Table Of Content
AQA Biology
2nd Edition
A
LEVEL
OXFORD
OXFORD
VNIVBRSITY PRESS
Great Clarendon Street, Oxford, OX2 6DP. United Kingdom
Oxford University Press is a department of the University of Oxford.
It furthers the University's objective of excellence in research,
scholarship, and education by publishing worldwide. Oxford is a
registered trade mark ofOxford University Press in the UK and in
certain other countries
© Glenn and Susan Toole 2015
The moral rights of the authors have been asserted
First published in 2015
All rights reserved. No part of this publication may be reproduced,
stored in a retrieval system, or transmitted, in any form or by any
means, without the prior permission in writing ofOxford University
Press, or as expressly permitted by law, by licence or under tem1s agreed
with the appropriate reprographics rights organization. Enquiries
concerning reproduction outside the scope of the above should be sent
to the Rights Department, Oxford University Press,
at the address above.
You must not circulate this work in any other form and you must
impose this same condition on any acquirer
British Library Cataloguing in Publication Data
Data available
978·0·19·835177·1
10 9 8 7 6 5
Paper used in the production of this book is a natural, recyclable
product made from wood grown in sustainable forests.
The manufacturing process conforms to the environmental regulations
of the country oforigin.
Printed in China by Golden Cup Printing Co Ltd
Message from AQA
This textbook has been approved by AOA for use with our qualification. This
means that we have checked that it broadly covers the specification and we
are satisfied with the overall quality. Full details of our approval process can be
found on our website.
We approve textbooks because we know how important it is for teachers and
students to have the right resources to support their teaching and learning.
However, the publisher is ultimately responsible for the editorial control and
quality of this book.
Please note that when teaching the AOA AS orA-Level Biology course, you must
refer to AOA's specification as your definitive source ofinformation. While this
book has been written to match the specification, it cannot provide complete
coverage of every aspect of the course.
A wide range of other useful resources can be found on the relevant subject
pages of our website: www.aqa.org.uk.
This book has been writcen co support students studying for AQA
A Level Biology. The sections covered are shown in the contents list,
which also shows you the page numbers for the main topics within
each section. There is also an index at the back to help you find what
you are looking for. If you are studying for AS Biology, you will only
need to know the content in the blue box for the AS exams.
E r
ca Year 1 content Yea r 2 content
><
Cl) 1 Biological molecules 5 Energy transfers in and
(/) 2 Cells between organisms
~
3 Organisms exchange 6 Organisms respond to changes
substances with their in their internal and external
environment environment E
4 Genetic information, variation, 7 Genetics, populations, evolution, ca
><
and relationships between and ecosystems
Cl)
organisms 8 The control of gene expression
Cl)
>
""' -Cl)
-' ~
ALevel exams will cover content from Year 1 and Year 2 and will be at a
higher demand. You will also carry out practical activities throughout
your course. There are twelve required practicals: six from the AS and
six A-Level.
How to use this book viii
Kerboodle xi
Section 1 4 Transport across cell membranes 84
Biological molecules 2
4.1 Structure of the cell surface membrane 84
4.2 Diffusion 87
1 Biological molecules 4
4.3 Osmosis 89
1.1 Introduction to biological molecules 4
4.4 Active transport 93
1.2 Carbohydrates and monosacharides 8
4.5 Co·transport and absorption of glucose
1.3 Carbohydrates - disaccharides and
in the ileum 95
polysaccharides 10
Practice questions 99
1.4 Starch, glycogen and cellulose 13
1.5 Lipids 16 5 Cell recognition and the immune system 102
1.6 Proteins 19 5.1 Defence mechanisms 102
1.7 Enzyme action 23 5.2 Phagocytosis 104
1.8 Factors affecting enzyme action 26 5.3 T Lymphocytes and cell mediated
1.9 Enzyme inhibition 32 immunity 106
Practice questions 34 5.4 B lymphocytes and humoral immunity 109
5.5 Antibodies 111
2 Nucleic acids 36
