Learner Guide

Cambridge IGCSE®
Biology
0610

Cambridge Secondary 2
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© Cambridge International Examinations 2014

Contents

How to use this guide ........................................................................................................... 3

Section 1: How you will be tested
Section 2: Examination tips
Section 3: What will be tested
Section 4: What you need to know
Section 5: Appendices
Section 6: Cambridge IGCSE Biology useful websites

Section 1: How you will be tested ....................................................................................... 5

1.2 About the theory Papers
1.3 About the practical Papers

Section 2: Examination tips ................................................................................................. 9

General advice
What you should look for in a question
The instructions
The style of questions
The rest of these tips concern the individual papers

Section 3: What will be tested........................................................................................... 29

Section 4: What you need to know ................................................................................... 31

How to use the table

Section 5: Appendices ...................................................................................................... 68

5.2 Other important information you need for your Biology Examination

Section 6: Cambridge IGCSE Biology useful websites ...................................................... 74

 How to use this guide

How to use this guide

It can be used to help you to plan your revision programme for the theory examinations and will explain
what we are looking for in the answers you write. It can also be used to help you revise by using the tick
boxes in Section 4, ‘What you need to know?’, to check what you know and which topic areas of Biology
you have covered.

The guide contains the following sections:

Section 1: How you will be tested

This section will give you information about the different types of theory and practical examination Papers
that are available.

Section 2: Examination tips

This section gives you advice to help you do as well as you can. Some of the tips are general advice and
some are based on the common mistakes that learners make in exams.

Section 3: What will be tested

This section describes the areas of knowledge, understanding and skills that you will be tested on.

Section 4: What you need to know

This shows the syllabus content in a simple way so that you can check:

• the topics you need to know about

• how the Extended syllabus (Supplement) differs from the Core syllabus
• details about each topic in the syllabus
• how much of the syllabus you have covered

Section 5: Appendices
This section covers the other things you need to know, including:
• information about the mathematical skills you need
• information about terminology, units and symbols, and the presentation of data
• the importance of the command words the Examiners use in the examination papers

Not all the information will be relevant to you. For example, you will need to select what you need to know
in Sections 1 and 3, by finding out from your teacher which examination Papers you are taking.

Section 6: Cambridge IGCSE Biology useful websites

Cambridge IGCSE Biology 3

How to use this guide

4 Cambridge IGCSE Biology

 Section 1: How you will be tested

Section 1: How you will be tested

1.1 The examinations you will take

You will be entered for three examination Papers, two theory Papers and one practical Paper.

You will need to ask your teacher which practical Paper you are taking. Nearer the time of the examination,
you will also need to ask which theory Papers you are being entered for:

• If your teacher thinks that you should enter for the examination based on the Core syllabus, you will take
Paper 1 (theory), Paper 2 (theory) and one of the practical Papers (4 or 5 or 6).
• If your teacher thinks that you should enter for the examination based on the Extended syllabus, you will
take Paper 1 (theory), Paper 3 (theory) and one of the practical Papers (4 or 5 or 6).
Whether you take Paper 2 or 3 will depend on the progress your teacher thinks you have made and which
Paper most suits your particular strengths. You should discuss this with your teacher.

1.2 About the theory Papers

The table gives you information about the theory Papers.

Paper How long and What’s in the paper? What’s the %

number how many of the total
marks? marks?

Paper 1 45 minutes 40 multiple-choice questions. You 30%

(40 marks) choose one answer you consider
correct from a choice of 4 possible
answers.

Paper 2 1¼ hours Short-answer questions and 50% (you do

(80 marks) structured questions. You should either Paper 2 or
write your answers in the spaces Paper 3)
provided. The Paper tests the Core
syllabus.

Paper 3 1¼ hours Short-answer questions and 50% (you do

(80 marks) structured questions. You should either Paper 2 or
write your answers in the spaces Paper 3)
provided. The Paper tests topics
in both the Core and Extended
syllabus. The Extended syllabus
consists of the core plus
supplement

Practical
see next table see next table 20%
Paper

Total 100%

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Section 1: How you will be tested

1.3 About the practical Papers

Twenty percent of the marks for IGCSE Biology are for practical work. Practical work is based only on the
Core syllabus.

You will do one of the practical Papers shown in the table. Your teacher will tell you which practical Paper
you will do. The number of marks varies between the Papers but your final mark will be calculated so that it
is worth the same percentage of the total examination as the other practical Papers.

Paper How long What’s involved?

number and and what
type it’s marked
out of?

Paper 4 no fixed time You design and carry out experiments, which are then marked
(coursework) (48 marks) by your teacher. You will be assessed on 4 skill areas. You
need to produce 2 pieces of work for each skill area.

Paper 5 1¼ hours You do a practical exam, which is supervised by a teacher.

(practical (40 marks) There are usually 2 questions testing 4 skill areas.
test)

Paper 6 1 hour You answer a written paper about practical work. There are
(alternative (40 marks) usually 2 or 3 questions, which test the same skill areas as
to practical) Paper 5.

Here is some more detail about each of the practical Papers. If you are unsure of anything, ask your teacher.

1.3.1 Paper 4 (Coursework)

You will carry out several experiments throughout your Biology course, which will be marked by your
teacher. Your teacher will mark you on four different skill areas (Using apparatus, Observing, Handling
results, Planning and Evaluating.)

What you have to do to get a basic (B), medium (M) or high (H) mark is shown below. The differences
between basic, medium and high marks are shown below in italics and underlined.

Skill C1: Using apparatus

You follow written instructions to set up and use apparatus correctly. You carry out your work safely.

B: You follow instructions correctly to do a single practical operation e.g. testing a sample of food to find
out if it contains starch.
You use familiar apparatus with a little help on points of safety.
M: You follow instructions correctly to do a series of step-by-step practical operations e.g. testing a leaf to
find out if it contains starch or investigate the digestion of starch by amylase
You use familiar apparatus fairly well with no help on points of safety
H: You follow instructions correctly to do a series of step-by-step practical operations, but you may need to
change one step if things don’t work out as you thought e.g. lower the concentration of amylase if the
digestion of starch goes too fast.
You use familiar apparatus very well with no help on points of safety.

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 Section 1: How you will be tested

Skill C2: Observing

You make observations and measurements and write them down clearly.

B: You make suitable observations when given some detailed instructions. You record results correctly
when given a detailed table or some help.
M: You make suitable observations when given minimal instructions. You record results correctly when
given an outline table or minimal help.
H: You make suitable observations without help and record results as accurately as the apparatus allows.
You record results correctly without help.

Skill C3: Handling results

You draw graphs and/or perform calculations from your results. You draw conclusions from your results and
recognize any results, which do not fit into the pattern.

B: You draw graphs or charts (or do some calculations) from your results when given detailed suggestions.
You draw simple conclusions from your results.
M: You draw graphs or charts (or do some calculations) from your results when given only a little help.
You draw simple conclusions from your results and comment on the patterns shown by the data
e.g. a high concentration of amylase causes a faster rate of reaction than a low concentration.
You comment on results which do not fit the pattern.
H: You draw graphs or charts (or do some calculations) from your results when given no help.
You draw more general conclusions from your results and comment on the patterns, e.g. the greater the
concentration of amylase, the faster the reaction. You comment on results which do not fit the pattern
and suggest how to deal with them e.g. ignore them.
You suggest what errors there are in your experiment.

Skill C4: Planning and evaluating

You plan your experiment given some basic information from your teacher. You suggest how well your plan
worked and modify if necessary.

B: You write a simple plan for your experiment.

You modify your plan after doing several experiments to see which works the best.
M: You write a plan for your experiment, which has a series of logical steps in it.
You modify your plan after doing trial experiments and give reasons why you need to alter your
original plan.
If there are two variables (things which can change e.g. concentration of amylase, concentration of
starch), you recognise that one variable needs to be changed, while the other is kept the same. E.g. keep
the concentration of starch the same but vary the concentration of amylase.
H: You write a plan for your experiment which has a series of logical and clearly reasoned steps.
You modify your plan after doing trial experiments and give reasons why you need to alter your original
plan and suggest to what extent your plan works and why. You suggest how to deal with unexpected
results. If there are more than two variables you recognise which need to be controlled (kept constant)
and which needs to be changed.

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Section 1: How you will be tested

1.3.2 Paper 5 (Practical test)

You do a practical exam, which is supervised by a teacher. In the exam you are given an instruction sheet
which enables you to carry out the experiments, handle the data and draw appropriate conclusions. You
may be asked to:
• carefully follow a set of instructions in a particular order.
• use familiar and unfamiliar methods to record observations and make deductions from them by
performing simple tests, for example tests for food substances, using hydrogen carbonate indicator,
litmus and Universal Indicator paper.
• use a scalpel or razor blade, forceps, scissors and mounted needles skilfully.
• use a hand lens to observe and record information about biological specimens.
• make clear line drawings of specimens.
• perform simple arithmetical calculations. E.g. the magnification of a drawing.

1.3.3 Paper 6 (Alternative to practical)

This is a written Paper. You may be asked to:
• carefully follow a set of instructions in a particular order.
• follow familiar and unfamiliar methods to record observations and make deductions from simple
tests, for example tests for food substances, using hydrogen carbonate indicator, litmus and Universal
Indicator paper.
• observe and record information about biological specimens from images.
• make clear line drawings of specimens from photographs or micrographs.
• perform simple calculations, including the magnification (enlargement) of a drawing.

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 Section 2: Examination tips

Section 2: Examination tips

How to use these tips

Much of this advice is given in response to the types of answers that learners have written in the past.
These tips are presented under various subheadings to help you when you prepare for your examinations.
Some examples of questions and answers are included to illustrate some of the tips.
• Make sure you read all the general tips. These can be important in any of the papers that you take.
• Have a copy of the syllabus to look at as you read through these tips. Note the different columns – the
left hand side has all the Core topics; the right hand side has the Supplement topics.
• Make sure you know which examination papers you are taking before you look at the tips for the
different papers.
○ You will take Paper 1, which is a multiple choice paper.
○ You will take EITHER Paper 2, which is set on the Core syllabus, OR Paper 3 which is set on the
Core and the Supplement.
○ You will take EITHER Paper 4, which is coursework, OR Paper 5, which is the Practical Examination,
OR Paper 6, which is the written paper about practical work known as the Alternative to Practical
(often called the ATP).

General advice
• Use your syllabus all the time while you are revising and preparing for the examination papers.
• You must know which topics you will be tested on.
• Make sure you have all the equipment you will need for the exam in a clear, plastic container. You
need two pens, pencils (preferably HB or B), a clean eraser, a ruler (which measures in mm), a pencil
sharpener and a calculator.

