This lesson describes the development and spread of antibiotic resistance in bacteria and discusses the difficulties in controlling this spread. The PowerPoint and accompanying worksheet have been designed to cover specification points 6.4 (i & ii) of the Edexcel A-level Biology B specification President Trump’s error ridden speech about antibiotics is used at the beginning of the lesson to remind students that this is a treatment for bacterial infections and not viruses as he stated. Moving forwards, 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 the development of resistance by evolution through natural selection. The main task of the lesson challenges the students to form a description to explain how this strain of bacteria developed resistance to methicillin, making use of the five key terms emphasised above. Moving forwards, there is a focus on the hospital as the common location for MRSA infections and students will recognise that this opportunistic pathogen can infect through open wounds to cause sepsis and potentially death. Figures from infections and deaths in hospitals in the US are used to increase the relevance and students will learn how a MRSA prevention program in VHA facilities includes screening of surgery patients to try to reduce its impact. The lesson concludes with a discussion about other methods that can be used by hospitals and general practitioners to reduce the spread of MRSA and to try to prevent the development of resistance in other strains.

This lesson describes the structure and function of the human heart and names the blood vessels associated with this organ . The PowerPoint and accompanying resources are part of the first lesson in a series of 2 lessons that have been designed to cover point (b) in topic 3 of AS unit 2 of the WJEC A-level Biology specification As this topic was covered at GCSE, the lesson has been planned to build on this prior knowledge whilst adding the key details which will enable students to provide A-level standard answers. The primary focus is the identification of the different structures of the heart but it also challenges their ability to recognise the important relationship to function. For example, time is taken to ensure that students can explain why the atrial walls are thinner than the ventricular walls and why the right ventricle has a thinner wall than the left ventricle. Opportunities are taken throughout the lesson to link this topic to the others found in topic 3 including those which have already been covered like circulatory systems as well as those which are upcoming such as the initiation of heart action. There is also an application question where students have to explain why a hole in the ventricular septum would need to be repaired if it doesn’t naturally close over time.

This lesson describes the roles of the SAN and Purkyne fibres in the coordination of the three stages of the cardiac cycle. The PowerPoint and accompanying resources are part of the first lesson in a series of 2 lessons that have been designed to cover point [c] in topic 3 of AS unit 2 of the WJEC A-level Biology specification and has a specific focus on the pressure changes that occur in each stage of 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 next part 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. This rest of the lesson focuses on the roles of the SAN and Purkyne fibres as well as the AVN and the bundle of His in the coordination of the heartbeat, continually linking back to the work on the cycle. The SAN is introduced as the natural pacemaker and then time is given to study each step of the conduction of the impulse as it spreads away from the myogenic tissue in a wave of excitation. Moving forwards, students are encouraged to consider why a delay would occur at the AVN and then they will learn that the impulse is conducted along the Bundle of His to the apex so that the contraction of the ventricles can happen from the bottom upwards. The structure of the cardiac muscle cells is discussed and the final task of the lesson challenges the students to describe the conducting tissue, with an emphasis on the use of key terminology.

This lesson describes how the structure of arteries, arterioles, capillaries, venules and veins in the mammalian circulatory system relate to their functions. The PowerPoint and accompanying resources are part of the second lesson in a series of 2 lessons which have been designed to cover specification point (b) of topic 3 in AS unit 2 of the WJEC A-level Biology A specification. The first lesson in this series covers the structure and function of the human heart and its associated blood vessels This lesson has been written to build on any prior knowledge from GCSE or earlier in this topic to enable students to fully understand why a particular type of blood vessel has particular features. Students will be able to make the connection between the narrow lumen and elastic tissue in the walls of arteries and the need to maintain the high pressure of the blood. A quick version of the GUESS WHO game is used to introduce smooth muscle and collagen in the tunica media and externa and again the reason for their presence is explored and explained. Moving forwards, it is quite likely that some students will not be aware of the transition vessels that are the arterioles. This section begins with an understanding of the need for these vessels because the structural and functional differences between arteries and capillaries is too significant. The action of the smooth muscle in the walls of these vessels is discussed and students will be challenged to describe a number of situations that would require blood to be redistributed. The middle part of the lesson looks at the role of the capillaries in exchange and links are made to diffusion to ensure that students can explain how the red blood cells pressing against the endothelium results in a short diffusion distance. The remainder of the lesson considers the structure of the veins and students are challenged to explain how the differences to those observed in arteries is due to the lower blood pressure found in these vessels.