5.6 Vaccination 115
2.1 Structure of RNA and DNA 36
5.7 Human immunodeficiency virus (HIV) 119
2.2 DNA replication 42
Practice questions 122
2.3 Energy and ATP 46
Section 2 summary 124
2.4 Water and its functions
so
Section 2 practice questions 126
Practice questions
Section 1 summary 52
Section 3
Section 1 practice questions 54
Organisms exchange substances with
their environment 128
Section 2
Cells 56 6 Exchange 130
6.1 Exchange between organisms and
3 Cell structure 58
their environment 130
3.1 Methods of studying cells 58
6.2 Gas exchange in single-celled
3.2 The electron microscope 61
organisms and insects 133
3.3 Microscopic measurements and
6.3 Gas exchange in fish 135
calculations 64
6.4 Gas exchange in the leaf of a plant 137
3.4 Eukaryotic cell structure 67
6.5 Limiting water loss 139
3.5 Cell specialisation and organisation 73
6.6 Structure of the human
3.6 Prokaryotic cells and viruses 75
gas-exchange system 142
3.7 Mitosis 77
6.7 The mechanism of breathing 144
3.8 The cell cycle 80
6.8 Exchange of gases in the lungs 146
Practice questions 82
6.9 Enzymes and digestion 151
6.10 Absorption ofthe products of digestion 155
Practice questions 158
•
7 Mass transport 161 Section 4 summary 260
7.1 Haemoglobin 161 Section 4 practice questions 262
7.2 Transport of oxygen by haemoglobin 163
7.3 Circulatory system of a mammal 168 Section 5
7.4 The structure of the heart 170 Energy transfer in and
7.5 The cardiac cycle 174 between organisms 266
7.6 Blood vessels and their functions 178
11 Photosynthesis 268
7.7 Transport of water in the xylem 183
11.1 Overview of photosynthesis 268
7.8 Transport of organic molecules in
11.2 The light-dependent reaction 271
the phloem 188
11.3 The light-independent reaction 275
7.9 Investigating transport in plants 191
Practice questions 281
Practice questions 194
Section 3 summary 196 12 Respiration 283
Section 3 practice questions 198 12.1 Glycolysis 283
12.2 Link reaction and Krebs cycle 286
Section 4 12 3 Oxidative phosphorylation 289
12.4 Anaerobic respiration 293
Genetic information, variation and
Practice questions 296
relationships between organisms 200
8 DNA, genes and protein synthesis 202 13 Energy and ecosystems 298
8.1 Genes and the triplet code 202 13.1 Food chains and energy transfer 298
8.2 ONA and chromosomes 205 13.2 Energy transfer and productivity 300
8.3 The structure of ribonucleic acid 208 13.3 Nutrient cycles 306
8.4 Protein synthesis - transcription 13.4 Use of natural and artificial fertilisers 311
and splicing 211 13.5 Environmental issues concerning
8.5 Protein synthesis - translation 213 use of nitrogen-containing fertilisers 313
Practice questions 217 Practice questions 315
9 Genetic diversity 220 Section 5 summary 318
9.1 Mutations 220 Section 5 practice questions 320
9.2 Meiosis and genetic variation 224
Section 6
9.3 Genetic diversity and adaptation 229
9.4 Types ofselection 231 Organisms respond to changes
Practice questions 235 in their environments 324
10 Biodiversity 237 14 Response to stimuli 326
10.1 Species and taxonomy 237 14.1 Survival and response 326
10.2 Diversity within a community 243 14.2 Plant growth factors 328
10.3 Species diversity and human activity 246 14.3 A reflex arc 334
10.4 Investigating diversity 249 14.4 Receptors 337
10.5 Quantitative investigations ofvariation 253 14.5 Control of heart rate 340
Practice questions 257 Practice questions 344
•
15 Nervous coordination and muscles 346 18 Populations and evolution 448
15.1 Neurones and nervous coordination 346 18.1 Population genetics 448
15.2 The nerve impulse 350 18.2 Variation in phenotype 451
15.3 Passage of an action potential 354 18.3 Natural selection 453
15.4 Speed of the nerve impulse 357 18.4 Effects of different forms of
15.5 Structure and function of synapses 360 selection on evolution 456
15.6 Transmission across a synapse 364 18.5 Isolation and speciation 460
15.7 Structure of skeletal muscle 367 Practice questions 464
15.8 Contraction of skeletal muscle 371
19 Populations in ecosystems 466
Practice questions 376
19.1 Populations in ecosystems 466
16 Homeostasis 378 19.2 Variation in population size 468
16.1 Principles of homeostasis 378 19.3 Competition 474
16.2 Feedback mechanisms 383 19.4 Predation 478
16.3 Hormones and the regulation of 19.5 Investigating populations 481
