scholarlab.KS5 Biology

COMMAND WORD · BIOLOGY

Show that

Prove the number the question has already stated, to at least one more figure than it printed.

All command words

Method

Their figure, then your fuller working, then the comparison.

What the parts mean

  • Their figurethe value in the question, and how many figures it has
  • Workingthe data and the calculation, taken one figure further
  • Comparisonyour result rounded back to their figure

How to build your answer

  1. 1Note how many significant figures their value has.
  2. 2Calculate from the data, not by copying their answer.
  3. 3Show at least one extra figure.
  4. 4Show that your result rounds to the stated value.

Biology exemplar

Original question

An illustrative mass increases by 0.753 g in 0.30 minutes. Show that the rate is 2.5 g min⁻¹.

Annotated answer

Their figure2.5 has two significant figures. Working0.753 ÷ 0.30 = 2.51 g min⁻¹. Comparison2.51 to two significant figures is 2.5, so the stated rate is shown.

The labels match the frame. Read them in order. This is one accurate route, not the only one.

Exam habit

Start from the measurements. Do not start by copying their number.

Common pitfall

Writing 2.5 again and calling that a proof.

Exam-style question

2 marks

Based on a sample question

Mark points shown after marking

The table shows conduction speeds in axons of two diameters.

AxonDiameter / µmSpeed / m s⁻¹Non-myelinated12.0Non-myelinated34.0Myelinated112.0Myelinated324.0
Illustrative data.
(a)

Calculate the increase in speed per µm of diameter for the non-myelinated axons.

(1)
m s⁻¹ per µm
(b)

Calculate it for the myelinated axons, and so show that the effect of diameter is six times greater in myelinated axons.

(1)
m s⁻¹ per µm

Total for this question: 2 marks

Answer discussion

Non-myelinated: (4.0 − 2.0) ÷ (3 − 1) = 1.0 m s⁻¹ per µm. Myelinated: (24.0 − 12.0) ÷ (3 − 1) = 6.0 m s⁻¹ per µm. 6.0 ÷ 1.0 = 6.0, which shows the stated six rather than copying it. Writing “6” with no route does not show it.

Where this comes from

Unit 5 sample paper. Question 5 (b)(i) asks you to show that the effect of diameter on conduction speed is six times greater in myelinated neurones than in non-myelinated neurones. Sample assessment, not a live paper.

Sample paper WBI15/01, question 5 (b)(i) (2 marks), 2017 sample assessment. Question page · Mark scheme page

Sources

Pearson Biology specification · Sample assessment PDF