This is a detailed and engaging lesson which has been designed to cover specification points 14.1 (a, b and c) of the CIE International A-level Biology specification which states that students should be able to explain the importance of homeostasis and the roles of negative feedback and the communication systems in this control. As homeostasis is a topic met at GCSE, this lesson has been written to build on this knowledge as well as to check on their prior knowledge of earlier A-level topics such as osmosis when considering blood water potential. Discussion points are written into the lesson at regular intervals to encourage the students to consider why a particular process or method takes place and understanding checks allow them to assess their progress. Students will recall how body temperature, blood water potential and blood glucose concentration are maintained within strict limits and the importance of these systems are looked into in detail. They will also learn that carbon dioxide concentration and blood pressure are aspects that are controlled in the body and key terminology such as chemoreceptors and baroreceptors are used throughout so that students are confident with the meaning when met later in the module. The key components of the control system are recalled and then time is taken to focus on the cell signalling that occurs between the coordination centre and the effectors. Students will learn to associate the response with either the use of the neuronal or hormonal system. The final part of the lesson looks at the importance of negative feedback in reversing the change in order to bring it back to the optimum and the differences to positive feedback are also explored. This lesson has been written for students who are studying the CIE International A-level Biology course and ties in well with the other uploaded lessons on this topic such as those on the kidney

This fully-resourced lesson explores how the presence of particular alleles at one locus can mask the expression of alleles at a second locus in gene interactions. The detailed and engaging PowerPoint and associated resources have been designed to cover the part of point 16.2 (b) of the CIE International A-level Biology specification which states that students should be able to use genetic diagrams to solve problems that involve gene interactions. This is a topic which students tend to find difficult, and therefore the lesson was written to split the topic into small chunks where examples of dominant, recessive and complimentary gene interactions are considered, discussed at length and then explained. Understanding checks, in various forms, are included throughout the lesson so that students can assess their progress and any misconceptions are immediately addressed. There are regular links to related topics such as dihybrid inheritance so that students can meet the challenge of interpreting genotypes and link to the different types of interactions

This fully-resourced lesson guides students through the use of the Hardy-Weinberg equation to calculate the frequency of alleles, genotypes and phenotypes in a population. Both the detailed PowerPoint and differentiated practice questions on a worksheet have been designed to cover the 2nd part of point 7.2 of the AQA A-level Biology specification which expects students to be able to use this mathematical model The lesson begins by looking at the equation and ensuring that 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. The rest of the lesson gives students 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.

This engaging REVISION LESSON has been designed to cover the content of topic 13 (Photosynthesis) of the CIE International A-level Biology specification. Filled with a wide range of activities, that include exam questions with explanations, quick tasks and quiz competitions, the students will be motivated whilst they assess their ability to apply their knowledge. Due to the obvious importance of this reaction, assessment questions are extremely common and so a deep understanding of this topic is key to success and the lesson has been designed to cover the important ideas. The following sub-topics have received particular attention in this lesson: Photophosphorylation An outline of cyclic and non-cyclic photophosphorylation Photolysis of water The light dependent reaction The structure of the chloroplast and the site of the different reactions The Calvin cycle The limiting factors of photosynthesis Investigating the effect of light intensity using DCPIP as a redox indicator and a Hill suspension The effect of temperature on the rate There is a focus on terminology throughout the lesson so that students are comfortable with the terms that will be encountered in exam questions. Revision lessons on the other topics of the specification are uploaded so please take a moment to look at those too

This fully-resourced lesson focuses on the role of meiosis in ensuring genetic variation through the production of non-identical gametes. The detailed PowerPoint and accompanying resource have been designed to cover point 3.9 of the Pearson Edexcel A-level Biology (Salters Nuffield) specification which states that students should be able to describe how crossing over and independent assortment result in genetically unidentical daughter cells. In order to understand how the events of meiosis like crossing over and random assortment and independent segregation can lead to variation, students need to be clear in their understanding that DNA replication in interphase results in homologous chromosomes as pairs of sister chromatids. Therefore the beginning of the lesson focuses on the chromosomes in the parent cell and this first part of the cycle and students will be introduced to non-sister chromatids and the fact that they may contain different alleles which is important for the exchange that occurs during crossing over. Time is taken to go through this event in prophase I in a step by step guide so that the students can recognise that the result can be new combinations of alleles that were not present in the parent cell. Moving forwards, the lesson explores how the independent segregation of chromosomes and chromatids during anaphase I and II results in genetically different gametes. The final part of the lesson looks at the use of a mathematical expression to calculate the possible combinations of alleles in gametes as well as in a zygote following the random fertilisation of haploid gametes. Understanding and prior knowledge checks are interspersed throughout the lesson as well as a series of exam questions which challenge the students to apply their knowledge to potentially unfamiliar situations.

