This fully-resourced lesson describes the structure of the human retina and explains how the rhodopsin in rod cells allows vision in low light intensity. The detailed PowerPoint and accompanying resources have been designed to cover points 9.7 (i), (ii) & (iii) of the Edexcel A-level Biology B specification but also makes links to previously covered topics such as cell structure and nervous transmission. It is likely that students will be aware that the human retina contains rod and cone cells, so this 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 in topic 9.5, 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. Cone cells are also introduced, with the main focus being their distribution in the centre of the fovea which is used to explain colour vision in bright light.

This fully-resourced lesson describes how the functional differences of the retinal rod and cone cells is related to their structures. The detailed PowerPoint and accompanying resources are part of the 2nd in a series of 2 lessons that have been designed to cover the details included in point 6.1.2 of the AQA A-level Biology specification. However, as explained at the start of the lesson, it has been specifically planned to be taught after the lessons in topic 6.3, so that students are aware and understand the meaning of terms such as depolarisation and hyperpolarisation. It is likely that students will be aware that the human retina contains rod and cone cells, so this lesson builds on that knowledge and adds the detail needed at this level. Over the course of the lesson, students will learn that these cells contain different optical pigments and that this feature along with their differing connectivity to the bipolar neurones means that they have different sensitivities to light, colour perception and visual acuity. Exam-style questions are interspersed throughout to check on current understanding and also make links to previously covered topics. For example, students are challenged to recognise a description of the mitochondria so they can discover that this cell structure is found in the inner segment where it is responsible for generating the ATP needed to pump sodium ions out of the cells. As detailed above, this lesson ties in closely with topic 6.3 and students will be expected to make links to synapses and to the changes in membrane potential that occur when sodium ions move in or out of a cell

This lesson describes the detailed structure of a skeletal muscle fibre and the structural and physiological differences between fast and slow twitch fibres. The engaging PowerPoint and acccompanying resources have been designed to cover points 7.10 (i) & (ii) of the Edexcel International A-level Biology specification. The start of the lesson uses an identification key to emphasise that skeletal muscle differs from cardiac and smooth muscle due to its voluntary nature. It is important that key terminology is recognised so once myology has been revealed as the study of muscles, key structural terms like myofibril, myofilament and myosin can be introduced. Moving forwards, students will be shown the striated appearance of this muscle so they can recognise that some areas appear dark where both myofilaments are found and others as light as they only contain actin or myosin. A quiz competition is used to introduce the A band, I band and H zone and students then have to use the information given to label a diagram of the myofibril. This part of the lesson has been specifically planned to prepare the students for the upcoming lesson which describes the contraction of skeletal muscles by the sliding filament mechanism The rest of the lesson focuses on the structural and physiological differences between fast and slow twitch fibres and the following characteristics are covered: Reliance on the aerobic or anaerobic pathways to generate ATP Resistance to fatigue mitochondrial density capillary density myoglobin content (and colour) fibre diameter phosphocreatine content glycogen content A wide variety of tasks are used to cover this content and include knowledge recall and application of knowledge exam-style questions with fully-displayed mark schemes as well as quick quiz competitions to maintain motivation and engagement.

This fully-resourced lesson describes the roles of the hypothalamus and the pituitary gland in the control of mammalian plasma concentration. The engaging PowerPoint and accompanying resources have been designed to cover point 7.21 of the Edexcel International A-level Biology specification The principles of homeostasis and negative feedback were covered in an earlier lesson in topic 7, so this lesson acts to build on that knowledge and challenges them to apply their knowledge. A wide range of activities have been included in the lesson to maintain motivation and engagement whilst the understanding and prior knowledge checks will allow the students to assess their progress as well as challenge themselves to make links to other Biology topics. The lesson begins with a discussion about how the percentage of water in urine can and will change depending on the blood water potential. Students will quickly be introduced to osmoregulation and they will learn that the osmoreceptors and the osmoregulatory centre are found in the hypothalamus. A considerable amount of time is taken to study the cell signalling between the hypothalamus and the posterior pituitary gland by looking at the specialised neurones (neurosecretory cells). Links are made to the topics of neurones, nerve impulses and synapses and the students are challenged to recall the cell body, axon and vesicles. The main section of the lesson forms a detailed description of the body’s detection and response to a low blood water potential. The students are guided through this section as they are given 2 or 3 options for each stage and they have to use their knowledge to select the correct statement. The final task asks the students to write a detailed description for the opposite stimulus and this task is differentiated so those who need extra assistance can still access the work.

