Biology SyllabusEffective for examinations from May/June 2008

STRUCTURE OF THE SYLLABUS

Unit 1: Biomolecules, Reproduction and Development

Module 1 - Cell and Molecular BiologyModule 2 - Genetics, Variation and Natural SelectionModule 3 - Reproductive Biology

Unit 2: Bioenergetics, Biosystems and Applications

Module 1 - BioenergeticsModule 2 – Biosystems MaintenanceModule 3 - Applications of Biology

UNIT 1: BIOMOLECULES, REPRODUCTION AND DEVELOPMENTMODULE 1: CELL AND MOLECULAR BIOLOGY

1. Aspects of Biochemistry

1.1 discuss how the structure andproperties of water relate to the rolethat water plays as a medium oflife;

Water as a most suitable solvent inrelation to its essential roles in transport:cellular and systemic levels.

1.2 explain the relationship betweenthe structure and function ofglucose;

Exact molecular ring structure in full.

1.3 explain the relationship betweenthe structure and function ofsucrose;

Exact molecular ring structure in full.

1.4 discuss how the molecularstructure of starch, glycogen andcellulose relate to their functions inliving organisms;

Molecular structure: types of bonds; chainand ring structure where appropriate; 3Dnature; hydrolysis and condensationreactions; relate structure to properties.

1.5 describe the molecular structure ofa triglyceride and its role as asource of energy;

Without going into detail, the studentshould be made aware of the relationshipbetween triglycerides and obesity.

1.6 describe the structure ofphospholipids and their role inmembrane structure and function;

Relate structure to properties and hence tofunction.

1.7 describe the generalised structureof an amino acid, and theformation and breakage of a

peptide bond;1.8 explain the meaning of the terms:primary, secondary, tertiary andquaternary structures ofproteins;

Describe the types of bonding (hydrogen,ionic, disulphide) and hydrophobicinteractions that hold the molecule in shape.

1.9 outline the molecular structure ofhaemoglobin, as an example of aglobular protein, and of collagen,as an example of a fibrous protein;

Ensure that the relationships between theirstructures and functions are clearlyestablished.

1.10 carry out tests for reducing andnon-reducing sugars, starch,lipids and proteins;

Benedict’s test, KI/I2 test, emulsion test,Biuret test.

1.11 investigate and comparequantitatively reducing sugarsand starch.

2. Cell Structure

2.1 make drawings of typical animaland plant cells as seen under thelight microscope;

Clear drawings required.Differences between electron and lightmicroscope and between resolution andmagnification.

2.2 describe and interpret drawingsand electron micrographs of thestructure of membrane systemsand organelles of typical animaland plant cells;

Rough and smooth endoplasmic reticulum,Golgi body, mitochondria, ribosomes,lysosomes, chloroplasts, cell membrane,nuclear envelope, centrioles, nucleus andnucleolus.

2.3 outline the functions of membranesystems and organelles;

As specified in the Explanatory Notes ofSpecific Objective 2.2.

2.4 compare the structure of typicalanimal and plant cells;

Stress similarities and differences.

2.5 describe the structure of aprokaryotic cell;2.6 compare the structure ofprokaryotic cells with that ofeukaryotic cells;

Outline the basis of the endosymbioticdevelopment of eukaryotic cells.

2.7 explain the concepts of tissue andorgan using as an example thedicotyledonous root;2.8 make plan drawings to show thedistribution of tissues within anorgan, such as the dicotyledonousroot.

Use transverse section of a dicotyledonousroot to illustrate tissues includingparenchyma, xylemand phloem. The root isused as an organ.

3. Membrane Structure and Function

3.1 explain the fluid mosaic model ofmembrane structure;

Outline the roles of phospholipids,cholesterol, glycolipids, protein andglycoproteins. Diagrams are required.

3.2 explain the processes of diffusion,facilitated diffusion, osmosis,active transport, endocytosis andexocytosis;

Emphasise the distinction betweendiffusion and osmosis; and active andpassive processes.Diagrams are required.

3.3 investigate the effects on plantcells of immersion into solutionsof different water potentials.

No calculations will be set on waterpotential.

