Inside the on-screen exam: tasks, tools, timing and command terms
By the end of this lesson you will be able to
- Describe the structure of the MYP Biology on-screen examination: 100 marks, 120 minutes, and roughly 25 marks for each of Criteria A, B, C and D.
- Identify each item type and on-screen tool, and state the mistake that loses marks with each one.
- Plan your 120 minutes so that the long design and discuss-and-evaluate questions get the time their marks deserve.
- Distinguish between the command terms examiners use — state, outline, describe, explain, suggest, justify, compare and contrast, evaluate, discuss — and write an answer at the depth each demands.
- Interpret markscheme conventions (ORA, WTTE, ECF, “do not accept”, gated marks) and use them to mark your own work honestly.
You met this before
- MYP sciences are assessed on four criteria: A Knowing and understanding, B Inquiring and designing, C Processing and evaluating, D Reflecting on the impacts of science. Each is judged on levels 0–8.
- The independent variable (IV) is what you change; the dependent variable (DV) is what you measure with an instrument; control variables are kept the same, each with a stated value (Year 1, Being a scientist).
- A table puts the IV in the first column, units in the headings only; a graph puts the IV on the horizontal axis with an even scale (Year 1, Being a scientist).
- A mean is the sum of the trials divided by the number of trials, rounded to the precision of the raw data.
- Every unit test in this course (Units 1–11) has used the same shape as the real exam: Task 1 Criterion A, Task 2 Criteria B and C, Task 3 Criterion D.
Three trials of the time for a colour change were 42 s, 45 s and 44 s. State the mean to the correct precision, and state which variable (IV, DV or control) the time is.
Reveal
Mean = (42 + 45 + 44) ÷ 3
Mean = 131 ÷ 3
Mean = 43.67 s, written as 44 s (the raw data are whole seconds)
The time is the dependent variable: it is read from an instrument (a stopwatch).
Revise it in full: Year 1 · Being a scientist · Lesson 3 — Variables and the fair test · Year 1 · Being a scientist · Lesson 4 — Tables and graphs: making the pattern visible · Year 1 · Being a scientist · Lesson 5 — Conclusions and evaluation: was I right, and how would I know?
The puzzle
Two students sit the same Biology paper. They studied the same course, and on a quiz of facts they score the same.
One scores 81 marks. The other scores 58. In the May 2025 session that gap was the difference between a grade 4 and a grade 6 — and in May 2023 it was the gap between a 5 and a 7.
Nobody knows more biology than they did the week before. So where did 23 marks go?
The examiners’ reports answer this every session, and the answer is not “revise harder”. It is the screen, the clock and the verb at the start of each question.
Before reading on, predict three ways a student who knows the biology could still lose marks on an on-screen exam. Write them down, then compare.
Compare your answer
The reports list the same losses every session. Answering “describe” when the question said “explain” (the command term). Leaving a drop-down on “?” or a grid row blank (the screen).
Running out of time before the last discuss-and-evaluate question, which is worth 11–15 marks (the clock). Copying the stem back instead of adding knowledge. Rounding a mean to the wrong precision or dropping a unit.
None of these is a gap in biology. All of them are fixable in five weeks — which is what this unit is for.
The science of the exam — structured notes
1.1 The paper at a glance: 100 marks, 120 minutes, four criteria
The MYP Biology eAssessment is a single on-screen examination of 2 hours and 100 marks. It assesses all four criteria, each worth roughly a quarter of the marks: A Knowing and understanding, B Inquiring and designing, C Processing and evaluating, D Reflecting on the impacts of science.
In this course we practise it as three tasks — Task 1 (A, 25 marks), Task 2 (one investigation, B 25 + C 25) and Task 3 (a real-world issue, D 25). The real paper mixes a little more: a data question may carry A and C marks together, and a short “suggest” inside a D question may test A knowledge.
