpolar R groups end up inside9 ideas · 3 questions
  6. Shape is the job21 ideas · 6 questions
  7. Change one amino acid14 ideas · 4 questions
  8. Practice questions10 multiple choice · 2 free response
  9. End-of-topic test: Proteins: Structure and Function18 multiple choice · 2 free response

Topic 1.6 · Nucleic Acids

  1. The nucleotide27 ideas · 14 questions
  2. Joining nucleotides into a strand21 ideas · 16 questions
  3. The second strand22 ideas · 17 questions
  4. Counting the bases14 ideas · 9 questions
  5. One strand, no partner8 ideas · 5 questions
  6. Antiparallel strands and the double helix21 ideas · 10 questions
  7. Writing a strand from its 5 end13 ideas · 4 questions
  8. DNA or RNA?11 ideas · 4 questions
  9. Reading a model of DNA12 ideas · 4 questions
  10. Practice questions10 multiple choice · 2 free response
  11. End-of-topic test: Nucleic Acids18 multiple choice · 2 free response

Topic 1.2 · Elements of Life

  1. Where the atoms in you come from27 ideas · 8 questions
  2. Practice questions9 multiple choice · 2 free response
  3. End-of-topic test: Elements of Life18 multiple choice · 2 free response

Unit 2 · Cells

Topic 2.3 · Plasma Membrane

  1. Two watery worlds and the film between them35 ideas · 11 questions
  2. A mosaic that flows20 ideas · 7 questions
  3. Practice questions9 multiple choice · 2 free response
  4. End-of-topic test: Plasma Membrane17 multiple choice · 2 free response

Topic 2.4 · Membrane Permeability

  1. What gets through the hydrophobic interior42 ideas · 16 questions

Topic 2.5 · Membrane Transport

  1. A drop of dye spreads42 ideas · 15 questions
  2. Millimoles: counting in thousandths10 ideas · 6 questions

Topic 2.6 · Facilitated Diffusion

  1. Doors for ions and sugars41 ideas · 26 questions
  2. Practice questions9 multiple choice · 2 free response
  3. End-of-topic test: Facilitated Diffusion16 multiple choice · 2 free response

Topic 2.8 · Mechanisms of Transport

  1. Pumping uphill43 ideas · 18 questions
  2. Why the inside of a cell is negative31 ideas · 15 questions
  3. Practice questions10 multiple choice · 2 free response
  4. End-of-topic test: Mechanisms of Transport16 multiple choice · 2 free response

Topic 2.5 · Membrane Transport (continued)

  1. Too big for any door27 ideas · 15 questions
  2. Practice questions10 multiple choice · 2 free response
  3. End-of-topic test: Membrane Transport17 multiple choice · 2 free response

Topic 2.7a · Tonicity and Osmoregulation

  1. Red cells in three beakers39 ideas · 23 questions

Topic 2.4 · Membrane Permeability (continued)

  1. Why celery goes limp37 ideas · 27 questions
  2. Practice questions10 multiple choice · 2 free response
  3. End-of-topic test: Membrane Permeability16 multiple choice · 2 free response

Topic 2.7a · Tonicity and Osmoregulation (continued)

  1. Keeping water in balance25 ideas · 9 questions
  2. Practice questions9 multiple choice · 2 free response
  3. End-of-topic test: Tonicity and Osmoregulation19 multiple choice · 2 free response

Topic 2.7b · Water Potential

  1. Water potential: a number for which way water goes26 ideas · 25 questions
  2. Solute potential from a concentration29 ideas · 27 questions
  3. The potato lab22 ideas · 19 questions
  4. Practice questions10 multiple choice · 2 free response
  5. End-of-topic test: Water Potential19 multiple choice · 2 free response

Topic 2.2 · Cell Size

  1. Why a cell can't just grow bigger32 ideas · 26 questions
  2. Folded surfaces21 ideas · 11 questions
  3. Mouse and elephant: heat and fuel per gram15 ideas · 10 questions
  4. Spheres, rods and slabs12 ideas · 8 questions
  5. Which cell exchanges faster?8 ideas · 12 questions
  6. Practice questions10 multiple choice · 2 free response
  7. End-of-topic test: Cell Size17 multiple choice · 2 free response

