Cambridge International AS and A Level Biology

528 Pages·2014·67.46 MB·english

by  C. J. Clegg

Cambridge
International AS and A Level
Biology
C J Clegg
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The cover image is of an orang-utan, mother and infant. The name of these primates means
‘people of the forest’, and they share over 96 per cent of our own genetic make-up. Today,
they live in the forests of Indonesia and Malaysia only. The future of orang-utan populations
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© C J Clegg 2014
First published in 2014 by
Hodder Education, a Hachette UK company
338 Euston Road
London NW1 3BH
Impression number 5 4 3 2 1
Year 2018 2017 2016 2015 2014
All rights reserved. Apart from any use permitted under UK copyright law, no part of this
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Cover photo by Eric Gevaert
Typeset in ITC Garamond by Aptara, Inc.
Printed in Italy
A catalogue record for this title is available from the British Library
ISBN 978 1444 17534 9
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Contents
Introduction ..........................................................................................................................................................................vii
AS Level
1 Cell structure ........................................................................................................................................................................1
1.1 The microscope in cell studies ..........................................................................................................................................1
1.2 Cells as the basic units of living organisms ....................................................................................................................14
2 Biological molecules ...........................................................................................................................................................29
2.1 Testing for biological molecules .................................................................................................................................... 29
2.2 Carbohydrates and lipids ................................................................................................................................................30
2.3 Proteins and water ..........................................................................................................................................................44
3 Enzymes ..............................................................................................................................................................................56
3.1 Mode of action of enzymes .............................................................................................................................................56
3.2 Factors that affect enzyme action ...................................................................................................................................63
4 Cell membranes and transport ...........................................................................................................................................74
4.1 Fluid mosaic membranes ................................................................................................................................................74
4.2 Movement of substances into and out of cells ...............................................................................................................78
5 The mitotic cell cycle ..........................................................................................................................................................97
5.1 Replication and division of nuclei and cells ....................................................................................................................97
5.2 Chromosome behaviour in mitosis ...............................................................................................................................105
6 Nucleic acids and protein synthesis .................................................................................................................................110
6.1 Structure and replication of DNA .................................................................................................................................110
6.2 Protein synthesis ...........................................................................................................................................................118
7 Transport in plants ...........................................................................................................................................................128
7.1 Structure of transport tissues .......................................................................................................................................128
7.2 Transport mechanisms ...................................................................................................................................................135
8 Transport in mammals ......................................................................................................................................................151
8.1 The circulatory system ..................................................................................................................................................151
8.2 The heart .......................................................................................................................................................................163
9 Gas exchange and smoking ..............................................................................................................................................172
9.1 The gas exchange system ..............................................................................................................................................172
9.2 Smoking ........................................................................................................................................................................181
10 Infectious disease ..........................................................................................................................................................192
10.1 Infectious diseases .....................................................................................................................................................192
10.2 Antibiotics ...................................................................................................................................................................210
11 Immunity ........................................................................................................................................................................218
11.1 The immune system ....................................................................................................................................................218
11.2 Antibodies and vaccination ........................................................................................................................................226
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Contents
A Level
12 Energy and respiration...................................................................................................................................................234
12.1 Energy .........................................................................................................................................................................234
12.2 Respiration..................................................................................................................................................................242
13 Photosynthesis ...............................................................................................................................................................261
13.1 Photosynthesis as an energy transfer process ...........................................................................................................261
13.2 Investigation of limiting factors .................................................................................................................................273
13.3 Adaptations for photosynthesis .................................................................................................................................279
14 Homeostasis ...................................................................................................................................................................286
14.1 Homeostasis in mammals ...........................................................................................................................................286
14.2 Homeostasis in plants .................................................................................................................................................307
15 Control and co-ordination .............................................................................................................................................311
15.1 Control and co-ordination in mammals ......................................................................................................................311
15.2 Control and co-ordination in plants ...........................................................................................................................334
16 Inherited change ............................................................................................................................................................342
16.1 Passage of information from parent to offspring ......................................................................................................342
16.2 The roles of genes in determining the phenotype .....................................................................................................350
16.3 Gene control ...............................................................................................................................................................372
17 Selection and evolution .................................................................................................................................................377
