Edexcel A-Level Biology Arithmetic and Numerical Computation

Practise Edexcel A-Level Biology arithmetic and numerical computation through ratios, percentage change, standard form, unit conversion and formula substitution.

Exam points

calculate biological ratios after converting units such as nm to µm or cm3 to dm3
work out percentages, percentage changes and proportions from biological data
use standard form, formula substitution and rounding instructions in calculation marks

Covered syllabus points

A.0.1—Units in calculations A.0.2—Decimal and standard form A.0.3—Ratios, fractions and percentages A.0.4—Estimating results A.0.5—Powers, exponentials and logarithms A.0.P—SI unit prefixes

[Maximum number: 1]

The diagram shows part of the carbon cycle.

Figure for Question A.0 Arithmetic and numerical computation question 1 — Edexcel A-Level Biology A2

Key

The numbers in smooth brackets ( ) show the mass of carbon in petagrams found in either the atmosphere, plants or surface ocean.

The numbers in square brackets [ ] show the mass of carbon in petagrams transferred between the atmosphere and the plants or surface ocean per year.

A petagram is equal to $10^{15}$ grams.

The mass of carbon recycling between the atmosphere and the plants, and the atmosphere and the oceans, are roughly balanced.

Calculate the increase in the mass of carbon in plants as a result of carbon exchange between the plants and the atmosphere in one year.

Give your answer in kilograms.

Answer. kg

$6.1 \times 10^{13} / 61000000000000(\mathrm{~kg})$

ACCEPT 61 trillion / 61 million
million

(1)

[Maximum number: 1]

Mycobacterium tuberculosis (Mtb) and human immunodeficiency virus (HIV) are two pathogens that infect people. When people infected with either pathogen become infected with the other pathogen the disease is worse.

In one year, it was estimated that 33.4 million people were infected with HIV. It was estimated that 30% of these people were also infected with M t b.

Calculate the number of people with both infections. Give your answer in standard form.

$1 \times 10^{7} / 1.002 \times 10^{7}(1)$

ACCEPT $1 \cdot 10^{7} / 1.002 \cdot 10^{7}$

[Maximum number: 2]

People can be infected by a number of different pathogens.

(a)

Pathogens can enter the digestive system in contaminated food or water.

[ 2 ]

(i)

Salmonella are bacteria that can cause food poisoning.

The chart shows the proportions of contaminated foods responsible for food poisoning caused by Salmonella in the European Union.

Figure for Question (i) — Edexcel A-Level Biology A2

The inside angle of the section representing poultry is $104^{\circ}$ .
Which percentage, to three significant figures, is caused by contaminated poultry?

A 28.0%
B 28.8\%
C 28.9\%
D 29%

[ 1 ]

(ii)

A group of people ate some food contaminated with Salmonella.

The table gives the time after eating the meal that people showed the first signs of food poisoning.

Table for Question (ii) — Edexcel A-Level Biology A2

The total number of people showing signs of food poisoning was 184.
Calculate the percentage showing signs of food poisoning in the first 24 hours.

[ 1 ]

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Covered syllabus points

A.0 Arithmetic and numerical computation question 1

A.0 Arithmetic and numerical computation question 2

A.0 Arithmetic and numerical computation question 3

Question (a)

Question (i)

Question (ii)