Topic 2.1 · Cell Structure and Function

  1. Two kinds of cell50 ideas · 19 questions
  2. Where a cell makes the proteins it sends out11 ideas · 3 questions
  3. A folded network with ribosomes on it20 ideas · 10 questions
  4. Where the bubbles from the ER go37 ideas · 16 questions
  5. A sac that digests32 ideas · 13 questions
  6. Where lysosomes come from, and what else they take apart25 ideas · 12 questions
  7. The endomembrane system34 ideas · 16 questions
  8. The cell that ships protein26 ideas · 11 questions
  9. Where a cell gets its energy44 ideas · 20 questions
  10. The cell that catches light33 ideas · 16 questions
  11. Read a cell’s job from its parts19 ideas · 15 questions
  12. Practice questions10 multiple choice · 2 free response
  13. End-of-topic test: Cell Structure and Function18 multiple choice · 2 free response

Topic 2.9 · Cell Compartmentalization

  1. Rooms with their own rules50 ideas · 16 questions
  2. Practice questions9 multiple choice · 2 free response
  3. End-of-topic test: Cell Compartmentalization16 multiple choice · 2 free response

Topic 2.10 · Origins of Cell Compartmentalization

  1. A cell inside a cell22 ideas · 7 questions
  2. Five pieces of evidence that mitochondria came from bacteria36 ideas · 16 questions
  3. The chloroplast’s story28 ideas · 9 questions
  4. Two ways to organize a cell’s inside14 ideas · 3 questions
  5. Practice questions9 multiple choice · 2 free response
  6. End-of-topic test: Origins of Cell Compartmentalization16 multiple choice · 2 free response

Unit 3 · Cellular Energetics

Topic 3.1 · Enzymes

  1. How fast: the rate of reaction35 ideas · 22 questions
  2. The energy hump51 ideas · 28 questions
  3. Used again and again70 ideas · 29 questions
  4. Why catalase ignores sugar46 ideas · 29 questions
  5. What happens in the pocket16 ideas · 19 questions
  6. What to change, measure and keep the same41 ideas · 25 questions
  7. Writing the prediction down35 ideas · 7 questions
  8. Practice questions10 multiple choice · 2 free response
  9. End-of-topic test: Enzymes19 multiple choice · 2 free response

Topic 3.2a · Environmental Impacts

  1. Warm the tube29 ideas · 16 questions
  2. Past the optimum47 ideas · 14 questions
  3. pH: a scale for hydrogen ions25 ideas · 16 questions
  4. Too sour, too bitter36 ideas · 22 questions
  5. Sometimes the fold comes back52 ideas · 19 questions
  6. More substrate35 ideas · 17 questions
  7. More enzyme, more product?40 ideas · 17 questions
  8. Blocking the door23 ideas · 11 questions
  9. Bending the frame29 ideas · 15 questions
  10. Practice questions10 multiple choice · 3 free response
  11. End-of-topic test: Environmental Impacts19 multiple choice · 2 free response

Topic 3.2b · Statistics: Mean, Standard Deviation and Error Bars

  1. One number for five tubes10 ideas · 6 questions
  2. How spread out: the standard deviation17 ideas · 16 questions
  3. How far off might the mean be?16 ideas · 14 questions
  4. Draw the error bar, read the caption20 ideas · 14 questions
  5. Do the bars overlap?14 ideas · 17 questions
  6. Practice questions10 multiple choice · 2 free response
  7. End-of-topic test: Statistics19 multiple choice · 2 free response

Topic 3.3 · Cellular Energy

  1. Where ATP’s energy comes from44 ideas · 27 questions
  2. How ATP drives the cell’s work45 ideas · 27 questions
  3. Transformed, never made22 ideas · 17 questions
  4. Order needs energy32 ideas · 27 questions
  5. One big step or dozens of small ones58 ideas · 38 questions
  6. Practice questions10 multiple choice · 2 free response
  7. End-of-topic test: Cellular Energy19 multiple choice · 2 free response

