snab t2 teaching scheme (104 kb)

SNAB T2 Teaching scheme

Topic 2 Genes and healthThis teaching scheme is divided into three parts. Introduction. Road map: a suggested route through Topic 2. Guidance notes for teachers and lecturers. These include a commentary that runs

parallel with the student book with hints and tips on teaching and references to the associated activities.

There are more detailed notes about individual activities in the teacher/lecturer sheets accompanying most activities.

Introduction

The Road map starting on page 2 is a suggested route through Topic 2.The learning outcomes are numbered as in the specification.

Here are notes a route through the topic if two teachers/lecturers are sharing a group for Topic 2. The first teacher starts introduces the topic context, making it clear that the problem is a faulty protein in the membrane. The first teacher looks at the effects of this on the lungs, while the second teacher is considering the effect on the digestive and reproductive system. The first teacher would complete sessions 2 / 3 / 6 / 7 / 8 / 9 / 17 / 18 /19 / 20 / 21. The second teacher would complete sessions 4 / 5 / 10 / 11 / 12 / 13 / 14 / 15 / 16 This covers protein structure before enzymes. The first teacher has more sessions, so if they have done the introduction the second teacher may need to complete genetic screening (sessions 20 and 21) at the end of their sequence.

Note that learning outcome 17 Explain how the expression of a gene mutation in people with cystic fibrosis impairs the functioning of the gaseous exchange, digestive and reproductive system appears in several places throughout the table that starts on page 2.

There is an AS summary chart map at the end of the guidance notes. This shows where concepts are introduced and revisited in later topics. (Some students will have studied cystic fibrosis and its effects, and the associated ethical dilemmas, at GCSE.)

It is assumed that each session is approximately an hour in length. There are more activities than can be done in the time available in most centres, so select a balanced collection according to your and your students’ interests, and the time and resources available. Some activities are labelled ‘Core’. Core activities contain experimental techniques included in the specification, and may appear in questions on the unit exam for this topic. These learning outcomes are in bold in the specification, and in the Read map below. They are underlined in the Guidance notes below. In the Road map, activities are in italics if there is an additional activity covering the same material more directly. Choose which activities students complete, and substitute activities when appropriate.

The Core practicals, and any other practicals completed by students, can be used to assess practical biological skills as part of the Unit 3 coursework assessment.

There are various activities – particularly the interactive tutorials associated with some of the activities – which could be completed by students outside of class time. These activities are shown in the lower half of each ‘Possible activities’ box.

Salters-Nuffield Advanced Biology, Edexcel Pearson © University of York Science Education Group 2008downloaded from www.advancedbiology.org This sheet may have been altered from the original. 1


Road map: a route through Topic 2 Genes and health

Session Areas to be covered Possible activities

1

Introductory presentation (Interactive tutorial)Activity 2.1 After the funeral (A2.01L)Activity 2.2 Personal CF stories (A2.02L)

GCSE review test (Interactive)

2

Diffusion and surface area to volume ratio

6 Describe the properties of gas exchange surfaces in living organisms (large surface area to volume ratio, thickness of surface, difference in concentration) and explain how the structure of the mammalian lung is adapted for rapid gaseous exchange.

17 Explain how the expression of a gene mutation in people with cystic fibrosis impairs the functioning of the gaseous exchange, digestive and reproductive systems.

Activity 2.3 The effect of size on uptake by diffusion (A2.03L) (Practical)

Q2.1–Q2.13

3

Structure of alveoli and SA:V ratio; properties of gas exchange surfaces

6 Describe the properties of gas exchange surfaces in living organisms (large surface area to volume ratio, thickness of surface, difference in concentration) and explain how the structure of the mammalian lung is adapted for rapid gaseous exchange.

Activity 2.4 The structure of alveoli (A2.04L) (Practical)

Activity 2.5 Alveoli and lung surface area (A2.05L) (Interactive)

Checkpoint question 2.1

4/5 Protein structure and function

7 Describe the basic structure of an amino acid (structures of specific amino acids are not required) and the formation of polypeptides and proteins (as amino acid monomers linked by peptide bonds in condensation reactions) and explain the significance of a protein’s primary structure in determining its three-dimensional

Activity 2.6 Proteins (A2.06L) (Interactive)




Session Areas to be covered Possible activities structure and properties (globular and fibrous proteins and types of bonds involved in three dimensionalstructure).

