9648_2012_H2_Biology

BIOLOGY

HIGHER 2

(Syllabus 9648)

CONTENTS

Page

PREAMBLE 1

INTRODUCTION 2

AIMS 2

ASSESSMENT OBJECTIVES 3

SCHEME OF ASSESSMENT 5

MARKS ALLOCATED TO ASSESSMENT OBJECTIVE 7

DISALLOWED SUBJECT COMBINATIONS 7

ADDITIONAL INFORMATION 7

NOTES ON THE USE OF STATISTICS IN BIOLOGY 8

STRUCTURE OF SYLLABUS 9

PRACTICAL ASSESSMENT 21

TEXTBOOKS AND REFERENCES 23

GLOSSARY OF TERMS 26

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PREAMBLE This preamble sets out the approach, objectives, directions and philosophy of the H2 Biology syllabus. With recent advancements in the Life Sciences, changes in knowledge have been tremendous. Many new and important fields of Biology have emerged as evident from the sprouting of scientific journals catering to niche areas of study and research. This poses a challenge in the development of Biology education in integrating the fundamental concepts, skills and new knowledge in Biology into a framework that is accessible to students at different levels. At the same time, the vast amount of knowledge needs to be refined and updated so that students can keep up with the relevant knowledge in preparation for their participation in a technologically driven economy. With this in mind, Biology education from Primary to ‘A’ levels has been organised in the following manner:

a. Primary 3 to Primary 6: How life works at the systems level.

b. Lower Secondary Science to ‘O’ level Biology: How life works at the physiological level.

c. ‘A’ level: How life works at the cellular and molecular level. The proposed framework will chart a new direction in Biology education in schools. Starting at the primary school levels, the focus has been for the students to be exposed at the systems level. At the secondary school levels, the syllabus will help the students relate concepts at the system level to the micro-level. In addition, at the ‘A’ level, the syllabus will encourage the students to look deeper (at the molecular level), yet balanced, with the study of Diversity and Evolution. In teaching the H2 syllabus, the following should be noted:

a. H2 Biology should provide the fundamental knowledge to enable students to understand the major emerging fields of knowledge;

b. H2 Biology should equip students with scientific skills and abilities that are relevant to the study and practice of biological science;

c. The Biology syllabus is developed as a continuum from the ‘O’ to ‘A’ levels. The H2 and ‘O’ level syllabuses are designed to be seamless without the need for topics to be revisited at the ‘A’ level. The ‘O’ level syllabus would be foundational and thus should provide the necessary background for the study at the ‘A’ level;

d. The teaching of H2 should relate information on the cellular and molecular level to the systems level;

e. The H2 syllabus is moving away from the current syllabus model that was based on a ‘survey’ of topics.

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INTRODUCTION Candidates will be assumed to have knowledge and understanding of ‘O’ level Biology, as a single subject or as part of a balanced science course. The syllabus has been arranged in the form of Core and Applications content to be studied by all candidates. The syllabus places emphasis on the applications of Biology and the impact of recent developments on the needs of contemporary society. Experimental work is an important component and should underpin the teaching and learning of Biology. All candidates following this syllabus should be encouraged to:

• use secondary sources of information;

• use information technology (I.T.) to analyse, store and retrieve data and to model biological phenomena;

• communicate biological information orally, as well as in writing. It is intended to keep the syllabus under frequent review, to ensure that it keeps abreast of knowledge in the biological sciences and other needs.

AIMS The syllabus aims to: 1. provide, through well designed studies of experimental and practical biological science, a

worthwhile educational experience for all students, whether or not they go on to study Biology beyond this level and, in particular, to enable them to acquire sufficient understanding and knowledge to: 1.1 become confident citizens in a technological world, able to take or develop an informed

interest in matters of scientific import; 1.2 recognise the usefulness, and limitations, of scientific method and to appreciate its

applicability in other discipline and in everyday life; 1.3 be suitably prepared for studies beyond ‘A’ level in biological sciences, in further higher

education, and for professional courses.

2. stimulate students, create and sustain their interest in Biology, and understand its relevance to society.

3. develop abilities and skills that: 3.1 are relevant to the study and practice of biological science; 3.2 are useful in everyday life; 3.3 encourage efficient and safe practice; 3.4 encourage effective communication.

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4. develop attitudes relevant to Biology such as: 4.1 concern for accuracy and precision; 4.2 objectivity; 4.3 integrity.

5. assist the development of: 5.1 the skills of scientific inquiry; 5.2 initiative; 5.3 inventiveness.

6. stimulate interest in and care for the local and global environment, and understand the need for conservation.

7. promote an awareness:

7.1 that scientific theories and methods have developed, and continue to do so, as a result of co-operative activities of groups and individuals;

7.2 that the study and practice of biological science is subject to social, economic, technological,

ethical and cultural influences and limitations; 7.3 that the applications of biological science may be both beneficial and detrimental to the

individual, the community and the environment; 7.4 that biological science transcends national boundaries and that the language of science,

correctly and rigorously applied, is universal; 7.5 of the importance of the use of I.T. for communication, as an aid to experiments and as a

tool for the interpretation of experimental and theoretical results.

ASSESSMENT OBJECTIVES These describe the knowledge, skills and abilities which candidates are expected to demonstrate at the end of the course. They reflect those aspects of the aims which will be assessed. A Knowledge with understanding Students should be able to demonstrate knowledge and understanding in relation to: 1. biological phenomena, facts, laws, definitions, concepts, theories; 2. biological vocabulary, terminology, conventions (including symbols, quantities and units); 3. scientific instruments and apparatus used in biology, including techniques of operation and

aspects of safety; 4. scientific quantities and their determination; 5. biological and technological applications with their social, economic and environmental

implications.