Topic 3.5 · Cellular Respiration

  1. Where sugar’s energy goes40 ideas · 20 questions
  2. Losing electrons, gaining electrons29 ideas · 23 questions
  3. The cell with no mitochondria30 ideas · 15 questions
  4. Every carbon breathed out47 ideas · 20 questions
  5. Downhill to oxygen25 ideas · 22 questions
  6. The one way back27 ideas · 17 questions
  7. Break the machine and see56 ideas · 22 questions
  8. When there is no oxygen28 ideas · 25 questions
  9. Two ATP or thirty28 ideas · 18 questions
  10. Graph the yeast25 ideas · 25 questions
  11. From the gas back to the pathway10 ideas · 4 questions
  12. Practice questions10 multiple choice · 3 free response
  13. End-of-topic test: Cellular Respiration19 multiple choice · 2 free response

Topic 3.4 · Photosynthesis

  1. The reaction, written out37 ideas · 19 questions
  2. Where a tree’s mass comes from42 ideas · 14 questions
  3. What a leaf does with its sugar28 ideas · 12 questions
  4. A plant in a sealed jar, day and night26 ideas · 19 questions
  5. What a chloroplast is, and its six places35 ideas · 14 questions
  6. Two rooms, two jobs38 ideas · 21 questions
  7. Light and color27 ideas · 19 questions
  8. Why leaves are green36 ideas · 20 questions
  9. One electron’s journey49 ideas · 20 questions
  10. The same machine, powered by light28 ideas · 17 questions
  11. Building sugar in the stroma27 ideas · 16 questions
  12. Break one room and the other fails44 ideas · 19 questions
  13. One machine, three places42 ideas · 19 questions
  14. Shared pathways, shared ancestry33 ideas · 18 questions
  15. Practice questions10 multiple choice · 2 free response
  16. End-of-topic test: Photosynthesis19 multiple choice · 2 free response

Unit 4 · Cell Communication and Cell Cycle

Topic 4.1 · Cell Communication

  1. A molecule released into the blood38 ideas · 24 questions
  2. Predict from the receptor28 ideas · 14 questions
  3. Cells that touch18 ideas · 7 questions
  4. Nearby cells28 ideas · 15 questions
  5. Far away27 ideas · 17 questions
  6. Single cells counting their neighbors36 ideas · 14 questions
  7. Which way did the message travel?25 ideas · 13 questions
  8. Practice questions10 multiple choice · 2 free response
  9. End-of-topic test: Cell Communication19 multiple choice · 2 free response

Topic 4.2 · Introduction to Signal Transduction

  1. The ligand fits48 ideas · 21 questions
  2. The message crosses, the molecule stays outside53 ideas · 24 questions
  3. Stopped at the surface, or straight through17 ideas · 13 questions
  4. The receptor goes to the DNA22 ideas · 19 questions
  5. A phosphate as a switch37 ideas · 34 questions
  6. A small molecule spreads the message41 ideas · 41 questions
  7. Switching the signal off23 ideas · 18 questions
  8. A door that opens19 ideas · 12 questions
  9. A door that hands the message on29 ideas · 23 questions
  10. Three kinds of response24 ideas · 16 questions
  11. Same signal, different cells35 ideas · 22 questions
  12. Practice questions10 multiple choice · 2 free response
  13. End-of-topic test: Introduction to Signal Transduction19 multiple choice · 2 free response

Topic 4.3 · Signal Transduction Pathways

  1. Bananas in a paper bag31 ideas · 16 questions
  2. From a changed cell to a changed organism15 ideas · 13 questions
  3. A signal that says: dismantle13 ideas · 7 questions
  4. A changed gene, a changed shape31 ideas · 30 questions
  5. Find the break26 ideas · 26 questions
  6. Stuck on, switched off51 ideas · 33 questions
  7. Practice questions9 multiple choice · 2 free response
  8. End-of-topic test: Signal Transduction Pathways18 multiple choice · 2 free response

Topic 4.4 · Feedback

  1. A set point, a stimulus, a response17 ideas · 20 questions
  2. The response cancels the stimulus26 ideas · 15 questions
  3. The same loop at three levels23 ideas · 18 questions
  4. Break one part of the loop15 ideas · 17 questions
  5. Contractions that get stronger38 ideas · 24 questions
  6. Predict what a disruption does20 ideas · 24 questions
  7. Practice questions9 multiple choice · 2 free response
  8. End-of-topic test: Feedback18 multiple choice · 2 free response

