This fully-resourced lesson describes the effects of enzyme and substrate concentration on the rate of enzyme-catalysed reactions. The PowerPoint and accompanying resources are the third in a series of 4 lessons which cover the details of point 3.2 (a) of the CIE A-level Biology specification. The first part of the lesson describes how an increase in substrate concentration will affect the rate of reaction when a fixed concentration of enzyme is used. Time is taken to introduce limiting factors and students will be challenged to identify substrate concentration as the limiting factor before the maximum rate is attained and then they are given discussion time to identify the possible factors after this point. A series of exam-style questions are used throughout the lesson and the mark schemes are displayed to allow the students to assess their understanding and for any misconceptions to be immediately addressed. Moving forwards, the students have to use their knowledge of substrate concentration to construct a graph to represent the relationship between enzyme concentration and rate of reaction and they have to explain the different sections of the graph and identify the limiting factors. The final section of the lesson describes how the availability of enzymes is controlled in living organisms. Students will come to recognise that this availability is the result of enzyme synthesis and enzyme degradation and a series of tasks will introduce the details of transcription and translation and therefore prepare them for the lessons in topic 6. Please note that this lesson explains the Biology behind the effect of concentration on enzyme-catalysed reactions and not the methodology involved in carrying out such an investigation as this is covered in a core practical lesson.

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.

This fully-resourced lesson describes how the release of ADH from the pituitary gland controls mammalian plasma concentration. The engaging PowerPoint and accompanying resources have been designed to cover the detail included in point 9.9 (iv) of the Edexcel A-level Biology B specification and also includes details of the roles of the osmoreceptors in the hypothalamus. The principles of homeostasis and negative feedback were covered in an earlier lesson in topic 9, 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 to use and manipulate the magnification formula to calculate the magnification or the actual size in a range of units. The PowerPoint and accompanying resources have been designed to cover point 2.1.1 (e) of the OCR A-level Biology A specification and contains a number of quiz rounds as part of the competition that runs throughout all of the module 2.1.1 lessons The students are likely to have met the magnification formula at GCSE so this lesson has been written to build on that knowledge and to support them with more difficult questions when they have to calculate actual size without directly being given the magnification. A step by step guide is used to walk the students through the methodology and useful tips are provided. Students could be asked to calculate the actual size in millimetres, micrometres, nanometres or picometres so time is taken to ensure that they can convert between one and another.

This fully-resourced lesson describes the ultrastructure of eukaryotic cells and the functions of the different cellular components. The engaging and detailed PowerPoint and accompanying resources have been designed to cover points 2.1.1 (g) & (i) of the OCR A-level Biology A specification and therefore also describes the interrelationship between the organelles involved in the production and secretion of proteins. As cells are the building blocks of living organisms, it makes sense that they would be heavily involved in all 6 modules in the OCR course and intricate planning has ensured that links to the lessons earlier in module 2.1.1 are made as well as to the upcoming modules. The lesson uses a wide range of activities, that include exam-style questions, class discussion points and quick quiz competitions, to maintain motivation and engagement whilst describing the relationship between the structure and function of the following organelles: nucleus nucleolus centrioles ribosomes rough endoplasmic reticulum Golgi apparatus lysosomes smooth endoplasmic reticulum mitochondria cell surface membrane vacuole chloroplasts plasmodesmata Details of the cilia and flagella are covered in the lesson on the importance of the cytoskeleton. All of the worksheets have been differentiated to support students of differing abilities whilst maintaining challenge Due to the detail that is included in this lesson, it is estimated that it will take in excess of 3 hours of allocated A-level teaching time to go through all of the tasks