Answering questions
• The questions are meant to let you show the biology that you have studied. When you are writing your
answers remember that another person has to be able to read it.
○ Do not waste time by writing out the question before you start to answer.
○ Keep your handwriting clear and legible.
○ Keep your answers on the lines on the question paper. Do not write in the left hand side of the
paper or in the column marked For Examiner’s use. This is because papers are scanned and the
Examiners mark them online. If you write in the margin your answers may not be visible.
○ If you wish to change an answer, cross out your first answer and rewrite. Do not write over what
you have already written.
○ If you have to cross out something, put a line through it, do not scribble over it.
○ If you run out of space, use white space on another part of the exam paper for a continuation
answer; do not try to squeeze in your answer by using very small writing.
○ If you have to use a different space for a rewritten another answer or to continue an answer, put a
note to tell the Examiner where it is, e.g. ‘see page 5’.

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Section 2: Examination tips

○ Always try to write accurately using the correct biological terms. Learners often lose marks because
they do not use the vocabulary of biology correctly.
○ Do not use words like ‘it’, ‘they’, ‘effect’, ‘affect’ without any more explanation. A sentence like ‘It
has an effect on the body’ or ‘They affect the process’ does not say anything.

Example 1
Question
State why magnesium ions are important for healthy plant development. [1]
Answers:
– “They are needed by the plant” is true but too vague.
– “They are needed by the leaves” is still too vague.

If these are the first answers that come into your head, ask yourself: What is it or they? What
is the “need”?
– “Magnesium is needed to make chlorophyll” is a better answer and would gain the mark
– “Magnesium is part of each chlorophyll molecule” Good answer, one mark!

○ If you want to use the word ‘it’ or ‘they’ – think ‘what is it?’ or ‘what are they?’ and then phrase your
answer more precisely.
○ If you want to use the word ‘affect’ or ‘effect’ – think ‘how do they affect’ or ‘what is the effect that
they have?’

Terms
• These are the names used in biology. Many of them are given in the syllabus. These terms will be
used in questions. You will get more marks if you can use them correctly in your examination. Ask
your teacher if you are unsure of the meanings of the biological terms used in the syllabus and in any
textbook you are using. It is a good idea to write your own biological dictionary using the glossaries at
the back of books. You will notice that many terms are defined in the syllabus, so that is a good place to
start when making your own dictionary.
○ Try to use the correct spelling. The person marking your answer will try to recognise what word you
mean, but if the spelling is too far out or ambiguous, then they cannot allow you a mark.
○ Some biological terms have very similar spelling. One example is ‘ureter’, urethra’ and ‘uterus’. If the
answer is ureter and your mis-spelling is ‘uretus’, it is not clear enough as you could have thought
the answer is ‘uterus’. Other common examples are ovum/ova, ovary and ovule; testes and testa;
sucrose and sucrase. Make sure you write clearly and always try to spell as accurately as you can.
○ Do not try to mix the spellings of two words when you are not sure which of them is the correct
answer. For example, you might write ‘meitosis’ when you are not sure whether the answer is
mitosis or meiosis, or urether, when you are not sure if the answer is ureter or urethra. In both cases
you would not get the mark.
○ You need to check carefully that you have used the right word when similar terms are used in the
same topic, e.g. urea and urine, ureter and urethra, semen and sperm.

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 Section 2: Examination tips

Writing in your own words.

• You sometimes have to write two or more sentences to answer a question.
○ Use short sentences. If you write long sentences you can become confused and your meaning
is lost. You might also write something contradictory. It is hard for the Examiner to find correct
statements in a muddled answer.
○ You are often asked to write down something you have learned. Make sure you have learnt the
meanings of the common terms used in biology, e.g. photosynthesis, osmosis and fermentation.
○ In the revision checklist there is a list of the terms which you should be able to define. You also need
to be able to write down the meaning of more complicated ideas, e.g. levels of organisation, natural
selection, artificial selection, global warming and eutrophication.

What you should look for in a question

The number of marks
• In Paper 1 there is one mark for each question.
• The number of marks is printed on the examination papers for Papers 2, 3, 5 and 6. The mark available
for each part question is printed in square brackets, e.g. [2]. The number of marks helps you decide how
much to write. The total number of marks for each question is printed at the end of the last question,
e.g. [Total: 12].
• The number of marks is a guide to how long to spend on each question or parts of a question.
• Do not waste time and write a long answer for a question which has one or two marks. You will not get
any extra marks even if your answer is full of many correct and relevant statements.
• If there are two or more marks do not write the same thing in two different ways, e.g. “The leaf is
very large. The leaf has a large surface area”. Notice that the second sentence is more accurate and is
preferable to the first one.

The instructions
• These are called command words and tell you what to do.
• You can find all the command words in the Glossary of terms used in science papers which is at the end
of your syllabus.
• If a question asks you to ‘Name’ or ‘State’ two things only the first two will be marked. Use the
numbered lines for your answers if they are given on the question paper. If you write more than two and
the first is correct, the second one is wrong, and the third one correct, you will only get one mark.
• Some questions have two commands in the question, for example ‘Predict and explain’. This means you
have to say what you think will happen AND then say why you think it will happen. Usually the word and
is printed in bold type to help you. See the section below for a tip about answering questions that have
two command terms and require an extended answer.
• The table on the following page has a list of terms used in biology papers to tell you what to do in an
answer. Make sure you know what you should do in response to each command word.

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Section 2: Examination tips

Example 2
Question 1
Name the process by which green plants make sugars. [1]
All you need to write for your answer is ‘photosynthesis’.

Question 2
Define the term photosynthesis. [2]
This requires a full sentence:
‘The process by which green plants make carbohydrates from raw materials using energy from light’.
This is very similar to the definition given in the syllabus so would easily gain both marks.

What the question is about

• Make sure you know which part of your biology is being tested.
• Read the whole of a question including all the stimulus material and parts (a), (b), (c) (i) and (c) (ii), etc.
carefully before you begin to answer. Some of the parts have similar answers so you need to work
out the differences between them. If you write exactly the same thing in different parts of the same
question, then only one of them might be a correct answer.
• There is often stimulus material for each question. This might be a photograph, diagram, drawing, flow
chart, table of data, graph or just some text. Read all of this information carefully and study any pictures,
tables or graphs that are included. All of it is relevant to the questions.
• The stimulus material is often about something you have not studied. Do not panic. There will be
enough information in the question for you to work out an answer. You are being tested on your ability to
apply your knowledge to new information.
• All the different parts of a question may be about the same topic, e.g. digestion or photosynthesis,
but you should be prepared for questions that test different topics, e.g. digestion, enzymes and
assimilation.
• Look for clues in the words of the question. For example, if you see the word mammal in the question,
you know that the animals are warm blooded and have biological systems like ours.
• If you are only given a Latin name or a name you do not recognise, e.g. eland, look to see if you are told
anything about it. If you are told that an eland is a herbivore, then you know it eats plants.
• Answer each question as far as you can. Do not spend a long time staring at a question.
• If you do not know the answer or how to work it out, then leave it and come back to it later. It is best
to put a mark by the side of the question so you can find it easily. An asterisk (*) is a good idea or a
large question mark against the letter of the part question. Not all part questions have answer lines so a
question you may not see a question that you have left out when you turn through your script towards
the end of the examination.
• Try not to leave blanks. Always check through your script towards the end of the examination. When
you come back to a question you may remember what to write an answer to a question that you left out
earlier in the exam.
• Do not waste time by writing about things unrelated to the question.

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 Section 2: Examination tips

Example 3
It helps to highlight the main features of a question. You cannot use a highlighter pen, so the best
thing to do is to underline or circle key words in the questions.

Question

Name the tissue that transports the sugars made by photosynthesis to other parts of the plant [1]

This tells you that should write a one word answer about plant transport of sugars. Underline the
command word (which is not always at the start of the question) and the biological terms as you read
the question.

Command words
• You can find out more about command terms in the ‘Glossary of terms used in science papers’
towards the end of the syllabus. These notes should help you know how to respond to each of
the command words.

Command words What you should do in response to each command word

Define Give a definition – use the definitions given in the syllabus

What do you Give a definition or a fairly brief explanation of what the term means. You
understand by the can use an example to illustrate if this seems appropriate
term .....?

State Brief answer – maybe one word or a phrase

List A number of brief answers should be given; usually you are asked for a
specific number of points. You do not gain extra marks by writing more
than the number stated

Describe You may have to describe the steps in a process or describe the
appearance of a biological structure
You may also have to describe some data given in a table or a graph.
Make sure you have the correct vocabulary for such a description. Use
the words increase, decrease, constant, peak, maximum, minimum, etc.

Explain This is not the same as describe. You should give an answer that has
some reasons. You may have to explain why something happens or how
it happens

Discuss You may be asked to discuss advantages and disadvantages – so make

sure you give some of both. Much depends on the type of question, but
‘discuss’ usually means you should give different sides of a story or an
argument

Outline This is not the same as describe. You should give the main important
points without any detail

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Section 2: Examination tips

Command words What you should do in response to each command word

Predict This means you should state what you think will happen. You may be
asked to justify your prediction or explain it; explanation is not required if
all the question says is “predict....”

Suggest This is often used when there is no one correct answer; you should
look through the information you have been given for some clues as to
what to ‘suggest’ in response to the question. Many problem-solving
questions use this command word

Calculate This is obvious; make sure you know how to calculate percentages,
percentage changes, rates and ratios (for genetics). Always give your
working even if not asked. Always make sure you use the correct units

Measure You should use a suitable measuring instrument to take a reading.

Usually this involves using a ruler to measure to the nearest mm. Make
sure you write down the unit after the numerical answer

Determine This is not the same as ‘measure’. Either you should explain how an
experiment should be set up to take measurements or how you should
make a calculation from some results or data given in a table or graph

Estimate You do not have to give an accurate answer – but your answer (which is
usually numerical) should only be approximate

Sketch This is usually used about graphs. You should put a line (straight or
curved) on a pair of axes. This may be a graph that has a line on it
already or it may be pair of axes printed on the exam paper without a line
or curve

The style of questions

Identify features of cells, tissues, organs or other structures
• You may be expected to name some structures that are identified by letters on a diagram or drawing.
• You may have to put labels on a diagram using label lines.

Example 4
Question
Use label lines to identify the following on the drawing of a flower: petal, sepal and stamen. [3]
To answer this question:
• You have to know the structure of a flower.
• You also have to be able to find the structures on a diagram of a flower that you may never have
studied.
• You then have to draw a label line to the structure and write the name next to the labelling line.
If you do not draw a label line you may not get any marks even if you have found the correct
structure.

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 Section 2: Examination tips

Use information given in the question

• Questions may ask you to ‘Use examples from...’ or ‘Use only the information in ....’ or ‘With reference
to Fig. 6.2’. If you read instructions like these, find out what you are expected to use as examples or take
information from. You will not get any marks if you use examples from somewhere else. The information
can be given to you in different ways:
○ a diagram, such as a food web, a set of apparatus or a biological structure;
○ a graph, which could be a line graph, a bar chart or a histogram – always check the headings and
units carefully;
○ a table – always read carefully the headings of the columns and/or rows and look for any units.