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The syllabus content, examples and elaborations define the factual materials that candidates need to recall and explain. Examiners will assume that the candidates have studied these and questions may refer to the syllabus content, examples and elaborations. Questions testing the objectives above will often begin with one of the following words: define, state, name, describe, explain or outline. (See the Glossary of Terms) B Handling information and solving problems Students should be able – using written, symbolic, graphical and numerical material – to: 1. locate, select, organise and present information from a variety of sources; 2. translate information from one form to another; 3. manipulate numerical and other data; 4. use information to identify patterns, report trends, draw inferences and report conclusions; 5. present reasoned explanation for phenomena, patterns and relationships; 6. make predictions and propose hypotheses; 7. apply knowledge, including principles, to novel situations; 8. solve problems. The assessment objectives above cannot be precisely specified in the syllabus content because questions testing such skills are often based on information which is unfamiliar to the candidate. In answering such questions, candidates are required to use principles and concepts that are within the syllabus and apply them in a logical, deductive manner. Questions testing these objectives may begin with one of the following words: discuss, predict, suggest, calculate or determine. (See the Glossary of Terms) C Experimental skills and investigations Students should be able to: 1. devise and plan investigations, select techniques, apparatus and materials; 2. use techniques, apparatus and materials safely and effectively; 3. make and record observations, measurements and estimates; 4. interpret and evaluate observations and experimental data; 5. evaluate methods and techniques, and suggest possible improvements.

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SCHEME OF ASSESSMENT All school candidates are required to enter for Papers 1, 2, 3 and 4. All private candidates are required to enter for Papers 1, 2, 3 and 5.

Paper Type of Paper Duration Marks Weighting (%)

1 Multiple Choice 1 h 15 min 40 20

2 Core Paper. Structured and free-response questions

2 h 100 35

3 Applications Paper. Structured and free-response questions Planning Question

2 h

60

12

25 5

4 School-based Science Practical Assessment (SPA)

- 40 15

5 Practical Paper 1 h 50 min 36 15

Paper 1 (1 h 15 min, 40 marks) This paper consists of 40 compulsory multiple choice questions. All questions will be of the direct choice type with 4 options.

Paper 2 (2 h, 100 marks) This paper consists of a variable number of structured questions, all compulsory and two free-response questions of 20 marks each, from which candidates will choose one. These include questions which require candidates to integrate knowledge and understanding from different areas of the syllabus. All questions will be based on material in the Core syllabus.

Paper 3 (2 h, 72 marks) This paper consists of a variable number of structured questions, all compulsory, including data-based or comprehension-type questions, one free-response question of 20 marks and one planning question of 12 marks. The planning question will assess appropriate aspects of objectives C1 to C5. Paper 3 will include questions which require candidates to integrate knowledge and understanding from different areas of the syllabus. Knowledge of Core material may be required.

Paper 4 (40 marks) The School-based Science Practical Assessment (SPA) will take place over an appropriate period that the candidates are following the course. There are two compulsory assessments which will assess appropriate aspects of objectives C1 to C5 in the following skill areas:

• Manipulation, measurement and observation (MMO)

• Presentation of data and observations (PDO)

• Analysis, conclusions and evaluation (ACE) Each assessment assesses these three skill areas, MMO, PDO and ACE, which may not be necessarily equally weighted, to a total of 20 marks. The range of marks for the three skill areas are as follows: MMO, 4–8 marks; PDO, 4–8; ACE, 8–10 marks. The assessment of PDO and ACE may also include questions on data-analysis which do not require practical equipment and apparatus. Candidates will not be permitted to refer to books and laboratory notebooks during the assessment. Refer to the Revised SPA Handbook for more detailed information on the conduct of SPA.

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Paper 5 (1 h 50 min, 36 marks) For private candidates, a timetabled practical paper will assess appropriate aspects of objectives C1 to C5 in the following skill areas:

• Manipulation, measurement and observation (MMO)

• Presentation of data and observations (PDO)

• Analysis, conclusions and evaluation (ACE) Each of these skill areas will be approximately equally weighted to a total of 36 marks. This paper may include data handling/interpretation questions that do not require apparatus, in order to test the skill areas of PDO and ACE.

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MARKS ALLOCATED TO ASSESSMENT OBJECTIVE This is given in the following Assessment Grid.

Assessment Objective Weighting (%) Assessment Components

A Knowledge with understanding 44 Papers 1, 2, 3

B Handling information and solving problems 36 Papers 1, 2, 3

C Experimental skills and investigations 20 Papers 3, 4 or

Papers 3, 5

Fifteen percent of the total marks will be awarded for awareness of the social, economic, environmental and technological implications and applications of Biology. These will be awarded within the ‘Knowledge with Understanding’ and the ‘Handling information and solving problems’ categories.

DISALLOWED SUBJECT COMBINATIONS Candidates may not simultaneously offer Biology at H1 and H2 levels.

ADDITIONAL INFORMATION Modern Biological Sciences draw extensively on concepts from the physical sciences. It is desirable therefore, that by the end of the course, candidates should have a knowledge of the following topics, sufficient to aid understanding of biological systems. No questions will be set directly on them.

The electromagnetic spectrum; Energy changes (potential energy, activation energy, chemical bond energy); Molecules, atoms, ions, electrons; Acids, bases, pH, buffers; Isotopes, including radioactive isotopes; Oxidation and reduction; Hydrolysis, condensation.

Questions set in the examination may involve the basic processes of mathematics for the calculation and use of decimals, means, ratios and percentages. Students will be expected to be familiar with the nomenclature used in the syllabus. The proposals in "Signs, Symbols and Systematics" (The Association for Science Education Companion to 16-19 Science, 2000) and the recommendations on terms, units and symbols in ‘Biological Nomenclature (2000)’ published by the Institute of Biology, in conjunction with the ASE, will generally be adopted although the traditional names sulfate, sulfite, nitrate, nitrite, sulfurous and nitrous acids will be used in question papers. Sulfur (and all compounds of sulfur) will be spelt with f (not with ph) in question papers, however students can use either spelling in their answers. Candidates may be required to (i) construct graphs or present data in other suitable graphical forms, (ii) calculate rates of processes. Candidates should be aware of the problems of drawing conclusions from limited data and should appreciate levels of significance, standard deviation and probability, and the use of chi-squared tests.