This lesson describes the Krebs cycle as a stage of aerobic respiration that liberates energy to produce ATP and reduced NAD and releases carbon dioxide. The PowerPoint and accompanying resource have been designed to cover specification point [c] in topic 3 of A2 unit 3 of the WJEC A-level Biology specification. The lesson begins with a version of the Impossible game where students have to spot the connection between 8 of the 9 terms and will ultimately learn that this next stage is called the Krebs cycle. The main part of the lesson challenges the students to use descriptions of the main steps of the cycle to continue their diagram of the reactions. Students are continually exposed to key terminology such as decarboxylation and dehydrogenation and they will learn where carbon dioxide is lost and reduced NAD and FAD are generated. They will also recognise that ATP is synthesised by substrate level phosphorylation. The final task challenges them to apply their knowledge of the cycle to work out the numbers of the different products and to calculate the number of ATP that must be produced in the next stage This lesson has been designed to tie in with the other uploaded lessons on glycolysis and the electron transport chain (in oxidative phosphorylation).

This lesson describes the concept of homeostasis using negative feedback control and also describes the role of positive feedback. The PowerPoint and accompanying resources have been designed to cover specification points (a & b) in topic 7 of A2 unit 3 of the WJEC A-level Biology specification and explains how this feedback control maintains systems within narrow limits but has also been planned to provide important details for upcoming topics such as osmoregulation. The normal ranges for blood glucose concentration, blood pH and body temperature are introduced at the start of the lesson to allow students to recognise that these aspects have to be maintained within narrow limits. A series of exam-style questions then challenge their recall of knowledge from AS units 1 & 2 and the earlier topics in A2 unit 3 as they have to explain why it’s important that each of these aspects is maintained within these limits. The students were introduced to homeostasis at GCSE, so this process is revisited and discussed, to ensure that students are able to recall that this is the maintenance of a state of dynamic equilibrium. A quick quiz competition is used to reveal negative feedback as a key term and students will learn how this form of control reverses the original change and biological examples are used to emphasise the importance of this system for restoring levels to the limits (and the optimum). The remainder of the lesson explains how positive feedback differs from negative feedback as it increases the original change and the role of oxytocin in birth and the movement of sodium ions into a neurone are used to exemplify the action of this control system.

This lesson describes sex linkage, focusing on the the inheritance of genes on the X chromosome that lead to haemophilia and Duchenne muscular dystrophy. The PowerPoint and accompanying resources have been designed to cover specification point [e] in topic 3 of A2 unit 4 of the WJEC A-level Biology specification. Key genetic terminology is used throughout and the lesson begins with a check on their ability to identify the definition of homologous chromosomes. Students will recall that the sex chromosomes are not fully homologous and that the smaller Y chromosome lacks some of the genes that are found on the X. This leads into one of the numerous discussion points, where students are encouraged to consider whether females or males are more likely to suffer from sex-linked diseases and they will be challenged to find evidence to support this decision later in the lesson. In terms of humans, the lesson focuses on haemophilia and a step-by-step guide is used to demonstrate how these specific genetic diagrams should be constructed and how the phenotypes should then be interpreted. The final tasks of the lesson challenge the students to carry out a dihybrid cross that involves a sex-linked disease and an autosomal disease before applying their knowledge to a question about chickens and how the rate of feather production in chicks can be used to determine gender. All of the tasks are differentiated so that students of differing abilities can access the work and all exam questions have fully-explained, visual markschemes to allow them to assess their progress and address any misconceptions

This lesson describes the reactants and products of the Haber Process and then explores and explains why the specific conditions are chosen for this reaction. The PowerPoint and accompanying worksheets have been designed to cover specification point 10.4.1 of the AQA GCSE Chemistry specification. The summary passage which is completed at the end of the lesson has been differentiated two ways. The lesson begins by challenging the students to use a description of the reaction to complete the balanced symbol equation. A quiz competition involving both Chemistry and Maths skills is used to reveal the temperature and pressure which are chosen for this reaction. Students will learn that this only produces a yield of 30% and therefore are encouraged to question why these conditions are chosen. In doing so, they are made to wear two “hats”, so that they consider it from both a Science angle but also a business angle. Their knowledge of reversible reactions and the effect of changing either the temperature or the pressure on the position of the equilibrium are constantly challenged and then checked through a range of progress check questions. As a result of this lesson, students will understand that these conditions are a compromise and be able to explain why.