The order, though, is stable. The five Biology papers from 2021 to 2023 all open with short knowledge items, place one long design question in the middle, and end with one or two long discuss and evaluate questions.
| Session | Questions | The design question | The longest discuss-and-evaluate question |
|---|---|---|---|
| May 2021 | 10 | Q6, stem length of Cabomba and photosynthesis [15] | Q9, medication for hypertension [11] |
| November 2021 | 8 | Q6, salt solution and bacterial growth [17] | Q8, lifestyle choices and cardiovascular health [15] |
| November 2022 | 9 | Q6, light intensity and photosynthesis [15] | Q9, personalised medicine [14] |
| May 2023 | 9 | Q7, plant fibres in rope and stretch [15] | Q9, biosolar green roofs [13] |
| November 2023 | 7 | Q5, temperature and yeast respiration [19] | Q7a, oral rabies vaccine for stray dogs [14] |
Two things follow. First, about 30 marks of every paper sit in just two or three questions — the design and the long discussion. A student who runs out of time before them cannot reach a high grade. Second, the long questions come with bullet points, and the markscheme follows those bullets.
“Because each criterion is worth about 25 marks, the real paper always has exactly three sections, one for A, one for B and C, and one for D.”
Reveal answer
False. The criteria are balanced across the paper — the May 2026 report says the paper followed “the assessment blueprint” — but questions are numbered continuously, and one question can carry marks for more than one criterion.
The November 2023 paper, for example, had a data-processing question (Q4) worth 20 marks followed by the design question (Q5). What is stable is the pattern: knowledge first, investigation in the middle, discussion last.
1.2 Item types and on-screen tools: what each one asks of you
Every item is answered on screen. Most are one of a small number of types, and each type has its own way of losing marks. The table lists the types seen in the Biology and Integrated Sciences papers from 2021 to 2023, with the trap the reports name.
| Item type | What you do | Real example | The trap |
|---|---|---|---|
| Select (multiple choice or drop-down) | Click one option, or choose from a drop-down inside a sentence | May 2023 Q8a: the name of evaporation of water from leaves — transpiration | Leaving a drop-down on “?” (Chemistry May 2024 report); reading too fast and choosing the near-miss |
| Drag-and-drop labels or words | Drag each label to a box on a diagram, equation or Venn diagram | May 2021 Q1c: nucleus, chromosome, DNA, gene, nucleotide on a zoom diagram | Leaving boxes empty; the first mark usually needs two or more correct |
| Tick grid | Tick every cell that applies | May 2021 Q1a: features of bacterial and animal cells | “One row or one column completely correct” is the minimum for any mark |
| Table cell (numeric) | Type a value into a gap in a data table | November 2023 Q4b: the mean CO₂ concentration and rate at 30 minutes | Wrong precision — the rate had to be a whole number, like the rest of the column |
| Plot and draw | Drag points onto a grid, drag axis labels, draw a line of best fit | May 2023 Q4f: two groups’ data on one graph with a key | Uneven scales; points that do not match the key; no line |
| Measure | Drag an on-screen ruler or scale onto an image and read it | November 2021 Q4g: zones of no bacterial growth, ±1 mm | Starting the reading from the end of the ruler instead of its zero |
| Media: video, animation, interactive infographic | Watch or hover; the transcript or data is the stimulus | May 2023 Q3e: hovering over countries to read lactose tolerance and milk consumption | Not opening every panel; copying the media back instead of using it |
| Open response box | Type your answer; for long questions, a large box with the bullets above it | November 2022 Q9: personalised medicine [14] | Ignoring a bullet; no concluding appraisal |
The tools sit in a toolbar. A calculator is provided, and the Biology May 2025 report accepted answers that “correctly copied the calculator screen into the response box”. A symbol palette gives °C, μ, ⁻¹, subscripts and arrows — the same report warned that students “must learn where symbols” such as ° are found.
Graph work uses a plotting tool: you set axis labels and scale values, drag points and draw a line. Measuring uses an on-screen ruler or scale that you drag onto the image. A timer counts down.
You meet every one of these in the IB familiarisation material. Your school’s MYP coordinator can give you access; the reports repeat, session after session, that students who practised with it managed their time better.
Four students measured the CO₂ concentration after 3 minutes from yeast exposed to UV radiation for 30 minutes: 1278, 1199, 1406 and 1321 ppm. The table asks for the mean concentration and the mean rate of CO₂ production in ppm min⁻¹, in the same precision as the rest of the table (whole numbers).