This fully-resourced lesson covers the meaning of the 9 genetic terms that are detailed in point 2.13 (i) of the Pearson Edexcel A-level Biology (Salters Nuffield) specification as well as four other key terms which will need to be used later in topic 2, 3 and 8. In the following lessons, students are expected to be able to demonstrate and apply their knowledge and understanding of genetic diagrams and phenotypic ratios to show patterns of inheritance and this is only possible with a clear understanding of the genetic terminology that will be used in related exam questions. As some of these terms were met at GCSE, this lesson has been designed to build on this prior knowledge and provide clear explanations as to their meanings as well as numerous examples of their use in both questions and exemplary answers. The main task provides the students with an opportunity to apply their understanding by recognising a dominance hierarchy in a multiple alleles characteristic and then calculating a phenotypic ratio when given a completed genetic diagram. Other tasks include prior knowledge checks, discussion points to encourage students to consider the implementation of the genetic terms and quiz competitions to introduce new terms, maintain engagement and act as an understanding check. The 13 terms are genome, gene, chromosome, gene locus, homologous chromosomes, alleles, dominant, recessive, genotype, phenotype, homozygotes and heterozygotes

This is a fully-resourced lesson which looks at the inheritance of genes that are carried on the sex chromosomes in sex-linkage. Students will explore sex-linked diseases in humans and then are challenged to apply their knowledge to examples in other animals. The detailed PowerPoint and associated resources have been designed to cover the second part of point 3.8 (ii) of the Pearson Edexcel A-level Biology (Salters Nuffield) specification which states that students should understand sex-linkage. 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. In terms of humans, the lesson focuses on haemophilia and red-green colour blindness 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 apply their knowledge to a question about chickens and how the rate of feather production in chicks can be used to determine gender.

This lesson focuses on the nature of the genetic code and specifically focuses on the degenerate nature to make a link to gene mutations which is covered later in topic 2. The PowerPoint has been designed to cover point 2.7 of the Pearson Edexcel A-level Biology (Salters Nuffield) specification which states that students should understand how the descriptive terms triplet code, degenerate and non-overlapping relate to the genetic code. The lesson begins by introducing the terms near universal and non-overlapping in addition to degenerate. A quick quiz competition is used to generate the number 20 so that the students can learn that there are 20 proteinogenic amino acids in the genetic code. This leads into a challenge, where they have to use their prior knowledge of DNA to calculate the number of different DNA triplets (64) and the mismatch in number is then discussed and related back to the lesson topic. Moving forwards, substitutions and deletions are briefly introduced so that they can see how although one substitution can change the primary structure, another will change the codon but not the encoded amino acid. The lesson concludes with a brief look at the non-overlapping nature of the code so that the impact of a base deletion can be understood when covered in greater detail with cystic fibrosis

This fully-resourced lesson looks at the detailed structure of a muscle fibre, and focuses on the proteins, bands and zones that are found in the myofibril. The engaging PowerPoint and acccompanying resource have been designed to cover point 7.10 (i) of the Pearson Edexcel A-level Biology A (Salters Nuffield) specification. The lesson begins with an imaginary question from the quiz show POINTLESS, where students have to recognise a range of fields of study. This will reveal myology as the study of muscles so that key terms like myofibril, myofilament and myosin can be introduced. Students should have met these terms as well as actin when learning about the sliding filament theory in topic 7.2, so this acts as a recall. 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. The final task challenges the students to use their knowledge of the sliding filament theory to recognise which of these bands or zones narrow or stay the same length when muscle is contracted.

This fully-resourced lesson explores how other respiratory substrates, such as lipids and proteins, can be used to produce molecules of ATP. The PowerPoint and accompanying resources have been designed to cover the 7th and final part of point 5.2 of the AQA A-level Biology specification which states that students should know how these substrates enter the Krebs cycle. This lesson has been written to challenge the knowledge of the earlier parts of the topic of respiration and so contains constant prior knowledge checks which come in a range of forms. Students will learn that lipids and proteins can be used as respiratory substrates and will recognise the different ways that they enter the respiratory pathway. Time is taken to look at the beta oxidation pathway and again students are challenged to compare the products of this pathway against that of the Link reaction.

This fully-resourced lesson explores how glucose as well as the other respiratory substrates, such as lipids and proteins, can enter the respiratory pathway and therefore can be respired to produce molecules of ATP. The engaging PowerPoint and accompanying resources have been designed to cover points 12.1 (f) and (g) of the CIE International A-level Biology specification which states that students should be able to explain the relative energy values of carbohydrates, lipids and proteins and be able to determine respiratory quotients from equations. This lesson has been written to challenge current understanding as well as introduce details of glycolysis, the link reaction and Krebs cycle as these stages have yet to be covered fully. Students will learn that lipids and proteins can be used as respiratory substrates and will recognise the different ways that they enter the respiratory pathway. A quick quiz competition is used to introduce the relative energy value for carbohydrates and students are challenged to predict how the values for lipids and proteins will compare. As a result, students will recognise that a greater number of hydrogen atoms results in a greater availability of protons to form the proton gradient to fuel the production of ATP. The rest of the lesson focuses on the calculation of the respiratory quotient and time is taken to look at how the result can be interpreted to determine which substrates were respired.

