Biology as Scheme of Work

Scheme of work Cambridge International AS and A Level Biology (9700) from 2016 Scheme of work Cambridge International AS and A Level Biology 9700 For examination from 2016

Scheme of work Cambridge International AS and A Level Biology (9700) from 2016

v2.1 5Y02 Cambridge International AS & A Level Biology (9700) from 2016 2

Contents Overview ........................................................................................................................................................................................................................................................... 3

Key concepts ............................................................................................................................................................................................................................................... 3Practical work .............................................................................................................................................................................................................................................. 4Suggested teaching order............................................................................................................................................................................................................................ 5Teacher support ........................................................................................................................................................................................................................................... 8

Unit 1: Biological molecules ............................................................................................................................................................................................................................ 11Unit 2: Cells as the basic units of life .............................................................................................................................................................................................................. 27Unit 3: DNA and the mitotic cell cycle ............................................................................................................................................................................................................. 40Unit 4: Transport and gas exchange ............................................................................................................................................................................................................... 48Unit 5: Disease and protection against disease ............................................................................................................................................................................................. 66Unit 6: The diversity of life .............................................................................................................................................................................................................................. 79Unit 7: Genetics, population genetics and evolutionary processes ................................................................................................................................................................ 92Unit 8: Molecular biology and gene technology ............................................................................................................................................................................................ 111Unit 9: Respiration ........................................................................................................................................................................................................................................ 129Unit 10: Mammalian physiology, control and coordination ........................................................................................................................................................................... 140Unit 11: Plant physiology and biochemistry .................................................................................................................................................................................................. 156



Overview This staged teaching scheme of work provides ideas about how to construct and deliver a two-year course of study with all of the AS Level syllabus taught in Year 1 and the remainder of the A Level syllabus taught in Year 2. The syllabus has been broken down into teaching units, which incorporate one or more of the syllabus units, with suggested teaching activities and learning resources to use in the classroom. Recommended prior knowledge Learners should have attained at least a grade C in IGCSE or O Level Biology, or the equivalent in another award such as Co-ordinated Science. Outline Whole class (W), group work (G), pair (P) and individual activities (I) are indicated, where appropriate, within this scheme of work. Suggestions for homework (H) and formative assessment (F) are also included. The activities in the scheme of work are only suggestions and there are many other useful activities to be found in the materials referred to in the learning resource list. Opportunities for differentiation are indicated as basic and challenging; there is the potential for differentiation by resource, length, grouping, expected level of outcome, and degree of support by the teacher, throughout the scheme of work. Length of time allocated to a task is another possible area for differentiation. Where a learning objectives has been divided so that part of that learning objective content is taught at a different time to the rest of the learning objective, these are identified by (i) or (ii), etc., and the specific part of the learning objective is in bold. Key concepts The key concepts on which the syllabus is built are set out below. These key concepts can help teachers think about how to approach each topic in order to encourage learners to make links between topics and develop a deep overall understanding of the subject. As a teacher, you will refer to these concepts again and again to help unify the subject and make sense of it. If mastered, learners can use the concepts to solve problems or to understand unfamiliar subject-related material.

Cells as the units of life A cell is the basic unit of life and all organisms are composed of one or more cells. There are two fundamental types of cell: prokaryotic and eukaryotic.

Biochemical processes Cells are dynamic: biochemistry and molecular biology help to explain how and why cells function as they do.

DNA, the molecule of heredity Cells contain the molecule of heredity, DNA. Heredity is based on the inheritance of genes.

Natural selection Natural selection is the major mechanism to explain the theory of evolution.


Organisms in their environment All organisms interact with their biotic and abiotic environment.

Observation and experiment The different fields of biology are intertwined and cannot be studied in isolation: observation and enquiry, experimentation and fieldwork are fundamental to biology.

Some of the ideas in this syllabus can take time to be fully understood. By linking them together through the key concepts, learners will have more opportunity for those ideas to make sense to them and how they connect to other areas of the syllabus. The key concepts themselves will not be directly assessed; rather they are themes that learners will be able to use to order their thoughts, themes and knowledge to express answers in examinations and interviews for work or the next stage of their study. As learners progress through the course, it is important that they do not regard the different topics as being totally self-contained and unconnected, studied in complete isolation from one another. By keeping the key concepts to the fore at all stages of your teaching, you can strongly encourage learners to regard the subject as a set of interconnected themes. Learners should be aware that an ability to see how different strands of the syllabus can be pulled together within one key concept is a high-level transferable skill. Linking different areas of their knowledge through a common thread of ideas, or ways of understanding and explaining, is enhancing their higher-order thinking skills. These skills are the building blocks of deeper and broader learning, those that universities look for in their students and which allow learners to answer examination questions fully and with links from more than one part of the syllabus. Teachers can introduce key concepts as an integral part of their teaching approach and consolidate them when appropriate. This will help their learners to appreciate that some themes and theories are revisited and built upon during the course and that, by bringing together very different areas of the syllabus, these themes are fundamental to our understanding of the subject. Focussing on these concepts will improve learners self-confidence in their ability to progress, as well as enabling them to revise more effectively; learners could make mind maps across the syllabus on each of the key concepts as a way of revising. By visualising the subject as being formulated from these basic ideas, they will become better prepared for interviews and future study at university, or be more adaptable to themes currently under research and development in industrial and academic institutions. There is also merit in showing learners how, during the course, they will be biologists studying in a number of inter-related fields that can be drawn together by the key concepts. Examples of these fields - cell biology, biochemistry, physiology, genetics, evolutionary biology, microbiology, epidemiology, immunology, biotechnology, ecology, population biology and conservation biology - can be discussed and linked to the different areas of the syllabus. The key concepts are listed under the relevant learning objectives, those in bold are where the coverage of the learning objective makes a significant contribution to the key concept.

Practical work Practical work is an essential part of science. Scientists use evidence gained from prior observations and experiments to build models and theories. Their predictions are tested with practical work to check that they are consistent with the behaviour of the real world. Learners who are well trained and experienced in practical skills will


be more confident in their own abilities. The skills developed through practical work provide a good foundation for those wishing to pursue science further, as well as for those entering employment or a non-science career.

Twelve Practical Booklets have been developed for this syllabus, six for Paper 3 and six for Paper 5, and are available on Teacher Support at http://teachers.cie.org.uk and are referenced within this scheme of work.

The Teaching A Level Science Practical Skills booklet is also available on Teacher Support at http://teachers.cie.org.uk which contains useful information and suggestions for teaching A Level practical skills. Suggested teaching order The learning objectives and activities in this scheme of work are arranged in a suggested teaching order rather than the order that they appear in the syllabus. It has been written for the staged route, with Units 1 to 5 covering the learning objectives to be studied by all learners in the first year, and which can be assessed by the AS Level qualification. This is followed by Units 6 to 11 which cover all learning objectives that will be assessed by the full A Level qualification at the end of the second year of the course.

For classes taking the linear route, where all learners take the full A Level, this allows for the integrated teaching of AS and A Level learning objectives across both years of the A Level course. The linear route is not covered in this scheme of work. The units within this scheme of work are:

Suggested time allocation (%) AS Level A Level

Unit 1. Biological molecules

10

Water 2.3.d Carbohydrates 2.2.b, 2.2.a, 2.2.c, 2.1.a(i), 2.1.b, 2.2.d, 2.2.e Lipids 2.2.f, 2.2.g, 2.1.a(ii) Proteins 2.1.a(iii), 2.3.a, 2.3.b, 2.3.c Biochemical tests 2.1.a Nucleic acids 6.1.a, 6.1.b Enzymes 3.1.a, 3.1.b, 3.1.c, 3.1.d, 3.2.a, 3.2.b, 3.2.c, 3.2.d

Unit 2. Cells as the basic units of life

9

Cells and microscopy 1.1.d, 1.1.a, 1.1.c Size and magnification calculations 1.1.b, 1.1.e Plant and animal cells 1.2.b, 1.2.c, 1.2.a Bacteria 1.2.d Prokaryotic versus eukaryotic cell structure 1.2.e


Viruses 1.2.f Cell membrane structure and function 4.1.a, 4.1.b, 4.1.c Transport across membranes 4.2.a(v), 4.2.c, 4.2.a(i), 4.2.d, 4.2.b, 4.2.a(ii), 4.2.a(iii), 4.2.f,

4.2.e, 4.2.a(iv) Unit 3. DNA and the mitotic cell cycle

7

Chromosome structure 5.1.a The mitotic cell cycle - overview 5.1.c The mitotic cell cycle DNA replication 6.1.c, 5.1.d The mitotic cell cycle mitosis and cytokinesis 5.1.b, 5.1.e, 5.2.a, 5.2.b Protein synthesis, introduction to genes and mutation 6.2.a, 6.2.b, 6.2.c, 6.2.d