4. Enzymes

4.1 explain that enzymes are globularproteins that catalyse metabolicreactions;

Definition of metabolism, anabolism,catabolismrequired.

4.2 explain the mode of action ofenzymes in terms of an active site,enzyme and/or substrate complex,lowering of activation energy andenzyme specificity;

Properties of enzymes. Induced-fithypothesis.

4.3 explain the effects of pH,temperature, enzymeconcentration and substrateconcentration on enzyme action;

Construction and interpretation ofgraphs.

4.4 explain the effects of competitiveand non-competitive inhibitors onenzyme activity;

Use succinic dehydrogenase, nicotine andinsecticides (pyrethroids) as examples ofenzyme inhibitors.

4.5 investigate the effects oftemperature and substrateconcentration on enzymecatalysedreactions, and explainthese effects.

UNIT 1 MODULE 2: GENETICS, VARIATION AND NATURAL SELECTION

1. Structure and Roles of Nucleic Acids

1.1 illustrate the structure of RNA andDNA using simple labelleddiagrams;

Draw a nucleotide using shapes;recognize (not draw) the structuralformulae of nucleotides, ribose,deoxyribose, pyrimidines, purines; natureof hydrogen bonds.

1.2 explain the importance ofhydrogen bonds and base pairingin DNA replication;

Recognize (include) the significance of 5’and 3’; semiconservative replication;genetic code; initiation, transcription,translation, termination.

1.3 explain the relationship betweenthe sequence of nucleotides and theamino acid sequence in apolypeptide;

1.4 describe the roles of DNA and RNAin protein synthesis;

Different types of RNA and their respectiveroles.

1.5 explain the relationship betweenthe structure of DNA, proteinstructure and the phenotype of anorganism;1.6 describe the relationship between DNA chromatin andchromosomes.

2. Mitotic and Meiotic Cell Division

2.1 describe with the aid of diagrams,the processes involved in mitoticcell division;

Include interphase.

2.2 make drawings from preparedslides, and/or a freshly preparedroot tip squash to show the stagesof mitosis;2.3 explain the importance of DNAreplication for maintaininggenetic stability;2.4 discuss the role and importance ofmitosis in growth, repair andasexual reproduction;2.5 explain what is meant byhomologous pairs ofchromosomes, and the termshaploid and diploid;2.6 describe with the aid of diagrams,the processes involved in meioticcell division;

Include crossing over, alignment ofchromosomes at metaphase, randomsegregation at anaphase. Names of theintermediate stages ofmeiosis not required.

2.7 construct models to demonstratechromosome behaviour in meiosis;

Pipe cleaners, plastic wire, embroiderythread. Bristol board may be used formodelling chromosome behaviour inmeiosis – biodegradable materials notrecommended.

2.8 describe how meiosis contributesto heritable variation.

3. Patterns of Inheritance

3.1 explain the terms: gene, allele,dominant, recessive, codominant,homozygous and heterozygous;

Use examples.

3.2 use genetic diagrams to solveproblems involving monohybridand dihybrid crosses;

Include those involving sex linkages,codominance multiple alleles and dominantepistasis. Candidates should understand theratios.

3.3 analyse the results of a geneticcross by applying the Chi-squaretest;

Formulae will be given. Set out data intabular form.

3.4 determine whether the differencebetween the observed and expectedratio is significant using the resultsof the Chi-square test.

Include the concept of probability. Explainthe use of 0.05 confidence limits and thenull hypothesis.

4. Aspects of Genetic Engineering

4.1 outline the principles of restrictionenzyme use in removing sections ofthe genome;4.2 explain the steps involved inrecombinant DNA technology;

Include isolation of genes; cloning of genes;vectors. Use examples including insulinproduction.

4.3 discuss the possible benefits andhazards of gene therapy;

Use examples including cystic fibrosis.

4.4 discuss the implications of the useof genetically modified organismson humans and the environment.

Medical, agricultural, ethical and socialimplications.

5. Variation and Natural Selection5.1 explain why sexually producedorganisms vary in characteristics;5.2 describe gene and chromosomemutations;5.3 discuss the implications of changesin DNA nucleotide sequence for cellstructure and function in sickle cellanaemia;5.4 explain how mutation brings aboutgenetic variation;

Consider sickle-cell anaemia, DownSyndrome.