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NOTES ON THE USE OF STATISTICS IN BIOLOGY

Candidates should know how to apply a chi-squared test, which allows the evaluation of the results of breeding experiments and ecological sampling. The chi-squared test is dealt with fully in many books on statistics for Biology. Candidates should know how to use the chi-square test to test the significance of differences between observed and expected results. Candidates are not expected to remember the following equations nor to remember for what the symbols stand. They are expected to be able to use the equations to calculate standard deviations and to perform a chi-squared test on suitable data from genetics or ecology. Candidates will be given access to the equations, the meaning of the symbols and a chi-squared table.

standard deviation s = Σ( )2x x

n

-

−1

χ2 test χ Σ

2=

−(O E)

E

2

1c v −=

Key to symbols

*s = standard deviation n = sample size (number of observations)

E = expected ‘value’

∑ = ‘sum of’ v = degrees of freedom

x = observation c = number of classes

x = mean O = observed ‘value’

*Candidates should note that on some calculators the symbol σ may appear instead of the symbol s.

Candidates are not expected to appreciate the difference between sn (σ n) and sn–1 (σ n–1). 2χ tests

will only be expected on one row of data. Candidates should have a brief understanding of what is meant by the term normal distribution and appreciate levels of significance. (Tables will be provided.)

Questions involving the use of a 2χ test may be set on Papers 2 or 3.

Electronic calculators will be allowed in the examination subject to the UCLES general regulations. Any calculator used must be on the Singapore Examinations and Assessment Board list of approved calculators.

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STRUCTURE OF SYLLABUS The syllabus is divided into two parts: the Core syllabus and the Applications syllabus, to be studied by all candidates. A. The Core syllabus. There are 7 Core topics:

1. Cellular Functions 2. DNA and Genomics 3. Genetics of Viruses and Bacteria 4. Organisation and Control of Prokaryotic and Eukaryotic Genomes 5. Genetic Basis for Variation 6. Cellular Physiology and Biochemistry 7. Diversity and Evolution

B. The Applications syllabus. There are 2 Applications topics:

8. Isolating, Cloning and Sequencing DNA 9. Applications of Molecular and Cell Biology

OVERALL FRAMEWORK FOR BIOLOGY H2 LEVEL SYLLABUS FOR 2012

HOW LIFE WORKS

UNDERSTANDING THE DIVERSITY OF

ORGANISMS

Genetics of Viruses & Bacteria Organisation & Control of Prokaryotic

& Eukaryotic Genomes

RELEVANCE TO ONESELF AND SOCIETY

Isolating, Cloning & Sequencing DNA

Applications of Molecular & Cell

Biology

Cellular Functions

DNA & Genomics

Diversity & Evolution

Genetic Basis for Variation

Cellular Physiology & Biochemistry

9648 H

2 B

IOLO

GY

(2012)

9

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A CORE SYLLABUS

1 Cellular Functions

Content

• Detailed structure of typical animal and plant cells, as seen under the electron microscope

• Outline functions of organelles in plant and animal cells

• The structure of carbohydrates, lipids and proteins and their roles in living organisms

• Mode of action of enzymes

• Replication and division of nuclei and cells

• Understanding of chromosome number and variation

• Effect of meiosis on chromosome number and variation

Learning Outcomes

Candidates should be able to:

(a) Describe and interpret drawings and photographs of typical animal and plant cells as seen under the electron microscope, recognising the following membrane systems and organelles: rough and smooth endoplasmic reticulum, Golgi body, mitochondria, ribosomes, lysosomes, chloroplasts, cell surface membrane, nuclear envelope, centrioles, nucleus and nucleolus. (Knowledge of the principles of TEM and SEM are not required.) (For practical assessment, students may be required to operate a light microscope, mount slides and use a graticule.)

(b) Outline the functions of the membrane systems and organelles listed in (a).

(c) Describe the formation and breakage of a glycosidic bond.

(d) Analyse the molecular structure of a triglyceride and a phospholipid, and relate these structures to their functions in living organisms.

(e) Describe the structure of an amino acid and the formation and breakage of a peptide bond.

(f) Explain the meaning of the terms primary structure, secondary structure, tertiary structure and quaternary structure of proteins, and describe the types of bonding (hydrogen, ionic, disulfide and hydrophobic interactions) which hold the molecule in shape.

(g) Analyse the molecular structure of a protein with a quaternary structure e.g. haemoglobin, as an example of a globular protein, and of collagen as an example of a fibrous protein, and relate these structures to their functions.

(h) Explain the mode of action of enzymes in terms of an active site, enzyme/substrate complex, lowering of activation energy and enzyme specificity.

(i) Follow the time course of an enzyme-catalysed reaction by measuring rates of formation of products (e.g. using catalase) or rate of disappearance of substrate (e.g. using amylase).

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(j) Investigate and explain the effects of temperature, pH, enzyme concentration and substrate concentration on the rate of enzyme catalysed reactions, and explain these effects.

(k) Explain the effects of competitive and non-competitive inhibitors (including allosteric inhibitors) on the rate of enzyme activity.

(l) Explain the importance of mitosis in growth, repair and asexual reproduction.

(m) Explain the need for the production of genetically identical cells and fine control of replication.

(n) Explain how uncontrolled cell division can result in cancer, and identify causative factors (e.g. genetic, chemical carcinogens, radiation, loss of immunity) which can increase the chances of cancerous growth. (Knowledge that dysregulation of checkpoints of cell division can result in uncontrolled cell division and cancer is required, but detail of the mechanism is not required.)

(o) Describe with the aid of diagrams, the behaviour of chromosomes during the mitotic cell cycle and the associated behaviour of the nuclear envelope, cell membrane and centrioles. (Names of the main stages are expected)

(p) Explain what is meant by homologous pairs of chromosomes.

(q) Explain the need for reduction division (meiosis) prior to fertilisation in sexual reproduction.

(r) Explain how meiosis and random fertilisation can lead to variation.

(s) Describe, with the aid of diagrams, the behaviour of chromosomes during meiosis, and the associated behaviour of the nuclear envelope, cell membrane and centrioles. (Names of the main stages are expected, but not the sub-divisions of prophase)

Use the knowledge gained in this section in new situations or to solve related problems.