Unit 4. Transport and gas exchange

14

Plant anatomy and histology 7.1.a, 7.1.b, 7.1.c Transport of water and mineral ions 7.2.a, 7.2.c, 7.2.b, 7.2.d, 7.2.e, 7.2.f Transport of assimilates 7.2.g, 7.2.h, 7.2.i Structure to function: plants 7.1.d The mammalian circulatory system 8.1.a, 8.1.b, 8.1.c, 8.1.d, 8.1.e The mammalian heart 8.2.a, 8.2.b, 8.2.c, 8.2.d The human gas exchange system 9.1.a, 9.1.b, 9.1.c, 9.1.d Carriage of respiratory gases 8.1.f, 8.1.g, 8.1.h

Unit 5. Disease and protection against disease

10

Disease and smoking 10.1.a, 9.2.a, 9.2.b Infectious disease 10.1.b, 10.1.c, 10.1.d, 10.1.e Antibiotics 10.2.a, 10.2.b, 10.2.c The immune response 11.1.d, 11.1.a, 11.1.b, 11.1.e, 11.1.c, 11.1.f Antibodies 11.2.a, 11.2.b, 11.2.c Vaccination 11.2.d, 11.2.e

Unit 6. The diversity of life

6

Definitions 18.1.a Classification 18.2.a, 18.2.b, 18.2.c, 18.2.d Biodiversity 18.1.b Fieldwork 18.1.c, 18.1.d, 18.1.e, 18.1.f Conservation, population control and maintaining 18.3.a, 17.3.e, 18.3.b, 18.3.g, 18.3.c, 18.3.d, 18.3.e, 18.3.f,


biodiversity 18.3.h Unit 7. Genetics, population genetics and evolutionary processes

10

Understanding terms 16.1.a, 16.1.b, 16.2.a(i) Meiotic cell division and heredity 16.1.c, 16.1.d, 16.1.e Genetic crosses 16.2.a(ii), 16.2.b, 16.2.c, 16.2.d Biological variation 17.1.a, 17.1.c, 17.1.b, 16.2.e, 16.2.f, 16.2.g Natural selection and population genetics 17.1.d, 17.2.a, 17.2.b, 17.2.c, 17.2.d Evolution and speciation 17.3.a, 17.3.b, 17.3.c, 17.3.d Artificial selection 17.2.e, 17.2.f

Unit 8. Molecular biology and gene technology

9

The control of gene expression 16.3.b, 16.3.a, 16.3.c, 19.1.i Recombinant DNA technology 19.1.a, 19.1.b, 19.1.h, 19.1.e, 19.1.f, 19.1.g, 19.2.c, 19.3.a,

19.3.b, 19.3.c Molecular biology techniques 19.1.c, 19.1.d, 19.2.g Bioinformatics 19.2.a, 19.2.b Prevention and treatment of inherited conditions. 19.2.d, 19.2.e, 19.2.f

Unit 9. Respiration

7

Energy and ATP 12.1.a, 12.1.b Aerobic respiration and ATP synthesis 12.2.a, 12.2.b, 12.2.c, 12.2.d, 12.2.e, 12.1.c, 12.2.g, 12.2.f,

12.1.e(i), 12.1.d, 12.2.i Anaerobic respiration 12.2.k, 12.2.l Comparing anaerobic and aerobic respiration 12.2.j Yeast practical 12.2.h Respiratory substrates, RQs and respirometers 12.1.f, 12.1.g, 12.2.m, 12.1.h

Unit 10. Mammalian physiology, control and coordination

10

Communication systems 15.1.a The nervous system 15.1.b, 15.1.c, 15.1.d, 15.1.e, 15.1.f, 15.1.g, 15.1.h Muscle contraction 15.1.i, 15.1.j, 15.1.k Homeostasis 14.1.a, 14.1.b, 14.1.c Excretion of nitrogenous waste and osmoregulation 14.1.d, 14.1.e, 14.1.f, 14.1.g Control of blood glucose concentration 14.1.h, 14.1.i, 14.1.j Detection of biological molecules in blood and urine 14.1.k, 14.1.l


Hormones of the menstrual cycle 15.1.l, 15.1.m Unit 11. Plant physiology and biochemistry

8

Photosynthesis overview 13.1.b The light dependent stage 13.1.c, 13.1.d, 13.1.e, 13.1.f The light dependent stage - chemiosmosis 12.1.e(ii) The light independent stage 13.1.a, 13.1.g, 13.1.h The chloroplast 13.3.a Factors affecting photosynthesis. 13.2.a, 13.2.b, 13.2.c, 13.2.d, 13.2.e, 13.3.b Control and coordination in plants. 15.2.a, 14.2.a, 14.2.b, 14.2.c, 15.2.b, 15.2.c, 15.2.d, 16.3.d

Suggested teaching order AS Level Unit 1, Biological molecules, could be studied either before or after Unit 2, Cells as the basic units of life. Learners with a good chemistry background will cope well with Unit 1, others will probably find the subject matter in Unit 2 to be more approachable. If Unit 2 is covered first, then learners will need a reminder of previous knowledge of biological molecules learned in earlier studies or a brief introduction to lipids and proteins. Knowledge and understanding from both of these will be used and applied in the rest of the course. The role of DNA in the mitotic cell cycle, Unit 3, follows on quite logically from the work done in Units 1 and 2. Unit 5, Disease and protection against disease is best taught after Unit 4, Transport and gas exchange, as there is a link between mammalian transport and gas exchange in mammals in Unit 4 and non-infectious disease and cells of the immune system in Unit 5. There is much work that can be done in improving data extraction and data analysis skills in Unit 5, where there are fewer opportunities to carry out practical work. As this unit is taught at the end of the AS Level course, teachers may wish to allocate some time to consolidate practical skills gained earlier in the course and prepare learners fully for Paper 3. A Level Having studied eukaryotic and prokaryotic cell structure in Unit 2 (AS Level), Unit 6, The diversity of life, is a straightforward introduction to the A Level syllabus. This covers knowledge and understanding that is useful for Unit 7, Genetics, population genetics and evolutionary processes. Unit 8, Molecular biology and gene technology, allows learners to use some of the concepts covered in Unit 7. Unit 11 can be taught at any time throughout the course if carrying out practical work is dependent on seasonal timing: if taught before Units 9 and 10, the idea of control and coordination and chemiosmosis should be covered. Units 9 and 11 are best taught with a gap in between to avoid confusion for learners when studying the biochemical processes of respiration and photosynthesis. Teacher support Teacher Support (http://teachers.cie.org.uk) is a secure online resource bank and community forum for Cambridge teachers, where you can download specimen and past question papers, mark schemes and other resources. We also offer online and face-to-face training; details of forthcoming training opportunities are posted online. This scheme of work is available as PDF and an editable version in Microsoft Word format; both are available on Teacher Support at http://teachers.cie.org.uk. If you are unable to use Microsoft Word you can download Open Office free of charge from www.openoffice.org.


Resources The resources for this syllabus, including textbooks endorsed by Cambridge, can be found at www.cie.org.uk and Teacher Support http://teachers.cie.org.uk. Endorsed textbooks have been written to be closely aligned to the syllabus they support, and have been through a detailed quality assurance process. As such, all textbooks endorsed by Cambridge for this syllabus are the ideal resource to be used alongside this scheme of work as they cover each learning objective.

Where other textbooks have shown to be useful for some learning objectives they are referred to by the first author. These include:

King T, Reiss M, Roberts M. Practical Advanced Biology. Nelson Thornes, 2nd Edition 2001. ISBN: 9780174483083

Siddiqui S. Comprehensive Practical Biology for A Level. Ferozsons, 1999. ISBN 9690015729

Bio Factsheets. Curriculum Press www.curriculum-press.co.uk These cover a wide range of topics and are also useful for revision and extension work. Individual factsheets can be obtained, as can a complete CD-ROM.

Biological Nomenclature, published by the Society of Biology (formerly the Institute of Biology). This publication can be ordered by emailing the Education Department at the Society of Biology https://www.societyofbiology.org. The symbols, signs and abbreviations used in examination papers follow these recommendations.

CD-ROM Bioscope. Cambridge University Press. ISBN: 9781845650261

A simulation of a real microscope that includes a large number of botanical and zoological microscope slides at a range of magnifications, accompanied by paper-based tasks. It can be used for whole class teaching via a whiteboard or data projector, or by individual students on PCs.

Websites: This scheme of work includes website links providing direct access to internet resources. Cambridge International Examinations is not responsible for the accuracy or content of information contained in these sites. The inclusion of a link to an external website should not be understood to be an endorsement of that website or the site's owners (or their products/services).