5.5 explain why heritable variation isimportant to selection;5.6 explain how environmental factorsact as forces of natural selection;

Include examples, such as resistance toantibiotics, Biston betularia (pepperedmoth).

5.7 explain how natural selection maybe an agent of constancy or anagent of change;

Directional, disruptive and stabilisingselection; knowledge of appropriate graphsis required.

5.8 discuss how natural selectionbrings about evolution;

Darwin’s theory, its observations andconclusions.

5.9 discuss the biological speciesconcept;

Discuss the limitations of this concept, forexample, in breeding.

5.10 explain the process of speciation. Include isolating mechanisms –reproductive, geographic, behaviouraland temporal, allopatric and sympatricspeciation with reference to two namedexamples.

UNIT 1 MODULE 3: REPRODUCTIVE BIOLOGY

1. Asexual Reproduction and Vegetative Propagation

1.1 explain the term asexualreproduction;

Discuss binary fission, budding, asexualspore formation, fragmentation; oneexample of asexual reproduction in plants,for example, ginger, meristems, hormonestimulation, details of the processesinvolved in tissue culture and theproduction of cuttings.

1.2 discuss the advantages anddisadvantages of asexualreproduction;1.3 explain the principles and theimportance of vegetativepropagation as exemplified by theuse of cuttings and tissue culture;1.4 discuss the genetic consequences ofasexual reproduction.

2. Sexual Reproduction in the Flowering Plant

2.1 describe the structure of the antherand the formation of pollen grains;

Annotated diagrams required.

2.2 describe the structure of the ovuleand the formation of the embryosac;

Annotated diagrams required.

2.3 make drawings of the anther andembryo sac fromprepared slides;2.4 explain how cross-fertilisation ispromoted;

Non-synchronous maturation of stamens(Protogyny) and carpels (protandry),separate sexes (dioecy), insect pollination,self incompatibility and sterility.

2.5 discuss the genetic consequences ofsexual reproduction;

Include self fertilization and crossfertilization.

2.6 explain the sequence of events frompollination to fertilization;

Annotated diagrams required.

2.7 explain the significance of doublefertilization in the embryo sac;2.8 discuss the development of the seedand the fruit from the embryo sacand its contents, the ovule and theavary.

Types of fruits not required.

3. Sexual Reproduction inHumans

3.1 describe the structure and functionof the male and femalereproductive systems;

Annotated diagrams required.

3.2 make drawings from preparedslides of the mammalian ovary andtestis;3.3 explain gametogenesis; Explain the difference between the

secondary oocyte and ovum.3.4 compare the structure of theovum and the sperm;3.5 discuss how the structure of theovum and the sperm suit theirfunctions;3.6 explain how hormones regulategametogenesis;3.7 discuss the importance ofhormones in the control of themenstrual cycle;

Emphasise the principle of negativefeedback mechanisms.

3.8 describe how and wherefertilization and implantationnormally occur;3.9 discuss how knowledge of humanreproductive anatomy andphysiology has been applied to thedevelopment of contraceptivemethods;3.10 explain the structure and functionsof the placenta;3.11 discuss the functions of theamnion;3.12 discuss the possible effects ofmaternal behaviour on foetaldevelopment.

Include the role of nutrition, alcohol abuse,use of legal and illicit drugs and cigarettesmoking.

UNIT 2: BIOENERGETICS, BIOSYSTEMS AND APPLICATIONSMODULE 1: BIOENERGETICS

1. Photosynthesis and ATP Synthesis

1.1 describe the structure of adicotyledonous leaf, a palisade celland a chloroplast relating thesestructures to their roles in theprocess of photosynthesis;

Annotated diagrams required.

1.2 make drawings from preparedslides of a transverse section of adicotyledonous leaf, and a palisadecell;1.3 explain the process ofphotophosphorylation;

Include ATP’s functions as the universalenergy “currency” in all living organisms.Include the role of pigments, and electroncarriers in the process. The conversion oflight energy into chemical energy of ATP,the reduction of NADP and the evolution ofoxygen as a by-product should be noted.No biochemical detail is required.