Example 5
You may have to give examples to show that you understand an idea in Biology.
Question that includes a food web as its stimulus material.
Name one example of each of the following from the food web: producer, primary consumer and
tertiary consumer.
• To answer this question you have to know definitions of producers, primary consumers and tertiary
consumers. Then you have to show that you understand how these terms apply to the food web
shown in the diagram. If you put examples from other food webs you have learned, you will not get
any marks.

Example 6
Question that includes a diagram of a cross section of a leaf.

Describe and explain the advantage of the distribution of chloroplasts in leaves, as shown in the
diagram.
• To answer this question you have to observe the diagram and describe which cells have the most
chloroplasts. Then you have to work out why this arrangement might help photosynthesis. If you
only write about the functions of chloroplasts you will not get any marks.

Interpret tables and graphs

• The stimulus material may be in the form of a table, line graph, bar chart or histogram.
• Always read the introductory text very carefully before you study the table or graph. Underline key
points in the information that you are given. In Paper 3, there may be quite a bit of introductory text
explaining how the information was collected, e.g. from an investigation.

Tables
• Look at the column and row headings in a table and make sure you understand them. If you have read
the introduction carefully, then you will.
• Find the units that have been used. Make sure you use them if you give any figures in your answer.
• Use a ruler to help read the table. Start on the left with the first column. This should be the independent
variable and should increase in steps. Now put the ruler to the right of the next column and look at the
figures in this second column. Look for a pattern or trend in the figures. Identify the pattern or trend first
before thinking of an explanation. Move the ruler across to the right of the third column if there is one
and continue in the same way. It may help to sketch a little graph on the exam paper to help you identify
any pattern or trend.

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Section 2: Examination tips

Line graphs
• Look carefully at the x-axis which is the independent variable and make sure you understand what has
been changed. Look carefully at the y-axis which is the dependent variable. Both variables should be
described in the introduction to the question.
• Put your ruler against the y-axis and move it gradually across the graph from left to right. Follow the
pattern or trend of the line (or each line if there is more than one). Mark on the graph where something
significant happens. For example, the line might show that the dependent variable becomes constant
(gives a flat horizontal line).

Bar charts and histograms

• Look carefully at the x-axis and the y-axis to see what has been plotted. Again, it is a good idea to move
a ruler across the bar graph or histogram to help you concentrate on one aspect at a time. You can
identify the highest and lowest figures and see if there is any pattern.
• You should make yourself some notes about the table, graph or histogram before answering the questions.
• On Papers 2 and 3, you might be asked to complete a graph, bar chart or histogram. If so, you should
look carefully at the question to see what you are being asked to do. You may have to add one or more
points to a line graph and then add a suitable line. There is advice about how to draw lines on line graphs
in the section of general tips for Papers 5 and 6.

Do calculations
• If you are asked to do a calculation:
○ You may have to find the figures from a table or graph.
○ Write out all the working for your calculation. If you make a mistake and give the wrong answer, you
may well be given marks for showing how to do the calculation.
○ Make sure that you show the units in the calculation.
○ If the units are not given on the answer line, then make sure you write them after your numerical
answer.
○ Often you will be asked to carry out a calculation and add the result to a table. Always express your
answer in the same way as the figures given in the table. If the other figures are 5.6 and 4.6, then
your answer should be given to one decimal place, even if the answer is a whole number where you
should write 7.0, not 7.
○ If you use a calculator, round up or down the figures – do not copy all the figures after the
decimal point.

Show or complete equations

○ If you are taking Paper 2, then you should know word equations for photosynthesis, aerobic and
anaerobic respiration. If you are taking Paper 3, then you should also know the chemical equations
and be able to use the chemical symbols correctly. You should know the correct formulae for the
compounds involved.
○ If you are asked to give either a word or a symbol equation, do not combine symbols and words in
the same answer.

16 Cambridge IGCSE Biology

 Section 2: Examination tips

Example 7
Question
Write the word equation for anaerobic respiration in yeast [2]

Correct answer:

glucose → carbon dioxide + ethanol + energy

This is an incorrect answer: “glucose → CO2 + ethanol and energy”, as there is a mixture of words
and symbols. It would probably get one mark out of two.

Question
Write the chemical equation for anaerobic respiration in yeast [2]

Correct answer:

C6H12O6 → 2C2H5OH + 2CO2 + energy

Note that you should use subscripts correctly when writing out the formulae of glucose, alcohol
(ethanol), carbon dioxide, lactic acid and water in these equations.

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Section 2: Examination tips

Example 8
Question
State two ways in which arteries differ from veins. [2]

Correct answer:
1 Arteries have thicker walls than veins.
2 Veins have semi-lunar valves, but arteries do not.
Ambiguous answer:
1 They have thick walls.
2 They don’t have valves.
No marks would be given to the second answer as the comparisons have not been made.
Question
Complete the table to compare the structure of arteries with the structure of veins [2]
Correct answer

Arteries Veins

has thick wall has thin wall

thick muscle layer very thin muscle layer

Incorrect answers as the comparisons are not made between the same features.

Arteries Veins

thick wall thick elastic layer

no valves small amount of muscle

In cases like this, it is much better to have an extra column that gives the features to be compared:

Feature Arteries Veins

thickness of wall thicker thinner

valves absent present

This ensures that you make direct comparisons in each row of the table. You can always add a first
column if it is not included in the question.

18 Cambridge IGCSE Biology

 Section 2: Examination tips

Make comparisons
• If you are asked to compare two things make sure you make it clear which thing you are writing about.
○ The question may ask you to compare two structures or two processes that you have learnt about.
Sometimes you may be expected to do this on answer lines in which case you must make clear the
items that you are comparing (see example 8).
○ You may be given a table to complete. This may be blank and you have to fill it in, or it may already
have some entries and you complete it.
○ If you are given lines to make the comparison, it is perfectly acceptable to draw a table for your
answer.
○ A question may give a table of data and then ask you about it. Make sure you only use information
from the table; for example, in a table that shows the composition of normal breast milk and
colostrum, you can see which milk contains more fat, protein and sugar. Your answers should start
with ‘colostrum has more …….. than breast milk’ or ‘breast milk has more …… than colostrum’. Do
not put ‘It has more protein’.

• Extended writing. You are required to write longer answers to questions that have four or more marks.
There are more of these questions in Paper 3 than in Paper 2.

Example 9
Question
Explain what happens if excess nitrogen fertiliser is washed into a stream or pond [4]

The mark scheme for a question like this will have a list of points that the Examiner will be looking for
in your answer. There will be more points than there are marks, so you do not need to put them all in
your answer. The points for this question could be:

– Algae and aquatic plants grow faster using the fertiliser.

– Algae cover the water surface.
– Light cannot pass to aquatic plants lower down.
– These plants die.
– Bacteria/decomposers, decay or feed on the dead plants.
– Bacteria/decomposers, increase in numbers.
– Bacteria/decomposers use aerobic respiration.
– They use up oxygen.
– There is not enough oxygen for the respiration of other organisms which live in the water.
– These organisms die.
– The process is called eutrophication.

If your answer is something like ‘The fertiliser causes low oxygen and it affects animals in the water’
you will not get any marks. The answer is much too short and too vague. If your answer is something
like ‘The animals do not have enough oxygen for their respiration and they die’ you may get two
marks.

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Section 2: Examination tips

○ When you answer these questions always use full sentences if you can. If you find it helps to write
bullet points, then make sure each bullet point is a full sentence. If you abbreviate your answer too
much by writing notes, then you may not convey enough information to gain the marks.
○ If you are giving a sequence of events (as in Example 9), then you should make sure they are in a
logical order. If you are explaining a biological principle or making comparisons, then give the main
points first.
○ If you are describing something that moves from one place to another, then make sure you include
the direction of movement. For example, ‘water moves by osmosis’ is unlikely to gain a mark unless
you include the direction; ‘water enters the cell by osmosis’ is a much better answer.

The rest of these tips concern the individual papers

Paper 1
• You have about one minute to read and answer each question. Each question tests just one topic.
• Some questions test what you know and understand. For example: What tissue in the eye detects light?
• Some questions test if you can apply what you have learned to understand new data. These questions
will often have a diagram, graph or table to use.
• Try to decide what the question is testing as you are reading it. The sequence of questions usually
follows the sequence of topics in the syllabus. Therefore you can expect the early questions to ask
about Section I on characteristics of life and classification and those at the end will be on Section IV
about ecology and the environment.

Example 10

Question
Four blood vessels are labelled as A, B, C and D on a diagram of the human circulatory system.
This is followed by the question:
In which vessel will absorbed alcohol first be found?

You need to think about what the question is asking

• Is it about digestion?
• Is it about excretion (of alcohol)?
• Is it about the circulation?

The question is asking about something absorbed from the gut to be transported, so it is about
circulation.
• Which vessel carries substances absorbed by the gut?
• Answer ‘The Hepatic Portal Vein’.

So you have to decide whether the vessel is an artery or a vein, then realise that it is a vein taking
blood away from the organ that absorbs alcohol.

Then choose the letter which labels the hepatic portal vein.

20 Cambridge IGCSE Biology

 Section 2: Examination tips

• Do not try to find a pattern in the order of your answers (e.g. A, B, C, D, A, B....)
○ The same letter could be the correct answer for several questions in a row.
○ Letter A might be the correct answers for more questions than B, C or D. Or there could be fewer
correct answers shown by letter D than any of the others.
○ Do not let what you have chosen for the previous questions influence which letter you choose.

Paper 2
• Most of the questions require short answers. This means that you write mainly one word or one
sentence answers worth one mark.
• Longer answers will need two or three sentences with two or three different ideas. Always look at the
number of marks for each part question to help you decide how much to write.
• Look at the number of command words: ask yourself ‘do you have to do one or two things?’
• Use the lines given. Stick to the point and do not write too much.
• Only give the number of answers that are asked. Use the numbered lines and give one answer per line.
• There will only be a few parts of questions that need extended writing. These will have four [4] or [5]
marks. The question will often be related to some information you are given. You will need to write
four or five sentences in a sequence that makes sense. You can think of it like ‘telling a story with a
beginning, a middle and an end’. Remember to refer to any information you are given.

