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© Mary Jones 2015

ISBN 978-1-4718-4384-6
eISBN 978-1-4718-4385-3

First printed 2015

Impression number 5 4 3 2 1

Year 2018 2017 2016 2015

All rights reserved; no part of this publication may be reproduced, stored in a retrieval system, or transmitted, in any other form or by any means, electronic, mechanical, photocopying, recording or otherwise without either the prior written permission of Hodder Education or a licence permitting restricted copying in the United Kingdom issued by the Copyright Licensing Agency Ltd, Saffron House, 6–10 Kirby Street, London EC1N 8TS.

This guide has been written specifically to support students preparing for the Edexcel AS and A-level Biology B (Topics 1 and 2) examinations. The content has been neither approved nor endorsed by Edexcel and remains the sole responsibility of the author.

Cover photo: Elena Pankova/Fotolia

Typeset by Greenhill Wood Studios

Printed in Italy

Hachette UK’s policy is to use papers that are natural, renewable and recyclable products and made from wood grown in sustainable forests. The logging and manufacturing processes are expected to conform to the environmental regulations of the country of origin.

Contents

    Getting the most from this book

    About this book

Content Guidance

    Topic 1 Biological molecules

        Carbohydrates

        Lipids

        Proteins

        DNA and protein synthesis

        Enzymes

        Core practical 1a: Investigating the effect of temperature on enzyme activity

        Core practical 1b: Investigating the effect of pH on enzyme activity

        Core practical 1c: Investigating the effect of enzyme concentration on rate of reaction

        Core practical 1d: Investigating the effect of substrate concentration on the rate of an enzyme-catalysed reaction

        Inorganic ions

        Water

    Topic 2 Cells, viruses and reproduction of living things

        Eukaryotic and prokaryotic cells

        Core practical 2: Magnification calculations and Measuring cells using a graticule

        Viruses

        Eukaryotic cell cycle and division

        Core practical 3: Making a root tip squash

        Sexual reproduction in mammals

        Sexual reproduction in plants

        Core practical 4: Investigating the effect of different sucrose concentrations on pollen tube growth

Questions & Answers

    Sample paper 1

    Sample paper 2

    Knowledge check answers

    Index

Getting the most from this book

Exam tips

Advice on key points in the text to help you learn and recall content, avoid pitfalls, and polish your exam technique in order to boost your grade.

Knowledge check

Rapid-fire questions throughout the Content Guidance section to check your understanding.

Knowledge check answers

Turn to the back of the book for the Knowledge check answers.

Summaries

•  Each core topic is rounded off by a bullet-list summary for quick-check reference of what you need to know.

About this book

This book is the first in a series of four covering the Edexcel AS and A-level Biology B specifications. It covers Topics 1 and 2:

•  Biological molecules

•  Cells, viruses and reproduction of living things

This guide has two main sections:

•  The Content Guidance provides a summary of the facts and concepts that you need to know for these two topics.

•  The Questions & Answers section contains two specimen papers for you to try, each worth 80 marks. There are also two sets of answers for each question, one from a candidate who is likely to get a C grade and another from a candidate who is likely to get an A grade.

The specification

It is a good idea to have your own copy of the Edexcel Biology B specification. It is you who is going to take this examination, not your teacher, so it is your responsibility to make sure you know as much about the exam as possible. You can download a copy free from www.edexcel.com.

The AS examination is made up of two papers:

•  Paper 1 Core Cellular Biology and Microbiology (1 hour 30 minutes, 80 marks)

•  Paper 2 Core Physiology and Ecology (1 hour 30 minutes, 80 marks)

The A-level examination is made up of three papers:

•  Paper 1 Advanced Biochemistry, Microbiology and Genetics (1 hour 45 minutes, 90 marks)

•  Paper 2 Advanced Physiology, Evolution and Ecology (1 hour 45 minutes, 90 marks)

•  Paper 3 General and Practical Principles in Biology (2 hours 30 minutes, 120 marks)

This book covers content that will be examined in Paper 1 of the AS examination and Papers 1, 2 and 3 of the A-level examination.

What is assessed?

It is easy to forget that your examination is not just testing what you know about biology — it is also testing your skills. It is difficult to emphasise just how important these are.

The Edexcel examination tests three different assessment objectives (AOs). The following table gives a breakdown of the proportion of marks awarded to each assessment objective in the AS and A-level examinations.

AO1 is about remembering and understanding all the biological facts and concepts you have covered. AO2 is about being able to use these facts and concepts in new situations. The examination paper will include questions that contain unfamiliar contexts or sets of data, which you will need to interpret in the light of the biological knowledge you have. When you are revising, it is important that you try to develop your ability to do this, as well as learning the facts.

AO3 is about practical and experimental biology. A science subject such as biology is not just a body of knowledge. Our knowledge and understanding of biology continues to develop, as scientists find out new information through their research. Sometimes new research means that we have to change our ideas.

You need to develop your skills at doing experiments to test hypotheses, and analysing the results to determine whether the hypothesis is supported or disproved. You need to appreciate why science does not always give us clear answers to the questions we ask. Finally, you will be asked to make judgements and reach conclusions, and need to be able to design and improve experiments and procedures, to produce results we can trust.

Scientific language

Throughout your biology course, and especially in your examination, it is important to use clear and correct biological language. Scientists take great care to use language precisely. If doctors or researchers do not use exactly the correct word when communicating with someone, then what they are saying could be misinterpreted.

Biology has a huge number of specialist terms and it is important that you learn them and use them. Your everyday conversational language, or what you read in the newspaper or hear on the radio, is often not the kind of language required in a biology exam. Be precise and careful in what you write, so that an examiner cannot possibly misunderstand you.

The examination

Time

In all of the examinations, the mark allocation works out at around 1 minute per mark. When you are trying out a test question, time yourself. Are you working too fast? Or are you taking too long? Get used to what it feels like to work at around a mark-a-minute rate.

It is not a bad idea to spend one of those minutes just skimming through the exam paper before you start writing. Maybe one of the questions looks as though it’s going to need a bit more of your time than the others. If so, make sure you leave a little extra time for it.

Read the question carefully

This sounds obvious but students lose large numbers of marks by not doing so.

•  There is often vital information at the start that you will need in order to answer the questions themselves. Don’t just jump straight to the first set of answer lines and start writing. Start reading at the beginning! Examiners are usually careful not to give you unnecessary information, so if it is there it is probably needed. You may like to use a highlighter to pick out any particularly important bits of information in the question.

•  Look carefully at the command words (the ones right at the start of the question) and do what they say. For example, if you are asked to explain something then you won’t get many marks — perhaps none at all — if you describe it instead. You can find all these words in an appendix near the end of the specification document.

Depth and length of answer

The examiners will give you two useful guidelines about how much you need to write.

•  The number of marks. Obviously, the more marks allocated, the more information you need to give. If there are 2 marks, then you will need to give two different pieces of information to get both of them. If there are 5 marks, you will need to write much more.

•  The number of lines. This is not such a useful guideline as the number of marks, but it can still help guide you to how much to write. If you find your answer won’t fit on the lines, then you probably haven’t focused sharply enough on the question. The best answers are short and precise.

Mathematical skills

Like all of the sciences, biology uses mathematics extensively. The specification contains an appendix that lists and describes the mathematical techniques that you will need to be familiar with. You will probably have met most of these before, but make sure that you are confident with all of them. If there are any of which you are uncertain, then do your best to improve your skills in them early on in the course — don’t leave it until the last minute, just before the exam. The more you practise your maths skills, the more relaxed you will be about them in the exam.