The particular website pages in the learning resource column of this scheme of work were selected when the scheme of work was produced. Other aspects of the sites were not checked and only the particular resources are recommended. Websites in this scheme of work, and some other useful websites, include: http://www.ncbe.reading.ac.uk/ The National Centre for Biotechnology Education: protocols and useful information http://www.saps.org.uk/ Science and Plants for Schools: protocols http://www.biology4all.com/resources_library/index.asp Biology 4all: wide range of resources and links to other useful siteshttp://www.s-cool.co.uk/alevel/biology.html S-cool: revision websitehttp://www2.estrellamountain.edu/faculty/farabee/BIOBK/BioBookTOC.html The Online Biology Book, hosted by Estrella Mountain Community Collegehttp://www.rothamsted.ac.uk/notebook/index.php?area=&page= The Molecular Biology Notebook


http://users.rcn.com/jkimball.ma.ultranet/BiologyPages/ Kimballs Biology Pages (especially useful for teacher reference)http://www.cellsalive.com/ Cells Alive: covers a range of topics with straightforward animationshttp://www.worldofteaching.com/A-ZBiologypowerpoints.html PowerPoint presentations donated by teachers http://www.ase.org.uk/resources/ Association for Science Education: educational resources http://www.nuffieldfoundation.org/practical-biology Practical Biology: ideas and lesson plans http://www.nationalstemcentre.org.uk/sciencepracticals The National Stem Centre provides many resources including ideas for practical work http://www.biology-resources.com For learners to revisit IGCSE topicshttp://www.biologyjunction.com/ap_biology_animations.htm Links to websites with animations - many different topics http://www.rsc.org/Education/Teachers/Resources/cfb/index.htm Royal Society of chemistry: Chemistry for biologists https://www.societyofbiology.org/ The Society of biology



Unit 1: Biological molecules Recommended prior knowledge Learners will need some background knowledge in chemistry before embarking on this unit. They should understand the terms atom, molecule, electron and ion. They should also have a basic understanding of covalent and ionic bonding, and of molecular and structural formulae. They should be able to write and understand simple chemical equations. Some knowledge of energy changes (potential energy and bond energy) would be helpful.

http://www.rsc.org/Education/Teachers/Resources/cfb/basicchemistry.htm is a good starting point for learners to revise their knowledge of chemistry. http://www.biology.arizona.edu/biochemistry/tutorials/chemistry/page1.html this also covers basic chemistry for biologists.

Context This unit provides essential reference material for learners when studying all future units in their Cambridge International AS and A Level course. Knowledge of how the structure and properties of biological molecules are related to their functions in cells and in organisms is fundamental to an understanding of many areas of biology. The molecule of heredity, DNA, is a key concept. Cells can be visualised as structural units requiring biological molecules and as dynamic units carrying out biochemical processes. Cells carry out biochemical processes, a key concept, and enzymes catalyse biological reactions. A thorough understanding of enzyme function can be applied to studying processes such as:

DNA replication and protein synthesis in Unit 3, The role of DNA in the mitotic cell cycle; the carriage of carbon dioxide in Unit 4, Transport and gas exchange; gene technology in Unit 8, Molecular biology and gene technology; respiration in Unit 9, Respiration; photosynthesis in Unit 11, Plant physiology and biochemistry.

As part of biotechnology, enzymes are used commercially in a range of applications, with many of these using immobilised enzymes for a more efficient process. Outline This unit introduces learners to the biological molecules that are required by cells for both structural purposes and physiological processes. The main groups of organic biochemicals, carbohydrates, lipids, proteins and nucleic acids, are studied. For carbohydrates, lipids and proteins, there is an emphasis on the relationship between molecular structure, properties and functions in living organisms. Learners study the structure of nucleic acids and discuss DNA as the ideal molecule of inheritance in preparation for Unit 3, The role of DNA in the mitotic cell cycle. Learning objective 2.3.d introduces the concepts of hydrogen bonding and solubility and considers the roles of water in living organisms. This unit builds on knowledge of protein structure in describing and explaining enzyme activity. The mode of action of enzymes and factors that affect enzyme action, including inhibitors, is covered. Learners are introduced to some basic enzyme kinetics. There are many opportunities to carry out practical work, where learning can be reinforced and individual and class results can be analysed. The last section of the unit considers the differences between enzymes free in solution and immobilised enzymes. Teaching time It is recommended that this unit should take approximately 10% of the complete A Level course.


Learning objectives Suggested teaching activities Learning resources

2.3.d explain how hydrogen bonding occurs between water molecules and relate the properties of water to its roles in living organisms (limited to solvent action, specific heat capacity and latent heat of vapourisation) Key concepts Cells as the units of life, Biochemical processes, Organisms in their environment

Discussion / brainstorm: the importance of water to the life of a cell, including hydrogen bonding and as a solvent in biological systems (e.g. blood, phloem sap, cytosol/cytoplasm). (I) (Basic).

Learners make notes, including the following: o Draw and describe hydrogen bonding between water molecules. (I) (Basic) o Make links between hydrogen bonding and the cohesive nature of water

molecules. (I) (Basic) o Explain the link between hydrogen bonding and

the high specific heat capacity of water the high latent heat of vapourisation of water. (I) (Challenging)

o Research examples to show the relationship between the properties of water and its roles in organisms. (I) (Challenging)

Discuss the concept of polar / non-polar and the solubility or otherwise of the biological molecules in this unit. (W) (Basic)

Note Ensure learners can use the following terms (see Unit 2):

hydrophilic hydrophobic polar non-polar charged / ionic uncharged / non-ionic water soluble water-insoluble lipid insoluble lipid soluble

Online http://faculty.fmcc.edu/mcdarby/majors

101book/chapter_03-chemistry/03-Water_Properties.htm

http://www.rsc.org/Education/Teachers/Resources/cfb/water.htm

http://www.worldofmolecules.com/solvents/water.htm

Textbooks/Publications Bio Factsheet 30: The biological

importance of water. Bio Factsheet 78: Chemical bonding in

biological molecules

2.2.b define the terms monomer, polymer, macromolecule, monosaccharide, disaccharide and polysaccharide Key concepts Biochemical processes, DNA, the molecule of heredity

Learners write definitions for macromolecule, monomer and polymer and consolidate. (W) (Basic) o Match the terms with relevant examples (include an introduction of DNA and

RNA nucleotides). o Discuss why lipids do not have monomers. o Construct a simple table (complete bond names later).

type of organic macromolecule

monomer polymer name of bond

carbohydrate monosaccharide polysaccharide protein amino acid polypeptide nucleic acid DNA nucleotide

RNA nucleotide polynucleotide

lipid - -

Online http://www.rsc.org/Education/Teachers

/Resources/cfb/carbohydrates.htm Textbooks/Publications Bio Factsheet 78: Chemical bonding in

biological molecules



Further discussion (W) (Basic) o The macromolecules are based on a skeleton of carbon atoms (life is based on

carbon'), which can form strong bonds with other atoms. o Of the wide range of organic compounds formed, some provide energy for the

cell. Introduce the terms condensation and hydrolysis by discussing the synthesis and

breakdown of polymers. (W) (Basic) Brainstorm some carbohydrates and agree whether monosaccharide, disaccharide

or polysaccharide (W) (Basic) o Learners make notes on: monosaccharides, using the terms triose, pentose and

hexose (glucose, galactose and fructose as e.g. of hexoses); disaccharides (lactose, maltose, sucrose and cellobiose), giving their constituent monosaccharides). (I) (Basic)

Note Useful terms for later:

o pentose - nucleotide and nucleic acid structure in this unit, o hexose for respiration (Unit 9 ) and photosynthesis (Unit 11).

2.2.a describe the ring forms of -glucose and glucose Key concepts Biochemical processes

Provide details of the molecular structure of glucose (see 2.2.b) which, in solution, is mainly in ring form (W) (Basic) o Show learners how to use a logical sequence to build up the ring form of the glucose molecule and number the carbon atoms. Learners practise then draw the molecule from memory. (I) (Challenging)

o Learners complete a range of incomplete diagrams prepared by you, e.g. by adding the -OH and -H groups. (F)

o Progress learners to be able to identify and draw a glucose molecule. (I) (Basic)

Learners make molecular models of and forms of glucose using plastic sphere / bond models or drinking straw models. (P) (Challenging)

Explain that knowledge of the and forms of glucose will help understanding of disaccharide and polysaccharide structures and properties. (W) (Basic)

Online http://www.biologie.uni-hamburg.de/b-

online/e17/17.htm http://www.rsc.org/Education/Teachers

/Resources/cfb/carbohydrates.htm#2 Past Papers Paper 22, Nov 2011, Q4 (a)

2.2.c describe the formation of a glycosidic bond by condensation, with reference both to polysaccharides and to

Outline how a glycosidic bond is formed to produce a disaccharide by a condensation reaction (no details yet of molecular structure). (W) (Basic)

Learners draw the formation of an , 1-4 glycosidic bond and add the name of the bond to their table from 2.2.b. (I) (Challenging)

Past Papers Paper 22, Nov 2011, Q4 (b) Textbooks/Publications



disaccharides, including sucrose Key concepts Biochemical processes

Work through the formation of a , 1-4 glycosidic bond (to form cellobiose). (W) (Challenging)

Tell learners that the glucose monomer of sucrose is -glucose and ask them to use a molecular diagram of a sucrose molecule to work out the structure of a fructose molecule (no need to memorise this). (W) (Challenging)

Learners use the -glucose models previously constructed to form a glycosidic bond. (P) (I) (Basic) o Produce a section of a polysaccharide, e.g. from an amylose or cellulose

molecule. (G) (P) (I) (Challenging)

Note Maltose is formed in nature from degradation reactions (i.e. breakdown) of starch, so

focus the activity on the concept of a condensation reaction to build up a macromolecule and the formation of a glycosidic bond. The formation of maltose illustrates the principle of glycosidic bond formation by a condensation reaction.