This lesson describes how solutes are selectively reabsorbed in the proximal tubule. The PowerPoint and accompanying resource have been designed to cover the first part of specification point 7.20 of the Edexcel International A-level Biology specification and builds on the knowledge gained in the previous lessons on the microscopic structure of the nephron and ultrafiltration. 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 PCT 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 detailed lesson describes how urea is produced from excess amino acids and then removed from the bloodstream by ultrafiltration. The PowerPoint and accompanying resources have been designed to cover point 7.19 of the Edexcel International A-level Biology specification. The first part of the lesson describes how deamination and the ornithine cycle forms urea. Although the students are not required to know the details of the cycle, it is important that they are aware of how the product of deamination, ammonia, is converted into urea (and why). Moving forwards, the rest of the lesson has been written to allow the students to discover ultrafiltration as a particular function of the nehron and to be able to explain how the mechanisms found in the glomerulus and the Bowman’s capsule control the movement of small molecules out of the blood plasma. Key terminology is used throughout and students will learn how the combination of the capillary endothelium and the podocytes creates filtration slits that allow glucose, water, urea and ions through into the Bowman’s capsule but ensure that blood cells and plasma proteins remain in the bloodstream. A number of quiz competitions are used to introduce key terms and values in a fun and memorable way whilst understanding and prior knowledge checks allow the students to assess their understanding of the current topic and to challenge themselves to make links to earlier topics. The final task of the lesson challenges the students to apply their knowledge by recognising substances found in a urine sample that shouldn’t be present and to explain why this would cause a problem

This fully-resourced lesson describes the mechanism of action of enzymes and explains how their specificity is related to their 3D structure. The engaging PowerPoint and accompanying resources have been designed to cover points 2.7 (i), (ii) and (iii) in unit 1 of the Edexcel International A-level Biology specification and introduces intracellular and extracellular enzymes where these proteins act to reduce the activation energy. The lesson has been specifically planned to tie in with related topics that were previously covered such as protein structure, globular proteins and intracellular enzymes. 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 and DNA polymerase so that students are aware of these important intracellular enzymes when learning about the details of respiration and DNA replication

This detailed lesson describes the gross and microscopic structure of the mammalian kidney. The engaging PowerPoint and accompanying resource have been designed to cover point 7.18 of the Edexcel International A-level Biology specification. The lesson was designed to tie in with the upcoming kidney lessons (7.19 - 7.21) on ultrafiltration, selective reabsorption and the control of mammalian plasma concentration and a common theme runs throughout to allow students to build their knowledge gradually and develop a deep understanding of this organ. Students will come to recognise the renal cortex and renal medulla as the two regions of the kidney and learn the parts of the nephron which are found in each of these regions. Time is taken to look at the vascular supply of this organ and specifically to explain how the renal artery divides into the afferent arterioles which carry blood towards the glomerulus and the efferent arterioles which carry the blood away. The main task of the lesson challenges the students to relate structure to function. Having been introduced to the names of each of the parts of the nephron, they have to use the details of the structures found at these parts to match the function. For example, they have to make the connection between the microvilli in the PCT as a sign that this part is involved in selective reabsorption.