6

Membrane structure

2 Explain how models such as the fluid mosaic model of cell membranes are interpretations of data used to develop scientific explanations of the structure and properties of cell membranes.

Activity 2.7 The fluid mosaic model (A2.07L)

Build models of membranes

7

Membrane structure

5 Describe how membrane structure can be investigated practically, eg by the effect of alcohol concentration or temperature on membrane permeability.

Activity 2.8 Why does the colour leak out of cooked beetroot? (Core) (A2.08L)

8

Transport across membranes

3 Explain what is meant by osmosis in terms of the movement of free water molecules through a partially permeable membrane (consideration of water potential is not required).

4 Explain what is meant by passive transport (diffusion, facilitated diffusion), active transport (including the role of ATP), endocytosis and exocytosis and describe the involvement of carrier and channel proteins in membrane transport.

Activity 2.9 Methods of transport within and between cells (A2.09L) (Practical)

9 Membrane transport in epithelial cells

3 Explain what is meant by osmosis in terms of the movement of free water molecules through a partially permeable membrane (consideration of water potential is not required).

4 Explain what is meant by passive transport (diffusion, facilitated diffusion), active transport (including the role of ATP), endocytosis and exocytosis and describe the involvement of carrier and channel

Activity 2.10 CFTR protein and membrane transport (A2.10L) (Interactive)



Session Areas to be covered Possible activities proteins in membrane transport.

10

Enzyme structure and function

8 Explain the mechanism of action and specificity of enzymes in terms of their three-dimensional structure and explain that enzymes are biological catalysts that reduce activation energy, catalysing a wide range of intracellular and extracellular reactions

17 Explain how the expression of a gene mutation in people with cystic fibrosis impairs the functioning of the gaseous exchange, digestive and reproductive systems.

Checkpoint questions 2.3 and 2.4

11/12

Enzyme concentration and digestion

9 Describe how enzyme concentrations can affect the rates of reactions and how this can be investigated practically by measuring the initial rate of reaction.17 Explain how the expression of a gene mutation in people with cystic fibrosis impairs the functioning of the gaseous exchange, digestive and reproductive systems.

Activity 2.11 Enzyme concentrations and enzyme activity (Core) (A2.11L) (Practical)


13

DNA structure

10 Describe the basic structure of mononucleotides (as a deoxyribose or ribose linked to a phosphate and a base, ie thymine, uracil, cytosine, adenine or guanine) and the structures of DNA and RNA (as polynucleotides composed of mononucleotides linked through condensation reactions) and describe how complementary base pairing and the hydrogen bonding between two complementary strands are involved in the formation of the DNA double helix.

Activity 2.13 Extraction of DNA (A2.13L) (Practical)

Activity 2.12 DNA model (A2.12L)




14/15

Protein synthesis

14 Outline the process of protein synthesis, including the role of transcription, translation, messenger RNA, transfer RNA and the template (antisense) DNA strand (details of the mechanism of protein synthesis on ribosomes are not required at AS).12 Explain the nature of the genetic code (triplet code only; non-overlapping and degenerate not required at AS).

Activity 2.14 Nucleic acids and protein synthesis (A2.14L) (Interactive)

16

DNA replication

11 Describe DNA replication (including the role of DNA polymerase), and explain how Meselson and Stahl’s classic experiment provided new data that supported the accepted theory of replication of DNA and refuted competing theories.15 Explain how errors in DNA replication can give rise to mutations and explain how cystic fibrosis results from one of a number of possible gene mutations

Activity 2.15 Meselson and Stahl’s experiment on DNA replication (A2.15L) (Interactive)

17

Monohybrid inheritance

16 Explain the terms: gene, allele, genotype, phenotype, recessive, dominant, homozygote and heterozygote; and explain monohybrid inheritance, including the interpretation of genetic pedigree diagrams, in the context of traits such as cystic fibrosis, albinism, thalassaemia, garden pea height and seed morphology

Activity 2.16 Reebops (A2.16L) (Practical)


18

Monohybrid inheritance

16 Explain the terms: gene, allele, genotype, phenotype, recessive, dominant, homozygote and heterozygote; and explain monohybrid inheritance, including the interpretation of genetic pedigree diagrams, in the context of traits such as cystic fibrosis, albinism, thalassaemia, garden pea height and seed morphology

