Solutions for All Life Sciences Grade 12 Learner's Book

79 Pages·2013·5.21 MB·English

Solutions for all
Life Sciences
Grade 12
Learner’s Book
J de Fontaine J Dugard R Freedman L Marchant
I McKay R Simenson J Webb
Life Sciences Gr12 LB.indb 1 5/27/13 2:04 PM
Solutions for All Life Sciences Grade 12 Learner’s Book
© J de Fontaine, J Dugard, L Marchant, R Freedman, I McKay, R Simenson, J Webb, 2013
© Illustrations and design Macmillan South Africa (Pty) Ltd, 2013
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First published 2013
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Published by
Macmillan South Africa (Pty) Ltd
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Typeset in Palatino LT Std 10.5pt on 12.5pt by Boss Repro & Design Studio
Cover image from Science Photo Library
Cover design by Deevine Design
Illustrations by: Greg Graney; Alan Kennedy; Brainwave India; Gareth Williams
Photographs by:
AAI Fotostock pp. 5 (fig 1.2); 8 (fig 1.7); 24 (fig 2.2, 2.4); 41 (fig 2.28); 43 (fig 2.30); 50 (fig 3.0); 57 (fig
3.13); 59 (fig 3.18); 78 (fig 4.24); 81 (fig 4.27a, b); 84 (fig 4.32); 85 (fig 4.35); 122 (fig 5.27); 166 (fig 6.11);
178 (fig 6.20b, d); 179 (fig 6.20f, h); 225 (fig 7.21b); 276 (fig 10.12); 283 (fig 10.17); 331 (fig 11.28);
Africa Media Online pp. 337 (fig 11.39); Afripics pp. 7 (fig 1.6); 8 (fig 1.8); 9 (fig 1.9); 54 (fig 3.5); 77
(fig 4.21b); 81 (fig 4.27c, d); 159 (fig 6.3b); 164 (fig 6.7); 178 (fig 6.20c); 179 (fig 6.20g); 180 (fig 6.20k);
201 (fig 6.38a); 203 (fig 6.39a, b); 246 (fig 9.0); 257 (fig 9.16); 258 (fig 9.19); 262 (fig 10.0); 289 (fig 10.25);
290 (fig 10.27a,b); 304 (fig 11.4b); 309 (fig 11.8a, b); 334 (fig 11.34); Biophoto Association pp. 30
(fig 2.12); 31 (fig 2.13, 2.14, 3.15); 32 (fig 2.16, 2.18); 33 (fig 2.19, 2.20); Brett Rubin pp. 90 (fig 5.0);
Fuse Gallo Images Getty Images pp. 354 (Fig 12.0); Gallo Images pp. 272 (fig 10.7); 361 (Fig 12.6);
Gallo HPH Image Library pp. 194 (fig 6.32a, b); Greatstock pp. 54 (fig 3.6); 224 (fig 7.20); 304
(fig 11.4c); 324 (fig 11.20a); Greatstock Barcroft Media pp. 313 (fig 11.11); Greatstock Corbis pp. 2
(fig 1.0); 18; 65 (fig 4.4); 66 (fig 4.7); 72 (fig 4.13); 73 (4.16); 85 (fig 4.34); 161 (fig 6.5); 209 (fig 7.1); 222
(fig 7.17); 224 (fig 7.19); 230 (fig 8.0); 242 (fig 8.15, 8.16); 252 (fig 9.9); 331 (fig 11.29); 343 (fig 11.47);
INPRA pp. 57 (fig 3.12); 101 (fig 5.8); 177 (fig 6.20a); 178 (fig 6.20e); 180 (fig 6.20i, j); 208 (fig 7.0); 273
(fig 10.9); 287 (fig 10.23a, b); 327 (fig 11.24a); Jane Dugard pp. 300 (fig 11.0); Maropeng Media Centre
pp. 339 (fig 11.42); Reinette Simenson pp. 189 (fig 6.25); Science Photo Library pp. 42 (fig 2.29); 43 (fig
2.31); 62 (fig 4.0); 91 (fig 5.1); 127 (fig 5.34); 131 (fig 5.35); 133 (fig 5.38); 154 (fig 6.0); 201 (fig 6.38b);
225 (fig 7.21a); 263 (fig 10.1); 277 (fig 10.15); pg 291 (fig 10.30); 293 (fig 10.31); 322 (fig 11.19); 324
(fig 11.20b); 325 (fig 11.21); 328 (fig 11.25a); 329 (fig 11.27a, b); 339 (fig 11.41a, b); 342 (fig 11.45); 360
(fig 12.5); 376 (fig 12.3d); University of the Witwatersrand – Dart Collection pp. 335 (fig 11.36, 11.37);
VMS Images pp. 22 (fig 2.0); 53 (fig 3.3); 55 (fig 3.7); 59 (fig 3.17); 68 (fig 4.9); 304 (fig 11.4a);
Wiki Commons pp. 336 (fig 11.38)
ISBN: 978-1-4310-1-4385 e-ISBN: 9781431024322
WIP: 4514M000
It is illegal to photocopy any page of this book
without written permission from the publishers.