1.4 outline the essential stages of theCalvin cycle involving the lightindependent fixation of carbondioxide;

Knowledge of C4 plants not required.Include the fixation of carbon dioxide byribulose bisphosphate to yieldphosphoglyceric acid (glycerate-3-P) andthe subsequent conversion to triosephosphate and other carbohydrates.Emphasize the roles of ATP and NADP.

1.5 discuss the concept of limitingfactors in photosynthesis;1.6 investigate the effect of limitingfactors on the rate ofphotosynthesis;

Light intensity and carbon dioxideconcentration.

1.7 discuss the extent to whichknowledge of limiting factors canbe used to improve plantproductivity.

2. Cellular Respiration and ATP Synthesis

2.1 outline the stepwise breakdown ofglucose in cellular respiration;

Names of enzymes not required.

2.2 explain the sequence of steps inglycolysis;

Include the initial phosphorylation ofglucose, lysis into two 3-carbon compoundsand the subsequent production of pyruvate,a small yield of ATP and reduced NAD.Recognition of simplified structuralformulae intermediate.

2.3 describe the structure of amitochondrion, relating itsstructure to its function;

Diagram required.

2.4 state the fate of pyruvate in thecytosol when oxygen is available;

Pyruvate enters thematrix and is convertedto acetyl CoA via oxidativedecarboxylation.

2.5 outline the Krebs cycle; Details of structures of intermediatesnot required.

2.6 explain the significance of theKrebs cycle in ATP formation;

Emphasise production of NADH andFADH2; oxidation anddecarboxylation.

2.7 explain the process of oxidativephosphorylation with referenceto the electron transport chain;

Include the roles of hydrogen andelectron carriers; the synthesis of ATPand the role of oxygen. No details of thecarriers are required. A summary ofATP production should be known.

2.8 investigate the rate of oxygenuptake during respiration usinga simple respirometer;

Germinating seeds may be used. Acontrol is needed.

2.9 compare the fate of pyruvate inthe absence of oxygen inanimals and yeast.

Fermentation allows for theregeneration of NAD so that glycolysiscan continue in the absence of oxygen.Include the concept of oxygen debt inmammals; and note that lactate can beconverted back (oxidized) to pyruvatewhen oxygen is again available. Includecommercial uses of yeast.

3. Energy Flow and Nutrient Cycling

3.1 distinguish among the termsecosystem, habitat, ecologicalniche;

Use examples.

3.2 discuss the way in which energyflows in an ecosystem;

Food chains and food webs. Emphasisethe advantages of the food web.

3.3 discuss the efficiency of energytransfer between trophic levels;3.4 discuss the concept of biologicalpyramids;

Include the limitations of the pyramidsof numbers, biomass and energy.

3.5 describe how nitrogen is cycledwithin an ecosystem;

Include the role of microorganisms.

3.6 distinguish between energy flowand nutrient cycling within anecosystem;3.7 explain how energy flow andnutrient cycling are importantfor ecosystems to remain selfsustainingunits.

4. Ecological Systems, Biodiversity and Conservations

4.1 discuss how ecosystems functionas dynamic systems;

Use a named example. Includeinteractions between biotic and abioticfactors.

4.2 explain the concept of biodiversity; Discuss genetic diversity, speciesdiversity and ecosystemdiversity.

4.3 discuss the importance of themaintenance of biodiversity;

Intrinsic, direct and indirect values,including medicine, natural products,tourism.

4.4 discuss how species diversity isrelated to the stability of anecosystem;4.5 explain how in situ and ex situconservation methods are used tomaintain biodiversity.

Protected areas and or reserves, seedbanks, botanic gardens, zoos, spermbanks, embryo banks.

UNIT 2 MODULE 2: BIOSYSTEMS MAINTENANCE

1. The Uptake and Transport ofWater andMinerals

1.1 explain the uptake of ions byactive transport in roots;

Emphasise the role of the endodermis.

1.2 describe the entry of water intoplant roots in terms of waterpotential;1.3 relate the structure of xylemvessels to their function;

Include transport and support roles.

1.4 make drawings from preparedslides of xylem vessels;1.5 outline the ascent of water inplants;

Root pressure, capillarity, cohesion,adhesion and transpiration pull. Includethe role of stomata in transpiration.