This lesson explains the effects of temperature increases on enzyme activity and describes how to calculate the temperature coefficient. The PowerPoint and the accompanying resource are part of the second lesson in a series of 3, which cover the content detailed in point 2.1.4 (d) [i] of the OCR A-level Biology A specification and this lesson has been specifically planned to tie in with an earlier lesson covering 2.1.4 (a, b & c) where the roles and mechanism of action of enzymes were introduced. The lesson begins by challenging the students to recognise optimum as a key term from its 6 synonyms that are shown on the board. Time is taken to ensure that the students understand that the optimum temperature is the temperature at which the most enzyme-product complexes are produced per second and therefore the temperature at which the rate of an enzyme-controlled reaction works at its maximum. The optimum temperatures of DNA polymerase in humans and in a thermophilic bacteria and RUBISCO in a tomato plant are used to demonstrate how different enzymes have different optimum temperatures and the roles of the latter two in the PCR and photosynthesis are briefly described to prepare students for these lessons in modules 6 and 5. Moving forwards, the next part of the lesson focuses on enzyme activity at temperatures below the optimum and at temperatures above the optimum. Students will understand that increasing the temperature increases the kinetic energy of the enzyme and substrate molecules, and this increases the likelihood of successful collisions and the production of enzyme-substrate and enzyme-product complexes. When considering the effect of increasing the temperature above the optimum, continual references are made to the previous lesson and the control of the shape of the active site by the tertiary structure. Students will be able to describe how the hydrogen and ionic bonds in the tertiary structure are broken by the vibrations associated with higher temperatures and are challenged to complete the graph to show how the rate of reaction decreases to 0 when the enzyme has denatured. The final part of the lesson introduces the Q10 temperature coefficient and students are challenged to apply this formula to calculate the value for a chemical reaction and a metabolic reaction to determine that enzyme-catalysed reactions have higher rates of reaction Please note that this lesson has been designed specifically to explain the relationship between the change in temperature and the rate of enzyme activity in a reaction and not the practical skills that is part of a lesson covering specification point 2.1.4 (d) [ii]

This lesson describes the light-dependent reactions of photosynthesis, focusing on the link to the light-independent reactions. The detailed PowerPoint and accompanying resources have been designed to cover the details included in point 5.7 of the Edexcel A-level Biology specification and therefore describes how light energy is trapped by exciting electrons in chlorophyll and the role of these electrons in generating ATP, reducing NADP in photophosphorylation and producing oxygen through photolysis of water. This is a topic which students tend to find difficult so this lesson has been intricately planned to walk them through each of the key reactions in the light-dependent stage. Time is taken to describe the roles of the major protein complexes that are embedded in the thylakoid membrane and this includes the two photosystems, the proton pump and ATP synthase. A series of exam-style questions have been written that link to other biological topics in this course such as cell structure and membrane transport as well as application questions to challenge them to apply their understanding. Some of these resources have been differentiated to allow students of differing abilities to access the work and to be pushed at the same time. Students will learn that there are two pathways that the electron can take from PSI and at the completion of the two tasks which describe each of these pathways, they will understand how ATP is generated in non-cyclic and cyclic fashion. The final task of the lesson asks them to compare these two forms of photophosphorylation to check that they understand when photolysis is involved and reduced NADP is formed. Due to the detail included in this lesson, it is estimated that it will take in excess of 2.5 hours of allocated A-level teaching time to complete

This fully-resourced lesson describes how Mycobacterium tuberculosis and Human Immunodeficiency virus infect human cells. The PowerPoint and accompanying resources have been designed to cover point 6.6 of the Pearson Edexcel A-level Biology A (Salters Nuffield) specification and ties in directly with the previous lesson where the structure of bacteria and viruses were compared. The lesson begins by ensuring that students recognise that TB is caused by the infection of a species of bacteria known as Mycobacterium tuberculosis and they will challenged to use their knowledge of scientific classification to recall that this pathogen is found in the mycobacteria genus. At this point, the students are told that the cell walls of this genus contain mycolic acids and later in the lesson they will have to work out that this specialist feature enables this pathogen to survive phagocytosis. A series of exam-style questions will challenge their knowledge of the respiratory and immune systems as they can understand how the bacterium travels to the alveoli where it is engulfed by a macrophage. Key terms like granuloma and necrosis are introduced and the sequence of events that occur following the formation of this aggregate of cells is described. The structure of viruses was covered during the previous lesson, so this next part of the lesson starts by challenging the students to recall the capsid, genetic material in the form of viral RNA and the lipid envelope. At this point, the students are introduced to gp120, the glycoprotein which is exposed on the surface of the lipid envelope, as this structure is critical for the entry of the virus into host cells. Students will annotate a basic diagram of HIV with these four structures which also has gp41 labelled. A quick quiz competition introduces the names of the enzymes found inside the capsid Moving forwards, the main task of this part of the lesson describes how HIV binds to the helper T cells, injects its capsid and integrates its DNA into the host’s genome in order to replicate to form virus particles (virions). Students are guided through the formation of a detailed answer about the mechanism of HIV and have to input key terms and structures where information is missing. Students will learn that the increase in the number of virus particles and a decrease in helper T cells and other immune cells results in infections like TB and by opportunistic pathogens and that this stage is recognised as AIDS

