Edexcel IGCSE Biology 2.33B Body mass index
Practise BMI and food energy data by calculating values, classifying categories and evaluating calorimeter methods and accuracy.
- Syllabus
- First assessment 2019
- Course
- Biology 4BI1
Practise BMI and food energy data by calculating values, classifying categories and evaluating calorimeter methods and accuracy.
Scientists have genetically modified soya plants so that the soya beans they produce contain less saturated fat.
The scientists produced one transgenic soya plant. Micropropagation was then used to make multiple copies of this transgenic soya plant.
A student uses this equipment to compare the energy content of transgenic soya beans with the energy content of non-transgenic soya beans.

Describe how the student could use the equipment to make a valid comparison of the energy content of the two types of soya bean.
A description that makes reference to four of the following:
- weigh beans / same mass of beans / (calculate) per gram of food / eq
- same volume of water / measure volume / same mass of water / stated volume of water / eq
- ignite bean / set fire, and hold under test tube / water / heat water / eq
- keep igniting until will no longer burn / burnt completely / eq
- measure temperature rise / start and end temp / start and highest temp / change in temp / eq
- repeats
Ignore amount
Ignore amount
Allow hold bean at same distance from test tube
If formula given, allow mp1, mp2 and mp5
The diagram shows a different type of apparatus that can be used for the investigation.

Explain two reasons why this apparatus will give a more accurate energy value than the apparatus used by the student.
1
2
An explanation that makes reference to four of the following:
- oxygen supply / oxygen gas inlet
- to ensure complete combustion / so burns fully / eq
OR
- insulated coat / lid / insulation / eq
- to prevent heat loss / keep heat in / not affected by outside temp / eq
OR
- stirrer / eq
- to provide even temperature / spreads heat around / eq
OR
- large(r) volume of water / smaller surface area : volume ratio of water
- so less heat loss / eq
OR
- burnt using ignition coil / ignition in the equipment / no need to move the burning bean / no need to relight / eq
- so less heat is lost / eq
OR
- placed inside a steel container
- conducts / transfers heat to water / eq
OR
- sample is surrounded by the water
- so more heat transferred to water / less heat lost / eq
Mark in pairs
Allow energy loss for heat loss throughout
insulated coat and ignition coil in equipment reduces heat loss = 4 marks
Allow lit inside the container