2 DNA and Genomics

Content

• DNA – structure and function

• Central Dogma – DNA to RNA, RNA to protein

Learning Outcomes


(a) Describe the structure and roles of DNA and RNA (tRNA, rRNA and mRNA). (Mitochondrial DNA is not required.)

(b) Describe the process of DNA replication and the experimental evidence for semi-conservative replication.

(c) Describe how the information on DNA is used to synthesise polypeptides in prokaryotes and eukaryotes. (Description of the processes of transcription, formation of mRNA from pre-mRNA and translation is required.)

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(d) Explain how a change in the sequence of the DNA nucleotide (gene mutation) may affect the amino acid sequence in a protein, and hence the phenotype of the organism e.g. sickle cell anaemia and cystic fibrosis. (Knowledge of substitution, addition, deletion and frameshift mutation may be required.)


3 Genetics of Viruses and Bacteria

Content

• The Genetics of Viruses

• The Genetics of Bacteria

Learning outcomes


(a) Discuss whether viruses are living or non-living organisms and explain why viruses are obligate parasites.

(b) Describe the structural components of viruses.

(c) Describe the reproductive cycles of the following virus types:

i. bacteriophages that reproduce via a lytic cycle, e.g. T4 phage;

ii. bacteriophages that reproduce via a lysogenic cycle, e.g. lambda phage;

iii. an enveloped virus e.g. influenza;

iv. retroviruses e.g. HIV.

(d) Explain how viral infections cause disease in animals, e.g. mammals, through the disruption of host tissue and functions (e.g. HIV and T helper cells [details of the immune system are not required], influenza and epithelial cells of the respiratory tract).

(e) Describe the structure of a bacterial chromosome including the arrangement of DNA within bacterial cells.

(f) Describe the process of binary fission, transformation, transduction and conjugation in bacteria and explain the role of F plasmids in bacterial conjugation. (Knowledge of Hfr is not required.)

(g) Distinguish between structural and regulatory genes. A structural gene is a region of DNA that codes for a protein or RNA molecule that forms part of a structure or has an enzymatic function (e.g. lacY, lacZ, lacA, but excludes lacI). A regulatory gene codes for a specific protein product that regulates the expression of the structural genes (e.g. lacI).

(h) Distinguish between the concept of repressible and inducible systems of gene regulation using trp and lac operon as examples respectively (attenuation of trp operon is not required).

(i) Describe the concept of a simple operon (using lac operon as an example).


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4 Organisation and Control of Prokaryotic and Eukaryotic Genome

Content

• The Structure of Eukaryotic Chromatin

• Genome Organisation at the DNA level

• The Control of Gene Expression

• The Molecular Biology of Cancer

Learning Outcomes


(a) Compare the structure and organisation of prokaryotic and eukaryotic chromosomes, in terms of size, packing of DNA, linearity/circularity, presence of introns and type of regulatory sequences.

(b) Describe the structure and function of the portions of eukaryotic DNA that do not encode for protein or RNA, with reference to intron, centromere, telomere, promoter, enhancer and silencer. (Knowledge of transposon, satellite DNA, pseudogenes and duplication of segments is not required.)

(c) Describe the role of telomeres and centromeres.

(d) Describe the process and significance of gene amplification within cells, for example in amplification of the genes that code for ribosomes early in cell development, to ensure that sufficient ribosomes can be made to synthesise the proteins that make up the cell.

(e) Describe the eukaryotic processing of pre-mRNA in terms of intron splicing, polyadenylation and 5′ capping.

(f) Define control elements and explain how control elements (e.g. promoter, silencer and enhancers) and other factors (e.g. transcription factors, repressors, histone modification and DNA methylation) influence transcription.

(g) State the various ways in which gene expression may be controlled at translational (e.g. half life of RNA, 5′ capping, initiation of translation) and post-translational level (e.g. biochemical modification and protein degradation).

(h) Outline the differences between prokaryotic control of gene expression with the eukaryotic model.

(i) Describe the functions of common proto-oncogenes and tumour suppressor genes (limited to ras and p53) and explain how loss of function mutation and gain of function mutation can contribute to cancer.

(j) Describe the development of cancer as a multi-step process.


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5 Genetic Basis for Variation

Content

• The passage of information from parent to offspring

• Genotypes and phenotypes

• Dihybrid crosses

• Mutations

• The effect of genotype and environment on phenotype

• Interaction between loci

• Linkage and crossing-over

Learning Outcomes


(a) Explain the terms, locus, allele, dominant, recessive, codominant, homozygous, heterozygous, phenotype and genotype.

(b) Explain how genotype is linked to phenotype and how genes are inherited from one generation to the next via the germ cells or gametes.

(c) Explain, with examples, how the environment may affect the phenotype.

(d) Use genetic diagrams to solve problems in dihybrid crosses, including those involving sex linkage, autosomal linkage, epistasis, codominance and multiple alleles.

(e) Use genetic diagrams to solve problems involving test crosses.

(f) Explain the meaning of the terms linkage and crossing-over and explain the effect of linkage and crossing-over on the phenotypic ratios from dihybrid crosses.

(g) Explain what is meant by the terms gene mutation and chromosome aberration. For chromosomal aberration, knowledge of numerical [aneuploidy] and structural [translocation, duplication, inversion, deletion] is required.

(h) Describe the differences between continuous and discontinuous variation and explain the genetic basis of continuous variation (many, additive, genes control a characteristic) and discontinuous variation (one or few genes control a characteristic).

(i) Describe the causes of genetic variation in a population.

(j) Describe the interaction between loci (epistasis) and predict phenotypic ratios in problems involving epistasis. (Knowledge of the expected ratio for various types of epistasis is not required; focus of this section is on problem solving.)

(k) Use the chi square test to test the significance of differences between observed and expected results.