17.1 Variation .....................................................................................................................................................................377
17.2 Natural and artifi cial selection ...................................................................................................................................383
17.3 Evolution .....................................................................................................................................................................399
18 Biodiversity, classifi cation and conservation ................................................................................................................416
18.1 Biodiversity .................................................................................................................................................................416
18.2 Classifi cation ..............................................................................................................................................................429
18.3 Conservation ...............................................................................................................................................................439
19 Genetic technology ........................................................................................................................................................454
19.1 Principles of genetic technology ................................................................................................................................454
19.2 Genetic technology applied to medicine ....................................................................................................................467
19.3 Genetically modifi ed organisms in agriculture ..........................................................................................................485
Answers to self-assessment questions ...............................................................................................................................492
Index ...................................................................................................................................................................................510
Acknowledgements ............................................................................................................................................................519
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Contents
Student’s CD contents
Appendix 1: Background chemistry for biologists
Appendix 2: Investigations, data handling and statistics
Appendix 3: Preparing for your exam
Also, for each topic:
• An interactive test
• A list of key terms
• A topic summary
• Additional work on data handling and practical skills
• Suggested websites and further reading
• A revision checklist
• A nswers to all the examination-style questions
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Introduction
Cambridge International AS and A Level Biology is an excellent introduction to the subject
and a sound foundation for studies beyond A Level, in further and higher education, for
professional courses and for productive employment in the future. Successful study of this
programme gives lifelong skills, including:
• confi dence in a technological world and informed interest in scientifi c matters
• understanding of how scientifi c theories and methods have developed
• awareness of the applications of biology in everyday life
• ability to communicate effectively
• concern for accuracy and precision
• awareness of the importance of objectivity, integrity, enquiry, initiative and inventiveness
• understanding of the usefulness and limitations of scientifi c methods and their
applications
• appreciation that biology is affected by social, economic, technological, ethical and
cultural factors
• knowledge that biological science overcomes national boundaries
• awareness of the importance of IT
• understanding of the importance of safe practice
• an interest and care for the local and global environment and their conservation.
This book is designed to serve students as they strive for these goals.
The structure of the book
The Cambridge International Examinations AS and A Level Biology syllabus is presented
in sections. The contents of this book follows the syllabus sequence, with each section the
subject of a separate topic.
Topics 1 to 11 cover Sections 1 to 11 of the AS Level syllabus and are for all students. AS
students are assessed only on these.
Topics 12 to 19 cover Sections 12 to 19, the additional sections of the syllabus for A Level
students only.
In addition, there are the answers to the self-assessment questions.
Cambridge International AS and A Level Biology has many special features.
• Each topic begins with the syllabus learning outcomes which identify essential objectives.
• The text is written in straightforward language, uncluttered by phrases or idioms that
might confuse students for whom English is a second language.
• Photographs, electron micrographs and full-colour illustrations are linked to support the
relevant text, with annotations included to elaborate the context, function or applications.
• Explanations of structure are linked to function. The habitat and environment of
organisms are identifi ed where appropriate. Application of biology to industries and the
economic, environmental and ethical consequences of developments are highlighted,
where appropriate.
• Processes of science (scientifi c methods) and something of the history of developments
are introduced selectively to aid a ppreciation of the possibilities and limitations of
science.
• Questions are included to assist comprehension and recall. Answers to these are given
at the back of the book. At the end of each topic, examination-style questions are given.
Answers to these are given on the CD.
vii
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Introduction
A new feature of the syllabus is Key concepts. These are the essential ideas, theories, principles or
mental tools that help learners to develop a deep understanding of their subject, and make links
between different topics. An icon indicates where each Key concept is covered:
Cells as the units of life
A cell is the basic unit of life and all organisms are composed of one or more cells. There are two
fundamental types of cell: prokaryotic and eukaryotic.
Biochemical processes
Cells are dynamic: biochemistry and molecular biology help to explain how and why cells function
as they do.
DNA, the molecule of heredity
Cells contain the molecule of heredity, DNA. Heredity is based on the inheritance of genes.
Natural selection
Natural selection is the major mechanism to explain the theory of evolution.
Organisms in their environment
All organisms interact with their biotic and abiotic environment.
Observation and experiment
The different fi elds of biology are intertwined and cannot be studied in isolation: observation and
enquiry, experimentation and fi eldwork are fundamental to biology.
Author’s acknowledgements
I am indebted to the experienced international teachers and the students who I have been
privileged to meet in Asia and in the UK in the process of preparing this material. I am especially
indebted to Christine Lea, an experienced teacher and examiner of Biology who has guided me
topic by topic on the special needs of the students for whom this book is designed.
Finally, I am indebted to the publishing team of project editor, Lydia Young, editor Joanna
Silman and designer Melissa Brunelli at Hodder Education, and to freelance editor Penny Nicholson
whose skill and patience have brought together text and illustration as I have wished. I am most
grateful to them.
Dr Chris Clegg
Salisbury, Wiltshire, UK
June, 2014
viii
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AS Level
1
Cell structure
All organisms are composed of cells. Knowledge of their structure The use of light microscopes is a fundamental skill that is developed
and function underpins much of biology. The fundamental in this topic and applied throughout several other sections of the
differences between eukaryotic and prokaryotic cells are explored syllabus. Throughout the course, photomicrographs and electron
and provide useful biological background for the topic on Infectious micrographs from transmission and scanning electron microscopes
disease. Viruses are introduced as non-cellular structures, which should be studied.
gives candidates the opportunity to consider whether cells are a
fundamental property of life.
1.1 The microscope in cell studies
An understanding of the By the end of this section you should be able to:
principles of microscopy
shows why light and a) compare the structure of typical animal and plant cells by making temporary preparations of
electron microscopes have live material and using photomicrographs
been essential in improving b) calculate the linear magnifi cations of drawings, photomicrographs and electron micrographs
our knowledge of cells. c) use an eyepiece graticule and stage micrometer scale to measure cells and be familiar with units
(millimetre, micrometre, nanometre) used in cell studies
d) explain and distinguish between resolution and magnifi cation, with reference to light
microscopy and electron microscopy
e) calculate actual sizes of specimens from drawings, photomicrographs and electron micrographs
Introducing cells
The cell is the basic unit of living matter – the smallest part of an organism which we can say is
alive. It is cells that carry out the essential processes of life. We think of them as self-contained units
of structure and function. Some organisms are made of a single cell and are known as unicellular.
Examples of unicellular organisms are introduced in Figure 1.1. In fact, there are vast numbers of
different unicellular organisms in the living world, many with a very long evolutionary history.
Question Other organisms are made of many cells and are known as multicellular organisms. Examples
of multicellular organisms are the mammals and fl owering plants. Much of the biology in this
1 State the essential
book is about multicellular organisms, including humans, and the processes that go on in these
processes characteristic
organisms. But remember, single-celled organisms carry out all the essential functions of life too,
of living things.
only these occur within the single cell.
1
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