Bio Factsheet 78: Chemical bonding in biological molecules

2.1.a (i) carry out tests for reducing sugars and non-reducing sugars, the iodine in potassium iodide solution test for starch, the emulsion test for lipids and the biuret test for proteins to identify the contents of solutions Key concepts Biochemical processes, Observation and experiment

Only the first part of this learning objective is included here: carry out tests for reducing sugars and non-reducing sugars, and the iodine in potassium iodide solution test for starch to identify the contents of solutions Discuss the tests and explain they are useful to identify biochemicals in a range of

plant and animal material. (W) (Basic) o Learners should describe the biochemical tests (food tests is a less helpful

term) and the results obtained, giving conclusions. (W) (Basic) Practical work: carrying out the Benedict's test for reducing sugars.

o Explain that a negative test does not mean an absence of carbohydrate. (I) (Basic)

o Learners test substances that will give positive results (e.g. glucose/fructose/ maltose/lactose solution) and negative results (e.g. sucrose solution, water, protein/starch suspension, vegetable oil). (I) (Basic)

o Learners test natural liquefied biological materials (e.g. fruits, tubers) and liquefied foods from the diet. (I) (Basic) (Challenging)

o Learners test a thin section of fruit placed on a microscope slide (add a few drops of Benedicts and heat over a spirit burner use forceps): use a microscope to observe colour changes. (P) (I) (Challenging)

Discuss the negative result for reducing sugar with sucrose and explain that hot acid is used to hydrolyse sucrose, but neutralisation is required before adding Benedicts. (W) (Basic)

Practical work carrying out the test for a non-reducing sugar, where learners use

Practical booklet 2 Online http://www.mrothery.co.uk/bio_web_pr

ac/practicals/2Food%20Tests.doc http://www.mrothery.co.uk/module1/Mo

d%201%20techniques.htm http://www.biotopics.co.uk/nutrition/foot

es.html Textbooks/Publications King p.19-22 Siddiqui p.56-60 Bio Factsheet 173: How to identify

foods: Food Tests and Chromatography



fresh samples of each of the substances that gave negative results for the reducing sugar test. (I) (Basic)

Practical work to consolidate reducing sugars and non-reducing sugar tests. o Learners identify which unmarked solution is: glucose; sucrose; a mixture of both

glucose and sucrose. (I) (Basic) o Extend this (excess of Benedicts solution) to filtering the precipitates for

comparison and using a colorimeter (if available) to compare filtrates. (P) (I) (Challenging)

Practical work to test for starch in a range of different types of starch (suspensions) and food substances using iodine in potassium iodide solution. Learners see a range of blue-black colours obtained (owing to the differing proportions of amylose to amylopectin). (I) (Basic)

Practical booklet 2 can be carried out after this stage. See the Teachers practical notes regarding the development of certain skills for Paper 3.

Note Remind learners to control variables. AR (analytical reagent) sucrose is preferred to LR (laboratory reagent) sucrose

(preferred to cane sugar) for the non-reducing sugar test (if cane sugar is used, explain that it will contain impurities and may give a slight positive Benedicts test results).

2.1.b carry out a semi-quantitative Benedicts test on a reducing sugar using dilution, standardising the test and using the results (colour standards or time to first colour change) to estimate the concentration Key concepts Biochemical processes, Observation and experiment

Practical work: learners practise, and get a visual impression of, diluting a coloured liquid, using water, to set concentrations. (I) (Basic)

Practical work: learners prepare glucose solutions of known concentration and then carry out the Benedict's test, recording the time taken for the first indication of colour change and to obtain colour standards. (I) (Basic) o Follow-up with a semi-quantitative analysis, comparing time taken and

colour/colour depth to determine the approximate concentration of an unknown solution. (I) (Challenging)

o Evaluate the test with learners and ask for ideas of other semi-quantitative tests (e.g. allow precipitate to settle, dry and weigh). (W) (Challenging)

Practical booklet 2 can be carried out after this stage. See the Teachers practical notes regarding the development of certain skills for Paper 3.

Practical booklet 2 Online http://www.saps.org.uk/secondary/teac

hing-resources/103-estimating-glucose-concentration-in-solution



2.2.d describe the breakage of glycosidic bonds in polysaccharides and disaccharides by hydrolysis, with reference to the non-reducing sugar test Key concepts Biochemical processes, Observation and experiment

Explain how a glycosidic bond can be broken by hydrolysis, referring to monomers and monosaccharides. (W) (Basic)

Learners draw diagrams of the breakage of glycosidic bonds (by hydrolysis) of maltose and sucrose. (I) (Challenging) o Add annotations to explain the ideas behind the non-reducing sugar test. (I)

(Basic) o Use the models of disaccharides previously constructed to demonstrate the

breakage of a glycosidic bond. (P) (I) (Basic) o Extension activity: using molecular diagrams of galactose, lactose and

cellobiose, learners draw diagrams or construct models to show the breakdown of lactose and cellobiose. (P) (I) (Challenging)

Note Learners should describe the breakage of the glycosidic bond in sucrose when

explaining non-reducing sugar test results (see 2.1.a)

Online http://www.rsc.org/Education/Teachers

/Resources/cfb/carbohydrates.htm#2

2.2.e describe the molecular structure of polysaccharides including starch (amylose and amylopectin), glycogen and cellulose and relate these structures to their functions in living organisms Key concepts Cells as the units of life, Biochemical processes

Use the molecular models to show short sections of amylose and amylopectin (or strings of beads on wire) and discuss glycogen structure. (G) (Basic)

Learners describe the difference between the structures (include bonds formed) and highlight the idea of structure to function . o More compact structures for storage linked to the coiling effect (amylose) and

branching (amylopectin). o Branching of amylopectin and glycogen provides large number of ends to

attach /detach glucose units. (I) (Basic) Demonstrate (molecular model / animation) how a straight chain is produced when

forming polysaccharides with alternate -glucose residues that rotate by 180.(W) (Basic)

Emphasise the structure to function of cellulose is different to that of the cell wall. (W) (Basic)

Discuss the role of cellulose, then learners produce explanatory notes with diagrams of how straight parallel chains are useful for structural purposes and how hydrogen bonding (2.3.d) allows parallel cellulose molecules to form fibrils (links to cell wall structure in Unit 2). (I) (Challenging)

Learners complete a gap-filling worksheet prepared by you to serve as a summary of the main learning points for carbohydrates. (F)

Online http://www.rpi.edu/dept/bcbp/molbioch

em/MBWeb/mb1/part2/sugar.htm http://www.calfnotes.com/pdffiles/CN1

02.pdf Textbooks/Publications Bio Factsheet 39: Carbohydrates:

revision summary Bio Factsheet 174: The structure and

function of polysaccharides Past Papers Paper 21, June 2011, Q5 Paper 22, Nov 2012, Q1 (d)

2.2.f Draw the general formula for a fatty acid. Online



describe the molecular structure of a triglyceride with reference to the formation of ester bonds and relate the structure of triglycerides to their functions in living organisms Key concepts Cells as the units of life, Biochemical processes

o Explain that it is a carboxylic acid and outline -COOH as the carboxyl group. o Explain R is a hydrocarbon chain, and extend this to explain saturated or

unsaturated fatty acids. (W) (Basic) Draw the molecular structure of glycerol and state that a triglyceride is produced with

the attachment of three fatty acids in condensation reactions. (W) (Basic) o With prompting, learners work out how ester bonds form and add the name of

the bond to their table of 2.2.b. (I) (Challenging) Learners make simple paper cut-out models of triglycerides to illustrate the absence

of polar groups and show the non-polar exposed fatty acids (so not soluble when in contact with watery liquids). (W) (Basic)

Learners describe evidence that makes triglycerides good energy stores (many C-C bonds; highly reduced so energy can be released by oxidation; insoluble in water so can be localised in the organism). (G) (P) (I) (Challenging)

http://www.biotopics.co.uk/as/lipidcondensation.html

http://www.chemguide.co.uk/organicprops/esters/background.html

Textbooks/Publications Bio Factsheet 42: The structure and

function of lipids. Bio Factsheet 74: The structure and

biological functions of lipids. Bio Factsheet 78: Chemical bonding in

biological molecules Past Papers Paper 21, June 2011, Q5 Paper 22, June 2011, Q5 (a)(b)(i) Paper 22, Nov 2011, Q4 (b)

2.2.g describe the structure of a phospholipid and relate the structure of phospholipids to their functions in living organisms Key concepts Cells as the units of life, Biochemical processes