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6 Cellular Physiology and Biochemistry

Content

• The need for energy in living organisms

• Photosynthesis as an energy-trapping process

• Respiration as an energy-releasing process

• Aerobic respiration

• Anaerobic respiration

• The fluid mosaic model of membrane structure

• Homeostasis

• Electrical and chemical signalling

• Nervous and hormonal control

• An overview of cell signalling and communication

o Signal reception and the initiation of transduction

o Signal transduction pathways

o Cellular responses to signals

Learning Outcomes


(a) With reference to the chloroplast structure, explain the light dependent reactions of photosynthesis (no biochemical details are needed but will include the outline of cyclic and non-cyclic light dependent reactions, and the transfer of energy for the subsequent manufacturing of carbohydrates from carbon dioxide).

(b) Outline the three phases of the Calvin cycle: (i) CO2 uptake (ii) carbon reduction and (iii) ribulose bisphosphate (RuBP) regeneration and indicate the roles of ATP and NADP in the process.

(c) Discuss limiting factors in photosynthesis and carry out investigations on the effects of limiting factors, such as light intensity, CO2 concentration and temperature, on the rate of photosynthesis.

(d) List and give an overview of the 4 stages of aerobic respiration and indicate where each stage takes place in an eukaryotic cell and mitochondria, and add up the energy captured (as ATP, reduced NAD and FAD) in each stage.

(e) Explain the production of a small yield of ATP from anaerobic respiration and the formation of ethanol in yeast and lactate in mammals.

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(f) Compare the storage and structural forms of starch, glycogen and cellulose and their roles in plants/animals.

(g) Describe and explain the fluid mosaic model of membrane structure, including an outline of the roles of phospholipids, cholesterol, glycolipids, proteins and glycoproteins.

(h) Outline the roles and functions of membranes within cells and at the surface of cells. (Knowledge of osmosis, facilitated diffusion, active transport, endocytosis and exocytosis is required.)

(i) Explain the need for control in organised systems and explain the principles of homeostasis in terms of receptors, effectors, and negative feedback.

(j) Explain the need for communication systems within organisms.

(k) Describe and explain the transmission of an action potential along a myelinated neurone. (The importance of Na

+ and K

+ ions in the impulse transmission should be emphasised.)

(l) Describe the structure of a cholinergic synapse and explain how it functions, including the role of Ca

2+ ions.

(m) Explain what is meant by an endocrine gland, with reference to the islets of Langerhans in the pancreas.

(n) Explain how the blood glucose concentration is regulated by insulin and glucagon.

(o) Describe the main stages of cell signalling – ligand-receptor interaction, signal transduction (inclusive of phosphorylation and signal amplification) and cellular responses. (Limited to an overview of insulin & RTK signalling and glucagon & G-protein signalling. Candidates will be expected to generalise their understanding of these systems in solving problems involving other cell signalling systems.) Advantages and significance of having a cell signalling system may be required.


7 Diversity and Evolution

Content

• Classification

• The concept of the species

• Variation, natural selection and evolution

• The neo-Darwinian revolution

• Evidence of evolution

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Learning Outcomes


(a) Explain the binomial nomenclature of a species and hierarchical classification.

(b) Describe the classification of species into taxonomic groups (genus, family, order, class, phylum, kingdom) and explain the various concepts of the species. (Knowledge of biological, ecological, morphological, phylogenetic concepts of species is required.)

(c) Explain how species are formed with reference to geographical isolation, physiological isolation and behavioural isolation.

(d) Explain the relationship between classification and phylogeny. (Evolutionary relationships between organisms should be reflected in systematic classification.) Classification is the organisation of species according to particular characteristics. Classification may not take into consideration evolutionary relationship between the species. Phylogeny is the organisation of species according to particular characteristics which takes into consideration the evolutionary relationship between the species.

(e) Explain why variation is important in selection.

(f) Explain, with examples, how environmental factors act as forces of natural selection.

(g) Explain how natural selection may bring about evolution.

(h) Explain why the population is the smallest unit that can evolve.

(i) Explain how homology (anatomical, embryological and molecular) supports Darwin’s theory of natural selection (with emphasis on descent with modification).

(j) Explain how biogeography and the fossil record support the evolutionary deductions based on homologies.

(k) Explain the importance of the use of genome sequences in reconstructing phylogenetic relationships and state the advantages of molecular (nucleotide and amino acid sequences) methods in classifying organisms.

(l) Explain how genetic variation (including recessive alleles) may be preserved in a natural population.

(m) Briefly describe the neutral theory of molecular evolution in terms of mutations producing new molecular variants which are selectively neutral. (Knowledge of genetic drift and molecular clock is required.)


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B. APPLICATIONS SYLLABUS

8 Isolating, Cloning and Sequencing DNA

Content

• DNA Cloning (Genetic Engineering)

• DNA Analysis and Genomics

• Human genome project

Learning Outcomes


(a) Describe the natural function of restriction enzymes.

(b) Explain the formation of recombinant DNA molecule.

(c) Outline the procedures for cloning an eukaryotic gene in a bacterial plasmid and describe the properties of plasmids that allow them to be used as DNA cloning vectors.

(d) Explain how eukaryotic genes are cloned using E. coli cells to produce eukaryotic proteins to avoid the problems associated with introns.

(e) Distinguish between a genomic DNA and cDNA library. (Outline of the process of the formation of the libraries and applications of each of the types of library is required.)

(f) Outline two important proteins that can be produced by genetic engineering technique (e.g. human growth hormone and insulin).

(g) Describe the polymerase chain reaction (PCR) and explain the advantages and limitations of this procedure.

(h) Explain how gel electrophoresis is used to analyse DNA.

(i) Outline the process of nucleic acid hybridisation and explain how it can be used to detect and analyse restriction fragment length polymorphism (RFLP).

(j) Explain how RFLP analysis facilitated the process of:

i. genomic mapping in terms of linkage mapping;

ii. diseases detection, e.g. sickle cell anaemia;

iii. DNA fingerprinting.

(Details of application of gel electrophoresis, PCR and nucleic hybridisation in RFLP may be required.)

(k) Discuss the goals and implications of the human genome project, including the benefits and difficult ethical concerns for humans. (Knowledge of the technical procedure of the human genome project and sequencing is not required.)


