Edexcel A-Level Biology AS A 4 Geometry and Trigonometry Questions

Practise Edexcel A-Level Biology geometry skills through surface area, volume, cross-sectional area, radius-diameter conversion and SA:V ratios.

Exam points

calculate surface area or volume from radius, diameter and biological measurements
convert between radius, diameter and units before using circle or sphere formulae
work out surface-area-to-volume ratios for cells, organisms or model shapes

Covered syllabus points

A.4.1—Circumference, area and volume

[Maximum number: 2]

Gametes are specialised for their function.

A student used a microscope and a graticule to view a human egg cell.

The actual diameter of the egg cell was calculated to be 0.10 mm .
Calculate the volume of this egg cell in $\mu \mathrm{m}^{3}$ .
Use the formula:

V=\frac{4}{3} \pi r^{3}

Give your answer in standard form.

[Maximum number: 2]

The structures of blood vessels relate to their functions.

The table shows some dimensions of two veins.

Table for Question 2 — Edexcel A-Level Biology AS

Calculate the cross-sectional area of the lumen of this small vein. Use the formula:

\text { cross-sectional area }=\pi r^{2}

Give your answer as a whole number. Answer $\mu \mathrm{m}^{2}$

diameter of lumen calculated as $38(\mu \mathrm{~m})$ / radius of lumen calculated as $19(\mu \mathrm{~m})(1)$

- cross-sectional area calculated as 1083 / 1119 / 1134 (1)

ACCEPT (38) ${ }^{\mathbf{2}}$

ACCEPT standard form written correctly and to 3 dps

Bald answer of 1083 / 1119 / 1134 = 2 marks Bald answer of correct value not rounded to whole number = 1 mark

Bald answer of 19 / 38 (ignore units) = 1 mark Bald answer of correct value as a whole number for diameter of 46 or 42 (1323 / 1367 / 1385 / 1386 / 1587 / 1640 / 1661 / 1662) = 1 mark

[Maximum number: 1]

All living organisms are made of cells. Some cells are specialised for their function.

A human egg cell is another example of a specialised cell.

A human egg cell has a radius of $50 \mu \mathrm{~m}$ . Calculate the volume of this human egg cell. Use the formula:

\mathrm{V}=\frac{4}{3} \pi r^{3}

Answer $\mathrm{mm}^{3}$

$=5.24 \times 10^{5} / 524000\left(\mu \mathrm{~m}^{3}\right)$

ACCEPT 500000 to 524000 $5.0 \times 10^{5}$ to $5.24 \times 10^{5}$

max number of 2 dp in standard form

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Covered syllabus points

Question 1

Question 2

Question 3