Learners label a printed diagram showing the structure of a phospholipid molecule and discuss how the presence of polar groups relates to phospholipid behaviour when in contact with watery liquids. (W) (Basic)

Discuss the function of phospholipids in forming the bulk of structure of cell membranes, forming bilayers (link to Unit 2). (W) (Basic)

Learners do research to find out that: there are many different fatty acids and phospholipids; some phospholipids have a nitrogen-containing (choline) portion. (H) (Basic) (Challenging)

Textbooks/Publications Bio Factsheet 152: Phospholipids Past Papers Paper 21, June 2011, Q5 Paper 22, June 2011, Q5 (a)(b)(i)(ii)

(c)(d) Paper 22, Nov 2011, Q4 (b)

2.1.a (ii) carry out tests for reducing sugars and non-reducing sugars, the iodine in potassium iodide solution test for starch, the emulsion test for lipids and the biuret test for proteins to identify the contents of solutions Key concepts

Only the second part of this learning objective is included here: carry out tests emulsion test for lipids to identify the contents of solutions Practical work, testing for lipids using the (ethanol) emulsion test.

o Test vegetable oil and yellow-dyed water. (I) (Basic) o Test crushed fruits and seeds. (I) (Basic)

Practical booklet 2 is designed to be carried out after learners have used the emulsion test as described above.

Note Ensure learners understand that lipids include triglycerides (fats and oils).




es.html



Biochemical processes, Observation and experiment

Textbooks/Publications King p.19-22 Siddiqui p.56-60 Bio Factsheet 173: How to identify


2.1.a (iii) carry out tests for reducing sugars and non-reducing sugars, the iodine in potassium iodide solution test for starch, the emulsion test for lipids and the biuret test for proteins to identify the contents of solutions Key concepts Biochemical processes, Observation and experiment

Only the third part of this learning objective is included here: carry out tests biuret test for proteins to identify the contents of solutions. Practical work, testing for proteins using the biuret test on a solution of egg white,

skimmed milk, chicken or tofu and water. (I) (Basic) Extension practical using a semi-quantitative biuret test: learners prepare a set of

standard solutions and compare the intensity of colour obtained of an unknown with the standards (control variables). (P) (I) (Challenging)

Practical booklet 2 is designed to be carried out after learners have used the biuret test as described above.




es.html Textbooks/Publications King p.19-22 Siddiqui p.56-60 Bio Factsheet 173: How to identify


2.3.a describe the structure of an amino acid and the formation and breakage of a peptide bond Key concepts Biochemical processes

Familiarise learners with the names of the 20 amino acids (encoded by the genetic code see Unit 3) and their three-letter shortened version from labelled diagrams.

Learners write out the general formula of an amino acid, and on the diagrams use a colour code to identify the: R group; part common to them all; amine group; carboxylic acid group. (W) (I) (Challenging) o Learners make notes to show understanding that the side-chain or R (residual)

group can take different forms and that the amino acids can be grouped according to the properties of their R-group. (I) (Basic)

Learners draw simple diagrams of: peptide bond formation (choose two amino acids from their diagram sheet) by condensation (add the name of the bond to their table of 2.3.b); hydrolysis of the dipeptide. (I) (Challenging)

Discuss how a series of condensation reactions leads to the formation of a

Online http://www.biotopics.co.uk/as/aa.html http://www.worldofmolecules.com/life/ Textbooks/Publications Bio Factsheet 78: Chemical bonding in

biological molecules Bio Factsheet 80: Structure and

biological functions of proteins Past Papers Paper 21, June 2011, Q5



polypeptide. (W) (Basic)

Note The names and structures of the amino acids are not required learning. Learners could be introduced to the one-letter abbreviations (useful for Unit 8).

Paper 22, Nov 2011, Q4 (b)

2.3.b 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) that hold these molecules in shape Key concepts Biochemical processes

Learners write down their own polypeptide, 25 amino acids long (choose from the sheet of 2.3.a) using encircled three-letter abbreviations and share with the rest of the group to highlight how an enormous number of different polypeptides can be obtained. Discuss the term primary structure. (W) (I) (Basic)

Make links forward to Unit 2 to the roles of cell structures in protein synthesis to fold / further modify the polypeptide chain. (W) (Basic)

Expand knowledge of hydrogen bonding (from 2.3.d) and 2.2.e) with an explanation of secondary structure. (W) (Basic)

Learners suggest what will hold the chain in place to form a specific 3-D structure before discussing tertiary structure. (W) (Basic) (Challenging) o Include interactions between R groups and the different types of bonding. (W)

(Basic) o Give a simple definition of quaternary structure. (W) (Basic) o Discuss how the loss of tertiary (and quaternary where it exists) results in the

loss of function of the protein. (W) (Basic) o Learners make notes on levels of organisation to highlight the relationship

between the structures and role of bonding in determining shape /stability. (I) (Challenging)

Note For quaternary structure learners should know that this is a protein composed of

more than one polypeptide chain details of the association between chains is not required.

Do not allow learners to think that proteins with quaternary structure must be composed of four polypeptides.

Online http://www.pdb.org/pdb/home/home.do http://www.biology.arizona.edu/bioche

mistry/tutorials/chemistry/page2.html Past Papers Paper 21, Nov 2011, Q3 (a)

2.3.c describe the molecular structure of 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 (The

Show diagrams/images of globular and fibrous proteins to learners for them to describe, and then discuss their features (include solubility) and overall roles (e.g. mainly metabolically active versus mainly structural). Discuss the fact that many fibrous proteins show little or no tertiary structure. (W) (G) (P) (I) (Basic) (Challenging)

Display a diagram / image of haemoglobin for learners to identify the features of a

Online http://en.wikipedia.org/wiki/Hemoglobin http://www.pdb.org/pdb/101/motm.do?

momID=4&evtc=Suggest&evta=Moleculeof%20the%20Month&evtl=TopBar



importance of iron in the haemoglobin molecule should be emphasised. A haemoglobin molecule is composed of two alpha () chains and two beta () chains, although when describing the chains the terms -globin and -globin may be used. There should be a distinction between collagen molecules and collagen fibres) Key concepts Cells as the units of life, Biochemical processes

globular protein and consolidate knowledge of levels of protein structure. (W) (Basic) (Challenging) o Give details of haem and explain the idea of a prosthetic group. (W) (Basic). o Notes made or construct a spider diagram / concept map relating haemoglobin

structure to function. (I) (Challenging) With textbook/internet research, learners make bullet-pointed notes on collagen

structure (include the difference between a molecule and a fibre), linking to its function (including role in blood vessel structure link to Unit 4). (W) (I) (Basic)

Learners construct a comparison table showing the similarities and differences between haemoglobin and collagen. (F)

Compile a set of multiple choice questions from past papers for learners to complete. (F)

Note Mention that haemoglobin has a role in the carriage of carbon dioxide (for Unit 4).

Textbooks/Publications Bio Factsheet 175: Haemoglobin:

structure & function Past Papers Paper 22, June 2011, Q3 (c) Paper 21, Nov 2011, Q3 (c)

2.1.a carry out tests for reducing sugars and non-reducing sugars, the iodine in potassium iodide solution test for starch, the emulsion test for lipids and the biuret test for proteins to identify the contents of solutions Key concepts Biochemical processes, Observation and experiment

Practical investigation, without using instructions, to analyse the biochemicals in a range of unknown solutions or liquefied solid foods. (F)

Practical booklet 2 is a suitable protocol (designed to develop skills for Paper 3). Practical booklet 2 Online http://www.mrothery.co.uk/bio_web_pr



es.html Textbooks/Publications King p.19-22 Siddiqui p.56-60, Bio Factsheet 173: How to identify


6.1.a describe the structure of nucleotides, including the phosphorylated nucleotide ATP (structural formulae are not required)

Draw a labelled diagram of a nucleotide to show the three components: phosphate, pentose sugar and nitrogenous organic base (e.g. using a circle, pentagon and rectangle) for learners to reproduce without help. (W) (I) (Basic)

Give out images of the structural formulae of the four RNA and four DNA nucleotides, ensuring learners know the names of the bases and explaining carbon

Online http://hyperphysics.phy-

astr.gsu.edu/hbase/biology/atp.html http://www.accessexcellence.org/RC/V

L/GG/basePair1.php



Key concepts Biochemical processes, DNA, the molecule of heredity

atom numbering. (W) (Basic) o In a small group, learners interpret how the diagram of a nucleotide has been

derived and identify similarities and differences between the DNA and RNA nucleotides. (G) (Basic) (Challenging)

o Learners draw a labelled generalised RNA and a DNA nucleotide, naming the different pentose sugars and indicating the four different bases for each. (I) (Basic)

Discuss briefly an image of the structural formula of ATP and agree it is a phosphorylated nucleotide before learners draw a simple diagrammatic, annotated version. Include the concept that on removal of a phosphate, energy is released (links with 1.2.c and idea of activated nucleotides for 6.1.c and 6.2.d). (W) (I) (Basic)

Introduce DNA base-pairing for 6.1.b by showing learners structural /skeletal formulae and diagrammatic forms. (W) (Basic) o Allow learners to volunteer that in the diagrams: A and G are the same length

and are longer than T and C (also the same length) as they are double ring structures; the end where the pairs meet shows a complementary nature (e.g. A pointed, T V shaped; G convex, C concave).

o Introduce the concept of complementary base pairing and hydrogen bonding between base pairs (mention also RNA/DNA base-pairing).