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9 Applications of Molecular and Cell Biology

Content

• Stem cells

• The treatment of genetic diseases in humans

• Gene therapy

• Cloning

• Genetic engineering and genetically modified organisms (GMOs)

Learning Outcomes


(a) Describe the unique features of zygotic stem cells, embryonic stem cells and blood stem cells, correctly using the terms totipotency (zygotic stem cells which have ability to differentiate into any cell type to form whole organisms and so are also pluripotent and multipotent), pluripotency (embryonic stem cells which have ability to differentiate into almost any cell type to form any organ or type of cell and so are not totipotent but are multipotent) and multipotency (blood stem cells which have ability to differentiate into a limited range of cell type and so are not pluripotent or totipotent).

(b) Explain the normal functions of stem cells in a living organism (e.g. embryonic stem cells and blood stem cells).

(c) Describe:

i. two types of genetic diseases e.g. SCID (severe combined immunodeficiency) and cystic fibrosis;

ii. the treatment of SCID and cystic fibrosis, using viral and non-viral gene delivery systems respectively. (Details of manipulation of genes and formation of vectors carrying genes are not required.)

(d) Explain what are the factors that keep gene therapy from becoming an effective treatment for genetic diseases.

(e) Discuss the social and ethical considerations for the use of gene therapy.

(f) Discuss cloning in plants in terms of plant tissue culture techniques. (Gene cloning in plants using Agrobacterium spp. and gene gun is not required.)

(g) Explain the significance of genetic engineering in improving the quality and yield of crop plants and animals in solving the demand for food in the world (e.g. Bt corn, golden rice, GM salmon).

(h) Discuss the ethical and social implications of genetically modified crop plants and animals (e.g. Bt corn, golden rice and GM salmon).

Use the knowledge gained in this section in new situation or to solve related problems.

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PRACTICAL ASSESSMENT Scientific subjects are, by their nature, experimental. It is therefore important that, wherever possible, the candidates carry out appropriate practical work to illustrate the theoretical principles to facilitate the learning of this subject. The guidance material for practical work, which is published separately, will provide examples of appropriate practical activities.

Candidates will be assessed in the following skill areas:

(a) Planning (P)

Candidates should be able to

• Define the question/problem using appropriate knowledge and understanding

• give a clear logical account of the experimental procedure to be followed

• describe how the data should be used in order to reach a conclusion

• assess the risks of the experiment and describe precautions that should be taken to keep risks to a minimum

(b) Manipulation, measurement and observation (MMO)


• demonstrate high level of manipulative skills in all aspects of practical activity

• make and record accurately, in a suitable manner, all observations with good details and/or all measurements to appropriate degree of precision

• recognise anomalous observations and/or measurements (where appropriate) with reasons indicated and suggest possible causes

(c) Presentation of data and observations (PDO)


• present all information in an appropriate form

• manipulate observations and/or measurements effectively in order to identify trends/patterns

• present all quantitative data to an appropriate number of significant figures

(d) Analysis, conclusions and evaluation (ACE)


• analyse and interpret data appropriately in relation to the task

• draw comprehensive conclusions based on underlying principles

• identify significant sources of errors, limitations of measurements and/or experimental procedures used, and explain how they affect the final result(s)

• state and explain how significant errors/limitations (including experimental procedures) may be overcome/improved as appropriate

Skill P will be assessed in Paper 3. Candidates will be required to answer a question constituting 12 marks among the compulsory questions in Paper 3. The assessment of Skill P will be set in the context of the content syllabus, requiring candidates to apply and integrate knowledge and understanding from different sections of the syllabus. It may also require treatment of given experimental data in drawing relevant conclusion and analysis of proposed plan. For school candidates, skills MMO, PDO and ACE will be assessed by two school-based assessments (SPA). For private candidates, skills MMO, PDO and ACE will instead be assessed by Paper 5 (Practical Paper). The school-based practical assessments and the practical paper will be set in the context of the syllabus.

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Centres will be notified in advance of the details of the apparatus and materials required for these assessments. The assessment of PDO and ACE may also include questions on data analysis, which do not require practical equipment and apparatus. Within the Schemes of Assessment, school-based practical assessment (for school candidates) or the practical paper (for private candidates) constitute 15% of the Higher 2 examination. The planning component in Paper 3 constitutes 5% of the Higher 2 examination. It is therefore recommended that the schemes of work include learning opportunities that apportion a commensurate amount of time for the development and acquisition of practical skills.

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TEXTBOOKS AND REFERENCES

Teachers may find reference to the following books helpful.

CORE SYLLABUS

1. Arms, Karen and Camp, P S (1995) Biology (Fourth Edition) (Harcourt Brace & Co., www.harcourtcollege.com)

2. Barret, D and Spencer, P (1992) Genetics and Evolution Biology Advanced Studies (Nelson)

3. Burnet, L (1986) Essentials Genetics – a course book (CUP)

4. Burnet, L (1988) Exercises in Applied Genetics (CUP)

5. Boyle, M and Senior, K (2002) Biology Collins Advanced Science (Collins Educational, www.collinseducational.com) ISBN 0 00713600 5

6. Calladine, C R and Drew, H R (2004) Understanding DNA (Third edition) (Academic Press www.apcatalog.com) ISBN 0121550893

7. Campbell, Neil A and Reece, J B (2005) Biology (Eighth Edition) (Addison Wesley-Benjamin Cummings, www.aw-bc.com) ISBN 978-0321501561

8. Campbell, Neil A and Reece, J B (2005) Biology: Concepts and Connections (Fifth Edition) (Benjamin Cummings) ISBN 978-0805371604

9. Carr, M and Cordell, R (1993) Biochemistry Biology Advanced Studies (Nelson Thornes) ISBN 0 17 448196 9

10. Clegg, C J with MacKean, D J (2000) Advanced Biology, principles and applications (Second Edition) (John Murray) ISBN 0 71 957670 9