This clear and concise lesson looks at the role of the link reaction in the conversion of pyruvate to acetyl coenzyme A which will then enter the Krebs cycle. The PowerPoint has been designed to cover point 12.2 © of the CIE International A-level Biology specification which states that students should be able to explain that this conversion occurs in the matrix when oxygen is present 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 this stage occurs 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. This lesson has been written to tie in with the other uploaded lessons on glycolysis and the Krebs cycle and oxidative phosphorylation.

This fully-resourced lesson explores how pyruvate can be converted to lactate or ethanol using reduced NAD and that the reoxidation of the coenzyme allows glycolysis to continue. The engaging and detailed PowerPoint and accompanying differentiated resources have been designed to cover points 12.2 (j) and (k) of the CIE International A-level Biology specification which states that students should be able to explain the production of a small yield of ATP in anaerobic conditions and recognise the concept of an oxygen debt The lesson begins with a focus on the coenzyme, NAD, and students are challenged to recall details of its role in the oxidation of triose phosphate. Students will learn that oxidative phosphorylation in aerobic respiration allows these coenzymes to be reoxidised but that another metabolic pathway has to operate when there is no oxygen. Time is taken to go through the lactate and ethanol fermentation pathways and students are encouraged to discuss the conversions before applying their knowledge to complete diagrams and passages about the pathways. Understanding checks in a range of forms are used to enable the students to assess their progress whilst prior knowledge checks allow them to recognise the links to earlier topics. Students will also be introduced to the oxygen debt and will learn how the volume consumed after vigorous exercise is used to catabolise lactic acid and restore the body’s stores to normal levels. This lesson has been written to tie in with the other uploaded lessons on the stages of aerobic respiration.

This clear and detailed lesson describes the process of oxidative phosphorylation, including the roles of the electron carriers, oxygen and the mitochondrial cristae. The PowerPoint has been designed to cover points 12.2 (f) and (g) of the CIE International A-level Biology specification and includes details of the electron transport system, the flow of protons and ATP synthase. The lesson begins with a discussion about the starting point of the reaction. In the previous stages, the starting molecule was the final product of the last stage but in this stage, it is the reduced coenzymes which release their hydrogen atoms. Moving forwards, the process of oxidative phosphorylation is covered in 7 detailed steps and at each point, key facts are discussed and explored in further detail to enable a deep understanding to be developed. Students will see how the proton gradient across the inner membrane is created and that the flow of protons down the channel associated with ATP synthase results in a conformational change and the addition of phosphate groups to ADP by oxidative phosphorylation. Understanding checks are included throughout the lesson to enable the students to assess their progress and prior knowledge checks allow them to recognise the clear links to other topics and modules. This lesson has been written to tie in with the other uploaded lessons on glycolysis, the Link reaction and the Krebs cycle

This fully-resourced lesson looks at the details of glycolysis as the first stage of respiration and explains how the sequence of reactions results in glucose being converted to pyruvate. The engaging PowerPoint and accompanying differentiated resources have been designed to cover point 12.2 (b) of the CIE International A-level Biology specification which states that students should know glycolysis as the phosphorylation of glucose and the subsequent splitting into triose phosphate which is then oxidised to pyruvate. The lesson begins with the introduction of the name of the stage and then explains how the phosphorylation of the hexoses and the production of the ATP, 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 detailed lesson introduces the four stages of aerobic respiration and looks at the relationship between structure and function of the mitochondrion. The engaging PowerPoint and accompanying resource have been designed to cover points 12.2 (a) and (i) of the CIE International A-level Biology specification which states that students should be able to demonstrate and apply an understanding of the inner and outer mitochondrial membranes, cristae, matrix and mitochondrial DNA. 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 isn’t present. 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. 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.

This fully-resourced lesson explores how the structure of arteries, veins and capillaries relates to their functions. The engaging and detailed PowerPoint and accompanying resources have been designed to cover point 1.3 of the Pearson Edexcel A-level Biology A (Salters Nuffield) specification. 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, 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. The final part of the lesson looks at the role of the capillaries in exchange. 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. It is estimated that it will take about 2 hours of allocated A-level Biology teaching time to cover the detail included in this lesson

This engaging and fully-resourced lesson looks at the myogenic nature of cardiac muscle and explores the roles of the SAN, AVN and Purkyne tissue in the initiation and control of heart action. The PowerPoint and accompanying resources have been designed to cover points 8.2 (d) of the CIE International A-level Biology specification. The lesson begins with the introduction of the SAN 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. The lesson has been written to make clear links to the cardiac cycle and the structure of the heart and students are challenged on their knowledge of this system from topic 8.1. 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 Due to the detailed nature of this lesson, it is estimated that it will take about 2 hours of A-level teaching time to cover the detail