Note Base names must be spelt correctly, e.g. thymine not thiamine, and learners must

be clear about the difference between adenine and adenosine. Emphasise that the structural/skeletal formulae of the bases is not required.

Textbooks/Publications Bio Factsheet 129: ATP what it is,

what it does. Past Papers Paper 23, Nov 2011, Q5 (a)

6.1.b describe the structure of RNA and DNA and explain the importance of base pairing and the different hydrogen bonding between bases (include reference to adenine and guanine as purines and to cytosine, thymine and uracil as pyrimidines. Structural formulae for bases are not required but the recognition that purines have a double ring structure and pyrimidines have a single ring structure should be included)

Discuss phosphodiester bond (strong, covalent) formation by condensation reactions to produce a polynucleotide (learners add the bond name to their table of 2.2.b). (I) (Basic)

Learners prepare cut-out nucleotides and, with verbal prompts, build up a short polynucleotide strand, learning about the sugar-phosphate backbone and noting the variation in sequences among the class (different information). (P) (I) (H) (Basic)

Explain the concept of direction of the strand (5 to 3) before learners build up the anti-parallel complementary strand (see final activity 6.1.a). (P) (I) (Challenging) o Point out how base pairing allows the strands to be parallel and the strength of

having many hydrogen bonds (from single weak H bonds). (W) (Basic) Groups of learners can join together their sections to give the idea of a (short!) gene

and the class can see each gene carries different information to code for different proteins. (W) (G) (Basic)

Online http://www.dnaftb.org http://www.hhmi.org/biointeractive/dna/

index.html http://accessexcellence.org/AB/GG/ http://www.ncbe.reading.ac.uk/ncbe/P

ROTOCOLS/DNA/extracting.html http://learn.genetics.utah.edu/content/l

abs/extraction/ http://www.nature.com/nature/dna50/ar

chive.html Past Papers



Key concepts Biochemical processes, DNA, the molecule of heredity

Learners fully label and annotate pre-existing diagrams of DNA. (I) (Basic) Extension activity (see website recommended): learners read about the discovery of

DNA. (I) (Challenging) Progress to RNA structure, giving an outline of the three types of RNA before

learners make notes, including diagrams. (W) (I) (Basic) Learners construct a summary table of the similarities and differences between DNA

and RNA. (F) Summary discussions (small group and class) about requirements of the ideal

molecule of inheritance, resulting in a large poster. (W) (G) (Basic) (Challenging) o Carrying information to allow proteins to be synthesised (sequence of

nucleotides). o Expression to obtain the proteins (transcription and translation, learned later). o Stability (strong sugar-phosphate backbone, many H bonds). o Faithful replication to pass on information to daughter cells (complementary

nature of the strands). o Ability to provide variation (mutations, learned later).

Note Save the nucleotides for DNA replication in Unit 3.

Paper 21, June 2011, Q3 Paper 21, June 2012, Q6 (a)

3.1.a explain that enzymes are globular proteins that catalyse metabolic reactions Key concepts Cells as the units of life, Biochemical processes

Brainstorm or provide multiple choice questions to gauge learner knowledge, including understanding of the terms globular, metabolic and catalyst. Emphasise that previous studies will be extended and name some enzymes they will learn about e.g. DNA polymerase and carbonic anhydrase. (W) (Basic)

State that most enzyme names end with ase and discuss the role of enzymes, e.g. synthesising macromolecules; transferring groups such as phosphates; rearranging molecules to form different ones. (W) (Basic).

Online http://highered.mcgraw-

hill.com/sites/0072495855/student_view0/chapter2/animation__how_enzymes_work.html

http://www.sumanasinc.com/webcontent/animations/content/enzymes/enzymes.html

Textbooks/Publications Bio Factsheet 163: Answering

Questions: enzyme activity. Past Papers Paper 23, Nov 2013, Q6 (c)

3.1.b state that enzymes function inside cells

Explain that enzymes are produced within cells. Learners volunteer the meanings of intra- and extra- and discuss these with respect to enzymes that remain to function

Textbooks/Publications Bio Factsheet 24: Human digestion.



(intracellular enzymes) and outside cells (extracellular enzymes) Key concepts Cells as the units of life, Biochemical processes

intracellularly and others that are released to act extracellularly (e.g. digestive enzymes) (this links later to role of the Golgi body). (W) (Basic)

Note Learners will benefit if they know the meaning of prefixes e.g. intra, extra, poly, milli,

mono. Explain that some have the same meaning but Latin or Greek origins (e.g. uni versus mono).

3.1.c explain the mode of action of enzymes in terms of an active site, enzyme/substrate complex, lowering of activation energy and enzyme specificity (the lock and key hypothesis and the induced fit hypothesis should be included) Key concepts Biochemical processes

Learners make notes on the mode of action of enzymes (remind them of protein structure), highlighting structure to function. (I) (Challenging) o Describe and explain enzyme structure, including the active site. o Include a set of annotated diagrams of the lock and key and induced fit

mechanisms (noting the role of the R groups of amino acids at the active site in binding with the substrate).

o Explain that many/most reactions can be catalysed in both directions. Learners use paper cut-out models to show how enzymes can break up substrates

into smaller molecules or can build up larger molecules from smaller ones. (P) (I) (Basic)

Discuss the concept of lowering activation energy. (W) (Challenging) o Learners annotate a boulder analogy graph to highlight that, although the

energy content of substrate and products is not changed, the reaction pathway follows a lower energy course. (H) (Basic)

o Learners summarise a discussion about the different ways activation energy can be lowered by adding notes to their diagrams or the graph. (I) (Challenging)

Note Use the term complementary to describe how the substrate fits into, and binds at,

the active site. Matches is incorrect. Check understanding of the term substrate - some may have used the term reactant.

Online http://highered.mcgraw-

hill.com/sites/0072495855/student_view0/chapter2/animation__how_enzymes_work.html

http://www.sumanasinc.com/webcontent/animations/content/enzymes/enzymes.html

http://www.learnerstv.com/animation/animation.php?ani=161&cat=Biology

Past Papers Paper 23, Nov 2013, Q6 (c)

3.1.d investigate the progress of an enzyme-catalysed reaction by measuring rates of formation of products (for example, using catalase) or rates of disappearance of substrate (for example, using amylase)

Explain that the course of an enzyme-catalysed reaction can be shown by substrate disappearance or product formation over time. (W) (Basic)

Emphasise that a rate measurement is given per unit time and that there will be a change in the rate during the course of the reaction. (W) (Basic)

Learners carry out practical work using catalase (e.g. from yeast, potato, celery, lettuce) to investigate the rate of release of oxygen (product) from hydrogen peroxide (substrate). (W) (G) (P) (I) (H) (Basic) (Challenging) o A graph should be constructed of volume produced (or mass lost if using an

Practical booklets 4, 5 Online http://www.practicalbiology.org/areas/a

dvanced/bio-molecules/factors-affecting-enzyme-activity/investigating-an-enzyme-controlled-reaction-catalase-and-



Key concepts Biochemical processes, Observation and experiment

electronic balance) over time intervals. o Use the graph to calculate initial rate and explain the initial steep release of

product, which then flattens out. Practical booklet 5. Learners carry out practical work using amylase to time how

long it breaks down starch. Remind learners that using iodine (in potassium iodide) solution on samples shows the loss of starch from the reaction mixture over time. This practical is designed to develop practical skills (itemised in the Teachers practical notes) assessed in Paper 3. (W) (G) (P) (I) (H) (Basic)

Extend practical using amylase if a colorimeter is available to get quantitative results. Trials are required to ensure that the colour of resulting solutions is not too intense for the colorimeter for a graph. (P) (I) (Challenging)

Practical booklet 4 (carry out after Practical booklet 5) is a modification of the method described above using catalase.

hydrogen-peroxide-concentration,47,EXP.html

www.csub.edu/~kszick_miranda/Enzymes%20part2.doc

http://www.saps.org.uk/secondary/teaching-resources/293-learner-sheet-24-microscale-investigations-with-catalase

Textbooks/Publications Bio Factsheet 130: Investigating

catalase Past Papers Paper 21, Nov 2011, Q2 (a)

3.2.a investigate and explain the effects of the following factors on the rate of enzyme-catalysed reactions: Temperature pH (using buffer solutions) enzyme concentration substrate concentration inhibitor concentration Key concepts Organisms in their environment

With prompting, learners explain why measuring the time taken for complete removal of substrate is unsuitable if trying to measure the effect of substrate concentration (with more substrate the rate of reaction is faster, but it takes longer for it all to disappear). (W) (I) (Challenging)

Discuss with learners why, ideally, initial rates should be calculated when comparing enzyme activity under different conditions. (W) (Challenging)

Develop planning skills: learners design an investigation in which several variables need to be controlled and carry this out (ensure that a range of plans is covered). (W) (I) (Basic) (Challenging)

Learners carry out practical activities on factors affecting the rate of an enzyme-catalysed reaction (examples below). (P) (I) (Basic) (Challenging) o Effect of temperature: the catalase experiment in 3.1.d. o Effect of pH: use trypsin to digest protein in a suspension of milk powder. o Effect of enzyme concentration or substrate concentration: use amylase or

diastase to digest a starch suspension. Then learners present their results and contribute to whole class discussion, following up with a written explanation. Construct and annotate graphs showing: o the impact of rate of collisions (temperature, substrate concentration, enzyme

concentration). o the effect on hydrogen bonding, tertiary structure, shape of active site and

complementary fit of substrate (temperature, pH, inhibitors).