Mean concentration = (1278 + 1199 + 1406 + 1321) ÷ 4
Mean concentration = 5204 ÷ 4
Mean concentration = 1301 ppm
Rate = concentration ÷ time
Rate = 1301 ppm ÷ 3 min
Rate = 433.67 ppm min⁻¹
Rate = 434 ppm min⁻¹ (whole number, matching 783 and 250 in the same column)
The markscheme gave the mark for 434 in the same precision as the column. Typing 433.666… showed the calculation but not the judgement.
A table shows mean heart rates of 77, 80, 84 and 87 bpm. The three trials for the next row are 127, 133 and 135 bpm. Calculate the value to type into the mean cell.
Reveal answer
Mean = (127 + 133 + 135) ÷ 3
Mean = 395 ÷ 3
Mean = 131.67 bpm
Typed value: 132 bpm (three significant figures, whole numbers like the rest of the column)
This was May 2023 Integrated Sciences Q6b [2]: one mark for the calculation, one for the rounding; 132 alone scored both.
Plant fibre cells swell as humidity rises. At 25 % humidity a highlighted cell is 80 μm across. You drag the on-screen scale onto the same cell at 75 % humidity and read 95 μm. Calculate the percentage increase in diameter to the nearest 1 %.
Increase = 95 μm − 80 μm
Increase = 15 μm
Percentage increase = (increase ÷ original) × 100
Percentage increase = (15 μm ÷ 80 μm) × 100
Percentage increase = 18.75 %
Percentage increase = 19 % (to the nearest 1 %)
The divisor is the original value, 80. The Biology May 2023 report named “not dividing by 80” as the common error. The measurement itself was allowed ±5 μm, and later marks carried the error forward (ECF).
A student plots mean enzyme activity against temperature on the graph tool. The x-axis values are 10, 20, 35, 40, 60 (the temperatures in the table); the label reads “Temperature C°”; the points are joined dot to dot with straight lines. Find three errors and correct each.
Reveal answer
Uneven scale: the table values were used as the axis numbers. Use equal steps (0, 10, 20 … 70 °C) and plot 35 between 30 and 40.
Wrong symbol: “C°” should be “°C”, taken from the symbol palette, and the label should read “Temperature / °C”.
Dot-to-dot lines: draw one smooth curve of best fit. Both errors — uneven scales and “all data values being used as axis values” — are quoted from the Biology May 2023 report.
1.3 Timing: 120 minutes, 100 marks, and where the minutes go
The simplest rule is about 1.2 minutes per mark. A 2-mark item deserves under three minutes; a 15-mark design question deserves 18 minutes. That rule, applied to the course’s three-task shape, gives the plan below.
| Block | Marks | Minutes | What you are doing |
|---|---|---|---|
| First read | — | 5 | Scroll the whole paper; find the design question and the long discuss-and-evaluate question; note their marks |
| Task 1 — Criterion A | 25 | 25 | Short items; never more than 3 minutes on a 1–2 mark item |
| Task 2 — Criteria B and C | 50 | 55 | Design (about 18 minutes for 15–19 marks), then data processing |
| Task 3 — Criterion D | 25 | 30 | Media first (5 minutes), then the long answer bullet by bullet |
| Check | — | 5 | Blanks, drop-downs on “?”, units, the concluding appraisal |
If one item is taking too long, write what you have, note the question number and move on. The last ten minutes of an unfinished discussion earn more than the fourth minute on a 1-mark label.
At 70 minutes a student has finished only the knowledge items and half of the data processing. The design question [17] and a discuss-and-evaluate question [14] remain. How should the remaining 50 minutes be split, and why?
Reveal answer
31 marks remain in two questions, plus the unfinished data items. At about 1.2 minutes per mark, the design needs about 20 minutes and the discussion about 17; leave the rest of the data items for any spare minutes at the end.
Both long questions are marked point by point against their bullets, so a structured partial answer to each scores far more than a perfect answer to one and nothing on the other. Writing the discussion first is also sensible: its concluding appraisal alone is worth 2 marks.