11. Cummings, Shelly (Ed) (1998) Current Perspectives in Biology (Wadsworth Pub)

12. Drlica, K (2003) Understanding DNA and Gene Cloning (Wiley and Sons) ISBN 0471434167

13. Gould, James L and Keeton, W T (1996) Biological Science (Sixth edition) (New York: W. W. Norton, www.wwnorton.com)

14. Gregory, J (2000) Applications of Genetics (Second edition) Cambridge Advanced Sciences (CUP, www.cambridge.org) ISBN 0521787254

15. Hayward, G (1990) Applied Genetics (Bath Science 16-19) (Nelson Thornes, www.nelsonthornes.com) ISBN 0 17 438511 0

16. Hogan, Kelley and Palladino, M A (2009) Stem Cells and Cloning, 2/E (Benjamin Cummings) ISBN 0321590023

17. Jones, M, Fosbery, R and Taylor, D (2000) Biology 1 Cambridge Advanced Sciences (CUP, www.cambridge.org) ISBN 052178719X

18. Jones, M and Gregory, J (2001) Biology 2 Cambridge Advanced Sciences (CUP, www.cambridge.org) ISBN 0521797144

19. Jones, M and Jones, G (1997) Advanced Biology (CUP) ISBN 0 52 148473 1

20. Kent, M (2000) Advanced Biology (Oxford University Press, www.oup.co.uk) ISBN 0199141959

21. Kimball’s Biology Pages (2008). E-textbook available free online at http://home.comcast.net/%7Ejohn.kimball1/BiologyPages/ http://users.rcn.com/jkimball.ma.ultranet/BiologyPages/

22. Kreuzer, H and Massey, A (2001) Recombinant DNA and Biotechnology: A guide for Teachers (American Society Microbiology) ISBN 1555811752

23. Kreuzer, H and Massey, A (2001) Recombinant DNA and Biotechnology: A guide for Students (American Society for Microbiology) ISBN 1555811760

24. Kreuzer, H and Massey, A (2001) Molecular Biology and Biotechnology: A Guide For Teachers (American Society for Microbiology) ISBN 1555814719

25. Lowrie, P and Wells, S (2000) Microbiology and Biotechnology Cambridge Modular Sciences (CUP) ISBN 0 52 178723 8

26. Mader, S S (2007) Biology (Ninth edition) (McGraw Hill) ISBN 0073301132

27. Marieb, E N (2006) Human Anatomy and Physiology (Seventh edition) (Benjamin/Cummings) ISBN 0805359095

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28. Micklos, D, Freyer, G A and Crotty, D A (2003) DNA Science – A first course (Second edition) (CSHL) ISBN 0 87969 632 2

29. Minkoff, C, Eli & Baker, Pamela J (2003) Biology Today: An issues approach (Third edition) (Garland Science) 0815341571

30. Nicholl, D S T (2008) An Introduction to Genetic Engineering (Third edition) Studies in Biology (CUP) ISBN 0521615211

31. Palladino, Michael A (2005) Understanding the Human Genome Project (Benjamin Cummins) ISBN-10: 0805348778

32. Purves, W K, Gordon H O, and Heller C H (2003) Life: The Science of Biology (Seventh edition) (W. H. Freeman) ISBN 0716798565

33. Raven, P H and Johnson, G B (2005) Biology (Seventh edition) (McGraw-Hill Publishers) ISBN 0071111824

34. Roberts, M B V, Monger G and Reiss M (2000) Advanced Biology (Nelson Thornes) ISBN 0 17 4887326

35. Rowland, M Biology (Bath Science 16-19) (Nelson Thornes) ISBN 0 17 438425

36. Salters Nuffield Advanced Biology AS Student Book (2008) (Edexcel A Level Sciences) University of York Science Education Group & Curriculum Centre Nuffield. ISBN 1405896078

37. Smith, J E (2008) Biotechnology (Studies in Biology) (Fourth edition) (CUP) ISBN 0521540771

38. Solomon, E, Berg, L R and Martin, D W (2007) Biology (Eighth edition) (Brooks Cole). ISBN 0495317144

39. Starr, C, Taggart, R, Evers, C and Starr, L (2008) Biology: The Diversity of Life (Twelfth edition) (Brooks Cole) ISBN 0495557927

40. Taylor, D J, Green, N P O, Stout, G W and Soper R (1997) Biological Science 1 and 2 (Third edition) (CUP) ISBN 0521561787

41. Taylor, J (2001) Microorganisms and Biotechnology (Bath Science 16-19) (CUP) ISBN 0 17 448255 8

42. Tomkins, S (1989) Hereditary and Human Diversity (CUP) ISBN 0521312299 43. Tobin, Allan J. and Dusheck, J (2004) Asking About Life (Third edition) (Brooks Cole) ISBN

053440653X 44. Vardy, P (1999) The Puzzle of Ethics (Fount) ISBN 0006281443 45. Wallace, R A, Sanders, G P, and Ferl, R J. (1999) Biology: The Science of Life (Fifth edition)

(Harper Collins) 0201502941 46. Wood, E J and Myers, A (1994) Essential Chemistry for Biochemistry BASC I

(The Biochemical Society) Available free online at http://www.biochemistry.org/education/basc01.htm

The following may also be useful.

47. Biological Nomenclature: Standard terms and expressions used in the teaching of Biology (2000) (Third edition) Edited by Alan Cadogan ISBN 0900490365

48. Cadogan, A and Sutton, R Maths for Advanced Biology (1994) (Thomas Nelson and Sons Waltonon-Thames) ISBN 0174482140

49. Edmonson, A and Druce, D (1996) Advanced Biology Statistics (OUP) ISBN 0199146543

50. Ennos, R (2000) Statistical and Data Handling Skills in Biology (Prentice Hall Harlow) ISBN 0582312787

51. Garvin, J W (1986) Skills in Advanced Biology 1: Dealing With Data (Stanley Thornes, Cheltenham) ISBN 085950588 X

52. Garvin, J W and Boyd, J D (1994) Skills in Advanced Biology Series: Volume 2 Observing, Recording and Interpreting Student Text and Teacher's Supplement (Nelson Thornes) ISBN 0 85950 817 X and 0 7487 0043 9