Activity 2.17 Inheritance problems (A2.17L)




19

Gene therapy

18 Describe the principles of gene therapy and distinguish between somatic and germ line therapy.

Activity 2.18 Gene therapy – another side to the story (A2.18L)

20

Genetic screening

19 Explain the uses of genetic screening: identification of carriers, preimplantation genetic diagnosis and prenatal testing (amniocentesis and chorionic villus sampling) and discuss the implications of prenatal genetic screening.20 Identify and discuss the social and ethical issues related to genetic screening from a range of ethical viewpoints.

Activity 2.19 Genetic screening (A2.19L)

21

Genetic screening

20 Identify and discuss the social and ethical issues related to genetic screening from a range of ethical viewpoints.

Activity 2.20 Passing it on (A2.20L)

Class discussion

Activity 2.21 Gene mutation – a personal story (A2.21L)



Guidance notes for teachers and lecturers

You could complete these continuing professional development modules before starting Topic 2: CPD1 A road map for SNAB: Building knowledge and principles through the course and CPD2 Contextualised biology teaching through storylines.

Introduction and GCSE reviewThe topic starts by introducing a couple, Claire and Nathan, and the dilemma they face in deciding whether or not to start a family knowing that Claire’s sister had cystic fibrosis (CF). A wide range of traditional biology concepts is required to understand the causes and consequences of cystic fibrosis. The ethical issues faced by the couple as they try to make the decision are highlighted. Some students will have studied cystic fibrosis and its effects, and the associated ethical dilemmas, at GCSE.

Teachers or lecturers may be presenting this material to groups containing either a student with CF or a student who has a close relative or friend who has or had the disease. A great deal of sensitivity will be needed. It is nearly always best to talk before the session to the student(s) concerned on a one-to-one basis, and see how they would like it to be handled.

Discussing the topic with students in advance may help you to find out if any of them have connections with CF. Encourage the student(s) in question to take a positive role within the group; their experiences can make a valuable contribution to discussions. If it is difficult for a student, you may need to present the material in a more traditional way as a series of biological principles.

The sections in the topic address the questions that Claire and Nathan may have asked in their search for information to help their decision-making. The opening page poses some of these questions.

On the first spread there is a reference to the initial GCSE review and the GCSE review test. These cover the main GCSE ideas that students will be expected to draw on during the topic – lung structure and function, digestion, genetics and enzymes. The test itself is open access, and it is assumed that it will be completed outside of class time.

The interactive introduction provides an overview of the topic.

Activity 2.1 After the funeral (A2.01L) This provides an overview of the topic. The play, performed or read as a group activity, provides the opportunity for some discussion. The play is set in the past when Claire was younger. Students use the text of the play to produce a mind map summarising the main issues. This acts as a framework for the topic. Additional notes could be added to this map as the topic unfolds.

Activity 2.2 Personal CF stories (A2.02L) These personal stories give further insights into the effect of CF on affected individuals and their families. This could be used as an alternative to Activity 2.1.

2.1 The effects of CF on the lungs The basic structure of the lungs and the mechanism of breathing are covered in the GCSE review. The media archive within the electronic resources contains the lung diagram of Figure 2.2 with and without labels. Labelling the diagram could be a starting-point. If students have completed the GCSE review this should be straightforward.



In CF patients there is a build up of sticky mucus in the airways. An X-ray of the lungs of a CF patient shows this clearly. There is a CF patient X-ray and CAT scan in the general weblinks for Topic 2. Photographs of normal and CF-affected lungs and pancreases can also be found via the weblinks.

There are two major consequences of sticky mucus in the lungs: the first is an increased chance of infection because the mucus cannot be cleared from the lungs, so pathogenic bacteria can take hold; the second is the blockage of airways by the mucus. The infection problem is described in the student book and Q2.1 and Q2.2 are linked to this section. The blockage of the airways occurs to a greater extent in the later stages of the disease.

The main consequence of airway blockage is a reduction in the effective surface area for gas exchange. The student book has a Key biological principle box with questions introducing the importance of a large surface area to volume ratio. This is followed by a section on the features and properties of gas exchange surfaces. These are complemented by Activities 2.3 to 2.5.

