This fully-resourced lesson describes how the structure of the xylem tissue allows water to be transported in the stem and leaves. Written for AQA A-level Biology, the engaging and detailed PowerPoint and the accompanying worksheets cover the 1st part of specification point 3.4.2 (mass transport in plants) and includes a detailed description of the cohesion-tension theory. The first part of the lesson focuses on the relationship between the structure and function of the xylem tissue. A number of quiz competitions have been included in the lesson to maintain engagement and to introduce key terms. The 1st round does just that and results in the introduction of lignin which leads into the explanation of how the impregnation of this substance in the cell walls result in the death and subsequent decay of the cell structures. Students are encouraged to discuss how the formation of this hollow tube enables the transport of water to be effective. Moving forwards, other structures such as the bordered pits are introduced and an understanding of their function is tested later in the lesson. The remainder of the lesson focuses on the transport of water in the stem and leaves by root pressure and the transpiration pull, which includes cohesion, tension and adhesion. The lesson has been designed to make links to information covered earlier in the lesson as well to topics from earlier in the specification such as cell structures and biological molecules Due to the extensiveness of this lesson, it is estimated that it will take in excess of 2/3 A-level teaching hours to cover the detail included in this lesson.

This fully-resourced lesson explores how projects to sequence the genomes of both simple and complex organisms can be used. Both the detailed PowerPoint and accompanying resources have been designed to cover the content of point 8.3 of the AQA A-level Biology specification. The start of the lesson describes each step of Sanger’s chain termination method and demonstrates how this method has paved the way for other projects. The use of the modified nucleotides are explained and links are made to the topic 4 and 2 where protein synthesis and DNA replication were first introduced. Students will learn how the radioactively-labelled nucleotide at the end of each fragment allows the next base to be determined. Key processes like gel electrophoresis are introduced and details provided to support the students when this is encountered in greater detail in 8.4.3. Moving forwards, the applications of sequencing in simple organisms like viruses and bacteria are explored and the students are challenged on their prior knowledge of bacterial pathogenesis and current understanding of sequencing through a series of exam-style questions. The final part of the lesson looks at the difficulties of translating genome knowledge into proteome knowledge and considers the development of automated methods. Due to the detail and extensiveness of this lesson, it is estimated that it will take in excess of 2 hours of allocated A-level teaching time to cover all of the points which have been written into the various tasks

This fully-resourced lesson describes the light independent reaction of photosynthesis and explains how reduced NADP is used to form a simple sugar. The detailed PowerPoint and accompanying resources have been designed to cover the second part of point 5.1 of the AQA A-level Biology specification and lengthy planning has ensured that links are continually made to the previous lesson on the light-dependent reaction so that students can understand how the products of that stage are essential for the Calvin cycle The lesson begins with an existing knowledge check where the students are challenged to recall the names of structures, substances and reactions from the light-dependent stage in order to reveal the abbreviations of the main 3 substances in the light-independent stage. This immediately introduces RuBP, GP and TP and students are then shown how these substances fit into the cycle. The main section of the lesson focuses on the three phases of the Calvin cycle and time is taken to explore the key details of each phase and includes: The role of RuBisCO in carbon fixation The role of the products of the light-dependent stage, ATP and reduced NADP, in the reduction of GP to TP The use of the majority of the TP in the regeneration of RuBP A step-by-step guide, with selected questions for the class to consider together, is used to show how 6 turns of the cycle are needed to form the TP that will then be used to synthesise 1 molecule of glucose. A series of exam-style questions are included at appropriate points of the lesson and this will introduce limiting factors as well as testing their ability to answer questions about this stage when presented with an unfamiliar scientific investigation. The mark schemes are included in the PowerPoint so students can assess their understanding and any misconceptions are immediately addressed. This lesson has been specifically written to tie in with the previous lessons on the structure of a chloroplast and the light-dependent stage as well as upcoming lesson on limiting factors