Practical booklet 5 Online http://www.ncbe.reading.ac.uk/NCBE/

PROTOCOLS/menu.html http://www.ncbe.reading.ac.uk/NCBE/

PROTOCOLS/juice.html http://www.saps.org.uk/secondary/teac

hing-resources/95-investigating-the-effect-of-competitive-and-non-competitive-inhibitors-on-the-enzyme-ss-galactosidase

http://www.southernbiological.com/ http://www.saps.org.uk/secondary/teac

hing-resources/261-the-inhibition-of-catechol-oxidase-by-lead

http://www.saps.org.uk/secondary/teaching-resources/106-the-effect-of-end-product-phosphate-on-the-enzyme-phosphatase

Textbooks/Publications



(W) (I) (Basic) (Challenging) Possibly demonstrate a practical that uses inhibitors considered to be hazardous to

the environment (minimises the volumes used). Check your local authority regulations concerning safe disposal.

Note Ensure learners can interpret correctly graphs with the same shaped curve, e.g.

course of an enzyme-catalysed reaction / the effect of increasing substrate concentration on the rate of a reaction.

For inhibitor concentration, 3.2.b should be covered first or incorporate this part of 3.2.a with 3.2.b.

To show that an inhibitor is competitive is difficult as separate reaction mixtures with different concentrations of the substrate need to be made up.

King p.64-68 Siddiqui p.69-75. Bio Factsheet 43: Factors affecting

enzyme activity Past Papers Paper 21, June 2011, Q4 Paper 32, June 2013, Q1

3.2.b explain that the maximum rate of reaction (Vmax) is used to derive the Michaelis-Menten constant (Km) which is used to compare the affinity of different enzymes for their substrates Key concepts Biochemical processes, Observation and experiment

Explain Vmax and Km (great detail not required) before learners make notes. (W) (I) (Basic) o Show learners how to obtain Vmax and Km from a graph. o Learners arrive at the idea that the enzyme is saturated with substrate at the

maximum rate of reaction, Vmax. o Show learners how to obtain Km from a graph, the concentration of substrate that

enables the enzyme to achieve half the maximum rate of reaction, or half Vmax Learners obtain (Vmax) and (Km) using one of the graphs constructed from their

practical work. (I) (Basic) Extend learner understanding of Km by discussion or a worksheet providing some

information accompanied by questions. (W) (I) (Challenging) o Explain that (Km) is the affinity of enzyme for its substrate. o Allow learners to suggest that an enzyme with a low Km

has a high affinity for its substrate needs a lower concentration of substrate to reach Vmax than an enzyme with

a high Km. o Explain that an enzyme with a low Km is more likely to be saturated with

substrate in the normal conditions of substrate within a cell, so variations in substrate will have less effect on the rate of formation of product.

o Ask learners to explain why an enzyme with a high Km is likely to vary its activity more (i.e. the concentration of substrate becomes more important).

Learners sketch out two graphs to show the differences between an enzyme with a high Km and an enzyme with a low Km o Annotate graphs with explanations. (I) (Challenging)

Online http://www.worthington-

biochem.com/introbiochem/substrateConc.html



3.2.c explain the effects of reversible inhibitors, both competitive and non-competitive, on the rate of enzyme activity Key concepts Biochemical processes

Following class discussion, learners use resources to make notes and annotated diagrams about enzyme inhibition. (I) (Challenging) o Draw graphs of increasing substrate concentration with and without inhibitors.

Learners construct a summary table showing the differences between competitive and non-competitive inhibition (include the different graphs). (I) (Challenging)

Extension activity: learners investigate and discuss the use of inhibitors as medicinal drugs, including the different uses of competitive versus non-competitive inhibitors. (G) (P) (I) (Challenging)

Note Irreversible inhibition and allosteric regulation could be worth mentioning briefly

when covering 3.2.c.

Online http://www.wiley.com/college/boyer/04

70003790/animations/enzyme_inhibition/enzyme_inhibition.htm

Textbooks/Publications Bio Factsheet 31: Enzyme control of

metabolic pathways. Past Papers Paper 21, Nov 2011, Q2 (b)

3.2.d investigate and explain the effect of immobilising an enzyme in alginate on its activity as compared with its activity when free in solution Key concepts Observation and experiment

Practical: Better milk for cats or similar protocol using a different enzyme. o Discuss how immobilised enzymes are used in everyday applications. (W)

(Basic) o Introduce the use of dipsticks containing glucose oxidase (useful for 14.1.k). (W)

(Basic) Demonstrate the same enzymatic reaction using the enzyme free in solution.

Learners suggest the advantages of immobilising the enzyme rather than using it free (not immobilised) and summarise with a comparison table. (W) (Challenging)

Extension practical: learners use immobilised yeast cells to investigate the effectiveness of their sucrase or catalase enzymes. (P) (I) (Challenging)

Learners complete a worksheet prepared by you to interpret and compare graphical and tabulated data for immobilised enzymes with free enzymes. o Data extraction to compare both for the following factors: temperature; pH;

substrate concentration; inhibitor presence. o Learners consider explanations of the differences between free and immobilised

enzymes, e.g. protective and stabilising effect of the alginate matrix; degradation over time; active sites of immobilised enzymes may not all be available; time taken for diffusion to occur; possibility of slightly altered active site shape when immobilised, amongst others. (I) (Challenging)

Note Experiment and observation, a key concept, has increasingly been used to develop

biotechnological applications here learners can appreciate how biological systems can be used to benefit humans in the everyday world.

Learners should know the method to prepare alginate beads.

Online http://www.rpi.edu/dept/chem-

eng/Biotech-Environ/IMMOB/Immob.htm

http://www.scienceinschool.org/repository/docs/issue10_catmilk.pdf

http://www1.lsbu.ac.uk/water/enztech/imeconom.html

Textbooks/Publications King p.69-73 Siddiqui p.72-73 Bio Factsheet 148: Industrial uses of

enzymes. Past Papers Paper 32, June 2012, Q1 (b) Paper 43, June 2011, Q2 Paper 43, Nov 2011, Q2 (b)



Unit 2: Cells as the basic units of life Recommended prior knowledge Little prior knowledge is required but a basic knowledge of cell structure and practical knowledge of the light microscope would be helpful. The ability to carry out simple mathematical calculations is required. Learners should understand kinetic theory (http://www.chemguide.co.uk/physical/kt/basic.html is a good basic introduction). If Unit 1, Biological molecules, is taught after this unit, some knowledge of lipids, proteins and carbohydrates is useful. Context Unit 1, Biological molecules, leads on to an understanding of the structure of cells and the functions of cell structures, including biological membranes. This unit deals with topics that are fundamental to almost every area of study covered in the AS and A Level course. Cell structure, and the functions of the various organelles, will reappear in numerous contexts. Learners should appreciate the key concept that cells are the basic unit of life and that all living organisms are composed of one or more cells. Learners will need to be reminded, or taught, how to use a light microscope. An understanding of how substances are transported across membranes is essential reference material for other topics in this syllabus, especially those covering plant and animal physiology. Outline Early on, learners are introduced to the use of the microscope in cell studies, including use of the graticule and micrometer to measure cells. Calculations of magnification and actual sizes are included in this unit. This unit covers the two fundamental types of cell, eukaryotic and prokaryotic. Details of cell structure are studied, including the functions of organelles. The fluid mosaic model of membrane structure highlights how membranes can fulfil their roles. The role of the membrane in cell signalling is introduced. The unit also covers the different mechanisms that enable the movement of substances into and out of cells. Teaching time It is recommended that this unit should take approximately 9% of the complete A Level course.