1.4 Command terms: the verb decides the depth
Every question starts with a command term. It tells you the depth of answer the marks are for. The Biology reports have asked teachers to model command terms in all seven sessions from May 2023 to May 2026; the May 2025 report complained that students “continue to provide levels of detail that are inconsistent with command term used in the question”.
| Command term | What it demands | From a real Biology paper |
|---|---|---|
| Select / Identify | Pick or name the one right thing from what is given | May 2021 Q3a: the plant giving the highest survival — Plant B |
| State | A name, value or short fact; no explanation | November 2023 Q1a: the organelle holding DNA — nucleus |
| Label | Place names on a diagram | May 2021 Q1c: chromosome, DNA, gene, nucleus, nucleotide |
| Outline | A brief account or summary: two linked points for two marks | May 2023 Q1c: how biceps and triceps work together |
| Describe | A detailed account of what happens or what the data show | May 2023 Q2b: why many foods are stored at 3–5 °C |
| Explain | Reasons or causes: a chain from cause to effect with the mechanism | November 2021 Q3c: why enzyme reactions depend on body temperature [5] |
| Suggest | Propose a plausible answer in an unfamiliar context; more than one answer may be right | May 2021 Q3b: why Plant B gave the highest survival |
| Calculate / Determine | Work out a numerical answer with working and unit; determine gives one value | November 2023 Q1e: the probability of a carrier child — 50 % |
| Formulate | Write a testable hypothesis or research question | November 2022 Q4c: If … then … because … |
| Justify | Give valid reasons or evidence for an answer or choice | May 2021 Q5c: why four trials were planned |
| Interpret | Use knowledge to recognise trends and draw conclusions from data | May 2021 Q7b: the enzyme rate between points A–B and B–C |
| Compare and contrast | Similarities and differences, each in a sentence that mentions both things | May 2021 Q3c: native and non-native plants |
| Comment | A judgement based on a given statement or result | November 2022 Q4f: the validity of a prediction |
| Design | Produce a plan: variables, hypothesis, equipment, method, sufficient data, safety | November 2023 Q5 [19] |
| Discuss / Evaluate | Discuss: a considered review with arguments on both sides. Evaluate: weigh strengths and limitations. Both end in a supported judgement | November 2023 Q7a: the oral rabies vaccine [14] |
One question says “Outline how the population of foxes could be affected” [2]. Another says “Explain why variation is important for the survival of a species” [5]. Write a one-line plan for each that shows how the command term changes the depth.
Reveal answer
Outline [2]: one change caused by the event, then its effect on the population — “more food from rubbish [1], so the fox population increases [1]” (May 2021 Q2b).
Explain [5]: a five-link chain — variation gives a range of characteristics → some individuals have a favourable characteristic and survive → survivors reproduce → the characteristic is passed to offspring → the species becomes better adapted (May 2021 Q1f). Five marks means five linked ideas, each a step in the mechanism.
“Compare and contrast the results for native and non-native plants” [2]. Native plants gave 55 % and 70 % prey survival; non-native plants 45 % and 40 %; no plants 30 %. Write the two sentences.
Reveal answer
Similarity: both native and non-native plants gave higher prey survival than no plants (all above 30 %) [1].
Difference: native plants gave higher survival (55 % and 70 %) than non-native plants (45 % and 40 %) [1]. Each sentence names both groups — that is what makes it a comparison, not two lists (May 2021 Q3c).
1.5 Reading the stem, the bullets and the media
Before you type anything, find four things. The command term. The marks — each mark is usually one point. The object of the question — “the deer population”, not “the ecosystem”. Any constraint: “using the graph”, “using information from the video”, “in terms of osmosis”, “to the nearest 1 %”.
Long questions add bullets. The markscheme follows them in order, often with a statement mark and a support mark per bullet. Students who “addressed the bullet points, in order, in a series of separate sections, were more likely to gain higher marks” (Biology May 2023 report).
Media — a video transcript, an infographic, a data table — is your starting material, not your answer. The May 2026 report again noted students who “simply repeated information from the media” in a hypothesis instead of applying it. Use the media’s facts, then add your own science.
| Stem phrase | What it forces |
|---|---|
| “Using the graph” / “using data from the table” | At least one value quoted, with its unit |
| “Using scientific terminology” | The named process: diffusion, osmosis, vasodilation, denaturation |
| “Use your answer to part b” | The next answer builds on your earlier one; the mark may be ECF |
| “Suggest … and justify” | A proposal plus the reason it would work |
| “… or …” in a bullet | Choose one; OR is not AND (Chemistry November 2024 report) |
| “From the perspective of …” | Argue from that seat only (Physics May 2023: an individual’s view scored nothing when a country’s was asked) |
“State one control variable shown in the flow chart” [1]. The flow chart says the fibres were of the same diameter and length and were immersed in sodium hydroxide solution. A student writes: “Use the same equipment and do a fair test so the results are reliable.” What is wrong, and what would score?