This detailed lesson describes the role of the strand of mRNA, the tRNA molecules, the amino acids and the ribosome during the second stage of protein synthesis - translation. Both the PowerPoint and accompanying resources have been designed to cover the second part of point 6.2 (d) of the CIE International A-level Biology specification and ties in with the first part of this specification point which covered transcription. Translation is a topic which is often poorly understood and so this lesson has been written to enable the students to understand how to answer the different types of questions by knowing and including the key details of the structures involved. The lesson begins by challenging the students to consider why it is so important that the amino acids are assembled in the correct order during the formation of the chain. Moving forwards, a quick quiz round called “LOST IN TRANSLATION” is used to check on their prior knowledge of the mRNA strand, the tRNA molecules, the genetic code and the ribosomes. The next task involves a very detailed description of translation that has been divided into 14 statements which the students have to put into the correct order. By giving them a passage that consists of this considerable detail, they can pick out the important parts to use in the next task where they have to answer shorter questions worth between 3 and 4 marks. These types of questions are common in the assessments and by building up through the lesson, their confidence to answer this type should increase. The final two tasks of the lesson involve another quiz called “The protein synthesis game”, where the teams compete to transcribe and translate in the quickest time before using all the information from the lessons on protein synthesis to answer some questions which involve the genetic code and the mRNA codon table.

This detailed lesson describes the pressure changes that occur during the cardiac cycle and explains how ECG traces can be interpreted. The PowerPoint and accompanying resources have been designed to cover points 4.4 (iii) & (v) of the Edexcel A-level Biology B specification and focuses on the importance of the valves in ensuring unidirectional movement of blood during the cycle. The start of the lesson introduces the cardiac cycle as well as the key term systole, so that students can immediately recognise that the three stages of the cycle are atrial and ventricular systole followed by diastole. Students are challenged on their prior knowledge of the structure of the heart as they have to name and state the function of an atrioventricular and semi-lunar valve from an internal diagram. This leads into the key point that pressure changes in the chambers and the major arteries results in the opening and closing of these sets of valves. Students are given a description of the pressure change that results in the opening of the AV valves and shown where this would be found on the graph detailing the pressure changes of the cardiac cycle. They then have to use this as a guide to write descriptions for the closing of the AV valve and the opening and closing of the semi-lunar valves and to locate these on the graph. By providing the students with this graph, the rest of the lesson can focus on explaining how these changes come about. Students have to use their current and prior knowledge of the chambers and blood vessels to write 4 descriptions that cover the cardiac cycle. The final part of the lesson covers the changes in the volume of the ventricle. The remainder of the lesson focuses on the ECG and explains how these traces can be interpreted to diagnose heart problems. A quiz competition is used to introduce the reference points of P, QRS and T on a normal sinus rhythm before time is taken to explain their representation with reference to the cardiac cycle. Moving forwards, a SPOT the DIFFERENCE task is used to challenge the students to recognise differences between sinus rhythm and some abnormal rhythms including tachycardia and atrial fibrillation. Bradycardia is used as a symptom of sinus node disfunction and the students are encouraged to discuss this symptom along with some others to try to diagnose this health problem.

A fully-resourced lesson, which explores how changes to the sequence of bases on DNA may or may not alter protein structure. The engaging PowerPoint and accompanying resources have been designed to cover point 8.1 of the AQA A-level Biology specification and it builds on the knowledge gained during topic 4 when gene mutations were first introduced. A quiz runs throughout the lesson where students compete to recognise key terms from their definitions and the lesson begins with an edition of this round as they are challenged to recognise the definition for primary structure. Other terms that arise during the lesson relate to the different gene mutations, the genetic code and mutagenic agents. The focus of the lesson is to support students in their explanations of how a particular mutation can result in a change in the primary structure as well as being able to explain why a substitution mutation may not. In this way, their understanding of the degenerate and non-overlapping nature of the genetic code will be tested and any misconceptions can be addressed. The main section of the lesson covers substitution, deletion and addition mutations before translocation, inversion and duplication mutations are introduced. Links are made to the latter parts of topic 8 so students can understand how the change in the sequence of bases may disrupt gene expression. The final part of the lesson looks at a range of mutagenic agents that can increase the rate of mutation.

This detailed lesson describes the role of the mRNA, tRNA, amino acids and the ribosome during the second stage of protein synthesis - translation. Both the PowerPoint and accompanying resources have been designed to cover the third part of point 4.2 of the AQA A-level Biology specification and ties in with the previous lessons in this topic on RNA and transcription. Translation is a topic which is often poorly understood and so this lesson has been written to enable the students to understand how to answer the different types of questions by knowing and including the key details of the structures involved. The lesson begins by challenging the students to consider why it is so important that the amino acids are assembled in the correct order during the formation of the chain. Moving forwards, a quick quiz round called “LOST IN TRANSLATION” is used to check on their prior knowledge of the mRNA strand, the tRNA molecules, the genetic code and the ribosomes. The next task involves a very detailed description of translation that has been divided into 14 statements which the students have to put into the correct order. By giving them a passage that consists of this considerable detail, they can pick out the important parts to use in the next task where they have to answer shorter questions worth between 3 and 4 marks. These types of questions are common in the assessments and by building up through the lesson, their confidence to answer this type should increase. The final two tasks of the lesson involve another quiz, where the teams compete to transcribe and translate in the quickest time before using all that they have learnt to answer some questions which involve the genetic code and the mRNA codon table.