53. Garvin, J W (1995) Skills in Advanced Biology 3: Investigating (Stanley Thornes Cheltenham) ISBN 0748720480

54. Jones, R and Reed, R and Weyers, J (1999) Practical Skills in Biology (Second edition) (Longman Harlow) ISBN 0582298857

55. King, T J, Reiss, M and Roberts, M (2001) Practical Advanced Biology (Nelson Thornes, www.nelsonthornes.com) ISBN 0174483082

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56. Morgan, S (2002) Advanced level practical work for Biology (Hodder Education) ISBN 9780340847121

57. Powell, S (1996) Statistics for science projects (Hodder and Stoughton London) ISBN 0340664096

58. Stewart, A (1995) LAB NOTES Guide to Research in Genetics The Wellcome Trust (http://library.wellcome.ac.uk)

59. Webb, N and Blackmore, R (1985) Statistics for Biologists: A Study Guide (CUP) ISBN 0 521 31712 6

These titles represent some of the texts available at the time of printing this syllabus. Teachers are

encouraged to choose texts for class use which they feel will be of interest to their students and which

will support their own teaching style.

List of readings for enrichment: books, landmark papers, journals

1. Genome (2000) – Matt Ridley

2. The Red Queen: Sex and the Evolution of Human Nature (1995) – Matt Ridley

3. Nature via Nurture: Genes, Experience and What makes us Human (2003) – Matt Ridley

4. DNA the Secret of Life (2003) – James Watson

5. The Double Helix (2001) – James Watson

6. A Passion for DNA (2000) – James Watson

7. My Life in Science (2002) – Sydney Brenner

8. The Blind Watchmaker (1996) – Richard Dawkins

9. The Selfish Gene – Richard Dawkins

10. The Eighth Day of Creation – Harold Judson

11. The Second Creation – Ian Wilmut

12. Genethics – David Suzuki

13. Life on Earth – David Attenborough

14. Trials of Life – David Attenborough

15. The Living Planet – David Attenborough

16. The Private Life of Plants – David Attenborough

17. Origin of Species – Charles Darwin

18. The Silent Spring – Rachel Carson

19. The Beak of the Finch: A Story of Evolution in Our Time – Jonathan Weiner

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GLOSSARY OF TERMS USED IN SCIENCE PAPERS

It is hoped that the glossary (which is relevant only to science subjects) will prove helpful to candidates as a guide, i.e. it is neither exhaustive nor definitive. The glossary has been deliberately kept brief not only with respect to the number of terms included but also to the descriptions of their meanings. Candidates should appreciate that the meaning of a term must depend in part on its context.

1. Define (the term(s)...) is intended literally. Only a formal statement or equivalent paraphrase being required.

2. What do you understand by/What is meant by (the term(s)...) normally implies that a definition should be given, together with some relevant comment on the significance or context of the term(s) concerned, especially where two or more terms are included in the question. The amount of supplementary comment intended should be interpreted in the light of the indicated mark value.

3. State implies a concise answer with little or no supporting argument, e.g. a numerical answer that can be obtained ‘by inspection’.

4. List requires a number of points, generally each of one word, with no elaboration. Where a given number of points is specified, this should not be exceeded.

5. Explain may imply reasoning or some reference to theory, depending on the context.

6. Describe requires candidates to state in words (using diagrams where appropriate) the main points of the topic. It is often used with reference either to particular phenomena or to particular experiments. In the former instance, the term usually implies that the answer should include reference to (visual) observations associated with the phenomena.

In other contexts, describe and give an account of should be interpreted more generally, i.e. the candidate has greater discretion about the nature and the organisation of the material to be included in the answer. Describe and explain may be coupled in a similar way to state and explain.

7. Discuss requires candidates to give a critical account of the points involved in the topic.

8. Outline implies brevity, i.e. restricting the answer to giving essentials.

9. Predict implies that the candidate is not expected to produce the required answer by recall but by making a logical connection between other pieces of information. Such information may be wholly given in the question or may depend on answers extracted in an early part of the question.

10. Deduce is used in a similar way as predict except that some supporting statement is required, e.g. reference to a law/principle, or the necessary reasoning is to be included in the answer.

11. Comment is intended as an open-ended instruction, inviting candidates to recall or infer points of interest relevant to the context of the question, taking account of the number of marks available.

12. Suggest is used in two main contexts, i.e. either to imply that there is no unique answer (e.g. in chemistry, two or more substances may satisfy the given conditions describing an ‘unknown’), or to imply that candidates are expected to apply their general knowledge to a ‘novel’ situation, one that may be formally ‘not in the syllabus’.

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13. Find is a general term that may variously be interpreted as calculate, measure, determine etc.

14. Calculate is used when a numerical answer is required. In general, working should be shown, especially where two or more steps are involved.

15. Measure implies that the quantity concerned can be directly obtained from a suitable measuring instrument, e.g. length, using a rule, or angle, using a protractor.

16. Determine often implies that the quantity concerned cannot be measured directly but is obtained by calculation, substituting measured or known values of other quantities into a standard formula, e.g. relative molecular mass.

17. Estimate implies a reasoned order of magnitude statement or calculation of the quantity concerned, making such simplifying assumptions as may be necessary about points of principle and about the values of quantities not otherwise included in the question.

18. Sketch, when applied to graph work, implies that the shape and/or position of the curve need only be qualitatively correct, but candidates should be aware that, depending on the context, some quantitative aspects may be looked for, e.g. passing through the origin, having an intercept, asymptote or discontinuity at a particular value.

In diagrams, sketch implies that a simple, freehand drawing is acceptable: nevertheless, care should be taken over proportions and the clear exposition of important details.

19. Compare requires candidates to provide both the similarities and differences between things or concepts.

20. Recognise is often used to identify facts, characteristics or concepts that are critical (relevant/appropriate) to the understanding of a situation, event, process or phenomenon.

21. Classify requires candidates to group things based on common characteristics.

Special Note Units, significant figures. Candidates should be aware that misuse of units and/or significant figures, i.e. failure to quote units where necessary, the inclusion of units in quantities defined as ratios or quoting answers to an inappropriate number of significant figures, is liable to be penalised.

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