Reveal answer
Equipment is not a variable — the Biology May 2025 report says “equipment is also not accepted as a control variable” — and “fair test” and “reliable” name no variable at all.
Any of the flow chart’s controls scores: the initial length or diameter of the fibre, the type of fibre (agave), or that all fibres were immersed in the same solution (May 2023 Q6a). The question said “shown in the flow chart”, so the answer is in the stimulus.
1.6 How the markscheme thinks: ORA, WTTE, ECF and gated marks
You will mark your own mock papers, so learn the markscheme’s language. ORA — “or reverse argument”: an answer argued the other way round is accepted (“if the temperature decreases…”). WTTE — “words to that effect”: the idea counts even if the wording differs. ECF — “error carried forward”: a later calculation using your wrong earlier value still earns its marks if the method is right.
“Do not accept” lists near-misses that score nothing: “rate of photosynthesis” as a dependent variable (it is calculated, not measured), “clearer” as an advantage of a 3D model, “die” for enzymes.
Some marks are gated. From May 2024 the Biology design question awarded control variables “only when marks for independent variable and dependent variable had been awarded”. A final “hence” mark is often given “only with at least one other mark”, as in the muscle-and-mitochondria item of May 2022 Integrated Sciences.
A contradiction cancels a mark: in November 2022 Q2a, writing “carbohydrates or protein” as the energy source lost the mark because protein was wrong.
“If I write three possible answers to a 1-mark ‘state’ question, the examiner will pick the right one.”
Reveal answer
False. A list that includes a wrong answer is a contradiction and scores zero — the November 2022 energy-source item and the May 2023 phenotype item (“incorrect use of ‘gene’ is a contradiction, award 0”) both say so. Commit to one answer.
A student’s mean for a row is wrong: 12.5 instead of 11.25. They then calculate the percentage change from a first row of 6.0, getting 108 %. The markscheme gives 1 mark for the mean and 2 for the percentage (method, then answer). Using ECF, how many of the 3 marks do they earn, and what is the correct percentage change?
Reveal answer
The mean mark is lost. With ECF, the percentage is marked using 12.5:
Percentage change = (12.5 − 6.0) ÷ 6.0 × 100
Percentage change = 6.5 ÷ 6.0 × 100
Percentage change = 108 % (to 3 significant figures)
Method and answer are both correct for their value, so they earn 2 of 3.
The correct value:
Percentage change = (11.25 − 6.0) ÷ 6.0 × 100
Percentage change = 5.25 ÷ 6.0 × 100
Percentage change = 87.5 %, or 88 %
ECF is why you always show working: a bare wrong number earns nothing.
Try it — work the lab as an on-screen data item
This lab is the yeast set-up behind the November 2023 Biology paper: yeast respiring in sugar solution in a water bath, with the carbon dioxide counted as bubbles. Use it to practise exactly what the on-screen items ask: identify the variables, fill a results table, calculate means to the right precision and comment on a prediction.
A student’s means are: 10 °C → 5; 20 °C → 9; 30 °C → 18; 40 °C → 35; 50 °C → 8; 60 °C → 0 bubbles per minute. Comment on the prediction “the higher the temperature, the more bubbles” [2], and name a precision improvement using the same equipment [1].
Reveal answer
The prediction is supported from 10 °C to 40 °C, where the count rises from 5 to 35 bubbles per minute [1]. It is not supported above 40 °C, where the count falls to 8 at 50 °C and 0 at 60 °C, as the enzymes denature [1].
Precision: collect the gas in an inverted measuring cylinder, or count for longer (for example 3 minutes), because bubbles differ in size — the May 2021 Q5d markscheme accepted both [1].
Common mistakes to avoid
- Treating the paper as evenly timed — the design and long discussion hold about 30 marks; protect their minutes.