1.1.d explain and distinguish between resolution and magnification, with reference to light microscopy and electron microscopy Key concepts Observation and experiment

Show images of both microscope types and agree more detail can be obtained about cells / cell structure using microscopes. (W) (Basic)

Agree the meaning of magnification learners write a worded version and link this later to the formula used in 1.1.c. Explain how the overall magnification is obtained (eyepiece x objective lens). (W) (Basic)

Introduce resolution, explaining why the resolution of electron microscopes is much higher than that of light microscopes (only enough detail of the workings of each to help understanding of resolution). (W) (Basic) (Challenging) o Explain that detail smaller than 200nm (approximately half the wavelength of

light) cannot be resolved by the light microscope. (W) (Challenging) Explain that increasing magnification is only desirable up to the limit of resolution,

e.g. up to approx. x 1000 for the light microscope (electron microscopes vary considerably).

Compare the TEM and SEM (no details of working required) and the micrographs produced, so learners see the difference between, and usefulness of, both.

Learners suggest advantages and disadvantages of the two types of microscope. (G) (Basic)

Learners observe a range of photomicrographs and electron micrographs and explain which type of microscope was used to produce the image. If these have a mixture of magnifications and scale bars on them, they can be used in 1.1.e. (G) (P) (Basic)

Online http://www.biology4all.com/resources_l

ibrary/details.asp?ResourceID=10 http://www.vcbio.science.ru.nl/en/virtua

llessons/#fesemsimulatie http://www.biology.arizona.edu/cell_bio

/tutorials/cells/cells2.html http://zeiss-

campus.magnet.fsu.edu/articles/basics/index.html

Textbooks/Publications King p.39-41 Bio Factsheet 75: Microscopes and

their uses in Biology Past Papers Paper 21, June 2012, Q2 (a) Paper 22, June 2013, Q2 (b) Paper 22, Nov 2012, Q1 (a)

1.1.a compare the structure of typical animal and plant cells by making temporary preparations of live material and using photomicrographs Key concepts Cells as the units of life, Observation and experiment

Practical: learning how to use the light microscope. (I) (Basic) (Challenging) Brainstorm knowledge of the plant cell structure and animal cell structure and

discuss cells as the units of life. (W) (Basic) Learners construct a comparison table, generalised animal cell v generalised plant

cell, the first row containing simple labelled diagrams. (I) (Basic) (Challenging) Practical: learners make a temporary preparation, check and give comments on

technique and slides made of peers. (I) (Basic) (Challenging) Discuss the slides and compare with the constructed table (links to the ideas in

1.1.d). (W) (Basic)

Note This may be combined with 1.1.c and 1.1.e. Diagram-drawing skills may be introduced here.

Online http://www.biology4all.com/resources_l

ibrary/details.asp?ResourceID=10 Textbooks/Publications Siddiqui p.28-29

1.1.c Revise the units of length commonly used during the course (see 1.1.c) with the Practical booklet 1



use an eyepiece graticule and stage micrometer scale to measure cells and be familiar with units (millimetre, micrometre, nanometre) used in cell studies Key concepts Cells as the units of life, Observation and experiment

metre (meter US) as the SI unit of length. o Learners to perform conversions between nm, m, mm and m. (W) (Basic)

Explain how to use a stage micrometer to calibrate an eyepiece graticule. (W) (Challenging) o Practical booklet 1 is designed to develop the skills required by learners (see

Teachers practical notes) when measuring using an eyepiece graticule and a stage micrometer.

o If learners always use the same microscope, then they can calibrate once only for each objective lens, and keep a record of it. (I) (Challenging)

o Learners use the Bioscope to learn the principles of use. (I) (Challenging) Learners use their calibrated eyepieces to measure a range of microscopic

specimens, choosing one specimen to draw (see 1.1.a). (I) (Basic) (Challenging) o Learners measure the actual length of a part of a specimen on the slide and by

measuring the length drawn on their diagram, they can calculate the linear magnification of their drawing. (I) (Basic)

Note Discourage measuring in cm as many forget to multiply by 10 to convert to mm

before converting to m. The eyepiece graticules can be fitted permanently into the eyepiece of the

microscope. Inexpensive stage micrometer scale kits and eyepiece graticules can be obtained

from the Cambridge publications catalogue www.cie.org.uk/cambridge-for/teachers/order-publications

CD-ROM Bioscope teaching and learning tool

for the skills required to use a graticule and stage micrometer successfully.

Online http://learn.genetics.utah.edu/content/c

ells/scale/ http://www.biology4all.com/resources_l

ibrary/details.asp?ResourceID=10 http://www.vcbio.science.ru.nl/en/virtua

llessons/#fesemsimulatie http://www.biology.arizona.edu/cell_bio

/tutorials/cells/cells2.html http://zeiss-

campus.magnet.fsu.edu/articles/basics/index.html

Textbooks/Publications King p.20-22 Siddiqui p.42-43 Past Papers Paper 31, Nov 2012, Q2 (b)(c) Paper 33, Nov 2012, Q2 (b) Paper 35, Nov 2012, Q2 (b) Paper 12, Nov 2011, Q5

1.1.b calculate the linear magnifications of drawings, photomicrographs and electron micrographs Key concepts Observation and experiment

Hold up an apple, then drawings of the apple: at the same size = magnification x 1; double the size = x 2; half the size = x 0.5. Discuss the mental calculation learners have made to get the right answer. o magnification = image size / actual size. (Group) (Basic)

Explain how to use scale bars to calculate magnification, emphasising that learners should measure the scale bar length and not the image. (W) (Challenging)

Learners complete a worksheet prepared by you with images of varying stated length (nm to mm) and with scale bars only. Use copyright-free images to prepare

Past Papers Paper 22, June 2011, Q4 (b) Paper 21, June 2011, Q1 (a) Paper 23, Nov 2011, Q1 (a) Paper 31, June 2011, Q2 (c)



the worksheet (e.g. Wikipedia). (P) (I) (Basic) (Challenging)

1.1.e calculate actual sizes of specimens from drawings, photomicrographs and electron micrographs Key concepts Observation and experiment

Discuss how the actual sizes can be calculated using the rearranged formula to calculate magnifications. (W) (Basic) o Explain also how to use scale bars to calculate actual sizes. (W) (Basic) o Learners calculate actual sizes from diagrams and the photomicrographs and

electron micrographs from 1.1.d using the given scale bar or magnification. (P) (I) (Basic) (Challenging)

Learners tackle worksheets prepared by you with exam-style (differentiated) questions to calculate actual sizes and magnifications (use past papers). (I) (H) (F) (Basic) (Challenging)

Online http://www.cellsalive.com/howbig.htm Past Papers Paper 21, Nov 2011, Q5 (a)

1.2.b recognise the following cell structures and outline their functions: cell surface membrane nucleus, nuclear envelope and

nucleolus rough endoplasmic reticulum smooth endoplasmic reticulum Golgi body (Golgi apparatus or

Golgi complex) mitochondria (including small

circular DNA) ribosomes (80S in the cytoplasm

and 70S in chloroplasts and mitochondria)

lysosomes centrioles and microtubules chloroplasts (including small circular

DNA) cell wall plasmodesmata large permanent vacuole and

tonoplast of plant cells Key concepts

Interactive session using diagrams and electron micrographs: agree descriptions of the cell structures and discuss their functions. o With reference to plant and animal cells, introduce the terms eukaryote and

eukaryotic, explaining the meaning of true nucleus. (W) (Basic) Provide an overview of how different cell structures are linked, e.g. outline sequence

of events in protein production and secretion. (W) (Basic) Learners identify particular cell structures and state their function using electron

micrographs and photomicrographs, at various magnifications. Include examples of both plant and animal cells (names of cell types not required). (G) (P) (I) (Basic) (Challenging)

Learners label the cell structures on diagrams drawn from electron micrographs of both plant cell and animal cells, and annotate each with a function. (F)

Note Learners should understand (no definition required) that an organelle is a structure

within a cell that has a function. Discuss the idea of the advantages of cellular compartments. For mitochondria and chloroplasts see also 1.2.c.

Online http://www.biologie.uni-hamburg.de/b-

online/library/falk/CellStructure/cellStructure.htm

http://publications.nigms.nih.gov/insidethecell/chapter1.html

http://www.cellsalive.com/cells/cell_model.htm

http://learn.genetics.utah.edu/content/cells/insideacell/

http://www.bscb.org/?url=softcell/index http://cellpics.cimr.cam.ac.uk/ http://library.med.utah.edu/WebPath/HI

STHTML/EM/EM006.html http://www.rothamsted.bbsrc.ac.uk/not

ebook/index.html Textbooks/Publications Bio Factsheet 4: Structure to function

in eukaryotic cells. Past Papers Paper 22, Nov 2011, Q6 (a) Paper 21, June 2012, Q2 (b)(c)(e)



Cells as the units of life, Biochemical processes, DNA, the molecule of heredity

1.2.c state that ATP is produced in mitochondria and chloroplasts and outline the role of ATP in cells Key concepts Biochemical processes

Extend 1.2.b so learners know that ATP is

Biology as Scheme of Work

Documents

Transcript of Biology as Scheme of Work