It may be helpful if the continuing professional development module CPD3 Developing practical skills is completed by teachers/lecturers before starting practical work with students.

Activity 2.3 The effect of size on uptake by diffusion (A2.03L) This provides a practical investigation of the effect of surface area on uptake by diffusion. It is supported by student book questions Q2.3 to Q2.13, which guide the student through the ideas.

Activity 2.4 The structure of alveoli (A2.04L)Students follow the instructions on the activity sheet as they observe slides of lungs. The activity is an opportunity to introduce the use of an eye-piece graticule and stage micrometer for measuring. See the Practical support sheet ’Measuring: Size and scale’ (P0.09S). Precision in measuring can be discussed.

Activity 2.5 Alveoli and lung surface area (A2.05L) In this interactive web-based tutorial, students determine the increase in surface area due to the presence of alveoli using calculations of volume. Students also examine a photomicrograph showing a section through lung tissue, and identify features that increase the efficiency of gas exchange. The interactive tutorial can support students as they complete the calculations on the activity sheet, it can also be done without the tutorial. This web-based tutorial could be used instead of Activity 2.4, or could be set as a class assignment to confirm the ideas covered in Activity 2.4.

Checkpoint question 2.1 can be used as a summary question at the end of this section or as a revision question later. Answers to Checkpoint questions are given on the snabonline website; these are only accessible to teachers.

2.2 Why is the CF mucus so sticky?To answer this question, students need to understand what is happening in epithelial cells not affected by the disease. Mucus in the lungs is ‘runny’ because of salt and water transport across the epithelial cells. The mucus is sticky in people with CF; this is due to disruption caused by a faulty transport protein channel in the surface membrane of the epithelial cells. Students therefore need to know about the structure and function of



proteins. They also need to know about membrane structure and methods of transport across membranes.

A Key biological principle box in the student book relates protein structure to function. Activity 2.6 is found within this box.

Activity 2.6 Proteins (AS2.06L)This interactive tutorial describes the basic structure of amino acids and follows the processes involved in the formation of polypeptides. The student worksheet can be completed using the student book without the tutorial.

The interactive tutorial does not differentiate between globular and fibrous proteins – this distinction is made in the student book. Checkpoint question 2.2 requires students to compare and contrast these two types of protein.

Cell membrane structureThe student book goes on to describe the structure of cell membranes, and considers evidence for the fluid mosaic model which explains the structure and properties of cell membranes. These ideas are covered in the interactive tutorial accompanying Activity 2.7. The information is applied in Activity 2.8. Building a model of the cell membrane may help students understand the three-dimensional structure of the membrane; plasticine can be used.

Activity 2.7 The fluid mosaic model (A2.07L)In this activity students evaluate the evidence for different models explaining the structure and function of cell membranes.

Activity 2.8 Why does the colour leak out of cooked beetroot? (A2.08L) Core practicalIn this core practical, students use beetroot to examine the effect of temperature or alcohol on cell membranes and relate this to membrane structure. The activity sheet provides detailed procedures for students to follow. Before starting, students are asked to make a hypothesis and check that the procedure will test their hypothesis. Prompts help them focus on various practical and investigative skills.

How so substances pass through cell membranes?The student book describes diffusion, osmosis, active transport, exocytosis and endocytosis.

Activity 2.9 Methods of transport within and between cells (A2.09L) This activity consists of a set of simple experiments or demonstrations for diffusion and osmosis. There is an interactive simulation of the final experiment using blood in the Biochemistry support on the snabonline website. Students will not have to do any calculations using water potentials.

Q2.16 enables students to check their understanding of the different sorts of transport across membranes.

The student book goes on to identify the types of transport involved in the epithelial cells of the airways. Activity 2.10 CFTR Protein and membrane transport (A2.10L) Chloride and sodium ions move across the membranes in epithelial cells, causing water to enter or leave the cells by osmosis and thus keeping the mucus lining the epithelial cell



surfaces runny. The interactive tutorial has an animation showing this. It also demonstrates how the non-functioning CFTR protein channel causes mucus to be sticky. Students view the animation and complete the accompanying worksheet. This guides students to an understanding of the mechanisms of salt and water secretion in the airways, and of what has gone wrong in people with CF. Ideas presented here were the latest understanding of the mechanism when the material was written. Reasearch into the mechanisms is ongoing. 2.3 How does cystic fibrosis affect other body systems? The student book describes how blockage of the pancreatic duct reduces enzyme secretion into the small intestine; this inevitably has an effect on digestion. To help students understand the consequences of this reduction in enzyme concentration, the student book includes a Key biological principle box on mechanisms of enzyme function. Students can use checkpoint questions 2.3 and 2.4 to produce summary notes on enzyme function before attempting the practical activity.