- Leaving a blank, a drop-down on “?” or a grid row empty — every blank is zero; a considered choice may score.
- Answering the topic, not the command term — “describe” for “explain” caps the mark at the description.
- Copying the stem or media back — “information that was given in the question … was not worthy of credit”.
- Typing symbols with letters — C° or um instead of °C and μm; use the symbol palette.
- Listing several answers to a “state” question — a wrong one in the list is a contradiction and cancels the mark.
- Hiding working — ECF can rescue a later mark only if the method is visible; copying the calculator display into the box is accepted.
- Answering “and” when the bullet said “or” — choose one and develop it.
Study smart: how this is examined
Study routine. Today: copy the command-term table from memory, then check it. In two days: take any five questions from your Unit 1–11 exams, and for each write only the command term, the marks and the number of points you need.
In a week: sit one past paper section in the practice course with the timer running at 1.2 minutes per mark, and note every item where you ran over.
How we found out — why science is written to a format
The on-screen exam rewards something older than any computer: writing science in a form another person can check. In 1660 a group of natural philosophers in London founded what became the Royal Society, chartered by King Charles II in 1662. Its motto, Nullius in verba — “take nobody’s word for it” — meant that claims had to be backed by evidence others could inspect.
In March 1665 its secretary, Henry Oldenburg, began publishing Philosophical Transactions, now the longest-running scientific journal in the world. Oldenburg’s innovation was procedural: he dated each report as it arrived, which helped settle arguments about who had found something first, and he consulted knowledgeable Fellows about what to print — a distant ancestor of peer review.
Over the next three centuries the scientific paper settled into a standard shape — question and background, methods detailed enough to repeat, results in tables and graphs, and a discussion of what the results do and do not show. By the second half of the twentieth century most biology journals used it.
Look at the MYP criteria and you will see the same structure. Criterion B is the introduction and method; Criterion C is the results and discussion; Criterion D is the question every scientist must now answer for funders and the public — so what? The examiners’ insistence on repeatable methods, units in headings and quoted data is the Royal Society’s rule, applied to you.
Explain why “a method detailed enough for another student to follow” matters to science in general, not only to the examiner.
Reveal answer
A result becomes trusted only when others can repeat the experiment and get the same result; that requires the exact quantities, equipment and steps. A method that cannot be followed cannot be tested, so its result must be taken on the author’s word — exactly what Nullius in verba rejects.
The Physics May 2026 report states the same standard: “a method should be detailed enough so that it can be carried out by another student.”
Where it is used now
- Clinical guidelines. Doctors in Botswana’s clinics follow treatment guidelines where “state the dose”, “monitor”, and “refer if” have exact meanings — the same precision of verbs the exam rewards.
- Laboratory reports. A water-quality laboratory reporting bacterial counts in a borehole must give units, the method and the uncertainty; a value without a unit is unusable, exactly as on the exam.
- Digital testing everywhere. Driving-theory tests, university entrance tests and professional licensing exams in many countries are now on screen, with the same item types: drop-downs, drag-and-drop and short typed responses.
- Research data. Genetic and ecological databases reject entries without units, dates and methods — the habits of Criterion C are the entry ticket to real science.
Science now — and the scientist you need to be
What is happening in 2026
MYP eAssessment has been on screen since its first examinations in May 2016, and the Biology paper is now a mature format: interactive diagrams, video with transcripts, simulations, drag-and-drop and plotting tools.
The IB is revising the MYP (“Enhancing the MYP”), and the first eAssessment in the new style is expected in May 2030; the knowledge and skills you are practising carry forward.
Around you, science itself has moved on screen. Laboratory notebooks are increasingly electronic; data are processed in spreadsheets and plotted in software; and AI assistants can now explain a topic, quiz you and check a calculation.
That changes what an examiner can reward. Recall alone is cheap; what the reports keep asking for is judgement — the right depth for the command term, the right precision for the data, and a conclusion that weighs evidence.
The mindshift
What you need to be able to do
Read any question for its command term, marks, object and constraint; plan 120 minutes; type values in the right precision with the right symbols; and mark your own work with the markscheme’s conventions.