Topic 4.5 · Cell Cycle

  1. New cells come from cells21 ideas · 23 questions
  2. What must be handed on16 ideas · 26 questions
  3. Copied and held together20 ideas · 28 questions
  4. The cycle in order17 ideas · 24 questions
  5. G1, S phase and G225 ideas · 21 questions
  6. Stepping out of the cycle15 ideas · 8 questions
  7. Building the machine: prophase and metaphase26 ideas · 24 questions
  8. Two cells from one: anaphase, telophase and cytokinesis31 ideas · 44 questions
  9. Name the stage28 ideas · 23 questions
  10. Why the two daughter cells match13 ideas · 15 questions
  11. From counts to time32 ideas · 27 questions
  12. Two tissues compared33 ideas · 31 questions
  13. Practice questions10 multiple choice · 2 free response
  14. End-of-topic test: Cell Cycle19 multiple choice · 2 free response

Topic 4.6 · Regulation of Cell Cycle

  1. Division has to be switched on24 ideas · 14 questions
  2. Three checkpoints18 ideas · 20 questions
  3. What each checkpoint checks39 ideas · 19 questions
  4. Cyclins rise and fall; CDKs wait for them50 ideas · 20 questions
  5. Cancer: division without the controls25 ideas · 18 questions
  6. The other outcome19 ideas · 8 questions
  7. Break a control and predict37 ideas · 18 questions
  8. Practice questions9 multiple choice · 2 free response
  9. End-of-topic test: Regulation of Cell Cycle18 multiple choice · 2 free response

Unit 5 · Heredity

Topic 5.1 · Meiosis

  1. Twenty-three pairs25 ideas · 20 questions
  2. Two sets or one12 ideas · 12 questions
  3. Forty-six, not ninety-two16 ideas · 18 questions
  4. Which division halves the count?30 ideas · 20 questions
  5. The pairs find each other30 ideas · 21 questions
  6. Pulled apart, still doubled23 ideas · 14 questions
  7. Which stage of meiosis I?15 ideas · 7 questions
  8. The second division26 ideas · 13 questions
  9. Count the DNA, not the chromosomes21 ideas · 17 questions
  10. Meiosis I or meiosis II?17 ideas · 11 questions
  11. Count the chromosomes and chromatids12 ideas · 14 questions
  12. Two divisions, side by side26 ideas · 8 questions
  13. Practice questions10 multiple choice · 2 free response
  14. End-of-topic test: Meiosis19 multiple choice · 2 free response

Topic 5.2 · Meiosis and Genetic Diversity

  1. Shuffled pairs30 ideas · 30 questions
  2. How many kinds of gamete?21 ideas · 12 questions
  3. Swapped segments33 ideas · 14 questions
  4. New combinations of old alleles33 ideas · 14 questions
  5. Which egg fuses with which sperm22 ideas · 22 questions
  6. A question you could test16 ideas · 12 questions
  7. When a pair fails to separate27 ideas · 27 questions
  8. Which division failed?12 ideas · 8 questions
  9. Three copies of one chromosome22 ideas · 24 questions
  10. Practice questions10 multiple choice · 2 free response
  11. End-of-topic test: Meiosis and Genetic Diversity18 multiple choice · 2 free response

Topic 5.3 · Mendelian Genetics

  1. The white flower that came back25 ideas · 24 questions
  2. Two alleles, one on each homolog24 ideas · 21 questions
  3. Which allele shows20 ideas · 23 questions
  4. One allele per gamete35 ideas · 38 questions
  5. Why three to one, and why not exactly26 ideas · 31 questions
  6. Rules of chance21 ideas · 33 questions
  7. PP or Pp?17 ideas · 22 questions
  8. Which allele is dominant?10 ideas · 8 questions
  9. The twenty-two matching pairs and the one odd pair14 ideas · 14 questions
  10. Who is who on a family tree22 ideas · 21 questions
  11. Fix the genotypes; dominant or recessive?23 ideas · 33 questions
  12. The next child11 ideas · 13 questions
  13. Two genes at once24 ideas · 22 questions
  14. The sixteen-cell square16 ideas · 22 questions
  15. Multiply the one-gene answers10 ideas · 12 questions
  16. Does the data fit? Stating the null, finding chi-square22 ideas · 33 questions
  17. Does the data fit? Reading the verdict21 ideas · 28 questions
  18. When chi-square is the wrong tool18 ideas · 11 questions
  19. From the cross to the verdict9 ideas · 10 questions
  20. Practice questions10 multiple choice · 2 free response
  21. End-of-topic test: Mendelian Genetics19 multiple choice · 2 free response

