new as biology teaching scheme

7/30/2019 New as Biology Teaching Scheme

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AS Biology Teaching scheme

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The last column of this table refers to the book:

Edexcel GCE Biology Students Book (Edexcel, 2008) ISBN 978-1-4058-9632-0

Unit 1 Topic 1 Lifestyle, health and risk

Weeknumber

Content of lessons Specificationreference

Students Bookpage numbers

1 Explain the importance of water as a solvent intransport, including its dipole nature.

Distinguish between monosaccharides, disaccharidesand polysaccharides (glycogen and starch amyloseand amylopectin) and relate their structures to their

roles in providing and storing energy (-glucose and

cellulose are not required in this topic).

2

3

12 13

36 - 38

2 Describe how monosaccharides join to formdisaccharides (sucrose, lactose and maltose) andpolysaccharides (glycogen and amylose) throughcondensation reactions forming glycosidic bonds, andhow these can be split through hydrolysis reactions.

Describe the synthesis of a triglyceride by theformation of ester bonds during condensation reactionsbetween glycerol and three fatty acids and recognisedifferences between saturated and unsaturated lipids.

4

5

39

40 - 41


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3 Explain why many animals have a heart and circulation(mass transport to overcome limitations of diffusion inmeeting the requirements of organisms).

Describe the cardiac cycle (atrial systole, ventricularsystole and diastole); the structure and operation ofthe mammalian heart related to its function, includingthe major blood vessels.

6

7

10 11

25 - 26

4 Explain how the structures of blood vessels (capillaries,arteries and veins) relate to their functions.

Describe how the effect of caffeine on heart rate inDaphnia can be investigated practicallyand

consideration of whether there are ethical issues inthe use of invertebrates.

Describe the blood clotting process (thromboplastinrelease, conversion of prothrombin to thrombin andfibrinogen to fibrin) and its role in cardiovasculardisease (CVD).

8

9

10

18 21

27

17

5 Explain the course of events that leads toatherosclerosis (endothelial damage, inflammatoryresponse, plaque formation, raised blood pressure).

Describe the factors that increase the risk of CVD

11

12

30 31


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(genetic, diet, age, gender, high blood pressure,

smoking and inactivity).

Describe the benefits and risks of treatments for CVD(antihypertensives, plant statins, anticoagulants andplatelet inhibitory drugs).

13 64 - 67

6 Analyse and interpret data on the possible significancefor health of blood cholesterol levels and levels ofhigh-density lipoproteins (HDLs) and low-densitylipoproteins (LDLs).

Describe the evidence for a causal relationshipbetween blood cholesterol levels (total cholesterol andLDL cholesterol) and CVD.

Discuss how people use scientific knowledge about theeffects of diet (including obesity indicators), exerciseand smoking to reduce their risk of coronary heartdisease.

14

15

68

69

69

7 Describe how to investigate the vitamin C content of

food and drink.

Analyse data on energy budgets and diet so as to beable to discuss the consequences of energy imbalance,including weight loss, weight gain, and development ofobesity.

16

17

34

50 53


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Analyse and interpret quantitative data on illness andmortality rates to determine health risks (includingdistinguishing between correlation and causation andrecognising conflicting evidence).

18 54 - 61

8 Evaluate design of studies used to determine healthrisks factors (including sample selection and samplesize used to collect data that is both valid andreliable).

Explain why peoples perceptions of risks are oftendifferent from the actual risks (includingunderestimating and overestimating the risks due todiet and other lifestyle factors in the development of

heart disease).

19

20

54 61

68 - 69


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Unit 1 Topic 2: Genes and health

Weeknumber



9 Explain how models such as the fluid mosaic model ofcell membranes are interpretations of data used todevelop scientific explanations of the structure andproperties of cell membranes.

Explain what is meant by the term osmosis in terms ofthe movement of free water molecules through apartially permeable membrane (consideration of waterpotential is not required).

Explain what is meant by passive transport (diffusion,facilitated diffusion), active transport (including therole of ATP), endocytosis and exocytosis and theinvolvement of carrier and channel proteins inmembrane transport.

2

3

4

100 103

106 107

104 - 109

10 Describe the properties of gas exchange surfaces in

living organisms (large surface area to volume ratio,thickness of surface, difference in concentration) andhow the structure of the mammalian lung is adaptedfor rapid gaseous exchange.

Describe how membrane structure can be investigated

5

6

110 113

102


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practically, e.g. by the effect of alcohol concentration

or temperature on membrane permeability.