See an example
For Unit 3 Enzymes an assistant wrote “Explain why pepsin works in the stomach [3]”. Its own model answer — “pepsin has an optimum pH of 2” — was a statement worth one mark.
A full answer adds the mechanism: the stomach contains hydrochloric acid, so its pH is about 2 [1]; pepsin’s active site has the right shape and charges at that pH [1]; so substrate binds and protein is digested fastest there [1].
Key terms
| eAssessment | The MYP on-screen examination: 2 hours, 100 marks, Criteria A–D. |
| Command term | The verb at the start of a question that sets the depth and type of answer. |
| Item type | The on-screen form of a question: select, drag-and-drop, tick grid, table cell, plot, measure, media, open response. |
| Stem | The information given in the question; repeating it earns nothing. |
| Markscheme | The list of points and conditions for each mark. |
| ORA | Or reverse argument: the same point argued the other way round is accepted. |
| WTTE | Words to that effect: the idea is credited even if the wording differs. |
| ECF | Error carried forward: a later step using a wrong earlier value can still score. |
| Gated mark | A mark available only if another has been earned (controls after IV and DV). |
| Contradiction | A right and a wrong answer given together; the mark is lost. |
| Familiarisation material | The IB’s practice package showing the on-screen tools and item types. |
Think like a scientist
Criterion A Mopane worms — the caterpillars of the emperor moth Gonimbrasia belina — feed on mopane leaves in northern Botswana and neighbouring countries and are harvested, dried and eaten as a protein-rich food. A class investigates a dried sample.
Exercise data: 50.0 g of fresh caterpillars dried to a constant mass of 15.0 g. The class also recorded that the caterpillars grow from about 1 g to about 15 g in five weeks of feeding.
(a) State the trophic level of a mopane worm. [1]
(b) Outline how energy from the Sun reaches the mopane worm. [2]
(c) Calculate the percentage of water in the fresh caterpillars. [2]
(d) Describe the growth recorded by the class. [2]
(e) Explain how the protein eaten by a person is used to build that person’s muscle. [3]
(f) Suggest one reason why harvesting too many mopane worms in one season could reduce the next season’s harvest. [2]
Model answer
(a) Primary consumer (herbivore) [1]. State = one term; no reason needed.
(b) The mopane tree photosynthesises, converting light energy into chemical energy in glucose and other organic molecules [1]; the caterpillar eats the leaves, so the chemical energy passes to it as food [1].
(c) Water lost = 50.0 g − 15.0 g = 35.0 g
Percentage water = (35.0 g ÷ 50.0 g) × 100
Percentage water = 70.0 % [1 for method, 1 for answer to 3 s.f.]
(d) The mass increases from about 1 g to about 15 g in five weeks [1], a fifteen-fold increase — describe means quote what happens, with values [1].
(e) Proteases digest the protein into amino acids [1]; amino acids are absorbed into the blood by diffusion and active transport in the small intestine and carried to muscle cells [1]; ribosomes in the muscle cells join the amino acids in the order coded by the DNA to make muscle proteins [1]. Explain = the chain, with the mechanism.
(f) Fewer caterpillars survive to become adult moths [1], so fewer eggs are laid and fewer caterpillars hatch the next season (or: overharvesting removes the breeding population) [1]. Suggest = a plausible, linked idea in a context you have not studied.
Probe deeper — exam-style questions
Attempt every question before opening the answer. Marks in brackets show what a full answer is worth.
State the length of the MYP Biology eAssessment and the approximate number of marks for each criterion.
Reveal answer
120 minutes (2 hours) [1]; about 25 marks for each of Criteria A, B, C and D, 100 in total [1].
Four trials give 5, 7, 5 and 7 bubbles in 5 minutes. The other means in the column are 11.25 and 1.5. Calculate the missing mean and state the value you would type.
Reveal answer
Mean = (5 + 7 + 5 + 7) ÷ 4
Mean = 24 ÷ 4
Mean = 6 [1]
The markscheme for May 2021 Q5e accepted 6, 6.0 or 6.00 [1]. Writing 6.00 matches the precision of 11.25 most closely.
Distinguish between “describe” and “explain” using the graph of enzyme activity against temperature.
Reveal answer
Describe: say what the graph shows with values — the rate rises from 10 °C to a peak at about 40 °C and then falls steeply to zero by 60 °C [1].