1.6 investigate the impact ofenvironmental factors on the rateof transpiration.

Include light and air movements.

2. Transport in the Phloem

2.1 relate the structure of sieve tubesand companion cells to theirfunction;2.2 make drawings of sieve tubes andcompanion cells from preparedmicroscope slides;2.3 label pertinent features in anelectron micrograph of a sievetube and companion cell;2.4 explain how phloem loading in

the leaves occurs against aconcentration gradient;2.5 discuss mass (pressure) flow as apossible mechanism oftranslocation.

Experimental evidence for and against thishypothesis.

3. The Circulatory System of Mammals

3.1 describe the structure of arteries,veins and capillaries, relatingtheir structures to their functions;3.2 make drawings of arteries andveins from prepared microscopeslides;3.3 describe the structure of theheart;

Annotated diagram of the heart andassociated major blood vessels.

3.4 make drawings of a longitudinalsection of the heart;

Use fresh or preserved specimens toemphasize the 3-D structure.

3.5 explain the cardiac cycle and itsinitiation;3.6 discuss the internal factors thatcontrol heart action;3.7 define the terms blood pressureand pulse;3.8 discuss factors affecting bloodpressure;3.9 make drawings of erythrocytesand leucocytes from preparedslides;3.10 explain the role of haemoglobin inoxygen and carbon dioxidetransport;

Flow charts not required.

3.11 describe oxygen dissociationcurves for adult haemoglobin;

Interpret data.

3.12 explain the significance of theeffect of carbon dioxide on oxygendissociation curves (Bohr Effect).

4. Homeostasis and Hormonal Action

4.1 discuss the concept homeostasis; Receptors, effectors, set point, feedbackand homeostatic equilibrium. Emphasizethe dynamics of feedback mechanisms.

4.2 outline the general principles ofhormonal action in animals;

Include ductless glands in animals; targetcells and receptors.

4.3 explain how insulin and glucagonregulate blood glucoseconcentration;4.4 explain the effect of the plantregular molecule, ethylene

Mention the gaseous nature of ethyleneand its effect on respiration. Types of

(ethene), on fruit ripening; fruits not required.4.5 discuss the commercial use made ofethylene in supplying marketreadyfruit.

5. The Kidney, Excretion and Osmoregulation

5.1 explain the need to removenitrogenous and other excretoryproducts from the body;

Review the formation of urea.

5.2 describe the gross structure of thekidney and the detailed structure ofthe nephron and associated bloodvessels;

Annotated diagrams required.

5.3 make drawings of sections of thekidney from prepared sides;5.4 explain the function of the kidneyin terms of excretion andosmoregulation;

Include the role of ADH.

5.5 discuss the clinical significance ofthe presence of glucose and proteinin the urine.

6. Nervous Co-ordination

6.1 describe the structure of motorand sensory neurones;

Annotated diagrams required.

6.2 explain the role of nerve cellmembranes in establishing andmaintaining the resting potential;6.3 describe the conduction of anaction potential along the nervecell membrane;

Emphasise the value of myelinatedneurons in increasing the speed oftransmission.

6.4 explain synaptic transmission; Structure of cholinergic synapse.Annotated diagrams required.

6.5 outline the role of synapses.

UNIT 2 MODULE 3: APPLICATIONS OF BIOLOGY

1. Health and Disease

1.1 discuss the meaning of the term‘health’;

Focus on the physical, mental and socialaspects of health.

1.2 explain the categories of diseaseor illness;

Include physical, mental, social, chronic,infectious, degenerate, inherited, selfinflicted,deficiency, with an example ofeach. Diseases will fit into more than onecategory.

1.3 discuss reasons for the regionaldistribution of Acquired Immune

AIDS: include the biology of the virus;length of incubation period; roles of

Deficiency Syndrome (AIDS),diabetes and cancer;

lifestyle, ease of travel, cost of drugs andlack of education on the spread of thevirus.Diabetes: include the effects of diet,obesity and prenatal malnutrition.Cancer: include roles of environmentalhazards, food additives, viruses, geneticfactors; implications of symptomawareness and failure to seek treatmentin management of the disease.