11 Describe the basic structure of an amino acid(structures of specific amino acids are not required)and the formation of polypeptides and proteins (asamino acid monomers linked by peptide bonds incondensation reactions); the significance of a proteinsprimary structure in determining its three-dimensionalstructure and properties (globular and fibrous proteinsand types of bonds involved in three-dimensionalstructure).

7 42 - 45


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12 Explain the mechanism of action and specificity ofenzymes in terms of their three-dimensional structure;enzymes as biological catalysts that reduce activationenergy, catalysing a wide range of intracellular andextracellular reactions.

Describe how enzyme concentrations can affect therates of reactions and how the effect of these onreaction rate can be investigated practically bymeasuring the initial rate of reaction.

8

9

84 89

88

13 Describe the basic structure of mononucleotides (as a

deoxyribose or ribose linked to a phosphate and a basei.e. thymine, uracil, cytosine, adenine or guanine) andthe structures of DNA and RNA (as polynucleotidescomposed of mononucleotides linked throughcondensation reactions); how complementary basepairing and hydrogen bonding between complementarystrands are involved in the formation of the DNAdouble helix.

Describe DNA replication (including the role of DNApolymerase) and how Meselson and Stahls classicexperiment provided new data which supported theaccepted theory of replication of DNA and refutedcompeting theories.

10

11

74 - 79


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14 Explain the nature of the genetic code (triplet codeonly, non-overlapping and degenerate are not requiredat AS).

Describe a gene as a sequence of bases on a DNAmolecule coding for a sequence of amino acids in apolypeptide chain.

Outline process of protein synthesis, including the roleof transcription, translation, messenger RNA, transferRNA and the template (antisense) DNA strand (detailsof the mechanism of protein synthesis on ribosomes isnot required at AS).

12

13

14

80 - 81


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15 Explain how errors in DNA replication can give rise tomutations with reference to cystic fibrosis (CF)resulting from one of a number of possible genemutations.

Explain the terms gene, allele, genotype, phenotype,recessive, dominant, homozygote and heterozygote;monohybrid inheritance, including the interpretation ofgenetic pedigree diagrams in the context of traits suchas cystic fibrosis (CF), albinism, thalassaemia, gardenpea height and seed morphology.

15

16

82 83

90 - 99

16 Explain how the expression of a gene mutation in

people with cystic fibrosis leads to impairment of thefunctioning of the gaseous exchange, digestive andreproductive systems.

Describe the principles of gene therapy and differencesbetween somatic and germ line therapy.

17

18

114 - 125


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17 Explain the uses of genetic screening in theidentification of carriers, preimplantation geneticdiagnosis and prenatal testing (amniocentesis andchorionic villus sampling) and the implications ofprenatal genetic screening.

Identify and discuss the social and ethical issuesrelated to genetic screening from a range of ethicalviewpoints.

19

20

126 - 129


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Unit 2 Topic 3: The voice of the genome

Weeknumber



18 Distinguish between eukaryotic and prokaryotic cells interms of their structure and ultrastructure.

Describe the ultrastructure of an animal (eukaryotic)cell (nucleus, nucleolus, ribosomes, rough and smoothendoplasmic reticulum, mitochondria, centrioles,lysosomes and Golgi apparatus) and recognise theseorganelles from EM images.

Explain the role of the rough endoplasmic reticulum

(rER) and the Golgi apparatus in protein transportwithin cells and its role in the formation ofextracellular enzymes.

2

3

4

134 - 143

19 Describe how the cells of multicellular organisms canbe organised into tissues, tissues into organs andorgans into systems.

Explain the role of mitosis and the cell cycle for growthand asexual reproduction.

Describe the stages of mitosis and how to prepare aroot tip squash in order to observe them practically.

5

6

7

144 - 155


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20 Explain the role of meiosis in the production ofgametes and genetic variation through recombinationof alleles and genes including independent assortmentand crossing over (details of the stages of meiosis arenot required)

Explain how mammalian gametes are specialised fortheir functions.

Describe the process of fertilisation in mammals andflowering plants (starting with the acrosome reactionin mammals and pollen tube growth in plants andending with the fusion of nuclei) and explain theimportance of fertilisation in sexual reproduction.

8

9

10

156 - 167

21 Explain what is meant by the terms stem cells,pluripotency and totipotency and discuss the way inwhich society uses scientific knowledge to makedecisions about the use of stem cells in medicaltherapies (e.g. regulatory authorities relating to humanembryo research, ability of stem cells to develop intospecialised tissues, potential sources of stem cells, who

could benefit from the therapies, procedures to obtainstem cells and their risks).