Topic 5.4 · Non-Mendelian Genetics

  1. Pink between red and white34 ideas · 24 questions
  2. Two pinks crossed12 ideas · 8 questions
  3. Three alleles, two per person17 ideas · 15 questions
  4. Whose child is this?17 ideas · 24 questions
  5. Genes that travel together45 ideas · 29 questions
  6. How far apart are the genes?24 ideas · 22 questions
  7. Putting genes in order21 ideas · 20 questions
  8. Linked, or just chance?15 ideas · 14 questions
  9. Where the X and the Y go14 ideas · 15 questions
  10. One X is enough21 ideas · 21 questions
  11. Predict an X-linked cross21 ideas · 23 questions
  12. Swap the parents16 ideas · 6 questions
  13. Birds, bees and the Y19 ideas · 19 questions
  14. One gene, many effects19 ideas · 7 questions
  15. Genes outside the nucleus16 ideas · 10 questions
  16. Traits that come only from the mother21 ideas · 16 questions
  17. Which pattern is this?31 ideas · 28 questions
  18. Which deviation is this? Decide from the counts17 ideas · 17 questions
  19. Practice questions10 multiple choice · 2 free response
  20. End-of-topic test: Non-Mendelian Genetics19 multiple choice · 2 free response

Topic 5.5 · Environmental Effects on Phenotype

  1. Same plant, two pots53 ideas · 35 questions
  2. Six cases16 ideas · 10 questions
  3. How to test one29 ideas · 22 questions
  4. Practice questions9 multiple choice · 2 free response
  5. End-of-topic test: Environmental Effects on Phenotype16 multiple choice · 2 free response

Unit 6 · Gene Expression and Regulation

Topic 6.1 · DNA and RNA Structure

  1. Where the instructions are kept41 ideas · 31 questions
  2. Extra circles31 ideas · 11 questions
  3. Instructions written in RNA45 ideas · 18 questions
  4. Two rings with one: the pairing rules55 ideas · 41 questions
  5. Use the rules40 ideas · 36 questions
  6. Practice questions10 multiple choice · 2 free response
  7. End-of-topic test: DNA and RNA Structure17 multiple choice · 2 free response

Topic 6.2 · DNA Replication

  1. Half old, half new39 ideas · 29 questions
  2. The bands in the tube59 ideas · 21 questions
  3. The fork opens59 ideas · 32 questions
  4. Only at the 3′ end39 ideas · 28 questions
  5. One strand in pieces52 ideas · 30 questions
  6. The whole fork, and what breaks it50 ideas · 28 questions
  7. Practice questions10 multiple choice · 2 free response
  8. End-of-topic test: DNA Replication18 multiple choice · 2 free response

Topic 6.3 · Transcription and RNA Processing

  1. A message leaves the nucleus28 ideas · 29 questions
  2. Three RNAs, three jobs47 ideas · 36 questions
  3. One strand is read56 ideas · 42 questions
  4. Write the transcript36 ideas · 25 questions
  5. A cap and a tail42 ideas · 24 questions
  6. Where did 1,500 nucleotides go?56 ideas · 37 questions
  7. From gene to mature message38 ideas · 29 questions
  8. Practice questions10 multiple choice · 2 free response
  9. End-of-topic test: Transcription and RNA Processing17 multiple choice · 2 free response

Topic 6.4 · Translation

  1. Where proteins are built40 ideas · 20 questions
  2. Three letters, one amino acid51 ideas · 35 questions
  3. Spare codons30 ideas · 11 questions
  4. The same code everywhere27 ideas · 7 questions
  5. Start, build, stop53 ideas · 42 questions
  6. Translate it50 ideas · 36 questions
  7. Change one thing47 ideas · 11 questions
  8. From gene to trait, link by link39 ideas · 14 questions
  9. Backwards: RNA to DNA67 ideas · 42 questions
  10. Practice questions10 multiple choice · 2 free response
  11. End-of-topic test: Translation18 multiple choice · 2 free response