Activity 2.11 Enzyme concentrations and enzyme activity (A2.11L) Core practicalThis core practical investigates the effect of enzyme concentration on rate of reaction. It provides an opportunity for students to plan an investigation and develop practical and investigative skills. The planning sheet includes a checklist of what students need to include in their plan, together with some suggested methods.

The effects of CF in the reproductive system are described in the student book. The associated Checkpoint question 2.5 requires students to summarise the effects of CF on the gas exchange, digestive and reproductive systems.

2.4 How is the CFTR protein made?Students need to understand how a mutation can result in a faulty protein. The student book and associated activities describe DNA structure, the genetic code and protein synthesis. At AS, students only need to know that the genetic code is a triplet code, and be able to outline the process of protein synthesis. Details of the mechanism of protein synthesis on ribosomes are not required at AS. Protein synthesis is revisited at A2, where the additional detail is added.

Activity 2.12 DNA model (A2.12L) The cut-out model of DNA requires the student to work out the pairing of bases according to base structure and bonding pattern. These are also explained in the student book. If constructed correctly the model will form a double helix.

Activity 2.13 Extraction of DNA (A2.13L) Students extract DNA from onions. This is an easy procedure and the result is always impressive. The DNA is visible largely due to the histone proteins associated with it. There is a diagram to show the packaging of DNA in Topic 3. The size of DNA can be emphasised at this point: it is 3.4 nm in length for every ten bases and one complete turn of the helix. There is no requirement for students to learn this detail.

Activity 2.14 Nucleic acids and protein synthesis (A2.14L)This web-based tutorial and its accompanying worksheet take the student through the process of protein synthesis. DNA and RNA structure and complementary base pairing in both DNA and transcription are clearly demonstrated. The genetic code and translation are illustrated.



(Note that the use of the sense and antisense in the student book follows common usage in academic and industrial literature. Many A-level textbooks use these terms wrongly.)

2.5 What goes wrong with DNA? DNA replication, how mutations can change the amino acids coded for, and the consequences for the functionality of the protein produced, are illustrated using CF and sickle cell anaemia.

This section starts with a description of DNA semi-conservative replication. Then it explains how Meselson and Stahl’s classic experiment provided new data that supported the accepted theory of replication of DNA and refuted competing theories.

Activity 2.15 Meselson and Stahl’s experiment on DNA replication (A2.15L)This is a challenging activity. The interactive tutorial takes students through the Meselson and Stahl experiments and the different theories of replication. Students interpret the results and draw conclusions for themselves about which theory the evidence supports. Teachers/lecturers need to check the activity to ensure that this approach is suitable for their students, and if necessary support them as they complete the activity.

The Public Health Genetics Foundation website has a good educational resources section. It includes information on a range of genetic diseases, epidemiology, ethical issues, and genetic testing. The Wellcome Trust Sanger Institute has good online educational resources. See the general weblinks for Topic 2.

The National Centre for Biotechnology Information in the USA has a series of gene maps showing the location of disease related genes. See the general weblinks for Topic 2.

2.6 How is CF inherited?Monohybrid inheritance is covered in this section. Although the title of the section refers to CF, students need to be able to answer questions on other instances of monohybrid inheritance.

Activity 2.16 Reebops (A2.16L) Construction of Reebops (marshmallow organisms) illustrates the principles of monohybrid inheritance in a student-friendly way.

Activity 2.17 Inheritance problems (A2.17L)Questions are based on the inheritance of genetic diseases and other characteristics including those mentioned in the specification: garden pea height and seed morphology. Co-dominance and sex linkage are included as extension questions; these are not described in the student book.