This lesson describes the effects of pH on the rate of an enzyme-catalysed reaction. The PowerPoint and accompanying resources are part of the second lesson in a series of 4 lessons which have been designed to cover the content of point 3.2 (a) of the CIE A-level Biology specification. The lesson begins with a short discussion, where the students are challenged to identify how the stomach and the small intestine differ in terms of a particular condition and to explain why the conditions in these neighbouring digestive organs are so important. This introduces pepsin and trypsin and these protease enzymes play a key role throughout the lesson as they are good examples of how different extracellular enzymes have different optimum pH values (which are not necessarily 7.0). Moving forwards, students will discuss how the rate of an enzyme-controlled reaction will change if there are small or large changes in pH, and then time is taken to ensure that students can explain these changes with reference to tertiary structure bonds and the shape of the active site. Through the use of a quick quiz competition, the students will be reminded of the key term “buffer” and a series of questions are used to challenge their understanding of how these substances could be used in a practical investigation. They will also learn how buffers are found in blood plasma as well as in red blood cells in the form of haemoglobin. As there is a considerable proportion of marks for Maths in a Biology context questions in the A-level assessments, the remainder of the lesson challenges the students to use a given formula to calculate the pH of blood when given the hydrogen ion concentration and to calculate percentage decrease. These questions have been differentiated to give assistance to those that need the support

This lesson describes the effects of pH on enzyme activity. The PowerPoint and accompanying resources are part of the first lesson in a series of 3 lessons which have been designed to cover the content of point 2.1.4 (d)(i)of the OCR A-level Biology A specification. The lesson begins with a short discussion, where the students are challenged to identify how the stomach and the small intestine differ in terms of a particular condition and to explain why the conditions in these neighbouring digestive organs are so important. This introduces pepsin and trypsin and these protease enzymes play a key role throughout the lesson as they are good examples of how different extracellular enzymes have different optimum pH values (which are not necessarily 7.0). Moving forwards, students will discuss how the rate of an enzyme-controlled reaction will change if there are small or large changes in pH, and then time is taken to ensure that students can explain these changes with reference to tertiary structure bonds and the shape of the active site. Through the use of a quick quiz competition, the students will be reminded of the key term “buffer” and a series of questions are used to challenge their understanding of how these substances could be used in a practical investigation. They will also learn how buffers are found in blood plasma as well as in red blood cells in the form of haemoglobin. With there being such a considerable proportion of marks for Maths in a Biology context questions in the A-level assessments, the remainder of the lesson challenges the students to use a given formula to calculate the pH of blood when given the hydrogen ion concentration and to calculate percentage decrease. These questions have been differentiated to give assistance to those that need the support Please note that this is a lesson which describes the effect on enzyme activity, as described in 2.1.4 (d)(i), and not the details of the practical investigation which is covered in a later lesson

This lesson describes the effects of pH on the rate of enzyme-controlled reactions. The PowerPoint and accompanying resources are part of the third lesson in a series of 5 lessons which have been designed to cover the content of point 1.4.2 (Many proteins are enzymes) of the AQA A-level Biology specification. The lesson begins with a short discussion, where the students are challenged to identify how the stomach and the small intestine differ in terms of a particular condition and to explain why the conditions in these neighbouring digestive organs are so important. This introduces pepsin and trypsin and these protease enzymes play a key role throughout the lesson as they are good examples of how different extracellular enzymes have different optimum pH values (which are not necessarily 7.0). Moving forwards, students will discuss how the rate of an enzyme-controlled reaction will change if there are small or large changes in pH, and then time is taken to ensure that students can explain these changes with reference to tertiary structure bonds and the shape of the active site. Through the use of a quick quiz competition, the students will be reminded of the key term “buffer” and a series of questions are used to challenge their understanding of how these substances could be used in a practical investigation. They will also learn how buffers are found in blood plasma as well as in red blood cells in the form of haemoglobin. With there being such a large proportion of marks for Maths in a Biology context questions in the AQA assessments, the remainder of the lesson challenges the students to use a given formula to calculate the pH of blood when given the hydrogen ion concentration and to calculate percentage decrease. These questions have been differentiated to give assistance to those that need the support

This lesson describes how the cells of the proximal tubule in the nephron of the kidney are adapted for reabsorption. The PowerPoint and accompanying resource which is filled with tasks have been designed to cover specification point [e] in topic 7 of A2 unit 3 of the WJEC A-level Biology specification and builds on the knowledge gained in the previous lessons on the structure of the nephron and the functions of the mammalian kidney. The lesson begins by challenging the students to recall the substances that are found in the glomerular filtrate so that each of them can be considered over the course of the rest of the lesson. Moving forwards, the first of the numerous discussion points which are included in the lesson is used to get students to predict the component of the filtrate which won’t be found in the urine when they are presented with pie charts from each of these situations. Upon learning that glucose is 100% reabsorbed, along with most of the ions and some of the water, the rest of the lesson focuses on describing the relationship between the structure of the proximal tubule and the function of selective reabsorption. Again, this section begins by encouraging the students to discuss and to predict which structures they would expect to find in a section of the kidney if the function is to reabsorb. They are given the chance to see the structure (as shown in the cover image) before each feature is broken down to explain its importance. Time is taken to look at the role of the cotransporter proteins to explain how this allows glucose, along with sodium ions, to be reabsorbed from the lumen of the PCT into the epithelial cells. The final part of the lesson focuses on urea and how the concentration of this substance increases along the tubule as a result of the reabsorption of some of the water.