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necessary arrangements at the first opportunity.
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Contents
Topic Topic LB Page
number numbers
Introduction v
How to use the Solutions for all, Life Sciences Grade 12 Learner’s Book
Strand: Life at molecular, cellular and tissue level
1 DNA: The code of life 2
Unit 1 Deoxyribonucleic acid (DNA) 4
Unit 2 Ribonucleic acid (RNA) 13
More questions on DNA: The code of life 19
Summary 21
2 Meiosis 22
Unit 1 Chromosomes 24
Unit 2 Meiosis: The process of reduction division 27
Unit 3 Comparison of mitosis and meiosis 44
More questions on meiosis 47
Summary 49
Strand: Life processes in plants and animals
3 Reproduction in vertebrates 50
Unit 1 Diversity of reproductive strategies 52
More questions on reproduction in vertebrates 61
Summary 61
4 Human reproduction 62
Unit 1 The male and female reproductive systems 64
Unit 2 Puberty 67
Unit 3 Gametogenesis 70
Unit 4 The hormones that control the menstrual cycle 74
Unit 5 Fertilisation and development of zygote to blastocyst 77
Unit 6 Development of the foetus and the role of the placenta 79
Unit 7 Contraceptive methods and devices 83
More questions on human reproduction 87
Summary 89
Strand: Life at molecular, cellular and tissue level
Strand: Diversity, change and continuity
5 Genetics and inheritance 90
Unit 1 Genetics and genes 92
Unit 2 Inheritance and variation 100
Unit 3 Sex chromosomes 120
Unit 4 Mutations 124
Unit 5 Genetic engineering 132
Unit 6 Using human DNA 143
More questions on genetics and inheritance 148
Summary 153
Strand: Life processes in plants and animals
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6 Responding to the environment: The human nervous system 154
Unit 1 The nervous system 156
Unit 2 Disorders and injuries of the nervous system 171
Unit 3 Receptors 184
More questions on responding to the environment: The human 205
nervous system
Summary 207
7 Responding to the environment: The human endocrine system 208
Unit 1 The endocrine system 210
More questions on responding to the environment: The human 228
endocrine system
Summary 229
8 Homeostasis in humans 230
Unit 1 Homeostasis 232
More questions on homeostasis in humans 243
Summary 244
9 Responding to the environment: Plants 246
Unit 1 Plant hormones 248
Unit 2 Tropisms in plants 253
Unit 3 Plant defence mechanisms 257
More questions on responding to the environment: Plants 260
Summary 261
Strand: Diversity, change and continuity
10 Evolution by natural selection 262
Unit 1 Origin of ideas about the origins of species 265
Unit 2 Artificial and natural selection 275
Unit 3 Formation of new species 287
Unit 4 Evolution in present times 293
More questions on evolution by natural selection 296
Summary 298
11 Human evolution 300
Unit 1 Evidence of common ancestors for living hominids, including
humans 302
Unit 2 Out of Africa hypothesis 316
Unit 3 The importance of the Cradle of Humankind 331
Unit 4 Alternative views to evolution 347
More questions on human evolution 351
Summary 352
12 Revision 354
Glossary 386
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Introduction
Life Sciences is the scientific study of living things. In your study of Life Sciences you will
be exploring living things at a molecular level as well as their interactions with one
another and the environment. The study of Life Sciences includes obtaining certain
knowledge.
In addition, you will be performing practical work in which you will practice the skills
necessary to study and investigate living things. Through the process of learning and
doing we hope you develop an interest and appreciation for living things on Earth – and
how to take care of our planet!
