Cambridge Biology for the IB Diploma
Exemplar exam question – Chapter 2, Cells
Structured questions
Structured questions in this style appear on Paper 2. These questions use the same command words as
essay questions. Always check the number of marks that are awarded for each part of the question.
Exemplar question
a
Outline the cell theory.
(2)
The diagram below shows the cell cycle of a eukaryotic cell for a diploid organism.
b
Identify the parts of the cell cycle labelled A and B.
(2)
c
State three activities that occur during phase B.
(3)
d
Define the term ‘diploid’.
(1)
Student response
a
Cell theory proposes that all cells come from cells that already exist. Cells are the
smallest units that can live and all living organisms are made up of cells.
b
The part of the cell cycle labelled A is mitosis and the part labelled B is interphase.
Interphase is divided into three phases – G1, S and G2.
c
During interphase, the cell replicates its DNA and carries out its normal activities. The
cell makes protein and grows larger. The number of mitochondria increases.
d
A diploid cell contains two sets of chromosomes. Body cells are diploid but gametes
are not – they have just one set of chromosomes and are called haploid.
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Cambridge Biology for the IB Diploma
Commentary
This is a good answer and would achieve good marks. The student has made one or two errors in
addressing the question, which are not serious here but could lose marks in other circumstances.
a
This is well answered, the student has outlined cell theory and included three important points.
This answer would be awarded both of the available marks.
b
The first sentence answers the question perfectly. The second sentence is correct but
unnecessary here, only 2 marks are available and these would be given for the statements in the
first sentence.
c
This is a correct answer but students should be careful to avoid vague statements such as ‘it
carries out its normal activities’, which do not provide any information and if incorrect could
lose marks even if later answers are correct. This answer would be awarded 3 marks, however.
d
Again the student has included too much. The first sentence defines diploid and the second,
which explains the difference between diploid and haploid cells, is not necessary, particularly
as there is only one mark available. This answer would be awarded 1 mark.
Total marks awarded: 8 out of 8, but the student should note the comments and be careful not to
include too much information.
Copyright Cambridge University Press 2011. All rights reserved.
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