Describe how totipotency can be demonstratedpractically using plant tissue culture techniques.

11

12

176 183

170


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22 Explain how cells become specialised throughdifferential gene expression, producing active mRNAleading to synthesis of proteins which in turn controlcell processes or determine cell structure in animalsand plants (details of transcription factors are notrequired at AS).

13 172 - 175

23 Explain how a phenotype of an organism is the result ofan interaction between genotype and the environment(e.g. animal hair colour, human height, MAOA andcancers), but the data on the relative contributions ofgenes and environment are often difficult to interpret.

Explain how some phenotypes are affected by alleles at

many loci (polygenic inheritance) as well as theenvironment (e.g. height) and how this can give rise tophenotypes which show continuous variation.

14

15

184 - 193


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Unit 2 Topic 4: Biodiversity and natural resources

Weeknumber



24 Compare the ultrastructure of plant cells (cell wall,chloroplasts, amyloplasts, vacuole, tonoplast,plasmodesmata, pits and middle lamella) with that

of animal cells.

Compare the structure and function of thepolysaccharides starch and cellulose, including the

role of hydrogen bonds between -glucose moleculesin the formation of cellulose microfibrils.

2

3

200 - 205

25 Explain how the arrangement of cellulosemicrofibrils in plant cell walls and secondarythickening contribute to the physical properties ofplant fibres which can be exploited by humans.

Compare the structures, position in the stem and

function of sclerenchyma fibres (support) and xylemvessels (support and transport of water and mineralions).

Identify sclerenchyma and xylem vessels as seenthrough a light microscope.

4

5

7

218 219

206 213


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Describe how to determine the tensile strength ofplant fibres practically.

8 218

26 Describe how the uses of plant fibres and starch maycontribute to sustainability e.g. plant-basedproducts to replace oil-based plastics.

Explain the importance of water and inorganic ions(nitrate, calcium ions and magnesium ions) toplants.

Describe how to investigate plant mineraldeficiencies practically.

6

9

10

220 221

214 - 215

27 Compare historic drug testing and contemporarydrug testing protocols, e.g. William Witheringsdigitalis soup; double blind trials, placebo andthree-phased testing.

How to investigate the antimicrobial properties ofplants.

12

11

222 227

222

28 Explain the terms biodiversity and endemism anddescribe how biodiversity can be measured within ahabitat using species richness and within a speciesusing genetic diversity, e.g. variety of alleles in agene pool.

13 228 - 229


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29 Describe the concept of niche and discuss examplesof adaptation of organisms to their environment(behavioural, physiological and anatomical).

Describe how natural selection can lead toadaptation and evolution.

14

15

234 - 245

30 Discuss the process and importance of criticalevaluation of new data by the scientific community,which leads to new taxonomic groupings (i.e. threedomains based on molecular phylogeny).

Discuss and evaluate the methods used by zoos andseedbanks in the conservation of endangered species

and their genetic diversity (e.g. scientific research,captive breeding programmes, reintroductionprogrammes and education).

16

17

230 233

246 - 263

EXAMS


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A2 Teaching scheme

(Last 4 weeks of the summer term making a start on A2)

Unit 4 Topic 5: On the wild side

Week

number

Content of lessons Specification

reference

Students Book

page numbers

31 Outline the causes of global warming including therole of greenhouse gases (carbon dioxide andmethane, CH4) in the greenhouse effect.

Describe the effects of global warming (rising

temperature, changing rainfall patterns and seasonalcycles) on plants and animals (distribution of species,development and life cycles).

Discuss how understanding the carbon cycle can leadto methods to reduce atmospheric levels of carbondioxide (including the use of biofuels andreforestation).

14

15

9

32 Explain that the numbers and distribution oforganisms in a habitat are controlled by biotic andabiotic factors.

10


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Explain how the concept of niche accounts for

distribution and abundance of organisms in a habitat.

Describe the concept of succession leading to aclimax community.

12

13

33 Describe how to carry out a study on the ecology of ahabitat to produce valid and reliable data (including

the use of quadrats and transects to assessabundance and distribution of organisms and themeasurement of abiotic factors, e.g. solar energyinput, climate, topography, oxygen availability andedaphic factors).

11

34 Explain the effect of increasing temperature on therate of enzyme activity in plants, animals andmicroorganisms.

Describe how to investigate the effects oftemperature on the development of organisms (e.g.seedling growth rate, brine shrimp hatch rates).

16

17

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