This detailed lesson describes the roles of the link reaction and the Krebs cycle in the complete oxidation of glucose which occur in the mitochondrial matrix. The PowerPoint and the accompanying resource have been designed to cover point 7.3 of the Edexcel International A-level Biology specification and includes descriptions of the formation of carbon dioxide, ATP, reduced NAD and FAD The lesson begins with a challenge, where the students have to recall the details of glycolysis in order to form the word matrix. This introduces the key point that these two stages occur in this part of the mitochondria and time is taken to explain why the reactions occur in the matrix as opposed to the cytoplasm like glycolysis. Moving forwards, the Link reaction is covered in 5 detailed bullet points and students have to add the key information to these points using their prior knowledge as well as knowledge provided in terms of NAD. The students will recognise that this reaction occurs twice per molecule of glucose and a quick quiz competition is used to test their understanding of the numbers of the different products of this stage. This is just one of the range of methods that are used to check understanding and all answers are explained to allow students to assess their progress. The rest of the lesson focuses on the Krebs cycle. In line with the detail of the specification, students will understand how decarboxylation and dehydrogenation reactions result in the regeneration of the oxaloacetate

This lesson describes the roles of glycolysis in aerobic and anaerobic respiration and links to the upcoming lessons on the link reaction and lactate formation. The engaging PowerPoint and accompanying resources have been designed to cover point 7.2 as detailed in the Edexcel International A-level Biology specification and includes details of the phosphorylation of the hexoses, the production of ATP by substrate-level phosphorylation, reduced NAD, pyruvate and lactate The lesson begins with the introduction of the name of the stage and then explains how the phosphorylation of the hexoses, the breakdown into GP and the production of the ATP, reduced coenzymes and pyruvate are the stages that need to be known for this specification. Time is taken to go through each of these stages and key points such as the use of ATP in phosphorylation are explained so that students can understand how this affects the net yield. A quick quiz competition is used to introduce NAD and the students will learn that the reduction of this coenzyme, which is followed by the transport of the protons and electrons to the cristae for the electron transport chain is critical for the overall production of ATP. Understanding checks, in a range of forms, are included throughout the lesson so that students can assess their progress and any misconceptions are immediately addressed

This lesson describes the overall reaction of aerobic respiration, introducing the 4 stages before the finer details are covered in the upcoming lessons. The engaging PowerPoint and accompanying resource have been designed to cover points 7.1 (i) and (ii) of the Edexcel International A-level Biology specification and explains how each step in this many-stepped process is catalysed by a specific intracellular enzyme. The lesson begins with an introduction to glycolysis and students will learn how this first stage of aerobic respiration is also the first stage when oxygen is not present. This stage involves 10 reactions and an opportunity is taken to explain how each of these reactions is catalysed by a different, specific intracellular enzyme. A version of “GUESS WHO” challenges students to use a series of structural clues to whittle the 6 organelles down to just the mitochondrion so that they can learn how the other three stages take place inside this organelle. Moving forwards, the key components of the organelle are identified on a diagram. Students are introduced to the stages of respiration so that they can make a link to the parts of the cell and the mitochondria where each stage occurs. Students will learn that the presence of decarboxylase and dehydrogenase enzymes in the matrix along with coenzymes and oxaloacetate allows the link reaction and the Krebs cycle to run and that these stages produce the waste product of carbon dioxide. Finally, time is taken to introduce the electron transport chain and the enzyme, ATP synthase, so that students can begin to understand how the flow of protons across the inner membrane results in the production of ATP and the the formation of water when oxygen acts as the final electron acceptor.

This fully-resourced lesson describes the structural and physiological differences between fast and slow twitch muscle fibres. The detailed PowerPoint and accompanying resources have been designed to cover point 7.10 (ii) of the Pearson Edexcel A-level Biology A (Salters Nuffield) specification and due to the obvious links, this lesson also challenges the students on their knowledge of respiration from earlier in topic 7 and cell structures and biological molecules from topics 1, 2 and 3 The following structural and physiological characteristics are covered over the course of this lesson: Reliance on the aerobic or anaerobic pathways to generate ATP Resistance to fatigue mitochondrial density capillary density myoglobin content (and colour) fibre diameter phosphocreatine content glycogen content A wide variety of tasks are used to cover this content and include knowledge recall and application of knowledge exam-style questions with fully-displayed mark schemes as well as quick quiz competitions to maintain motivation and engagement. This lesson has been specifically planned to tie in with the previous lesson in this topic covering the contraction of skeletal muscles by the sliding filament mechanism

