CAIE A-Level Biology A2 As and a Level Mathematical Requirements Questions

Practise CAIE Biology calculations from unit conversions and image measurements to ratios, percentages, graph interpretation and rates of change.

Exam points

Convert biological units and prefixes, expressing very large or small quantities in standard form.
Use geometric formulae and biological image measurements to estimate the surface area of cell structures.
Calculate means, ratios and percentage changes in biological data, showing working and required precision.
Describe patterns in biological graphs by comparing trends across groups or time points.
Calculate rates from graph gradients or timed measurements and report units per interval.

Covered syllabus points

M.1—Prefixes, units, symbols and standard form M.2—Calculator use, estimations and significant figures M.3—Magnification, actual size and geometry M.4—Averages, ratios, percentages and experimental error M.5—Graphs, data transformation and rates of change

[Maximum number: 1]

In 2014, scientists published a phylogenetic (evolutionary) tree diagram showing how and when different groups of insects developed from ancestral groups.

To construct the diagram, the scientists compared nucleotide and amino acid sequence data for 1478 genes from each of 103 different insect species. The 103 species represented all 32 orders of the class Insecta.

The data were used to arrange the species in related groups according to their degree of molecular similarity and to track how sequences changed over time.

For this study, new software for processing large quantities of data was developed.

Calculate the total number of sequences that were compared, considering both the nucleotide and amino acid sequences for each gene.

$(1478 \times 103 \times 2=) 304468 ;$

[Maximum number: 2]

Fig. 6.1 is a diagram of mitochondrion.

Fig. 6.1

Assume that the mitochondrion in Fig. 6.1 is a cylinder.

Calculate the surface area of this mitochondrion.
Use the formula: Surface area of cylinder $=2 \pi r^{2}+2 \pi r h$
Show your working.

\text{surface area = }\underline{\hspace{4cm}}\,\mu\mathrm{m}^{2}

b(ii)

$\left(2 \times \pi \times 0.36^{2}\right)+(2 \times \pi \times 0.36 \times 5.25)$

or

$2 \pi \times 0.36(0.36+5.25) ;$

12.7

or

12.68

or

12.69 ;

Marking guidance:

accept 3.14 or $\pi$ in workings

[Maximum number: 3]

The glomerular filtration rate (GFR) is the rate at which fluid filters from the blood in the glomerulus into the Bowman's capsule.

Fig. 6.2 shows the mean GFR values for healthy males and females of different age groups.

Use Fig. 6.2 to calculate the yearly rate of decrease in mean GFR from the 20-29 age group to the 80-89 age group for females.

Show your working.
Give your answer to one decimal place and include units.
answer

$\frac{118-52}{60} \text { or } \frac{118-52}{69} \text { or } \frac{118-52}{51} \text {; }$

1.1 or 1.0 or 1.3 ;

$\mathrm{cm}^{3} \mathrm{~min}^{-1} \mathrm{y}^{-1} ; \mathrm{A} \mathrm{cm}^{3} \mathrm{~min}^{-1} /$ year

A year(s) ${ }^{-1}$

R yr or yrs or mins

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Covered syllabus points

Question 1

Question 2

Question 3