blood glucose concentration 386 19.6 Succession 484
16.4 Diabetes and its control 391 19.7 Conservation of habitats 488
16.5 Control of blood water potential - Practice questions 490
structure of the nephron 394
Section 7 summary 492
16.6 Role of the nephron in osmoregulation 399
Section 7 practice questions 494
16.7 The role of hormones in osmoregulation 404
Practice questions 407
Section 8
Section 6 summary 410
The control of gene expression 498
Section 6 practice questions 412
20 Genet' p ·e on 500
Section 7 20.1 Gene mutations 500
20.2 Stem cells and totipotency 504
Genetics, populations, evolution,
20.3 Regu lation of transcription
and ecosystems 416
and translation 510
17 Inherited change 418
20.4 Epigenetic control of gene expression 513
17.1 Studying inheritance 418
20.5 Gene expression and cancer 519
17.2 Monohybrid inheritance 421
20.6 Genome projects 525
17.3 Probability and genetic crosses 424
Practice questions 528
17.4 Dihybrid inheritance 426
21 Recomb'nan ONA t chnol y 530
17.5 Codominance and multiple alleles 429
17.6 Sex-linkage 433 21.1 Producing DNA fragments 530
17.7 Autosomal linkage 437 21.2 In vivo gene cloning - the use
of vectors 535
17.8 Epistasis 440
17.9 The chi-squared (x2) test 443 21.3 In vitro gene cloning - the
polymerase chain reaction 5"40
Practice questions 446
•
21.4 Locating genes, genetic screening,
and counselling 545
21.5 Genetic fingerprinting 550
Practice questions 556
Section 558
Section 8 practice questions 560
Section 9
Skills in A level Biology 564
Chapter 22 Mathematical skills
(including statistics) 564
Chapter 23 Practical skills 581
AS additional practice questions 589
A level additional practice questions 597
Synoptic questions 603
Answers 607
Practical skills answers 651
Glossary 655
Index 665
Acknowledgements and Imprint 675
•
Learning objectives This book contains many different features. Each feature is designed to
foster and stimulate your interest in Biology, as well as supponing and
' At the beginning of each
developing the skills you will need for your examinations.
topic, there is a list of
learning objectives. Terms that you will need to be able to define and understand are
' These are matched to the shown in bold type within the text.
specification and allow you
Where terms are not explained within the same topic, they are
to monitor your progress.
highlighted in bold orange text. You can look these words up in
' A specification reference is
the glossary.
also included.
Specification reference: 3.1.1
Synoptic link These features contain important and interesting applications of
biology in order to emphasise how scientists and engineers
These highlight how the sections
have used their scientific knowledge and understanding to develop
relate to each other. Linking new applications and technologies. Theree are. a lso application features to
different areas of biology together
develop your maths skills, with the icon and to develop your practical
O·
becomes increasingly important,
skills, with the icon
and you will need to be able to
do this.
There are also links to the
mathematical skills on the
specification. More detail can be Extension features
found in the maths section.
These features contain material that is beyond the specification
designed to stretch and provide you with a broader knowledge and
understanding and lead the way into the types of thinking and areas
you might study in further education. As such, neither the detail nor
the depth of questioning will be required for the examinations. But
this book is about more than getting through the examinations.
1 Extension and application features have questions that link the
material with concepts that are covered in the specification.
Answers can be found in the answers section at the
back of the book.
Study tips
Study tips contain prompts to
help you with your revision.
Summary questions
1 These are short questions that test your understanding of the
Hint topic and allow you to apply the knowledge and skills you have
aquired. The questions are ramped in order of difficulty.
Hint features give other
fi
information or ways of thinking 2 Questions that will test and develop your mathematical
about a concept to support your and practical skills are labelled with the mathematical symbol
understanding. [fi) and the practical symbol [O J.
•