1.4 analyze data involving incidenceand mortality rates of disease.

Explain the meanings of incidence andmortality rates; students should interpretand analyse data and draw conclusionsand or make predictions.

2. Immunology

2.1 describe the mode of action ofphagocytes;

Review phagocytosis; include role of mastcells and histamine production;complement; phagocytes as antigenpresentingcells.

2.2 define the term, “immuneresponse”;2.3 compare the origin andmaturation of B- and Tlymphocytes;

Include the types of T-cells and theirfunction (refer to HIV); B-cells and theirfunction.

2.4 distinguish between the humoraland the cell-mediated immuneresponses;

Details required.

2.5 explain the role of memory cells inlong-term immunity;

T- and B- memory cells.

2.6 relate the molecular structure of atypical antibody molecule to itsfunction;

Labelled diagram of typical antibodyshowing its ‘Y-shaped’ structure; includethe function of the various parts;specificity of antibody to antigen.

2.7 distinguish between active andpassive immunity, natural andartificial immunity;

Include examples.

2.8 explain the role of vaccination inproviding immunity;2.9 state what is meant by amonoclonal antibody;2.10 describe the use of monoclonalantibodies in diagnosis andtreatment.

The anticancer drug, MabThera; detailsrequired of the use of monoclonalantibodies in pregnancy testing.

3. Social and Preventative Medicine

3.1 discuss the causative relationshipamong diet, obesity and diabetes;

Review the concept of a balanced diet;Body Mass Index (BMI); Type 1 and Type2 diabetes.

3.2 describe the effects of fats on thecardiovascular system;

Atherosclerosis, coronary heart disease,hypertension and stroke. Details of plaqueformation.

3.3 investigate the immediate effectsof exercise on the body;3.4 discuss the consequences ofexercise on the body and thebenefits of maintaining aphysically fit body;

Include long-term and short-termconsequences; relate benefits to theprevention of chronic diseases; refer toVO2 max and cardiac efficiency.

3.5 describe the mechanisms ofinfection for AIDS and denguefever and their causitive agents;

Include processes of infection; replicationof the disease-causing organisms.

3.6 explain how AIDS and denguefever are transmitted;

AIDS: mention lifestyle.Dengue fever: the vector is Aedes aegypti.

3.7 assess the impacts of AIDS anddengue fever regionally;

Include social and economic issues.

3.8 discuss the roles of social,economic and biological factors inthe prevention and control ofAIDS and dengue fever.

4. Substance Abuse

4.1 discuss the meaning of the term,“drug abuse”;

Legal and illegal drugs.

4.2 distinguish between psychologicaland physical dependence;4.3 describe the short-term and long termconsequences of alcoholconsumption on the nervoussystem and the liver;

Short-term - fatty liver, hepatitis; longterm- cirrhosis, cancer, impaired nervoustransmission, demyelination, dehydrationof the brain cells.

4.4 discuss the social consequences ofexcessive alcohol use;

Drinking and driving, aggressivebehaviour, intra-family violence, familybreakdown and petty crime; Include adefinition of ‘a unit of alcohol’; DailyAlcohol Limits (DAL) – safe limits (that is,blood and breath limits)for driving.

4.5 describe the effects of thecomponents of cigarette smoke onthe respiratory andcardiovascular systems.

Passive smoking; effects of nicotine, tarand carbon monoxide on cilia, oxygenuptake, mucus secretion; development ofhyperplasia, emphysema, chronicbronchitis, cancers including lung cancer;vasoconstriction, increase in number oferythrocytes, increase in blood viscosity,formation of blood clots.

OUTLINE OF ASSESSMENT

EXTERNAL ASSESSMENT(80%)Paper 01(1 hour 30minutes)Forty-five multiple-choice items, 15 from eachModule. Each itemis worth 1mark.40%

Paper 02(2 hours 30minutes)Section A - Three compulsory structuredquestions, one from each Module. Each questionis worth 15 marks.Section B – Three compulsory essay questions onefrom each Module. Each question is worth 15marks.40%

INTERNAL ASSESSMENT (20%)The internal assessment will consist of selected practical laboratory exercises.