This lesson describes biodiversity and explains how it can be calculated within a species, a habitat and how it can be compared between habitats. The detailed PowerPoint and accompanying resources have been designed to cover points 4.16, 4.17 & 4.18 in unit 2 of the Edexcel International A-level Biology specification and the meaning of endemism is also explained. A quiz competition called BIOLOGICAL TERMINOLOGY SNAP runs over the course of the lesson and this will engage the students whilst challenging them to recognise key terms from their definitions. This quiz will introduce species, population, biodiversity, endemic, heterozygote and natural selection and each of these terms is put into context once introduced. Once biodiversity has been revealed, the students will learn that they are expected to be able to measure biodiversity within a habitat, within a species and within different habitats so that they can be compared. The rest of the lesson uses step by step guides, discussion points and selected tasks to demonstrate how to determine species richness, the heterozygosity index and an index of diversity. Students are challenged with a range of exam-style questions where they have to apply their knowledge and all mark schemes are displayed and clearly explained within the PowerPoint to allow students to assess their understanding and address any misconceptions if they arise.

This lesson evaluates the methods used by zoos and seed banks in the conservation of endangered species and their genetic diversity. The PowerPoint and accompanying resources have been primarily designed to cover point 4.21 of the Edexcel International A-level Biology specification but as this is potentially the last lesson in this topic, lots of questions and activities have been included that will challenge the students on their knowledge and understanding of topic 4 (Plant structure and function, Biodiversity and Conservation). Hours of research went into the planning of this lesson to source interesting examples and although the main focus of the lesson is the zoo and seed banks as ex situ conservation methods, the lesson begins with a consideration of the importance of the in situ methods that are used in the Lake Télé Community reserve in the Republic of Congo and the marine conservation zone in the waters surrounding Tristan da Cunha. Students will learn how this form of active management conserves habitats and species in their natural environment, with the aim of minimising human impact whilst maintaining biodiversity. To enrich their understanding of ex situ conservation, the well-known examples of ZSL London zoo, Kew Gardens and the Millennium Seed Bank Project in Wakehurst are used. Students will understand how conserving animal species outside of their natural habitat allows for human intervention that ensures the animals are fed and given medical assistance when needed as well as reproductive assistance to increase the likelihood of the successful breeding of endangered species. An emphasis is placed on the desire to reintroduce the species into the wild and the example of some initial successes with the mountain chicken frog in Dominica and Montserrat is discussed. As stated in the specification point, these methods must be evaluated and therefore the issues are also considered and there is a focus on the susceptibility of captive populations to diseases as a result of their limited genetic diversity. The final part of the lesson considers how seed banks can be used to ensure that plant species, which may contain the molecules for medicine development, avoid extinction, and how the plants can be bred asexually to increase plant populations quickly. Due to the extensiveness of this lesson, it is estimated that it will take in excess of 2/3 hours of allocated A-level teaching time to cover the tasks and content included in the lesson and as explained above, it can also be used as revision of topic 4 content

This fully-resourced lesson describes the role of transcription factors in the regulation of gene expression. The detailed PowerPoint and accompanying resources have been designed to cover the details of specification points 7.2 (i) and (ii) of the Edexcel A-level Biology B course. This is one of the more difficult concepts in this A-level course and therefore key points are reiterated throughout this lesson to increase the likelihood of student understanding and to support them when trying to make links to actual biological examples in living organisms. There is a clear connection to transcription and translation as covered in topic 1.4, so the lesson begins by reminding students that in addition to the structural gene in a transcription unit, there is the promotor region where RNA polymerase binds. Students are introduced to the idea of transcription factors and will understand how these molecules can activate or repress transcription by enabling or preventing the binding of the enzyme. At this point, students are challenged on their current understanding with a series of questions about DELLA proteins so they can see how these molecules prevent the binding of RNA polymerase. Their understanding is then tested again with another example with oestrogen and the ER receptor. The final and main section of the lesson focuses on the lac operon. Students will be able to visualise the different structures that are found in this unit of DNA and time is taken to go through the individual functions. A step by step guide is used to walk students through the sequence of events that occur when lactose is absent and when it is present before they are challenged to apply their understanding to an exam question.