Explain: give the reasons — collisions increase with kinetic energy up to the optimum; above it the active site changes shape (denaturation) so fewer enzyme–substrate complexes form [1].
A question worth 15 marks asks you to design an investigation and gives five bullets. State how long you should spend, how you should lay out the answer, and one thing to check before moving on.
Reveal answer
About 18 minutes (1.2 minutes per mark) [1]. Answer under the bullets in order, as separate sections or subheadings, because the markscheme follows them [1]. Check: five IV values, three repeats and a mean are stated; every control has a value; the DV is read from an instrument [1].
Explain what “ECF” means and why it is a reason to show your working.
Reveal answer
Error carried forward: when an earlier answer is wrong, a later step that uses it correctly can still earn its marks [1]. The examiner can only see that the method was right if the working is shown; a bare wrong number scores nothing [1].
“Rate of photosynthesis” was not accepted as the dependent variable in May 2021 Q4b, but “volume of gas produced” was. Explain the difference.
Reveal answer
A dependent variable must be read directly from an instrument: the volume of gas is read from a measuring cylinder [1]. A rate is calculated from that measurement and the time, so it is not measured directly (“rate is not directly measurable and needs to be calculated” — Biology November 2023 report) [1].
7. A student has 120 minutes for a paper whose items are worth: sixteen short items totalling 26 marks, a data question of 20 marks, a design question of 19 marks, a short media question of 8 marks, a discuss-and-evaluate question of 14 marks and three final short items totalling 13 marks.
Build a timed plan, including 5 minutes to read and 5 to check, and justify the one change you would make if you were a slow writer.
Reveal answer
Marks total 26 + 20 + 19 + 8 + 14 + 13 = 100; 110 minutes of working time gives 1.1 minutes per mark [1].
Short items: 26 × 1.1 ≈ 29 min
Data question: 20 × 1.1 = 22 min
Design: 19 × 1.1 ≈ 21 min
Media question: 8 × 1.1 ≈ 9 min
Discuss and evaluate: 14 × 1.1 ≈ 15 min
Final items: 13 × 1.1 ≈ 14 min [2 for a complete plan summing to about 110]
A slow writer should take minutes from the short items (answer them tersely: state means a word) and give them to the design and discussion, which are marked point by point and need the most typing [1].
8. The grade 7 boundary in Biology was 75 marks in May 2023, 84 in May 2025 and 76 in May 2026. A student scores 21 on Criterion A, 20 on B, 17 on C and 12 on D. Calculate the total and the marks missing for a 7 in each session, and explain which criterion offers the cheapest marks to gain, using the reports.
Reveal answer
Total = 21 + 20 + 17 + 12
Total = 70 marks [1]
Short of a 7 in May 2023: 75 − 70 = 5 marks
Short of a 7 in May 2025: 84 − 70 = 14 marks
Short of a 7 in May 2026: 76 − 70 = 6 marks [1]
Criterion D is the cheapest to raise: 12 of 25 is lost mainly by structure, not knowledge [1]. The reports say one-sided answers are capped, a missing conclusion costs 2 marks and cost-only economic points score nothing — so answering every bullet with a statement and support, and ending with a supported appraisal, could add 5–8 marks with no new biology [1].
Summary
- The Biology eAssessment is 120 minutes and 100 marks, about 25 for each of Criteria A–D; papers open with short knowledge items, put a long design question in the middle and end with long discuss-and-evaluate questions.
- Item types — select, drag-and-drop, tick grid, table cell, plot, measure, media, open response — each have a trap: blanks, “?” in drop-downs, wrong precision, uneven scales, symbols typed with letters.
- Spend about 1.2 minutes per mark; protect the 30 or so marks in the design and discussion questions.
- The command term sets the depth: state a fact, outline briefly, describe what happens, explain the mechanism, suggest in a new context, discuss and evaluate both sides with a judgement.
- Markschemes use ORA, WTTE, ECF, “do not accept”, gated marks and contradictions — show working, commit to one answer, and never offer equipment as a control variable.
Next time → Criterion A across the whole course: a topic-by-topic checklist of everything the Biology eAssessment can ask, with a retrieval question for each.