Unit 7 · Natural Selection

Topic 7.1 · Introduction to Natural Selection

  1. One field of dandelions43 ideas · 24 questions
  2. Why the plants differ37 ideas · 31 questions
  3. More seeds than space28 ideas · 17 questions
  4. We call it natural selection32 ideas · 28 questions
  5. Populations evolve, individuals do not33 ideas · 23 questions
  6. A wet year and a dry year35 ideas · 25 questions
  7. Practice questions10 multiple choice · 2 free response
  8. End-of-topic test: Introduction to Natural Selection16 multiple choice · 2 free response

Topic 7.2 · Natural Selection

  1. What selection can see34 ideas · 24 questions
  2. Good here, bad there39 ideas · 27 questions
  3. Resistance was already there39 ideas · 25 questions
  4. Explain the numbers18 ideas · 16 questions
  5. Three ways a trait can move32 ideas · 13 questions
  6. Practice questions10 multiple choice · 2 free response
  7. End-of-topic test: Natural Selection16 multiple choice · 2 free response

Topic 7.3 · Artificial Selection

  1. When people choose the parents50 ideas · 28 questions
  2. Draw the heights31 ideas · 26 questions
  3. Before and after, in one picture48 ideas · 39 questions
  4. Practice questions10 multiple choice · 2 free response
  5. End-of-topic test: Artificial Selection18 multiple choice · 2 free response

Topic 7.4 · Population Genetics

  1. Counting alleles, not rabbits33 ideas · 37 questions
  2. Has it evolved, and was it luck?45 ideas · 27 questions
  3. New alleles, and lucky ones49 ideas · 30 questions
  4. A crash, or a small group leaving59 ideas · 34 questions
  5. Alleles that travel54 ideas · 31 questions
  6. Which force was it?32 ideas · 23 questions
  7. Practice questions10 multiple choice · 2 free response
  8. End-of-topic test: Population Genetics18 multiple choice · 2 free response

Topic 7.5 · Hardy–Weinberg Equilibrium

  1. Two shares of two different things32 ideas · 24 questions
  2. p, q and two draws from the pool44 ideas · 30 questions
  3. Start from the ones you can be sure of26 ideas · 7 questions
  4. Five things that must be true, and never are53 ideas · 29 questions
  5. Read the frequency over time58 ideas · 31 questions
  6. How big was the change?23 ideas · 8 questions
  7. Does the census fit?42 ideas · 22 questions
  8. From the census to the verdict49 ideas · 16 questions
  9. Practice questions10 multiple choice · 2 free response
  10. End-of-topic test: Hardy–Weinberg Equilibrium18 multiple choice · 2 free response

Topic 7.6 · Evidence of Evolution

  1. Five kinds of evidence, and the oldest kind53 ideas · 33 questions
  2. Decay is a clock48 ideas · 30 questions
  3. Where they live, and what came before37 ideas · 27 questions
  4. Same bones, look-alikes, leftovers60 ideas · 36 questions
  5. Count the differences46 ideas · 25 questions
  6. Practice questions10 multiple choice · 2 free response
  7. End-of-topic test: Evidence of Evolution18 multiple choice · 2 free response

Topic 7.7 · Common Ancestry

  1. One ancestor for every eukaryote42 ideas · 20 questions
  2. Two more shared features, and a test53 ideas · 29 questions
  3. Practice questions8 multiple choice · 2 free response
  4. End-of-topic test: Common Ancestry16 multiple choice · 2 free response

Topic 7.8 · Continuing Evolution

  1. Still happening39 ideas · 23 questions
  2. Resistance: selection we can watch58 ideas · 22 questions
  3. The next disease37 ideas · 17 questions
  4. Counts that climb by tens37 ideas · 18 questions
  5. Plot the counts26 ideas · 13 questions
  6. What was wrong with the study, and what to do next51 ideas · 19 questions
  7. Practice questions8 multiple choice · 2 free response
  8. End-of-topic test: Continuing Evolution16 multiple choice · 2 free response