This fully-resourced lesson describes the range of potential treatments for kidney failure. The PowerPoint and accompanying resources have been designed to cover specification point (h) in topic 7 of A2 unit 3 of the WJEC A-level Biology specification. This lesson involves the diagnosis of a number of different kidney-related conditions and the potential treatments for kidney failure. This lesson is designed to get the students to take on the numerous roles of a doctor who works in the renal ward which include testing, diagnosis and treatment. Having obtained measurements by GFR and results by taking urine samples, hey are challenged to use their knowledge of the function of the kidney to study urine samples (and the accompanying GP’s notes) to diagnose one of four conditions. They then have to write a letter to the patient to explain how they made this diagnosis, again focusing on their knowledge of the structure and functions of the Bowman’s capsule and PCT. The rest of the lesson focuses on haemodialysis, peritoneal dialysis and kidney transplant. There are regular progress checks throughout the lesson so that students can assess their understanding and there are a number of homework activities included in the lesson.

This lesson describes the inheritance of two genes and guides students through the calculation of phenotypic ratios, before considering linkage. The PowerPoint and the accompanying resources have been designed to cover point [c] in topic 3 of A2 unit 4 of the WJEC A-level Biology specification. As the previous lesson described the construction of genetic crosses and pedigree diagrams, students are aware of the methods involved in writing genotypes and gametes for the inheritance of a single gene. Therefore, the start of this lesson builds on this understanding to ensure that students recognise that genotypes contain 4 alleles and gametes contain 2 alleles when two genes are inherited. The students are taken through the steps of a worked example to demonstrate the key steps in the calculation of a phenotypic ratio before 2 exam-style questions challenge them to apply their newly-acquired knowledge. Mark schemes are displayed within the PowerPoint to allow students to assess their progress. The phenotypic ratio generated as the answer to the next question is 9:3:3:1 and time is taken to explain that this is the expected ratio when two heterozygotes for two unlinked genes are crossed which they may be expected to use when meeting the chi squared test in an upcoming lesson The remainder of the lesson considers how linkage, where two genes have loci on the same chromosome, affects the outcome of dihybrid inheritance. This is a difficult topic which can be poorly understood by students so extra time was taken during the planning to split the concept into small chunks. There is a clear focus on using the number of parent phenotypes and recombinants in the offspring as a way to determine linkage and suggest how the loci of the two genes compare. Important links to other topics such as crossing over in meiosis are made to enable students to understand how the random formation of the point of contact (chiasma) determines whether new phenotypes will be seen in the offspring or not. Linkage is an important cause of variation and the difference between observed and expected results and this is emphasised on a number of occasions and a link to the chi squared test which is covered in an upcoming lesson is also made. The main task of the lesson act as understanding check where students are challenged to analyse the results of genetic crosses involving the inheritance of the ABO blood group gene and the nail-patella syndrome gene n humans and also the inheritance of body colour and wing length in Drosophila.

This lesson guides students through the use of a chi-squared test to determine the significance of the difference between observed and expected results. It is fully-resourced with a detailed PowerPoint and differentiated worksheets that have been designed to cover point (d) in topic 3 of A2 unit 4 of the WJEC A-level Biology specification The lesson includes a step-by-step guide to demonstrates how to carry out the test in small chunks. At each step, time is taken to explain any parts which could cause confusion and helpful hints are provided to increase the likelihood of success in exam questions on this topic. Students will understand how to use the phenotypic ratio to calculate the expected numbers and then how to find the critical value in order to compare it against the chi-squared value. A worked example is used to show the working which will be required to access the marks and then the main task challenges the students to apply their knowledge to a series of questions of increasing difficulty. This lesson has been specifically designed to tie in with the previous lessons in this topic as there are regular references to dihybrid inheritance as well as to topics in the AS units like meiosis

This engaging lesson describes how chromosome mutations result in changes to the number or structure of chromosomes The PowerPoint and accompanying resources are part of the second lesson in a series of 2 lessons that have been designed to cover specification points (f) in topic 3 of A2 unit 4 of the WJEC A-level Biology specification, and there is a key focus on Down syndrome A human karyotype which has not been altered by a mutation is studied at the start of the lesson to allow students to recall the usual number of chromosomes as well as the sex chromosomes. They are then challenged to identify the differences when presented with the karyotypes of sufferers of Down, Turner’s and Klinefelter’s syndrome. Students will learn that in the majority of cases, these conditions are the result of non-disjunction and having been assisted in the explanation of the outcome for Down and Klinefelters, they have to form their own for Turner’s. The remainder of the lesson looks at other types of mutations, including translocation, and students will also see how whole sets of chromosomes can be duplicated in polyploidy