This lesson describes the role of the hypothalamus and the mechanisms of thermoregulation that maintain the body in dynamic equilibrium during exercise. The PowerPoint has been designed to cover point 7.12 of the Pearson Edexcel A-level Biology A (Salters Nuffield) specification. Students were introduced to homeostasis at GCSE and this lesson has been written to build on that knowledge and to add the key detail needed at this level. Focusing on the three main parts of a homeostatic control system, the students will learn about the role of the internal and peripheral thermoreceptors, the thermoregulatory centre in the hypothalamus and the range of effectors which bring about the responses to restore optimum levels. The following responses are covered in this lesson: Vasodilation Increased sweating Body hairs In each case, time is taken to challenge students on their ability to make links to related topics such as the arterioles involved in the redistribution of blood and the high specific latent heat of vaporisation of water.

This fully-resourced lesson describes the structure and general properties of slow and fast skeletal muscle fibres. The detailed PowerPoint and accompanying resources are the second in a series of 2 lessons that cover the content detailed in point 6.3 of the AQA A-level Biology specification and due to the obvious links, this lesson also challenges the students on their knowledge of respiration, cell structures and biological molecules like glycogen and haemoglobin The following structure and properties are covered over the course of this lesson: Reliance on the aerobic or anaerobic pathways to generate ATP Resistance to fatigue mitochondrial density capillary density myoglobin content (and colour) fibre diameter phosphocreatine content glycogen content A wide variety of tasks are used to cover this content and include knowledge recall and application of knowledge exam-style questions with fully-displayed mark schemes as well as quick quiz competitions to maintain motivation and engagement. This lesson has been specifically planned to tie in with the previous lesson in topic 6.3, titled “Contraction of skeletal muscles”, and this lesson has been uploaded for free

This fully-resourced lesson introduces bacteriostatic and bactericidal antibiotics and describes their differences, focusing on their modes of action. The engaging PowerPoint and accompanying resources have been designed to cover point 6.14 of the Pearson Edexcel A-level Biology A (Salters Nuffield) specification but also makes continual links to earlier lessons in topic 6 as well as related topics from the previous year such as protein synthesis from topic 2 The lesson begins by challenging the students to use their knowledge of the previous topic 6 lessons to identify the suffixes cidal and static. Students will learn that when the prefix is added, these form the full names of two types of antibiotics. Their understanding of terminology is tested further as they have to recognise that Polymyxin B is an example of a bactericidal antibiotic as its actions would result in the death of the bacterial cell. Tetracycline is used as the example of a bacteriostatic antibiotic and students will discover that its prevention of the binding of tRNA that inhibits protein synthesis and this reduction and stopping of growth and reproduction is synonymous with these drugs. Students are challenged on their knowledge of translation and will also be given time for a class discussion to understand that these antibiotics encourage the body’s immune system to overcome the pathogen in natural, active immunity. The final part of the lesson uses a quick quiz competition and a series of exam-style questions to ensure that students can recognise the different antibiotics from descriptions.

This fully-resourced lesson describes the development of the humoral and cell-mediated immune responses. The detailed PowerPoint and accompanying resources have been designed to cover points 6.7 (ii) & (iii) as detailed in the Edexcel A-level Biology B specification and includes descriptions of the roles of antigen-presenting cells, T helper cells, cytokines, T killer cells, B cells, clonal selection and plasma cells. Antigen presentation was introduced at the end of the previous lesson so the task at the start of this lesson challenges students to recognise the name of this process and then they have to spot the errors in the passage that describes the details of this event. This reminds them that contact between the APC and T lymphocytes is necessary to elicit a response which they will come to recognise as the cell-mediated response. A series of quick quiz rounds reveals key terms in a memorable way and one that is introduced is helper T cells. Time is then taken to describe the importance of cell signalling for an effective response and students will learn how the release of chemicals by these cells activates other aspects of the response. The role of the killer T cells and their production of cytotoxins is also described before an exam-style question is used to check on their understanding at this point of the lesson. This leads into the section of the lesson that deals with the humoral response and students will understand how this involves the antibodies that are produced by the plasma cells that are the result of clonal selection and expansion. The T and B memory cells are also introduced so that students can understand how they are retained in the body even after the pathogen has been overcome and will play a critical role in the development of immunity. This prepares the students for the next lesson about the role of these memory cells in the secondary immune response.