Topic 7.9 · Phylogeny

  1. Reading a tree74 ideas · 43 questions
  2. Cladogram or phylogenetic tree?36 ideas · 11 questions
  3. What the branches are built from66 ideas · 32 questions
  4. Build the cladogram49 ideas · 17 questions
  5. Build from sequences38 ideas · 18 questions
  6. Read the clock49 ideas · 25 questions
  7. When the trees disagree96 ideas · 19 questions
  8. Practice questions10 multiple choice · 2 free response
  9. End-of-topic test: Phylogeny19 multiple choice · 2 free response

Unit 8 · Ecology

Topic 8.1 · Responses to the Environment

  1. The pill bug and the damp side39 ideas · 31 questions
  2. A change inside, a change outside, and why the answer helps37 ideas · 18 questions
  3. Turning toward, speeding up: taxis, kinesis and the plant that leans43 ideas · 33 questions
  4. Testing the pill bug41 ideas · 23 questions
  5. Nine to one, or chance?31 ideas · 21 questions
  6. A call in the grass33 ideas · 26 questions
  7. What the signal is for32 ideas · 18 questions
  8. Who leaves offspring36 ideas · 14 questions
  9. Born knowing it, or learned it39 ideas · 25 questions
  10. Safety in numbers60 ideas · 31 questions
  11. Capstone: a change in the environment, a change in behavior, a change in the population23 ideas · 20 questions
  12. Practice questions10 multiple choice · 2 free response
  13. End-of-topic test: Responses to the Environment17 multiple choice · 2 free response

Topic 8.2 · Energy Flow Through Ecosystems

  1. What the energy is used for36 ideas · 20 questions
  2. Gain or loss: the energy budget25 ideas · 13 questions
  3. Warm from inside, warm from outside49 ideas · 28 questions
  4. Breeding when the energy is there29 ideas · 13 questions
  5. From a pond to a biome, and the two things that pass through it43 ideas · 22 questions
  6. Boxes and arrows: how every cycle is drawn44 ideas · 34 questions
  7. Where the rain came from29 ideas · 26 questions
  8. Where your carbon has been58 ideas · 25 questions
  9. Surrounded by nitrogen, and unable to use it38 ideas · 27 questions
  10. Four more steps, by what goes in and what comes out43 ideas · 19 questions
  11. The cycle that starts in rock57 ideas · 29 questions
  12. Who makes the food56 ideas · 38 questions
  13. Net primary productivity23 ideas · 13 questions
  14. Who eats the food52 ideas · 27 questions
  15. Levels, chains and the direction of the arrow47 ideas · 26 questions
  16. Build the web52 ideas · 26 questions
  17. Ten percent43 ideas · 35 questions
  18. Measuring the loss, and why the chain stops30 ideas · 17 questions
  19. Less sun, fewer hawks, and why maize beats beef36 ideas · 15 questions
  20. Explain the result by following the energy41 ideas · 7 questions
  21. Practice questions10 multiple choice · 2 free response
  22. End-of-topic test: Energy Flow Through Ecosystems19 multiple choice · 2 free response

Topic 8.3 · Population Ecology

  1. Counting frogs45 ideas · 20 questions
  2. More births, more deaths32 ideas · 21 questions
  3. The equation: births minus deaths31 ideas · 20 questions
  4. How many next year?21 ideas · 11 questions
  5. Each one makes more36 ideas · 26 questions
  6. The equation for unchecked growth36 ideas · 32 questions
  7. The J and the straight line53 ideas · 33 questions
  8. Draw the growth graph32 ideas · 15 questions
  9. Practice questions10 multiple choice · 2 free response
  10. End-of-topic test: Population Ecology18 multiple choice · 2 free response

Topic 8.4 · Effect of Density on Populations

  1. How crowded?35 ideas · 17 questions
  2. The curve that levels off55 ideas · 23 questions
  3. Limits that bite harder in a crowd61 ideas · 30 questions
  4. The braking term54 ideas · 16 questions
  5. Calculate the rate, brake on38 ideas · 22 questions
  6. Past K, and a moving K51 ideas · 10 questions
  7. Percent change40 ideas · 13 questions
  8. A limit changes, the population answers50 ideas · 8 questions
  9. Practice questions10 multiple choice · 2 free response
  10. End-of-topic test: Effect of Density on Populations18 multiple choice · 2 free response