The Channel 4 website includes an interactive activity which investigates the inheritance of sickle cell anaemia within one family. It is a good activity, although for an able student who grasps the idea, having to complete the sequence of questions for every family member could be tiresome. See the general weblinks for Topic 2.

2.7 How is CF treated? Current ways of treating CF are described in a Did you know? box; they are not required by the specification. However, gene therapy as a possible future treatment is included in the specification and is described in the student book.



Activity 2.18 Gene therapy – another side to the story (A2.18L)In this activity students use the student book to review the techniques used in gene therapy. The activity also considers some of the problems encountered in the trials of this treatment.

The BBSRC website has downloadable information and activity sheets about new technologies, including gene therapy. There is an excellent MRC update on cystic fibrosis on the School Science website under biology 16–18 resources. It includes information about the symptoms, causes and use of gene therapy with questions on each section. Duncan Geddes at the Royal Brompton Hospital describes the UK trials in which he is involved. See the general weblinks for Topic 2, and the Activity 2.18 weblinks.

Students could also search the Internet for the latest progress in the development of gene therapy. Students should be aware that gene therapy research is being used not only for CF but for other conditions too.

2.8 Testing for CFDetailed descriptions in the student book and suggested activities cover testing for both CF and for the presence of the CF mutation. Early diagnosis of CF, and consequent early treatment, can have a significant beneficial effect on the health of the individual.

The student book describes the uses of genetic screening. Students need to be able to explain the uses of genetic screening: identification of carriers, preimplantation genetic diagnosis and prenatal testing (amniocentesis and chorionic villus sampling) and discuss the implications of prenatal genetic screening. The BBSRC website has downloadable information and activity sheets about CF, including a section on testing, it gives examples of DNA samples that students can interpret. See the general weblinks for Topic 2.

It may be helpful if the continuing professional development module CPD4 Ethical debate is completed by teachers/lecturers before undertaking Activity 2.19. The activity within the CPD unit uses genetic screening to illustrate the use of the ethical frameworks and could be used with students – see Ethical debate (D0.04F and D0.04L).

Students need to identify and discuss the social and ethical issues related to genetic screening from a range of ethical viewpoints. The student book section ‘Making ethical decisions – What is right and what is wrong?’ provides a set of ethical frameworks for students to use when discussing and making decisions about ethical issues. Students should study this before completing Activity 2.19 or engage in general class discussion about these issues. The aim of Activity 2.19 is to encourage students to make a decision about an ethical issue, and to support their decision using ideas based on the ethical frameworks. The BioEthics Education Project (BEEP) website supports the teaching and learning of bioethics. It includes a section on genes and health including CF.

Activity 2.19 Genetic screening (A2.19L)Students read the newspaper article raising issues surrounding widespread carrier screening, and then compose a reply either supporting or opposing the position taken by the epidemiologist quoted in the article.

In Checkpoint question 2.7 students use the ethical frameworks to make decisions about genetic screening.



The topic could finish with a class discussion about the options open to Claire and Nathan, the couple in the opening story, and whether they should or should not have a child. It would be interesting to recall any views expressed at the start of the topic and find out if the students’ views have changed.

Activity 2.20 Passing it on (A2.20L) This role-play provides a more structured format to discuss some of the issues covered in the topic.

Activity 2.21 Gene mutation – a personal story (A2.21L)This activity uses a real life story of a girl who has PKU to revise some of the ideas covered in the topic. Activity 2.23 Check your notesStudents can use the checklist of learning outcomes in this activity in their revision.

End-of-topic testsThere is an online interactive end-of-topic test. This test is not accessible to students initially unless set by their teacher/lecturer. The teacher has the option to ‘flick a switch’ to make it open access. There is also a paper-based test for Topic 2 with examination-style questions on the teacher’s and technician’s sites. A mark scheme is also available on these sites. The questions are similar in layout and style to those that are found on exam papers. However, the restriction of questions to only one topic in each test has meant that it has not been possible to include some types of questions that draw on material from different topics.



AS Summary chart

The grid below shows where concepts are introduced and then revisited in later topics.Note: Some of these concepts will be revisited and built on in A2.