This detailed lesson describes the role of haemoglobin in the transport of respiratory gases and compares the dissociation curves for foetal and adult haemoglobin. The PowerPoint and accompanying resource have been designed to cover points 4.5 (i), (ii) and (iv) of the Edexcel A-level Biology B specification. The structure of haemoglobin was covered during topic 1, so the start of the lesson acts as a prior knowledge check where the students are challenged to recall that it is a globular protein which consists of 4 polypeptide chains. A series of exam-style questions are then used to challenge them to make the link between the solubility of a globular protein and its role in the transport of oxygen from the alveoli to the respiring cells. Moving forwards, the students will learn that each of the 4 polypeptide chains contains a haem group with an iron ion attached and that it is this group which has a high affinity for oxygen. Time is taken to discuss how this protein must be able to load (and unload) oxygen as well as transport the molecules to the respiring tissues. Students will plot the oxyhaemoglobin dissociation curve and the S-shaped curve is used to encourage discussions about the ease with which haemoglobin loads each molecule. At this point, foetal haemoglobin and its differing affinity of oxygen is introduced and students are challenged to predict whether this affinity will be higher or lower than adult haemoglobin and to represent this on their dissociation curve. The remainder of the lesson looks at the different ways that carbon dioxide is transported around the body that involve haemoglobin. Time is taken to look at the dissociation of carbonic acid into hydrogen ions so that students can understand how this will affect the affinity of haemoglobin for oxygen in an upcoming lesson on the Bohr effect.

This is a detailed lesson resource that covers the content of point 5.1.3 (a) of the OCR A-level Biology A specification which states that students should be able to demonstrate and apply their understanding of the roles of mammalian sensory receptors. There is a particular focus on the Pacinian corpuscle to demonstrate how these receptors act as transducers by converting one form of energy into electrical energy which is then conducted as an electrical impulse along the sensory neurone. The lesson begins by looking at the different types of stimuli that can be detected. This leads into a written task where students have to form sentences to detail how thermoreceptors, rods and cones, hair cells in the inner ear and vibration receptors in the cochlea convert different forms of energy into electrical energy. Students will be introduced to the term transducer and will be challenged to work out what these cells carry out by using their sentences. As stated above, students will meet a Pacinian corpuscle and learn that this receptors detects pressure changes in the skin using the concentric rings of connective tissue in its structure. The rest of the lesson focuses on how ions are involved in the maintenance of resting potential and then depolarisation. Time is taken to look into the key details of these two processes so students are confident with this topic when met again during a lesson on the generation of action potentials. All of the tasks are differentiated to allow students of different abilities to access the work. As well as understanding checks to allow the students to assess their progress against the current topic, there are also a number of prior knowledge checks on topics like inorganic ions and methods of movement. This lesson has been designed for students studying the OCR A-level Biology course

This highly detailed and engaging lesson which explains how a nerve impulse (action potential) is conducted along an axon). The PowerPoint and accompanying resources have been designed to cover point 8.3 of the Pearson Edexcel A-level Biology A (Salters Nuffield) specification which states that students should be able to describe how the changes in the membrane permeability to sodium and potassium ions results in conduction. This topic is commonly assessed in the terminal exams so a lot of time has been taken to design this resource to include a wide range of activities that motivate the students whilst ensuring that the content is covered in the depth of detail that will allow them to have a real understanding. Interspersed within the activities are understanding checks and prior knowledge checks to enable the students to not only assess their progress against the current topic but also to challenge themselves on the links to earlier topics such as methods of movements across cell membranes and saltatory conduction. There are also a number of quiz competitions which are used to introduce key terms and values in a fun and memorable way and discussion points to encourage the students to consider why a particular process or mechanism occurs. Over the course of the lesson, the students will learn and discover how the movement of ions across the membrane causes the membrane potential to change. They will see how the resting potential is maintained through the use of the sodium/potassium pump and potassium ion leakage. There is a real focus on depolarisation to allow students to understand how generator potentials can combine and if the resulting depolarisation then exceeds the threshold potential, a full depolarisation will occur. At this point in the lesson students will discover how the all or nothing response explains that action potentials have the same magnitude and that instead a stronger stimulus is linked to an increase in the frequency of the transmission. The rest of the lesson challenges the students to apply their knowledge to explain how repolarisation and hyperpolarisation result and to suggest advantages of the refractory period for nerve cells.

