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

This detailed and engaging lesson covers the detail of specification points 5.1.4 (c and d) of the OCR A-level Biology A specification which states that students should be able to demonstrate and apply an understanding of the histology of the pancreas and the control of insulin secretion. There is a particular emphasis on structure throughout the lesson so that students can recognise the exocrine and endocrine tissues of the pancreas as well as describe their specific functions. The lesson begins with a list of endocrine glands and the students are challenged to select the gland which also has exocrine functions. This leads into a focus on the exocrine tissues of the pancreas, beginning with the enzymes that are secreted and form pancreatic juice. Students will discover how groups of these cells are called acini and the secretion of the enzymes into the lobule at the centre will lead to the intralobular ducts and finally the formation of the pancreatic duct. Moving forwards, students are introduced to the Islets of Langerhans and the specialised alpha and beta cells that are found within this endocrine tissue. The rest of this lesson looks at how the release of insulin from the beta cells is controlled. Some of the structures and substances involved have been met in earlier topics so a fun quiz round is used to see which students can recall these parts first. A series of questions and discussion points challenge the students to verbalise answers and to discuss key points so that the cascade of events that take place in the lead up to the release can be considered. In the final task, students have to describe these events in detail and this task has been differentiated so that students of differing abilities can access the work. This lesson has been specifically designed for students on the OCR A-level Biology A course and ties in well with the other lessons from module 5.1.4 on the control of blood glucose concentration and diabetes mellitus type I and II

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 engaging REVISION lesson has been designed to cover the content of topic 3 (Enzymes) of the CIE International A-level Biology specification. A wide range of activities have been written into the lesson to engage the students whilst they assess their understanding of the topic content. All of the exam questions contain detailed answers which students can use to identify missed marks and quiz competitions are used, like FROM NUMBERS 2 LETTERS (shown in the cover image) to recall key concepts and check on the finer details. The lesson has been planned to cover as much of the specification content as possible but the following sub-topics have received particular attention: Enzymes as globular proteins that act as biological catalysts Formation of the enzyme-substrate complex The lock and key theory and induced-fit hypothesis Competitive and non-competitive inhibitors The Michaelis-Menten constant The effect of changes in pH and temperature on the tertiary structure of the enzymes The immobilisation of enzymes using alginate Time has been taken in the design to ensure that links to other topics are made. For example, when checking the knowledge of the denaturation of enzymes due to pH and temperature, the bonds found in the tertiary structure are recalled and considered in depth.

This lesson acts as an introduction to topic 7.1 of the AQA A-level Biology specification and focuses on 16 key genetic terms that will support students in forming a deep understanding of inheritance. As some of these terms were met at GCSE, this fully-resourced lesson has been designed to include a wide range of activities that 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 16 terms are genome, gene, chromosome, gene locus, homologous chromosomes, alleles, dominant, recessive, genotype, codominance, multiple alleles, autosomes, sex chromosomes, phenotype, homozygous and heterozygous

This fully-resourced REVISION lesson has been designed to enable the students to challenge their knowledge of the content of topic 16 (Inherited change) of the CIE A-level Biology specification. The engaging PowerPoint and accompanying differentiated worksheets will motivate the students whilst they assess their understanding of the content and identify any areas which may require further attention. The wide range of activities have been written to cover as much of the topic as possible but the following specification points have been given particular focus: Homologous pairs of chromosomes The meanings of haploid and diploid The behaviour of chromosomes in meiosis Crossing over and random assortment as causes of genetic variation The use of key genetic terminology The use of genetic diagrams to solve problems including autosomal and sex-linkage, dihybrid inheritance and gene interactions The use of the chi-squared test Gene mutations Genetic control of protein production in prokaryotes Gibberellins and how they cause the breakdown of DELLA proteins Due to the extensiveness of this resource, it is likely that it will take a number of lessons to go through all of the activities

This fully-resourced lesson explores the inheritance of genetic characteristics that involve multiple alleles and codominant alleles. The engaging and detailed PowerPoint and differentiated worksheets 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 which involve codominance and multiple alleles. The main part of the lesson uses the inheritance of the ABO blood groups to demonstrate how the three alleles that are found at the locus on chromosome 9 and the codominance of the A and B alleles affects the phenotypes. Students are guided through the construction of the different genotypes and how to interpret the resulting phenotype. They are challenged to use a partially completed pedigree tree to determine the blood group for some of the family members and to explain how they came to their answer. To further challenge their ability to apply their knowledge, a series of questions about multiple alleles and codominance in animals that are not humans are used. All of the questions are followed by clear, visual mark schemes to allow the students to assess their progress and address any misconceptions

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 lesson guides students through the use of genetic diagrams to solve problems involving monohybrid and dihybrid crosses. The engaging PowerPoint and accompanying worksheets have been designed to cover the part of topic 16.2 (b) of the CIE A-level Biology specification which involves the inheritance of one or two genes As you can see from the cover image, this lesson uses a step by step guide to go through each important stage of drawing the genetic cross. Extra time is taken over step 2 which involves writing out the different possible gametes that a parent can produce. This is the step where students most commonly make mistakes so it is critical that the method is understood. Helpful hints are also given throughout, such as only writing out the different possible gametes in order to avoid creating unnecessary work. Students are shown how to answer an example question so that they can visualise how to set out their work before they are challenged to try two further questions. This first of these is differentiated so that even those students who find this very difficult are able to access the learning. The final question will enable the students to come up with the ratio 9:3:3:1 and they will be shown how they can recognise when this should be the expected ratio as this links to the chi-squared test which is covered later in the topic.