This lesson describes how the immune system uses molecules on the surface of a cell to identify it, focusing on the identification of pathogens by their antigens. The PowerPoint and accompanying resources which are differentiated are part of the 1st lesson in the series of 7 that cover the content detailed in topic 2.4 of the AQA A-level Biology specification. As this is the first lesson in topic 2.4, it has been specifically planned to introduce a number of key concepts which include phagocytosis, T and B cells, antibodies and memory cells so that students are prepared for upcoming lessons. The lesson begins by challenging the students to use their knowledge of cells to recall the common internal components of a cell before they are informed that all cells also have molecules on their outer membrane. Students will recognise that these molecules are used by the immune system for identification before a quick quiz competition reveals that this allows toxins, abnormal body cells and pathogens to be identified. Moving forwards, the next part of the lesson focuses on the antigens that are found on the outside of a pathogen and links are made to upcoming lesson topics which include: phagocytosis following the identification of a pathogen antigen-presentation by macrophages and dendritic cells production of antibodies which are specific to the antigens the use of antigens in a vaccination program The final task challenges the students to describe and explain how antigen variability will affect disease and disease prevention and this task has been differentiated two ways to allow students of differing abilities to be challenged and supported.

This lesson describes the key structural features of viruses and challenges the students to compare them against those of a bacteria as covered in topic 3. The PowerPoint and accompanying resource have primarily been designed to cover point 6.5 of the Pearson Edexcel A-level Biology A (Salters Nuffield) specification but can be used a revision tool for point 3.4 as students need to recall the structures of a prokaryotic cell. Details of the COVID-19 epidemic are included in the lesson to increase relevance and to help students to understand this biological topic in greater depth. They will understand that a virus’ lack of cell structures results in an non-cellular classification and the fact that it is unable to reproduce without a host is one of the additional reasons that renders it as non-living. The main focus of the lesson is the nucleic acid, the capsid and the attachment proteins that are present in these microorganisms and time is taken to explain how these structures are involved in the infection of a host cell. The lipid membrane is also introduced and links are made to the previous lessons on eukaryotic cells. The final section of the lesson challenges the students to recognise the following prokaryotic cell structures from their descriptions: plasmid pili capsule cell wall flagellum circular DNA ribosomes mesosomes This lesson has been specifically planned to link to the next lesson which covers point 6.6 on the infection of human cells by Mycobacterium tuberculosis and human immunodeficiency virus

This fully-resourced lesson describes the differences between the roles of the B cells and T cells in the body’s immune response. The PowerPoint and accompanying resources have been designed to cover points 6.9 & 6.10 in unit 4 of the Edexcel International A-level Biology specification and includes descriptions of the role of the antigens and the production of antibodies by plasma (effector) cells In the previous lesson on the non-specific responses, the students were introduced to macrophages and dendritic cells as antigen-presenting cells and the start of this lesson challenges their recall and understanding of this process. Time is taken to discuss how the contact between these cells and lymphocytes is critical for the initiation of the body’s (specific) immune response. Moving forwards, a quick quiz competition is used to introduce the names of the different T cells that result from differentiation. Their specific roles are described including an emphasis on the importance of the release of cytokines in cell signalling to activate other immune system cells. T memory cells are also introduced so that students can understand their role in immunological memory and active immunity as described in an upcoming lesson. The next part of the lesson focuses on the B cells and describes how clonal selection and clonal expansion results in the formation of memory B cells and effector cells. A series of understanding and application questions are then used to introduce the structure of antibodies and to explain how the complementary shape of the variable region allows the antigen-antibody complex to be formed. The lesson concludes by emphasising that the pathogen will be overcome as a result of the combination of the actions of phagocytes, T killer cells and the antibodies released by the effector cells

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 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 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 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 lesson describes the tests that detect reducing and non-reducing sugars and starch using Benedict’s solution and iodine/potassium iodide. The PowerPoint and accompanying resource are part of the last lesson in a series of 4 lessons which have been designed to cover the content of topic 1.2 (Carbohydrates) of the AQA A-level Biology specification. The lesson begins with an explanation of the difference between a qualitative and quantitative test so that the students recognise that the two tests described within this lesson indicate the presence of a substance but not how much. The students are likely to have met these tests at GCSE so this lesson has been planned to build on that knowledge and to add the knowledge needed at this level. A step by step guide walks the students through each stage of the tests for reducing and non-reducing sugars and application of knowledge questions and prior knowledge checks are included at appropriate points to ensure understanding is complete. Time is also taken to ensure that students understand the Science behind the results. The rest of the lesson focuses on the iodine test for starch and the students will learn that the colour change is the result of the movement of an ion into the amylose helix.