Paper 3
• There is more to read in this paper than in Paper 1 and Paper 2.
• Many questions will be based on one, two or three sentence answers. Always look carefully at the
number of marks for each part question.
• Look carefully at the number of command words – do you have to do one or two things, for example
describe and explain.
• Look carefully to see if you are asked for an actual number of answers. Only give that number. Use the
numbered lines and give one answer per line.
• There are questions that may start in one part of the syllabus and link to another, e.g. the information
could be about the animals in a particular habitat and what they eat. The first parts of the question might
be about the food chains or food webs which include these animals. A later part of the question could
be about teeth or about factors in the environment.
• You are likely to be asked to interpret unfamiliar data, e.g. results from an experiment that you may not
have carried out or could not be carried out in a school. Do not be put off. Follow the same advice as
before. There will always be enough information in the question for you to answer it.
• You are likely to have questions about events and situations that are new to you. Do not be put off. The
question will tell you all you need to know. Read the information carefully and if it is not immediately
apparent, look for clues that will tell you which part of the syllabus the question is about.

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Section 2: Examination tips

Papers 5 and 6
General tips
• Read through the questions carefully, looking to see how many marks are given for each question.
• In Paper 5, you have to follow a set of instructions. Read these to the end first, before you start.
• In Paper 6, you will have to read some information about an experiment. Again, read these very
carefully.
• Divide the time of your examination in proportion to the marks given.
• If you are taking Paper 6, make sure that you have done plenty of practical work so you can imagine
what has happened to obtain the results that you will process, analyse and interpret in the questions.
• Make sure that you have a sharp pencil to use for making drawings and drawing graphs and charts. Do
not draw in ink because you cannot make changes as you can when using a pencil.
• Make sure you have a good, clean eraser for rubbing out your pencil lines if necessary. Do not press too
hard when using a pencil for making drawings, graphs or charts. Sometimes it is hard for an Examiner to
tell which is your final line on a scanned script.

Recording your observations

In both papers you are expected to make observations and record them.
• You can record your observations:
○ as statements in writing
○ in tables
○ by using drawings
○ by constructing tally charts
• You can process your observations by:
○ carrying out calculations, e.g. percentages and percentage changes
○ plotting graphs – line graphs, bar charts and histograms.
• Use all the space available on the paper for your observations.
• Do not write an explanation until the question asks for one.
• Use a sharp HB or B pencil. It can be rubbed out easily if you need to correct a mistake. Use a good
eraser as traces of pencil lead are detected when your paper is scanned.
• Do not forget headings for the columns and the rows in tables and in axes on graphs. Do not forget to
include the units.
• Make drawings as big as the space allows.
• Use a ruler for labelling lines.
• Label in pencil.
• Use one clear continuous outline not an artistic drawing. Do not shade other than using very light dots.

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 Section 2: Examination tips

Drawing tables
• If you are asked to draw a table:
○ Use a ruler and a pencil to draw the table. Make sure you rule lines for the columns and the rows.
○ Write headings for each column and/or row of the table.
○ Write in units if they are needed, e.g. volume of water/cm3, mass of seed/g. The unit should be
written after the oblique line (forward slash).
○ Do not put units in the table spaces where you write numbers.
• Make sure you use the same number of decimal places in each column and/or row.
○ If you are asked to draw and/or complete a tally chart for recording data:
○ Make sure that you rule up a table and use clear headings.
○ Record the numbers by using strokes and putting an oblique line to represent 5:
/// = 3; //// = 4 and //// = 5
○ Include a column to show the total numbers.

Drawing line graphs

• If you are asked to draw a graph:
○ Choose a scale which uses most of the grid provided on the exam paper.
○ Choose a simple scale, e.g. one large square is equal to 1, 2, 5 or 10 units in the data. Do not make it
difficult to plot the data by using a scale such as one large square = 3 or 6.
○ Write the name of each axis and the correct unit, e.g. rate of water loss/g per h, temperature/ °C,
time/s.
○ Plot the points exactly using a sharp pencil. Draw the points lightly so that you can rub them out if
you need to. Make them more definite when you are sure they are right.
○ Use a cross (x) or a dot in a circle ( ) for your plot points. Do not use a single dot as it may not be
seen after you have drawn your line.
○ If you have to plot two lines on a graph, use two different symbols for the plot points. You can use
a cross, a dot in a circle or a plus sign (+). Label each line carefully or use a key. Use a pencil for
both lines; do not use a blue or black pen or different colours as these do not show up on scanned
scripts.
○ Read the question carefully before you put a line in the graph. Look carefully at the points. You have
to decide whether to use a straight line of best fit, a smooth curve of best fit or join the points by
straight lines. Always use a sharp pencil.
○ Remember that lines of best fit do not have to pass through the point where the two axes meet (the
origin). If you are sure that 0, 0 is a point then you can include it. For example, in an investigation of
the effect of the concentration of enzyme on enzyme activity 0, 0 means that there is no enzyme
present. If there is no enzyme there can be no activity, so 0, 0 could be included.
• Do not extend your line graph beyond the last plotted point.

Bar charts have separate columns that do not touch – there are gaps in between; histograms have
columns that do touch each other. Bar charts are used to show data on discontinuous variables, for
example blood groups, eye colour, etc.; histograms are used to show data on continuous variables,
e.g. length, mass, speed, volume, etc.

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Section 2: Examination tips

Drawing bar charts

• You may have to draw a bar chart (Papers 5 or 6) or add some data to a bar chart (Papers 2 and 3). You
draw a bar chart when you have different categories, such as the numbers of six different species in a
habitat.
○ Choose a scale which uses most of the grid provided on the exam paper; do not make the chart too
small.
○ Draw the chart in pencil.
○ Rule the columns evenly so that they are all the same width.
○ Take care to rule the top of each block in the correct place – double check with the table of data
each time.
○ The spaces between the columns on the x-axis should be identical; they should be the same length,
e.g. one large square on graph paper.
○ The y-axis should be properly scaled with equal intervals just as in a line graph.
○ The y-axis should be labelled with units.
○ The lines or blocks can be arranged in any order, but to make comparisons it helps if they are
arranged in descending or ascending order of size.
○ You should identify each block by putting a label directly underneath each block. Do not shade the
blocks or colour code them.

Drawing histograms
• Histograms are ways of displaying the variation in a particular feature, for example the lengths of leaves
on a tree. If you measure the lengths of leaves you would have to divide the data into classes, such as
50–54 mm, 55–59 mm, 60–64 mm, etc. The numbers would be recorded in a tally table.
○ Choose a scale which uses most of the grid provided on the exam paper; do not make the histogram
too small.
○ Draw the histogram in pencil. The x-axis represents the independent variable and is continuous. It
should be properly scaled and labelled with appropriate units.
○ The blocks should be drawn touching.
○ The area of each block is proportional to the size of the class. It is usual to have similar-sized classes
(as in the example above) so the widths of the blocks are the same.
○ The blocks should be labelled either by putting the class ranges (e.g. 60–64, 65–69 etc.) underneath
each block or by putting the lowest number in each range (e.g. 60, 65, 70, etc.) under the left-hand
side of the relevant block.
○ The y-axis represents the number or frequency and should be properly scaled with equal intervals. It
should be labelled with appropriate units.

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 Section 2: Examination tips

Planning investigations
Sometimes you are asked to suggest a way of carrying out an investigation or to improve the method that is
in the question paper.

• When you read through an investigation try to work out three main things:
1. What is being changed – this is called the independent variable.
2. What is being measured – this is called the dependent variable.
3. What is being kept the same – these are the control variables.

Example 11
In a question to investigate the effect of temperature on enzyme activity:
• the independent variable is temperature.
• the dependent variable may be the time taken for a solution of the substrate to change its
appearance.
• the key control variables are the concentration of the enzyme solution, the volume of the enzyme
solution, the concentration of the substrate solution and the volume of the substrate solution.
These are the variables that must be kept constant if you are to find out the effect of changes in
temperature.

• Some investigations need to have two parts:

○ The experimental – which measures the process being studied and contains the living organism,
part of an organism (e.g. a leaf) or enzyme being tested.
○ The control – which will be exactly the same as the experimental except that the living organism will
be missing or replaced by something non-living. The control shows that the results are due to the
activity of the living organism and is not due to the apparatus or an environmental factor.
• All investigations should be repeated to increase the reliability of the results. If the same results are
achieved (or the results are very similar) then they are reliable.
• The precision of results taking may not be very good. For example, if you are measuring using a syringe
or measuring cylinder it may be difficult to measure to the nearest cm3. You should think about ways in
which the precision can be improved.
• Give quantities in appropriate terms – avoid the use of term ‘amount’ as this does not convey precise
meaning to any specific quantity. ‘Amount’ could mean volume, mass or concentration. Always be
precise and use these words; avoid writing the word ‘amount’. For example, you can give the volume in
cm3, mass in grams and concentration in an appropriate unit such as grams per 100 cm3.

Tips for paper 5

In paper 5 you are following instructions, using laboratory equipment, making observations, recording
results and drawing conclusions.
• Start by reading the entire first question.
• Think about the apparatus that you will use for each step and imagine using it in your mind.
• Check the time to be allowed and imagine following the instructions.
• Do the same when you are ready to begin the next question.

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Section 2: Examination tips

Following the instructions

• Follow the instructions for practical methods exactly. If you make a change in the method you can alter
the results.
• Do not take short cuts.
• Always label test tubes and other containers to help you remember which is which.
• If you are told to ‘Wash the apparatus thoroughly after each use’ make sure you do. If there is anything
left in the apparatus the next stage may not work.
• If you have to measure a specimen make sure you draw a line on your drawing to show where you
made your measurement.
• It is a good idea to put a tick by the side of each instruction when you have completed it. This helps you
to find the right place in the instructions, so that you do not leave out a step or repeat a step when it is
not required.
• Keep your exam paper on a part of the bench which you can keep dry. Do not pour liquids or use
syringes or pipettes over your exam paper. If you keep our exam paper away from the ‘wet’ part of your
bench you are unlikely to spill anything on it.

Recording your observations

• Do not forget that observations can be seen, heard, felt and smelled, e.g. colour, fizzing, warming, smell
of a flower, texture (feel) of a fruit.
• You can always find something to observe, so make sure you record something for each observation.
• Write down exactly what you observe.
• e.g. if you add a drop of iodine solution to a drop of starch solution on a white tile, the colour changes.
○ You should write ‘the colour changed from yellow to blue-black’.
○ If you write ‘it turned black’ you have not given all the information.
○ If you add iodine solution to a drop of water on a white tile, you should write down ‘the colour
stayed yellow’. If you write ‘the colour stayed the same’, or ‘no change’, you have left out important
information.

Drawings
These will be from specimens or photographs.
• Read the question carefully, the drawing may have to be an accurate size e.g. twice the original.
• Make each drawing as big as the space allows.
• Use a ruler for labelling lines.
• Label in pencil.
• Use one clear continuous outline not an artistic drawing. Do not shade other than using very light dots.
• Observe details carefully, such as number of seeds in a seed case, thickness of a layer in a shell, etc.
Show these accurately on your drawing.