This lesson describes how the Hardy-Weinberg equation can identify changes in allele frequency that can be the result of mutation and natural selection. The detailed PowerPoint and accompanying resources have been designed to cover points 4.20 (i) & (ii) of the Edexcel International A-level Biology specification The lesson begins with a focus on the equation to ensure that the students understand the meaning of each of the terms. The recessive condition, cystic fibrosis, is used as an example so that students can start to apply their knowledge and assess whether they understand which genotypes go with which term. Moving forwards, a step-by-step guide is used to show students how to answer a question. Tips are given during the guide so that common misconceptions and mistakes are addressed immediately and then students are given the opportunity to apply their knowledge to a set of 3 questions, which have been differentiated so that all abilities are able to access the work and be challenged The rest of the lesson focuses on describing how the mutations which create the variation needed for natural selection to occur can be given as reasons for any change in allele frequency. 2 quick quiz competitions are used to introduce MRSA and then to get the students to recognise that they can use this abbreviation to remind them to use mutation, reproduce, selection (and survive) and allele in their descriptions of evolution through natural selection. The main task of the lesson challenges the students to form a description that explains how this strain of bacteria developed resistance to methicillin to enable them to see the principles of natural selection. This can then be used when describing how the anatomy of the modern-day giraffe has evolved over time.

This lesson describes the extracellular action of peptide hormones and the role played by steroid hormones in binding to DNA transcription factors. The detailed PowerPoint and accompanying resources have been designed to cover point 7.22 of the Edexcel International A-level Biology specification and focuses on the differing effects of these two types of hormones on their target cells Students should have a base knowledge of the endocrine system from GCSE so this lesson has been planned to build on that knowledge and to add the detail needed at this level. The lesson begins by challenging this knowledge to check that they understand that endocrine glands secrete these hormones directly into the blood. Students will learn that most of the secreted hormones are peptide (or protein) hormones and a series of exam-style questions are used to challenge them on their recall of the structure of insulin as well as to apply their knowledge to questions about glucagon. Moving forwards, the students are reminded that hormones have target cells that have specific receptor sites on their membrane. The relationship between a peptide hormone as a first messenger and a second messenger on the inside of the cell is covered in detail in an upcoming lesson but students are briefly introduced to G proteins and cyclic AMP so they are prepared. The rest of the lesson focuses on steroid hormones and specifically their ability to pass through the membrane of a cell and to bind to transcription factors, as exemplified by oestrogen. Students covered transcription and the control of gene expression in topics 2 and 3 so the final tasks challenge their recall of these concepts

This lesson describes how the nervous system detects stimuli, focusing on the detection of light by the rods in the the retina of mammals. The PowerPoint has been designed to cover the content of specification point 8.8 of the Edexcel International A-level Biology specification and includes descriptions of the roles of rhodopsin, opsin, retinal, sodium ions, cation channels and hyperpolarisation in the formation of action potentials in the optic neurones. The lesson begins by using a quiz to get the students to recognise the range of stimuli which can be detected by receptors. This leads into a task where the students have to form 4 sentences to detail the stimuli which are detected by certain receptors and the energy conversion that happen as a result. Students will be introduced to the idea of a transducer and learn that receptors always convert to electrical energy which is the generator potential. It is likely that students will be aware that the human retina contains rod and cone cells, so the next part of the lesson builds on that knowledge and adds the detail needed at this level. Students will discover that the optical pigment in rod cells is rhodopsin and that the bleaching of this into retinal and opsin results in a cascade of events that allows an action potential to be initiated along the optic nerve. Time is taken to go through the events that occur in the dark and then the students are challenged to use this as a guide when explaining how the events differ in the light. Key terms like depolarisation and hyperpolarisation, that were met earlier in topic 8, are used to explain the changes in membrane potential and the resulting effect on the connection with the bipolar and ganglion cells is then described. The remainder of the lesson focuses on the Pacinian corpuscle and describes how this responds to pressure on the skin, resulting in the opening of the sodium channels and the flow of sodium ions into the neurone to cause depolarisation