This engaging and fully-resourced lesson looks at examples of stabilising, directional and disruptive selection as the three main types of selection. The PowerPoint and accompanying resources have been designed to cover the 1st part of point 6.1.2 (e) of the OCR A-level Biology specification which states that students should be able to demonstrate and apply an understanding of the factors that affect the evolution of a species. The lesson begins by making a link to a topic from module 4 as the students are challenged to use the mark, release, recapture method to calculate numbers of rabbits with different coloured fur in a particular habitat. Sketch graphs are then constructed to show the changes in the population size in this example. A quick quiz competition is used to engage the students whilst introducing the names of the three main types of selection before a class discussion point encourages the students to recognise which specific type of selection is represented by the rabbits. Key terminology including intermediate and extreme phenotypes and selection pressure are used to emphasise their importance during explanations. A change in the environment of the habitat and a change in the numbers of the rabbits introduces directional selection before students will be given time to discuss and to predict the shape of the sketch graph for disruptive selection. Students are challenged to apply their knowledge in the final task of the lesson by choosing the correct type of selection when presented with details of a population and answer related questions. This lesson has been designed to tie in with another uploaded lesson on genetic drift which covers the second part of this specification point.

This engaging and fully-resourced lesson looks at how genetic drift can arise after a genetic bottleneck or as a result of the Founder effect. The detailed PowerPoint and accompanying resources have been designed to cover the second part of point 6.1.2 (e) of the OCR A-level Biology A specification which states that students should be able to demonstrate and apply an understanding of the factors that affect the evolution of a species. A wide range of examples are used to show the students how a population that descends from a small number of parents will have a reduction in genetic variation and a change in the frequency of existing alleles. Students are encouraged to discuss new information to consider key points and understanding checks in a range of forms are used to enable them to check their progress and address any misconceptions. Students are provided with three articles on Huntington’s disease in South Africa, the Caribbean lizards and the plains bison to understand how either a sharp reduction in numbers of a new population beginning from a handful of individuals results in a small gene pool. Links to related topics are made throughout the lesson to ensure that a deep understanding is gained. This lesson has been designed to tie in with another uploaded lesson on types of selection which is part of this specification point

This fully-resourced lesson looks at the contribution of environmental and genetic factors to phenotypic variation. The engaging PowerPoint and accompanying worksheets have been designed to cover point 6.1.2 (a) of the OCR A-level Biology A specification which states that students should be able to demonstrate and apply an understanding of how mutations and meiosis and the lack of availability of ions can cause variation within a species. Students are challenged at the start of the lesson to recognise the terms phenotype and species from their definitions in order to begin a discussion on the causes of the phenotypic variation within a species. Moving forwards, students will recall that mutations are the primary source of genetic variation and time is taken to look at the effect of gene and chromosome mutations. Gene mutations were covered earlier in module 6 so these tasks act as a prior knowledge check as students have to recognise the different types of gene mutations and explain their effects on the primary structure with reference to the genetic code. These prior knowledge checks are found throughout the lesson and challenge the knowledge of other topics that include photosynthesis and meiosis. The karyotype of an individual who has Down syndrome is used to introduce chromosome mutations and students will be introduced to the different types, with a focus on non-disjunction. The key events of meiosis that produce variation (crossing over and independent assortment) are explored and students will be given a mathematical formula to use to calculate the number of chromosome combinations in gametes and in the resulting zygote. The final part of the lesson looks at chlorosis and how an environmental factor can prevent the express of a gene. If you would like a lesson that goes into chromosome mutations in even greater detail, please search for the uploaded lesson on that topic which complements this lesson

This fully-resourced lesson focuses on the events of meiosis which specifically contribute to genetic variation. The detailed PowerPoint and accompanying resources have been designed to cover the 4th and final part of point 4.3 of the AQA A-level Biology specification which states that students should be able to describe how meiosis produces daughter cells that are genetically different from each other. 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. Due to the detail of this lesson, it is estimated that this will take about 2 hours of A-level teaching time to deliver

This lesson focuses on the degenerate nature of the genetic code and explains how a mutation may not result in a change to the sequence of amino acids. The PowerPoint has been designed to cover the first part of point 4.3 of the AQA A-level Biology specification and it makes links to the upcoming lesson on gene mutations. 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, base substitutions and base 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 (or insertion) can be understood when covered in greater detail in topic 8. This lesson has been specifically designed to tie in with the other lessons from topic 4.3 on gene mutations, chromosome mutations and meiosis.

This fully-resourced lesson explores how new species arise when changes in the gene pool of two populations prevents members from interbreeding and producing fertile offspring. The engaging PowerPoint and accompanying resources have been designed to cover the fifth part of point 7.3 of the AQA A-level Biology specification which states that students should be able to describe allopatric and sympatric speciation. The lesson begins by using the example of a hinny, which is the hybrid offspring of a horse and a donkey, to challenge students to recall the biological classification of a species. Moving forwards, students are introduced to the idea of speciation and the key components of this process, such as isolation and selection pressures, are covered and discussed in detail. Understanding and prior knowledge checks are included throughout the lesson to allow the students to not only assess their progress against the current topic but also to make links to earlier topics in the specification. Time is taken to look at the details of allopatric speciation and how the different mutations that arise in the isolated populations and genetic drift will lead to genetic changes. The example of allopatric speciation in wrasse fish because of the isthmus of Panama is used to allow the students to visualise this process. The final part of the lesson considers sympatric speciation and again a wide variety of tasks are used to enable a deep understanding to be developed.

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