26 Cambridge IGCSE Biology

 Section 2: Examination tips

Taking measurements
• Make your measurements as accurate as you can. Measure to the nearest unit, e.g. mm. Do not try and
‘guess’ 0.5 mm.
• Make sure you put units! Use the correct SI units, do not use other units; for example measure in
millimetres not inches.
• Always measure in millimetres, not centimetres.
• If you have to make calculations on your measurements, use the blank pages within the paper but
indicate if the answer is continued elsewhere on the blank pages. Do not write in the margins.
• Write neatly and show your working. The person marking your paper might be able to give you marks for
knowing what to do if you make a mistake or do not finish the calculation.

Conclusions
• Use your own results for your conclusions.
• Before planning what to write for a conclusion, turn back to the beginning of the question and read the
introduction. You may have forgotten what you were told about the investigation you have just carried
out. Think about the theory and apply it to the results you have obtained.
• Sometimes you are expected to make conclusions about some other data, not the data you have
collected.
• Do not write the conclusion you have learned from a class experiment or from theory.

Tips for paper 6

The topics on Paper 6 will be very similar to those on Paper 5, so the tips are very much the same as for
that paper. Because you are not doing any practical work, there is usually a third question, so Paper 6 tests
more of the syllabus.

In this paper you are making observations from information given in the paper, recording results and drawing
conclusions. Try to imagine doing the practical which has produced the results in the questions and look
very carefully at the information you are given as it will almost certainly be unfamiliar to you.

Recording observations
• Some of your observations are based on photographs or diagrams on the paper.
• Write down exactly what you see – as differences or similarities. Measurements may need to be made
and magnifications calculation.
• Look carefully at photomicrographs as these will be enlarged, e.g. x 100. If you are asked to calculate a
magnification follow these steps:
○ measure the structure in the photograph in millimetres (not centimetres).
○ look for the actual size of the object – you will be given this.
○ divide the length of the structure in the photograph (in mm) by the actual size (in mm).
○ the answer is the magnification; round up or down the answer from your calculator.
○ usually magnifications are given as whole numbers, so do not give the answer to one or more
decimal places.

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Section 2: Examination tips

If you are asked to calculate an actual size follow these steps:

○ measure the structure in the photograph in millimetres (not centimetres).
○ look for the magnification – you will be given this.
○ divide the length of the structure in the photograph (in mm) by the magnification.
○ the answer is the actual size in millimetres; round up or down the answer from your calculator.
○ actual sizes could be given as whole numbers or you could include one or two decimal places, but
no more.

28 Cambridge IGCSE Biology

 Section 3: What will be tested

Section 3: What will be tested

The Examiners will take account of the following areas in your examination Papers:
• your knowledge (what you remember) and understanding (how you use what you know and apply it to
unfamiliar situations).
• how you handle information and solve problems.
• your use of experimental skills.
These areas of knowledge and skills are called Assessment Objectives. The theory Papers (Papers 1 and 2
or 3) test mainly Assessment Objectives A (knowledge with understanding) and Assessment Objective B
(handling information and problem solving). The purpose of the practical Paper (Paper 4 or 5 or 6) is to test
Assessment Objective C (experimental skills). Your teacher will be able to give you more information about
how each of these is used in the examination Papers.

The table shows you the range of skills you should try to develop:

Skill What the skill What you need to be able to do?

means?

A: knowledge remembering 1. use scientific ideas, facts and theories

with facts and 2. know scientific definitions e.g. what is excretion?
understanding applying these 3. know about biological apparatus and how it works
facts to new 4. know about S I units, quantities (e.g. mass) and
situations symbols (e.g. dm3)
5. understand the importance of science in everyday
life

B: handling how you extract 1. select and organize information from graphs, tables
information and information and written text
problem solving and rearrange 2. change information from one form to another, e.g.
it in a sensible draw chart and graphs from data
pattern and 3. arrange data and carry out calculations
how you carry 4. identify patterns from information given and draw
out calculations conclusions
and make 5. explain scientific relationships, e.g. changes in heart
predictions rate in relation to activity
6. make predictions and develop scientific ideas
7. solve problems

C: experimental planning and 1. set up and use apparatus safely

skills carrying out 2. make observations and measurements and record
experiments them
and recording 3. analyse experimental results and suggest how valid
and analysing they are
information 4. plan and carry out your own experiment and
describe to what extent your plan worked and
suggest improvements

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Section 3: What will be tested

30 Cambridge IGCSE Biology

 Section 4: What you need to know

Section 4: What you need to know

The table describes the things you may be tested on in the examination. It is arranged in 14 topic areas. If
you are studying only the Core material (Papers 1 and 2), you will need to refer only to the column headed
Core material. If you are studying the Extended syllabus (Papers 1 and 3), you will need to refer to both the
Core and Supplement material columns. Read Section 1 (How will you be tested?) if you are unsure about
which material to use.

How to use the table

You can use the table throughout your course to check the topic areas you have covered. You can also use
it as a revision aid. When you think you have a good knowledge of a topic, you can tick the appropriate box
in the checklist column. The main headings in the topic areas are usually followed by the details of what you
should know.

Test yourself as follows:

• cover up the details with a piece of paper.
• try to remember the details.
• when you have remembered the details correctly, put a tick in the appropriate box.

If you use a pencil to tick the boxes, you can retest yourself whenever you want by simply rubbing out the
ticks. If you are using the table to check the topics you have covered, you can put a tick in the topic column
next to the appropriate bullet point.

The column headed ‘Comments’ can be used:

• to add further information about the details for each bullet point.
• to add learning aids.
• to highlight areas of difficulty/things which you need to ask your teacher about.

Cambridge IGCSE Biology 31

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Section 4: What you need to know

Cambridge IGCSE Biology

Topic Core material Supplement material

You should be able to: Checklist Comments You should be able to: Checklist Comments

Section I

1. Features • list and describe the features

of living of living organisms, state the
organisms meaning of the terms:
○ nutrition
○ excretion
○ respiration
○ growth
○ movement
○ reproduction
○ sensitivity

2. Classification
and diversity
of living
organisms

2.1 The idea • explain the meaning of and • know that there are
and use of a describe the binomial (two other classification
classification name) system of naming systems based on
system species, e.g. Felis leo and DNA and RNA data
Felis tigris
• identify and name the five
main classes of vertebrates by
using visible, external features
only
 Topic Core material Supplement material

You should be able to: Checklist Comments You should be able to: Checklist Comments

2.2 Adaptations • list the main, visible, external • list the main features
of organisms to features used to identify and used to identify and
their environment name the groups, also name name the groups, also
examples: list their adaptation to
○ Flowering plants (mono- the environment as
and dicotyledons) appropriate.

○ arthropods (insects, ○ viruses

arachnids, crustaceans ○ bacteria
and myriapods) ○ fungi
○ annelids
○ nematodes
○ molluscs

Section II

3. Simple keys • use simple dichotomous

(forked) keys that use easily
identified features

1. Cell • State that living organisms are • Know how the

structure and made of cells structures in plant and
organisation • Recognise and describe the animal cells are related
structure of: to their functions

Section 4: What you need to know

Cambridge IGCSE Biology

○ a plant cell (palisade cell)

○ an animal cell (liver cell)
• Know the differences in
structure between animal and
plant cells
33
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Section 4: What you need to know

Cambridge IGCSE Biology

Topic Core material Supplement material

You should be able to: Checklist Comments You should be able to: Checklist Comments

2. Levels of • Relate the structure of the

organisation following to their functions:
○ ciliated cells – in
respiratory tract
○ root hair cells – absorption
○ xylem vessels –
conduction and support
○ muscle cells – contraction
○ red blood cells – transport

• Define with examples:

○ tissue as a group of cells
with similar structures,
working together to
perform a shared function
○ organ as a structure made
up of a group of tissues,
working together to
perform specific functions
○ organ system as a group
of organs with related
functions, working
together to perform body
functions

3. Size of Be able to calculate magnification

specimens and size of biological specimens
using millimetres as units
 Topic Core material Supplement material

You should be able to: Checklist Comments You should be able to: Checklist Comments

4. Movement in • Know the importance of • Define active transport

and out of cells diffusion of gases, solutes and as movement of
water ions in or out of a
• Define diffusion as: the net cell through the cell
movement of molecules membrane, from a
from a region of their higher region of their lower
concentration to a region of concentration to a
their lower concentration region of their higher
down a concentration concentration against
gradient, as a result of their a concentration
random movement gradient, using energy
released during
respiration

• Know the importance of • Discuss the

osmosis in the uptake of importance of active
water by plants, and its transport e.g. ion
effects on plant and animal uptake by root hairs
tissues and uptake of glucose
• Define osmosis as the by epithelial cells of villi
diffusion of water molecules • Describe and explain
from a region of their higher the importance of
concentration (dilute solution) a water potential
to a region of their lower gradient in the uptake

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Cambridge IGCSE Biology

concentration (concentrated of water by plants

solution), through a partially
permeable membrane
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5. Enzymes • Define the term catalyst as a • Explain the ‘lock and

substance that speeds up a key’ model
chemical reaction and is not • Explain how
changed by the reaction temperature and pH
• Define enzymes as proteins effect enzyme activity
that function as biological • Describe what use
catalysts enzymes have in:
• Describe the effect of ○ seed germination
changes in temperature and ○ biological washing
pH on enzyme activity products
○ food industry
(including
pectinase and fruit
juice)

• Describe the use of

microorganisms and
fermenters to make:
○ penicillin
○ enzymes for use in
biological washing
powders
• Describe the role of
the fungus Penicillium
in the making
antibiotic (penicillin)
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6. Nutrition • Define nutrition as taking in

of nutrients which are organic
substances and mineral ions,
containing raw materials
or energy for growth and
tissue repair, absorbing and
assimilating them

6.1 Nutrients • List the chemical elements • Describe how

that make up: microorganisms are
○ carbohydrates used to make:
○ fats ○ yoghurt
○ proteins ○ single cell protein
• Describe the synthesis of • Describe the uses,
large molecules from smaller benefits and health
basic units, i.e. hazards associated
○ simple sugars to starch with food additives,
and glycogen including colourings
○ amino acids to proteins
○ fatty acids and glycerol to
fats and oils

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• Describe tests for:

○ starch (iodine solution)
○ reducing sugars
(Benedict’s solution)
○ protein (biuret test)
○ fats (ethanol)
• List the principal sources of,
and describe the importance
of:
○ carbohydrates
○ fats
○ proteins
○ vitamins (C and D only)
○ mineral salts (calcium and
iron only)
○ fibre (roughage)
○ water
• Describe the deficiency
symptoms for:
○ vitamins (C and D only)
○ mineral salts (calcium and
iron only)

6.2 Plant nutrition • Define photosynthesis as • Know the balanced

the fundamental process by equation for
which plants manufacture photosynthesis in