This detailed lesson describes how recombinant DNA is produced using restriction endonucleases and DNA ligase and is inserted into other cells. The engaging PowerPoint and accompanying resources have been designed to cover points 8.18 & 8.19 of the Edexcel International A-level Biology specification. The lesson begins with a definition of genetic engineering and recombinant DNA to allow students to begin to understand how this process involves the transfer of DNA fragments from one species to another. Links are made to the genetic code and transcription and translation mechanisms, which were met in topic 2, in order to explain how the transferred gene can be translated in the transgenic organism. Moving forwards, the method involving reverse transcriptase and DNA polymerase is introduced and their knowledge of the structure of the polynucleotides and the roles of enzymes is challenged through questions and discussion points. Restriction endonucleases are then introduced and time is taken to look at the structure of a restriction site as well as the production of sticky ends due to the staggered cut on the DNA. A series of exam-style questions with displayed mark schemes are used to allow the students to assess their current understanding. The second half of the lesson looks at the culture of transformed host cells as an in vivo method to amplify DNA fragments. Students will learn that bacterial cells are the most commonly transformed cells so the next task challenges their recall of the structures of these cells so that plasmid DNA can be examined from that point onwards. Time is taken to explore the finer details of each step such as the addition of the promoter and terminator regions, use of the same restriction enzyme to cut the plasmid as was used to cut the gene and the different types of marker genes. As well as understanding and prior knowledge checks, quick quiz competitions are used throughout the lesson to introduce key terms such as cDNA and EcoR1 in a fun and hopefully memorable way

This lesson describes the structure of enzymes and explains how their specificity enables them to act as catalysts intracellularly and extracellularly. The engaging PowerPoint and accompanying resources have been designed to cover points 1.5 (i), (ii), (iii) & (vii) of the Edexcel A-level Biology B specification and describes Fischer’s lock and key hypothesis and Koshland’s induced-fit model to deepen student understanding of the mechanism of enzyme action The lesson has been specifically planned to tie in with topic 1.3 where protein structure and globular proteins were covered. This prior knowledge is tested through a series of exam-style questions along with current understanding and mark schemes are included in the PowerPoint so that students can assess their answers. Students will learn that enzymes are large globular proteins which contain an active site that consists of a small number of amino acids. Emil Fischer’s lock and key hypothesis is introduced to enable students to recognise that their specificity is the result of an active site that is complementary in shape to a single type of substrate. Time is taken to discuss key details such as the control of the shape of the active site by the tertiary structure of the protein. The induced-fit model is described so students can understand how the enzyme-susbtrate complex is stabilised and then students are challenged to order the sequence of events in an enzyme-controlled reaction. The lesson finishes with a focus on ATP synthase, DNA helicase and DNA polymerase and students are challenged on their recall of DNA replication with an exam question before they are challenged on their knowledge of carbohydrates, lipids and proteins from topics 1.1 - 1.3 as they have to recognise some extracellular digestive enzymes from descriptions of their substrates.

This fully-resourced lesson describes the different effects that gene mutations can have on the amino acid sequence of a protein. The engaging and detailed PowerPoint and accompanying resources have been designed to cover points 1.4 (viii) & (ix) as detailed in the Edexcel A-level Biology B specification and includes substitutions, deletions and insertions and considers a real life example in sickle cell anaemia. In order to understand how a change in the base sequence can affect the order of the amino acids, students must be confident in their understanding and application of protein synthesis which was covered earlier in this topic. Therefore, the start of the lesson focuses on transcription and translation and students are guided through the use of the codon table to identify amino acids. Moving forwards, a task called known as THE WALL is used to introduce to the names of three types of gene mutation whilst challenging the students to recognise three terms which are associated with the genetic code. The main focus of the lesson is substitutions and how these mutations may or may not cause a change to the amino acid sequence. The students are challenged to use their knowledge of the degenerate nature of the genetic code to explain how a silent mutation can result. Students will learn that a substitution is responsible for the new allele that causes sickle cell anaemia and they are tested on their understanding through an exam-style question. As with all of the questions, a mark scheme is included in the PowerPoint which can be displayed to allow the students to assess their understanding. The rest of the lesson looks at base deletions and base insertions and students are introduced to the idea of a frameshift mutation. One particular task challenges the students to evaluate the statement that base deletions have a bigger impact on primary structure than base substitutions. This is a differentiated task and they have to compare the fact that the reading frame is shifted by a deletion against the change in a single base by a substitution