Concept Topic 1 Topic 2 Topic 3 Topic 4Biological molecules (monomers combine to form polymers)

Carbohydrate structures and roles in providing and storing energy (not cellulose)

Lipid structures

Phospholipids Protein structures Structures of DNA and RNA

Starch and cellulose structures and functions

Enzymes Enzyme structure and mechanism of action

Effect of enzyme concentration on rate of reaction

Role of ER and Golgi apparatus in formation of extracellular enzymes

Chemical reactions

Condensation and hydrolysis reactions

Antioxidants and radicals

Condensation reactions Hydrophobic and

hydrophilic effects

Condensation reactions

Cell structure Unit membrane structure Prokaryotic and typical eukaryotic (animal) cell structure and ultrastructure

Role of ER and Golgi apparatus in protein transport

Gamete structures and functions Stem cells Cell specialisation and

organisation into tissues, organs and organ systems

Recall typical ultrastructure of animal cell and compare with plant cell ultrastructure

Xylem and sclerenchyma structure and function

Genes help determine the nature of organisms

Roles of DNA and RNA Genetic code Protein synthesis DNA replication and

mutations

Cell specialisation through differential gene expression

Genetic diversity

Cell cycle DNA replication and cell and nuclear division

Role of mitosis and cell cycle for growth and asexual reproduction

Differentiation and the role of stem cells

Energy Energy units, energy balance Role of ATP in active transport

Transport in and out of cells

Passive transport, diffusion, facilitated diffusion, osmosis, active transport, exocytosis and endocytosis

Protein transport Diffusion and osmosis

Salters-Nuffield Advanced Biology, Edexcel Pearson © University of York Science Education Group 2008This sheet may have been altered from the original. 14


Concept Topic 1 Topic 2 Topic 3 Topic 4Transport in organisms to and from exchange surfaces

Mass transport Structure and function of the

circulatory system Solvent properties of water

Mass transport of waters and minerals through plant stems

Organisms exchange materials with the environment

Surface area to volume ratio

Properties of gas exchange surfaces

Inheritance Genetic risk factors for CVD Interaction of genotype and the

environment on development of CVD

Monohybrid inheritance Importance of meiosis and fertilisation in sexual reproduction

Role of meiosis in production of genetic variation, including independent assortment and crossing over

Some characteristics are affected by genotype and the environment

Polygenic inheritance Discontinuous and continuous

variation

Genetic variation (loss and conservation)

Gene technology Gene therapy Gene therapy Genetic screening and

embryo testing Evolution and natural selection

Importance of meiosis and fertilisation in sexual reproduction

Introduction of genetic variation through random assortment (stages of meiosis and chiasmata formation are not required)

Some characteristics affected by genotype and the environment

Adaptation Evolution by natural selection

Classification Prokaryotes and eukaryotes The concept of species Taxonomic groupings

Interactions with the environment

Effect of environment on CVD risk

Some characteristics are affected by genotype and the environment

Biodiversity Endemism Concept of Niche Adaptations of organisms Sustainable resource utilisation Microbial properties of plants

importance of water and mineral ions to plants

Energy flow and recycling of materials in ecosystems

Sustainable resource utilisation



Concept Topic 1 Topic 2 Topic 3 Topic 4Coordination Diabetes Endocrine and exocrine

hormones introduced Melanocyte stimulating

hormone (MSH)

Risk and perception

Concept of risk, risk perception, risk factors for CVD, reducing risk of CVD

Genetic risk factors Risk factors for cancer

Maths/science skills

Calculating probabilities, correlation and causation, calculating obesity indicators, analysis of quantitative health data

Calculating surface area to volume ratios

Continuous/discontinuous variation

The nature of theories, scientific consensus and evidence

Critical evaluation of new data Ecological sampling Measurement of biodiversity and

genetic diversityHealth and Disease

CVD (CHD and stroke) Cancer Atherosclerosis Blood clotting Evaluate design of health studies

Cystic fibrosis, (briefly) sickle cell and thalassaemia, PKU, achondroplasia, Huntington’s disease)

Cancer Drug development

Ethics Experimental use of invertebrates

Ethical frameworks Genetic screening

Stem cells

Applications of biology

Sphygmomanometers / blood pressure monitors

Use of scientific knowledge to reduce health risk

Genetic testing / screening Gene therapy

Use of stem cells for research Use of plant fibres Use of plant starch and oils Drug development Role of zoos and seedbanks


snab t2 teaching scheme (104 kb)

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