(6CO2 + 6H2O →
carbohydrates from raw symbols
materials using energy from
light C6H12O6 + 6O2)
• State the word equation for • Define the term
photosynthesis limiting factor as
something
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• Know that photosynthesis present in the

needs chlorophyll, light and environment in such
carbon dioxide short supply that it
• Describe how plants get restricts life processes
carbon dioxide and water • Explain limiting factors
• Explain that chlorophyll traps in photosynthesis such
light energy and converts it as
into chemical energy for the ○ light intensity,
formation of carbohydrates ○ carbon dioxide
• Be able to label a leaf with: concentration
○ cuticle ○ temperature
○ cellular structure • Explain the use of
○ tissue structure ○ carbon dioxide
• Describe the significance of enrichment,
these features in terms of ○ optimum light
functions: ○ optimum
○ distribution of chloroplasts temperatures
(for photosynthesis) in glasshouse
○ stomata and mesophyll systems
cells (gas exchange) • Explain the effects of
○ vascular bundles (xylem ○ nitrate ion
and phloem) (for transport ○ magnesium ion
and support) deficiency on plant
• Describe the importance of: growth

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Cambridge IGCSE Biology

○ nitrate ions for protein

synthesis
○ magnesium ions for
chlorophyll synthesis
• Describe the uses, and
dangers of overuse of nitrogen
fertilisers
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6.3 Animal • Define balanced diet • Discuss the problems

nutrition and describe a balanced diet of world food supplies
related to age, sex and activity • Discuss the problems
of an individual which contribute
• Describe the effects of to famine (unequal
malnutrition in relation to distribution of food,
starvation, coronary heart drought and flooding
disease, constipation and and increasing
obesity population)
• Discuss how modern
technology has resulted in
increased food production
(including modern agricultural
machinery, chemical
fertilisers, pesticides and
herbicides, artificial selection)
• Define ingestion as taking
substannces (e.g. food, drink)
into the body through the
mouth
• Define egestion as passing
out of food that has not been
digested, as faeces, through
the anus
• Identify the main regions and
organs of the alimentary canal
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And including mouth, salivary

glands, oesophagus, stomach,
small intestine (duodenum
and ileum), pancreas, liver, gall
bladder, large intestine (colon)
and rectum, anus
• Describe the functions
of the regions of the
alimentary canal listed
above, in relation to:
○ ingestion
○ digestion
○ absorption
○ assimilation
○ egestion
• Define digestion as the
break-down of large,
insoluble food molecules
into small, water soluble
molecules using mechanical
and chemical processes
• Know the types of human
teeth and describe their
structure and functions

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Cambridge IGCSE Biology

• State the causes of dental

decay and describe the
proper care of teeth
• Describe the process of
chewing
• Describe the role of
longitudinal and circular
muscles in peristalsis
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• Outline the role of bile in • Describe how fluoride

emulsifying fats reduces tooth decay
• State the significance of • Explain arguments
chemical digestion in the on the addition of
alimentary canal fluoride to public water
• State where amylase, supplies
protease and lipase enzymes • Describe the structure
are secreted of a villus (including
• State the functions of capillaries and lacteals)
amylase, protease and lipase • State the role of the
• Define absorption as hepatic portal vein
movement of digested food in the transport of
molecules through the wall of absorbed food to the
the intestine into the blood or liver
lymph • Identify the role of the
• Identify the small intestine as small intestine and
the region for the absorption colon in absorption of
of digested food water
• Describe the function of villi
• Define assimilation as
movement of digested food
molecules into the cells of the
body where they are used,
becoming part of the cells
• Describe the role of the liver in

○ glucose → glycogen
the metabolism of:

○ amino acids → proteins

○ destruction of excess
amino acids
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• Describe the role of fat as an • Define deamination

energy storage substance as removal of the
nitrogen-containing
part of amino acids to
form urea, followed by
release of energy from
the remainder of the
amino acid
• State that the liver is
the site of breakdown
of alcohol and other
toxins

7. • State the functions of xylem • Relate the structure

Transportation and phloem and functions of root
7.1 Transport in • Know where xylem and hairs to their surface
plants phloem are found in area and to water and
dicotyledonous roots, stems ion uptake
and leaves • Explain how water
• Identify root hair cells and uptake happens in
state their functions terms of transpiration
• State the pathway taken by producing a tension
water through root, stem and (‘pull’) from above,
leaf (root hair, root cortex creating a water

Section 4: What you need to know

Cambridge IGCSE Biology

cells, xylem, mesophyll cells) potential gradient in

the xylem, pulling
cohesive water
molecules up the
plant.
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• Define transpiration as • Discuss the

evaporation of water at the adaptations of leaves,
surfaces of the mesophyll stems and roots to
cells followed by loss of water three contrasting
vapour from plant leaves, environments
through stomata (including a pond,
• Describe how water vapour garden and desert)
loss is related to cell surfaces, • Describe translocation
air spaces and stomata of applied chemicals
• Describe how temperature, (including systemic
humidity and light intensity pesticides)
affect the transpiration rate • Compare the role
• Describe how wilting occurs of transpiration and
• Define translocation in terms translocation in the
of the movement of sucrose transport of materials
and amino acids in phloem; from sources to sinks,
from regions of production at different seasons
to regions of storage OR
to regions of utilisation in
respiration or growth

7.2 Transport in • Describe the circulatory

humans system as a system of tubes
with a pump and valves to
ensure oneway flow of blood
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• Describe the double

circulation in terms of
○ a low pressure circulation
to the lungs
○ a high pressure circulation
to the body tissues
(also relate the differences to the
different functions of the two
pathways)
• Describe the structure of the
heart including:
○ muscular wall
○ septum
○ chambers
○ valves
○ associated blood vessels
• Describe the function of the
heart in terms of:
○ muscular contraction
○ how the valves work
• Explain how physical activity
affects pulse rate
• Describe coronary heart
disease as the blockage of

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Cambridge IGCSE Biology

coronary arteries
• State the possible causes
(diet, stress and smoking)
and preventative measures of
heart disease
• Name the main blood vessels
to and from the heart, lungs,
liver and kidney
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• Describe the structure and • Explain how structure

functions of: and function are
○ arteries related in:
○ veins ○ arteries
○ capillaries ○ veins
• Recognise red and white ○ capillaries
blood cells • Describe the transfer
• List the components of blood of materials between
as: capillaries and tissue
○ red blood cells, fluid
○ white blood cells • Describe the immune
○ platelets system in terms of:
○ plasma ○ antibody
• State the functions of blood: production
○ red blood cells ○ tissue rejection
(haemoglobin and oxygen phagocytosis
transport) • Describe the function
○ white blood cells of the lymphatic
(phagocytosis and system including:
antibody formation) ○ circulation of body
○ platelets (clotting (no fluids, production
details)) of lymphocytes
○ plasma (transport of • Describe the process
blood cells, ions, soluble of clotting (fibrinogen
nutrients, hormones, to fibrin only)
carbon dioxide, urea and
plasma proteins)
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8. Respiration • Define respiration as the • State the balanced

chemical reactions that break equation for anaerobic
down nutrient molecules in respiration in:
○ muscles (C 6 H12O 6
→ 2C 3 H 6 O 3)
living cells to release energy

○ yeast (C 6 H12O 6 →
• State the uses of energy in
the body of humans:
○ muscle contraction 2C2H 5OH + 2CO2)
○ protein synthesis • Describe the effect of
○ cell division lactic acid in muscles
○ active transport during exercise
○ growth (include oxygen debt
○ passage of nerve impulses in outline only)
○ maintenance of a constant
body temperature
• Define anaerobic respiration
as the release of a relatively
small amount of energy
by the breakdown of food
substances in the absence of
oxygen
• State the word equation for
anaerobic respiration
○ in muscles during hard
exercise (glucose →lactic

Section 4: What you need to know

Cambridge IGCSE Biology

○ in yeast (glucose →
acid)

alcohol + carbon dioxide)

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• Describe the role of anaerobic • Describe the role of:

respiration in yeast during ○ ribs
brewing and bread-making ○ internal intercostal
• Compare aerobic respiration muscles
and anaerobic respiration in ○ external intercostal
terms of how much energy is muscles
released ○ diaphragm
• List the features of gas in producing volume and
exchange surfaces in animals pressure changes during
• Know the labels for: ventilation of the lungs
○ larynx • Explain the role of
○ trachea mucus and cilia in
○ bronchi protecting the gas
○ bronchioles exchange system
○ alveoli from pathogens and
○ capillaries particles
• State the differences in • Explain the link
composition between inspired between physical
and expired air activity and rate and
• Know the lime water test for depth of breathing in
carbon dioxide terms of:
• Describe the effects of ○ changes in the rate
physical activity on rate and at which tissues
depth of breathing respire
○ carbon dioxide
concentration and
pH in tissues and
in the blood
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9. Excretion in • Define excretion as the • Describe the structure

humans removal from organisms of: of a kidney (cortex,
○ toxic materials medulla, and the start
○ waste products of of the ureter) outline
metabolism (chemical the structure and
reactions in cells including functioning of a kidney
respiration) tubule including:
○ substances in excess of ○ role of renal
requirements (including capsule in filtration
carbon dioxide, urea and from blood of
salts) water, glucose,
• Describe the function of the urea and salts
kidney in terms of: ○ role of tubule in
○ removal of urea and reabsorption of
excess water glucose, most
○ reabsorption of glucose of the water
and some salts and some salts
(details of kidney structure and back into the
nephron are not required) blood, leading to
• Know the position in the body concentration of
of urea in the urine
○ ureters as well as loss of
○ bladder excess water and
○ urethra salts

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Cambridge IGCSE Biology

• Know that urea is formed in • Explain dialysis in

the liver from excess amino terms of maintenance
acids of glucose and protein
• Know that alcohol, drugs and concentration in blood
hormones are broken down in and diffusion of urea
the liver from blood to dialysis
fluid
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• Discuss the application

of dialysis in kidney
machines
• Compare the
advantages and
disadvantages of
kidney transplants
with dialysis

10. • Describe the human nervous • Distinguish between

Coordination system in terms of: voluntary and
and response ○ the central nervous involuntary Actions
system (brain and
spinal cord as areas of
coordination)
○ the peripheral nervous
system which together
serve to coordinate and
regulate body functions
• Recognise:
○ motor (effector) neurones
○ relay (connector) neurones
○ sensory neurones
• Describe a simple reflex arc
in terms of sensory, relay and
motor neurones
• Describe a reflex action as
a means of automatically
and rapidly integrating and
coordinating stimuli with
responses
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• Know that muscles and glands • Know the difference

can act as effectors in function and
• Describe the action of distribution of rods
antagonistic muscles and cones
(including the biceps and • Discuss the use of
triceps at the elbow joint) hormones in food
• Define sense organs as production
groups of receptor cells
responding to specific
stimuli: light, sound, touch,
temperature and chemicals
• Describe the structure and
function of the eye (including
accommodation and pupil
reflex)
• Define a hormone as a
chemical substance, produced
by a gland, carried by the
blood, which alters the activity
of one or more specific target
organs and is then destroyed
by the liver
• Know the role of the hormone
adrenaline in chemical control