Life Sciences Grade 12 Learner’s Book has content knowledge and background information
to ensure that you acquire enough, and a bit more, knowledge than required by the
Curriculum and Assessment Policy Statement (CAPS).
Life Sciences Grade 12 Learner’s Book, includes enough practical tasks to ensure that you
develop the skills necessary to become a true scientist.
In the Further Education and Training band the Life Sciences content framework is
organised according to four knowledge strands. Knowledge strands are developed
progressively over the three years of FET. These knowledge strands are:
(cid:114)(cid:1) Knowledge Strand 1: Life at the Molecular, Cellular and Tissue Level
(cid:114)(cid:1) Knowledge Strand 2: Life Processes in Plants and Animals
(cid:114)(cid:1) Knowledge Strand 3: Environmental Studies
(cid:114)(cid:1) Knowledge Strand 4: Diversity, Change and Continuity.
As you progress in your studying of Life Sciences you will come to realise how
interlinked these strands are. Not all of these knowledge strands are covered in each year
of FET. In Grade 11, Knowledge Strand 1: Life at the Molecular, Cellular and Tissue Level
is not covered. Also note that Knowledge Strand 3: Environmental Studies is not covered
in Grade 12, but you will be examined in Grade 12 on the work done in Environmental
studies in Grade 11.
The three specific aims in Life Sciences are:
(cid:114)(cid:1) Specific Aim 1, which relates to knowing the subject content facts
(cid:114)(cid:1) Specific Aim 2, which relates to doing science or practical work and investigations
(cid:114)(cid:1) Specific Aim 3, which relates to understanding the applications of Life Sciences in
everyday life, as well as understanding the history of scientific discoveries and the
relationship between indigenous knowledge and science.
You might be taking Life Sciences to obtain background knowledge for further studies in
one or more of the biological sub-disciplines. There are many different careers in the field
of Life Sciences. Each career requires special knowledge and skills. The table on the next
page shows a few of these careers.
Introduction (cid:116) v
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Career/job Brief description of job
Dentist Diagnoses, prevents and treats problems related to teeth and the
gums.
Doctor Diagnoses, treats and prevents diseases in humans.
Dietician Advises patients about suitable diets for their individual needs or
conditions.
Biokineticist Specialises in exercise therapy for sportsmen/women and injured
people.
Palaeontologist Studies the fossilised remains of plants, animals and humans, and
uses this information to provide a picture of the history of life on
Earth.
Forensic scientist Analyses physical evidence collected at crime scenes.
Geneticist Studies the inheritance of characteristics, particularly the
characteristics that lead to disorders or diseases in humans.
Animal scientist Conducts research in selecting, breeding, rearing and studying
diseases of domestic animals.
Aquaculturist Studies fish populations and ways of breeding fish for commercial
use.
Veterinarian Diagnoses, prevents and treats diseases in domestic and/or wild
animals.
Landscape architect Designs outdoor and public spaces to achieve environmental,
social and aesthetic outcomes. Includes urban design, urban or
town planning, environmental restoration, parks and recreation
planning and private residence planning.
Food scientist Studies the chemical, physical and biological aspects of different
kinds of food to ensure that it is prepared, preserved and
packaged correctly. Also that it is tasty and safe to eat.
Microbiologist Studies the biology of microscopic organisms such as viruses,
bacteria, fungi and protists. Investigates how these organisms
affect living organisms and the environment.
Ecotoxicologist Studies substances that are toxic to the environment and their
effect on animal life.
Environmental Provides specialist advice on environmental impacts. Conducts
consultant environmental impact assessments.
Environmental health Helps to ensure that public health standards are met in relation
officer to water, sanitation, air, land etc.
Conservationist Works to preserve biological diversity, especially in natural
environments.
vi
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How to use Solutions for all Life Sciences Grade 12
Learner’s Book
The content knowledge in Life Sciences Grade 12 Learner’s Book is organised according
to Topics. Each topic is structured in the same way:
Topic opener page: The topic starts with a full colour photograph of something that is
related to the content of the topic. On the opener page is listed What you will learn about in
this topic, which links to what you should know after you have worked through the topic.
There is also a section called Let’s talk about ... This introduces the topic and includes
questions related to the photograph. The idea is for you to start thinking about new
things you will learn about in the topic.
What you know already: On the second page of a topic is What you know already and
Check myself. These two features make sure that you know what you need to know before
continuing with the new work. It is revision of a previous grade’s work.