This fully-resourced lesson describes the role of memory cells in the secondary immune response. The PowerPoint and accompanying resources have been designed to cover specification point 6.7 (iv) of the Edexcel A-level Biology B specification but also contains a detailed description of the structure and function of antibodies and therefore covers this part of 6.7 (ii) As memory B cells differentiate into plasma cells that produce antibodies when a specific antigen is re-encountered, it was decided to link the immune responses and antibodies together in one lesson. The lesson begins by checking on the students incoming knowledge to ensure that they recognise that B cells differentiate into plasma cells and memory cells. This was introduced in a previous lesson on the specific immune response and students must be confident in their understanding if the development of immunity is to be understood. A couple of quick quiz competitions are then used to introduce key terms so that the structure of antibodies in terms of polypeptide chains, variable and constant regions and hinge regions are met. Time is taken to focus on the variable region and to explain how the specificity of this for a particular antigen allows neutralisation and agglutination to take place. The remainder of the lesson focuses on the differences between the primary and secondary immune responses and a series of exam-style questions will enable students to understand that the quicker production of a greater concentration of these antibodies in the secondary response is due to the retention of memory cells.

This fully-resourced lesson describes how vaccinations are used to control disease and how immunity can be natural, artifical, active and passive. The engaging PowerPoint and accompanying resources have been designed to cover points 6.7 (v) & (vi) of the Edexcel A-level Biology B specification and there is also a description and discussion on the development of herd immunity. The previous lesson finished with a series of exam questions where students observed differences between the primary and secondary immune responses so the start of this lesson uses an imaginary game of TOP TRUMPS to challenge them on the depth of their understanding. This will act to remind them that a larger concentration of antibodies is produced in a quicker time in the secondary response. The importance of antibodies and the production of memory cells for the development of immunity is emphasised and this will be continually referenced as the lesson progresses. The students will learn that this response of the body to a pathogen that has entered the body through natural processes is natural active immunity. Moving forwards, time is taken to look at vaccinations as an example of artificial active immunity. Another series of questions focusing on the MMR vaccine will challenge the students to explain how the deliberate exposure to antigenic material activates the immune response and leads to the retention of memory cells. A quick quiz competition is used to introduce the variety of forms that the antigenic material can take along with examples of diseases that are vaccinated against using these methods. The eradication of smallpox is used to describe the concept of herd immunity and the students are given time to consider the scientific questions and concerns that arise when the use of this pathway is a possible option for a government. The remainder of the lesson looks at the different forms of passive immunity and describes the drawbacks in terms of the need for a full response if a pathogen is re-encountered.

This lesson describes the mode of actions of macrophages, neutrophils and lymphocytes. The engaging PowerPoint and accompanying resource have been primarily designed to cover point 6.7 (i) of the Edexcel A-level Biology B specification but includes an introduction to antigen-presentation so that the students are prepared for upcoming lessons on the cell-mediated and humoral responses. At the start of the lesson, the students are challenged to recall that cytosis is a suffix associated with transport mechanisms and this introduces phagocytosis as a form of endocytosis which takes in pathogens and foreign particles. This emphasis on key terminology runs throughout the course of the lesson and students are encouraged to consider how the start or end of a word can be used to determine meaning. The process of phagocytosis is then split into 5 key steps and time is taken to discuss the role of opsonins as well as the fusion of lysosomes and the release of lysozymes. A series of application questions are used to challenge the students on their ability to make links to related topics including an understanding of how the hydrolysis of the peptidoglycan wall of a bacteria results in lysis. Students will be able to distinguish between neutrophils and monocytes from a diagram and at this point, the role of macrophages and dendritic cells as antigen-presenting cells is described so that it can be used in the next lesson. The lesson concludes with an introduction to lymphocytes so that initial links between phagocytosis and the specific immune responses are made.