Section 4: What you need to know

Cambridge IGCSE Biology

of metabolic activity, including

increasing the blood glucose
concentration and pulse rate
• Know examples of situations
in which adrenaline secretion
increases
• Compare nervous and
hormonal control systems
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• Define geotropism as a • Explain the chemical

response in which a plant control of plant growth
grows towards or away from (in terms of regulating
gravity differential growth) by
• Define phototropism as a auxins including:
response in which a plant ○ geotropism
grows towards or away from ○ phototropism
the direction from which light • Know how synthetic
is coming plant hormones are
• Define homeostasis as the used as weedkillers
maintenance of a constant
internal environment
• Know the following labels of
the skin:
○ hairs
○ sweat glands
○ temperature receptors
○ blood vessels
○ fatty tissue
• Describe the maintenance of a
constant body temperature in
humans in terms of:
○ insulation
○ the role of temperature
receptors in the
○ skin
○ sweating
○ shivering
○ vasodilation and
vasoconstriction of
arterioles supplying skin
surface capillaries
○ coordinating role of the
brain
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• Define a drug as any • Explain the concept

substance taken into the of control by negative
body that modifies or affects feedback
chemical reactions in the body • Describe the control of
• Describe the medicinal use of glucose content of the
antibiotics for the treatment of blood:
bacterial infection ○ by the liver
• Describe the effects of the ○ by insulin and
abuse of heroin: a powerful glucagon from the
depressant including: pancreas
○ problems of addiction Explain why antibiotics kill
○ severe withdrawal bacteria but not viruses
symptoms associated
problems such as crime
○ infection e.g. HIV/AIDS
• Describe the effects of
excessive consumption of
alcohol:
○ reduced self-control
depressant
○ effect on reaction times
damage to liver
○ social implications
• Describe the effects of

Section 4: What you need to know

Cambridge IGCSE Biology

tobacco smoke and its

major toxic components (tar,
nicotine, carbon monoxide,
smoke particles) on the gas
exchange system
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Section III

1. Reproduction

1.1 Asexual • understand that asexual • consider the

reproduction reproduction is the production advantages and
of new individuals of the same disadvantages to a
type/species by one parent species of asexual
describe asexual reproduction reproduction
in
○ bacteria
○ spore production in fungi
○ tuber formation in
potatoes

1.2 Sexual • understand that sexual • consider the

reproduction reproduction is the production advantages and
of new individuals of the same disadvantages to a
type/species by the fusing species of sexual
together of gametes from two reproduction
parents

1.2.1 Sexual describe the structure and • Know the differences

reproduction in functions of the flower of a between and consider
plants named dicotyledonous plant the implications to a
• understand that pollination is species of
the transfer of pollen from an ○ self-pollination
anther to a stigma ○ cross-pollination
• name agents of pollination
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• compare the different

structural adaptations of
○ insect-pollinated flowers
○ wind-pollinated flowers
describe the
○ growth of the pollen tube
○ process of fertilisation
○ formation of seed and fruit
○ structure of a non-
endospermic seed
• understand that dispersal of
seeds and fruits is the carriage
of these away from the parent
plant describe seed and fruit
dispersal by
○ wind
○ animals

1.2.2 Sexual • describe the structure and • compare the size,

reproduction in functions of the reproductive numbers and mobility
humans system of the human of sperm and eggs
○ male • Explain the functions
○ female of the menstrual
• describe the female menstrual hormones

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Cambridge IGCSE Biology

cycle
• describe
○ sexual intercourse
○ fertilisation
○ implantation
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• describe the development of • outline the functions

the fetus in terms of of the
○ placenta ○ amniotic sac
○ maternal and fetal blood ○ amniotic fluid
supplies • describe the
• exchange of materials advantages of breast-
describe ante-natal care in feeding compared
terms of with bottle-feeding
○ dietary needs of the
mother
○ maintaining good health
• describe birth

1.3 Sex • describe the roles, in the • describe the sites of

hormones development and regulation production and the
of secondary sexual roles of oestrogen and
characteristics at puberty, of progesterone in
○ testosterone ○ the menstrual
○ oestrogen cycle
○ pregnancy

1.4 Methods of • name and describe the • consider social

birth control following methods of birth aspects of
control ○ artificial
○ natural insemination
○ chemical ○ the use of
○ mechanical hormones in
○ surgical fertility drugs
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1.5 Sexually • describe the signs, symptoms, • outline how HIV

transmissible effects and treatment of affects the immune
diseases gonorrhoea system
• describe for human
immunodeficiency virus (HIV)
• the methods of transmission
• the ways in which it can be
prevented from spreading

2. Growth and • understand that growth can

development be measured by the increase
in dry mass of an organism
• understand that development
can be thought of as the
increase in complexity of an
organism
• describe the environmental
conditions that affect
germination

3. • understand that inheritance

Inheritance is the transfer of genetic
information from one
generation to the next,

Section 4: What you need to know

Cambridge IGCSE Biology

and that this leads to both

continuity and variation
within a species
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3.1 • understand the following

Chromosomes terms
○ a chromosome is a
thread like structure in
the nucleus of a cell that
carries genes
○ a gene is a unit of
inherited information on a
chromosome that controls
an inherited feature e.g.
eye colour
○ alleles are forms of a
gene that control different
versions of a feature e.g.
blue eye colour or brown
eye colour
○ a haploid nucleus is
one that has one copy
of each of the different
chromosomes that exist
for a species
○ a diploid nucleus is one
that has a pair of copies
of each of the different
chromosomes that exist
for a species
• describe the inheritance of
sex in humans (XX and XY sex
chromosomes)
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3.2 Mitosis • describe mitosis simply (no

details of stages needed) in
terms of:
○ exact duplication of
chromosomes
○ producing identical diploid
daughter nuclei

3.3 Meiosis • describe the production of

gametes by meiosis simply
(no details of stages needed)
in terms of:
○ halving of chromosome
number
○ producing variation in the
haploid daughter nuclei

3.4 Monohybrid • understand the terms gene explain

inheritance and allele and additionally the • codominance
following terms • the inheritance of A,
• genotype is the alleles an B, AB and O blood
individual has groups (IA, IB and IO)
• phenotype is the observable
feature of an individual describe

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Cambridge IGCSE Biology

• homozygous is having two • sickle cell anaemia

identical alleles for a feature • its occurrence linked
• heterozygous is having two to that of malaria
different alleles for a feature
• a dominant allele is one which
when present always affects
the phenotype
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• a recessive allele is one which

only affects the phenotype
if it is the only type of allele
present
• calculate and predict the
results of monohybrid crosses
involving:
○ 1 : 1 ratios
○ 3 : ratios

3.5 Variation • describe continuous and • describe variation

discontinuous variation, • understand that
illustrated by height and A, B, competition leads to
AB and O blood groups, as differential survival
affected by of, and reproduction
○ the environment by, those organisms
○ genes best fitted to the
• understand that mutation environment
is a change in the genes or
chromosomes of an individual
• describe mutation as a source
of variation, e.g. Down’s
syndrome outline the effects,
on the rate of mutation, of
○ radiation
○ chemicals

3.6 Selection • describe the role of artificial

selection in producing
varieties of animals and plants
with increased economic
importance
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• understand that natural • consider the

selection involves the transfer importance of natural
of genes by the best adapted selection as a possible
organisms to their offspring mechanism for
evolution

3.7 Genetic • understand that genetic • describe the

engineering engineering is the transfer of development of
a gene from one species into strains of antibiotic
another species resistant bacteria, as
an example of natural
selection
• explain why human
insulin genes were put
into bacteria
• outline how this is
achieved using genetic
engineering

Section IV

1. Energy flow • state that the Sun is the

principal source of energy

Section 4: What you need to know

Cambridge IGCSE Biology

input to biological systems.

• describe the non-cyclical
nature of energy flow
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2. Food chains • understand the following • understand that there

and food webs terms is
○ a food chain shows links ○ increased
between a series of efficiency in
organisms feeding on one supplying green
another plants as human
○ a food web shows a group food
of interlinked food chains ○ relative
○ producers are green plants inefficiency, in
that produce their own terms of energy
food by photosynthesis loss, in feeding
○ consumers are organisms crop plants to
that depend on the food animals
produced by plants
○ herbivores (primary
consumers) obtain their
energy by feeding directly
on producers
 Topic Core material Supplement material

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○ carnivores (secondary
consumers) obtain their
energy by feeding on
herbivores or (tertiary
consumers) on other
carnivores
○ decomposers are
microorganisms that feed
on the dead remains of
animals and plants
• an ecosystem is an area and
the organisms that live in that
area
• trophic level is the position an
organism occupies in a food
chain. Trophic level 1 is always
the producers
• describe
○ energy loss between
trophic levels
○ the advantages of short
food chains
• describe and interpret
pyramids of

Section 4: What you need to know

Cambridge IGCSE Biology

○ biomass
○ energy
○ numbers
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Section 4: What you need to know

Cambridge IGCSE Biology

Topic Core material Supplement material

You should be able to: Checklist Comments You should be able to: Checklist Comments

3. Nutrient • describe the • describe the

cycles ○ carbon cycle nitrogen cycle in
○ water cycle terms of the roles
of microorganisms
(names of individual
bacteria are not
needed) and other
processes
• producing usable
nitrogen containing
substances by
decomposition and
by nitrogen fixation in
roots
• absorption of these
substances by plants
and their conversion
into protein
• the passage of protein
through food chains
• death and decay
• nitrification
• denitrification
• return of nitrogen to
the soil or atmosphere
• consider the effects,
on the balance
between oxygen and
carbon dioxide, of

○ burning fossil fuels

○ cutting down of
forests
 Topic Core material Supplement material

You should be able to: Checklist Comments You should be able to: Checklist Comments

4. Population • understand that a population • Explain the factors that

size is a groups of one species, lead, in the sigmoid
living in the same area at the curve of population
same time growth, to the
• state the factors affecting ○ lag phase
the rate of population growth ○ exponential (log)
(food supply, predation, phase
disease) ○ stationary phase
• describe their importance
• identify the phases of a
sigmoid curve of population
growth resulting from the
action of a limiting factor
• describe the
○ increase in population size
in the absence of limiting
factors (human population)
○ social implications of
current human survival
rate
○ interpret graphs and
diagrams of human
population growth
○ with emphasis on

Section 4: What you need to know

Cambridge IGCSE Biology

examples of international
importance (e.g. tropical
rain forests, oceans and
rivers)
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Section 4: What you need to know

Cambridge IGCSE Biology

Topic Core material Supplement material

You should be able to: Checklist Comments You should be able to: Checklist Comments

5. Human
influences on
the ecosystem

5.1 Agriculture • consider, using suitable

examples, ways in which the
use of modern technology
has resulted in increased food
production
• describe the undesirable
effects of deforestation
• describe the overuse of
fertilisers on the land

5.2 Pollution • describe the undesirable • consider the

effects of ○ significance of
○ water pollution by sewage non-biodegradable
and chemical waste plastics and other
○ air pollution by sulphur materials used in
dioxide the manufacturing
○ pollution by pesticides and industry
herbicides ○ causes and
○ pollution by nuclear fallout apparent effects of
acid rain
○ measures that
might be taken
to reduce the
incidence of acid
rain
 Topic Core material Supplement material

You should be able to: Checklist Comments You should be able to: Checklist Comments

5.3 Conservation • describe the need for describe the principle

conservation of of recycling materials
○ species including sewage (water)
○ their habitats and paper
○ natural resources

Section 4: What you need to know

Cambridge IGCSE Biology
67
Section 5: Appendices

Section 5: Appendices

5.1 The mathematical skills you need

This is a checklist of the mathematical skills you need for your Biology examination. You should tick each box in
the checklist when you know that you have learned the skill. Ask your teacher to explain any skill you are unsure
about. The ‘Comments’ column is for extra notes and examples.