Units and lessons: Each topic is divided into units that are broken up into lessons. The
lessons break the work up into little chunks of information. This helps you to make sure
you know and understand a certain section of the work before moving on to the next new
section of work. A lesson consists of content and then an Activity that could be a Learning
task or a Practical task. The Learning task might be done in class or given as homework. The
activities are also opportunities for formal and informal assessment. Your teacher will tell
you which activities will be assessed. One Practical task per term is a suggested formal
assessment task. You could be assessed on these tasks, so watch out for them. The
Learning tasks and Practical tasks can be done alone, in pairs or in groups. Your teacher will
tell you how to work.
Enrichment activities: The enrichment activities are additional activities. These are for
you to find out more about what was covered in the lesson.
More questions on ... : The topic ends with a variety of additional questions to give you
extra practice.
Summary: Each topic ends with a summary of the work covered in the topic. You could
use these summaries to go over the content.
Other features to look out for are:
Word boxes: In the margins on the pages there are boxes with certain words. An
explanation of the meaning of the word is given for you to understand the information
better. Also always keep a dictionary at hand. If you understand a word, your learning is
made much easier.
Cool fact, Something interesting and Hot topic: This is some interesting information.
Diagrams and illustrations: Scientifically accurate diagrams are included to help you
understand the written words. Make good use of the pictures when working through the
text. When you see something, you will remember it a lot better.
The publisher and authors wish you all the best in your study of Life Sciences Grade 12.
Good luck!
vii
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TT ooppii
11cc
DNA: The code of life
What you will learn about in this topic
(cid:114)(cid:1) the location of DNA in the cell
(cid:114)(cid:1) the structure of DNA
(cid:114)(cid:1) the discovery of the structure of DNA
(cid:114)(cid:1) DNA profiling
(cid:114)(cid:1) the role of DNA in the genetic code
(cid:114)(cid:1) the replication of DNA
(cid:114)(cid:1) the structure of RNA
(cid:114)(cid:1) the types of RNA and the location of RNA in the cell
(cid:114)(cid:1) the transcription of RNA from DNA
(cid:114)(cid:1) the translation of RNA into proteins
(cid:114)(cid:1) the role of RNA in expressing the genetic code.
Let’s talk about this topic
DNA is so small that its structure cannot even be seen under the strongest
microscopes currently in use. It is for this reason that the photograph shows a model
of a double helix DNA molecule and not an actual DNA molecule.
What is DNA and why is it so important to life? How does DNA determine what
and who we are? In this topic you will find the answers to these questions.
2 (cid:116) Topic 1: DNA: The code of life
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Life at molecular, cellular and tissue level
What you know already
nucleic acid: an In Grade 10 you learnt about the cell – the basic unit of life – and its structure. The cell
organic
contains many different types of organic compound, including proteins, lipids and
compound that
contains the carbohydrates. Proteins consist of chains of amino acids. Organic compounds called
elements nucleic acids are also found in cells. Nucleic acids are organic compounds that contain
carbon, the elements carbon, hydrogen, oxygen, nitrogen and phosphorus.
hydrogen,
oxygen,
nitrogen and There are two types of nucleic acid:
phosphorus. A (cid:114)(cid:1) deoxyribonucleic acid (DNA)
polynucleotide (cid:114)(cid:1) ribonucleic acid (RNA).
such as DNA
and RNA
You also learnt, in Grade 10, that cells divide by mitosis. During interphase of the cell
cycle, the DNA in the nucleus replicates itself exactly so that each daughter cell that is
formed, receives an identical copy of the DNA.
nucleus
lysosome nucleolus nucleoplasm
centriole
nuclear
membrane
mitochondrion Golgi apparatus
endoplasmic
cytoplasm
reticulum
ribosomes cell
membrane
Fig. 1.1 Diagram of an animal cell
C h e c k S1.t udWy Fhiagtu isre t h1e.1 n auncdle aunss mwaedr ea lul pth oef q?uestions below:
m y s e l f 2. What is the function of the nucleus?
3. How do substances get into and out of the nucleus?
4. Where in a cell will you find ribosomes?
5. What is the function of ribosomes?
6. What is the function of mitochondria?
7. In a plant cell there are chloroplasts. What is the function of
chloroplasts?
Topic 1: DNA: The code of life (cid:116) 3
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