You can use a calculator for all the examination Papers. If your calculator is one that can be programmed, you
should make sure that any information in it is removed before the examination.

You should be able: Checklist Comments

• add
• subtract
• multiply
• divide

Use:
• averages
• decimals
• fractions
• percentages
• ratios
• reciprocals

• recognise standard notation (notation is

putting symbols for numbers e.g. x = 2,
y = 5, atomic mass, Z = 12)
• use standard notation

• use direct proportion (stepwise increases) the inverse of 4 is ¼ (= 0.25)

• use inverse proportion (inverse means
turned up side down)

1 × 102 = 100
• use numbers to the ‘power of 10’ e.g. Your calculator will often show
number to the power of 10
when you do calculations. Do
not worry too much though –
your calculator does the work
for you.

• draw charts You will be given the data

68 Cambridge IGCSE Biology

 Section 5: Appendices

You should be able: Checklist Comments

• graphs with line of best fit

interpret:
• bar graphs
• pie charts
• line graphs

• select suitable scales and axes for graphs

• make approximations

• area = length × width

use the formulas: e.g. 100cm = 1 m
1000g = 1 kg
• volume = length × width × height
• use and convert metric units into one
another

• use mathematical and measuring

instruments e.g. ruler, compasses,
protractor

understand the meaning of:

• radius
• diameter
• square
• rectangle

5.2 Other important information you need for your Biology

Examination
The terms used in Biology examination Papers are given in the sections that follow. It is very important that
you know and understand all of them before you take your examination. You should ask your teacher to
explain anything that you are unsure about.

5.2.1 Numbers
The decimal point will be placed on the line, e.g. 52.35.

Numbers from 1000 to 9999 will be printed without commas or spaces.

Numbers greater than or equal to 10 000 will be printed without commas. A space will be left between each
group of three whole numbers, e.g. 4 256 789.

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Section 5: Appendices

5.2.2 Units
The International System of units will be used (SI units). Units will be indicated in the singular not in the
plural, e.g. 28 kg.

(a) SI units commonly used in Biology are listed below.

N.B. Care should be taken in the use of mass and weight. In most biological contexts, the term mass is
correct, e.g. dry mass, biomass.

Quantity Name of unit Symbol for unit

length kilometre metre centimetre km m cm mm µm

millimetre micrometer

mass tonne (1000 kg) kilogram gram (no symbol) kg g mg µg

milligram microgram

time year day hour minute second y d h min s

amount of substance mole mol

(b) Derived SI units are listed below.

energy kilojoule joule (calorie is obsolete) kJ J

(c) Recommended units for area, volume and density are listed below.

area hectare 10 4 m2 ha
square metre m2
square decimetre dm2
square centimetre cm2
square millimetre mm2
volume cubic kilometre km3
cubic metre m3
cubic decimetre (preferred to dm3 litre) litre dm3 (not l)
cubic centimetre cm3 (not ml) cubic millimetre mm3
density kilogram per cubic metre or kg m –3
gram per cubic centimetre or g cm –3

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 Section 5: Appendices

(d) Use of Solidus

The solidus (/) must not be used for a quotient, e.g. m / s for metres per second.

5.2.3 Presentation of data

The solidus (/) is to be used for separating the quantity and the unit in tables, graphs and charts, e.g. time/s
for time in seconds.

(a) Tables
(i) Each column of a table will be headed with the physical quantity and the appropriate unit,
e.g. time / s.
There are three acceptable methods of stating units:
○ metres per sec
○ m per s
○ m s –1
(ii) The column headings of the table can be directly rewritten on to the axes of a constructed graph.

(b) Graphs
(i) The independent variable should be plotted on the x-axis (horizontal axis) and the dependent
variable plotted on the y-axis (vertical axis).
(ii) Each axis will be labelled with the physical quantity and the appropriate unit, e.g. time/s.
(iii) The graph is the whole diagrammatic presentation. It may have one or several curves plotted on it.
(iv) Curves and lines joining points on the graph should be referred to as ‘curves’.
(v) Points on the curve should be clearly marked as crosses (x) or encircled dots ( ). If a further
curve is included, vertical crosses (+) may be used to mark the points.

(c) Pie Charts

Use pie charts with the sectors in rank order, largest first, beginning at 12:00 and proceeding
clockwise, with no more than six sectors.

(d) Bar Charts

Use bar charts when one of the variables are categories, e.g. percentage of vitamin C in different fruits.
They should be made up of narrow bars of equal width with a gap (not touching) between each bar.

(e) Histograms
Use histograms to plot frequency graphs with continuous data, e.g., frequency of occurrence
of leaves of different lengths. The blocks should be drawn in order of increasing or decreasing
magnitude and they should be touching.

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Section 5: Appendices

5.2.4 Taxonomy
Taxonomy is the study of how organisms are arranged into groups. There are seven levels of taxon –
kingdom, phylum, class, order, family, genus and species. These are the rule you need to know:
(a) The Five Kingdoms are:
○ Prokaryotes (Prokaryotae), including bacteria and blue-green bacteria
○ Protoctists (Protoctista), including green, red and brown algae and protozoans
○ Fungi (Fungi)
○ Plants (Plantae)
○ Animals (Animalia)

The viruses cannot be fitted into this classificatory system.

(b) The binomial system of naming gives each organism a two-word name. The first word is the generic
name and the second word is the trivial name, e.g. Homo sapiens. The trivial name should never be
used without the generic name as well.
(c) Generic and trivial names are distinguished from the rest of the text either by underlining (when written
or typed) or by being set in italics (in print).
(d) The generic name always takes an initial capital letter. The trivial name can be left off if it is clear which
organsism it is. e.g. Plasmodium, and in these circumstances can stand alone.
(e) The common name should not normally be written with an initial capital letter, e.g. cat and dog. The
exception is Man, where it is the common name for a species where the two sexes are distinguished by
the terms man and woman.
(f) A species is not easy to define but an acceptable general definition is as follows.

‘A group of organisms capable of interbreeding and producing fertile offspring.’

5.2.5 Genetics
(a) The terms gene and allele do not mean the same thing.
A gene is a specific length of DNA occupying a position called a locus. A specific function can be
assigned to each gene. An allele is one of two or more different forms of a gene.

(b) Use this standard form of presenting genetic crosses:

○ Use P for the cross of pure-breeding (homozygous) individuals
○ Use F1 for the offspring of homozygous parents
○ Use F2 for the offspring produced by crossing F1 parents.

(c) The format for the course of a genetic cross should be labelled in the following order:
○ Parental phenotypes
○ Parental genotypes
○ Gametes
○ Offspring genotypes
○ offspring phenotypes

(d) Chose a letter for the gene so that upper and lower case versions are ease to see the difference
e.g. B and b. The upper case letter indicates the dominant allele and the lower case letter indicates
the recessive allele.

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 Section 5: Appendices

(e) The symbols for gametes should be circled to indicate the discrete nature of each gamete.
(f) Use a checkerboard to show genotypes that can result from random fusion of gametes.
(g) Use the word ‘codominance’ if the alleles are equally dominant, e.g. the AB blood group in humans.

5.2.6 Terminology
Use English terms rather than Latin or Greek terms, e.g. red blood cell (not erythrocyte) unless there is
none e.g. atrium, brinchi, villi.

Cambridge IGCSE Biology 73

Section 6: Cambridge IGCSE Biology useful websites

Section 6: Cambridge IGCSE Biology useful websites

These websites are useful resources to help you study for your Biology IGCSE.

IGCSE Bitesize Biology

http://www.bbc.co.uk/schools/gcsebitesize/biology
A secondary revision source for GCSE examinations. The site contains revision material, tests and SOS
teacher. The site also gives references to other relevant websites. There are two versions: 56kb and
broadband.

Click4Biology
http://www.clickbiology.com/igcse-biology-2/
A number of videos, animations and games for revision resources for IGCSE Biology.

Skool Revision site

http://www.skoool.com/
You will need to select your location before accessing this revision site. There are numerous quizzes on
topics, but like with many general revision sites, check which topics match the IGCSE syllabus.

S-cool! GCSE Biology Revision Guide

http://www.s-cool.co.uk
A revision guide that can be used to complement your learning.

Purchon.com
http://purchon.com/biology/revision.htm
This website has information about revising and lots of useful resources about GCSE Biology which are also
are relevant to IGCSE.

Revision Central
http://revisioncentral.co.uk/gcse/biology/index.html
There are lots of Biology revision notes on this website including notes on Classification, Cells, Tissues and
Organs and Transportation in Plants.

Revision Link
http://revisionlink.co.uk/biology/index.html
This site is a portal to lots of useful Biology and other educational web sites.

Revision for human physiology

http://www.abpischools.org.uk/
The Association of the British Pharmaceutical Industry (ABPI) has a numer of useful interactive revision
activities and games on many of the physiology topics.

Apps
http://itunes.apple.com/gb/app/biology-gcse-revision/id367827149?mt=8
These are new resources which are being developed.
• Ipad:
• http://www.educationapps.co.uk/ipad/revisionguide/gcse/biology/
• Andriod:
• http://www.educationapps.co.uk/apps/android/gcse/science/biology-revision
• iphone:
• http://www.educationapps.co.uk/apps/iphone/self-assessment/gcse/biology

74 Cambridge IGCSE Biology

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