This fully-resourced lesson describes the meaning of the terms stem cell, pluripotency and totipotency. The PowerPoint and accompanying worksheets have been designed to cover points 3.11 (i) and (ii) of the Pearson Edexcel A-level Biology A (Salters Nuffield) specification and therefore this lesson also contains discussion periods where the topic is the decisions that the scientific community have to make about the use of stem cells in medical therapies. The lesson begins with a knowledge recall of the structure of eukaryotic cells and the students have to use the first letters of each of the four answers to reveal the key term, stem cell. Time is then taken to consider the meaning of cellular differentiation, and this leads into the key idea that not all stem cells are equal when it comes to the number of cell types that they have the potential to differentiate into. A quick quiz round introduces the five degrees of potency, and then the students are challenged to use their understanding of terminology to place totipotency, pluripotency, multipotency, oligopotency and unipotency in the correct places on the potency continuum. Although the latter three do not have to be specifically known based on the content of specification point 3.11 (i), an understanding of their meaning was deemed helpful when planning the lesson as it should assist with the retention of knowledge about totipotency and pluripotency. These two highest degrees of potency are the main focus of the lesson, and key details are emphasised such as the ability of totipotent cells to differentiate into any extra-embroyonic cell, which the pluripotent cells are unable to do. The morula, and inner cell mass and trophoblast of the blastocyst are used to demonstrate these differences in potency. The final part of the lesson discusses the decisions that the scientific community have to make about the use of embryonic stem cells, adult stem cells and also foetal stem cells which allows for a link to chorionic villus sampling from topic 2. There is also a Maths in a Biology context question included in the lesson (when introducing the morula) to ensure that students continue to be prepared for the numerous calculations that they will have to tackle in the terminal exams. This resource has been differentiated two ways to allow students of differing abilities to access the work

This lesson describes the role of the rER and the Golgi apparatus in the formation of proteins, the transport within cells and their secretion. The PowerPoint and accompanying resources have been designed to cover point 3.3 of the Pearson Edexcel A-level Biology A (Salters Nuffield) specification and also includes key details about the role of the cytoskeleton in the transport of the vesicles that contain the protein between the organelles and the membrane. The lesson begins with the introduction of the cytoskeleton and explains how this network of protein structures transverses across the cytoplasm and is fundamental to the transport of molecules between organelles. The lesson has been planned to closely tie in with the previous lesson on the ultrastructure of eukaryotic cells and students are challenged on their knowledge of the function of the organelles involved in protein formation (and modification) through a series of exam-style questions. By comparing their answers against the mark scheme embedded in the PowerPoint, students will be able to assess their understanding of the following: Transcription in the nucleus to form an mRNA strand and the exit of this nucleic acid through the nuclear pore Translation at the ribosomes on the surface of the rER to assemble the protein Transport of the vesicles containing the protein to the Golgi apparatus Modification of the protein at the Golgi apparatus Formation of the Golgi vesicle and its transport to the cell membrane for exocytosis Time is taken to discuss the finer details of this process such as the arrival of the vesicle at the cis face and the transport away from the trans face and the requirement of ATP for the transport of the vesicles along the microtubule track and exocytosis. The remainder of the lesson uses a series of exam-style questions about digestive enzymes (extracellular proteins) to challenge the students on their recall of the structure of starch and proteins

This lesson describes the principles of ex situ conservation and discusses the advantages and issues surrounding this method. The PowerPoint and accompanying worksheet are part of the second lesson in a series of 2 which have been designed to cover the content of point 3.3 (iii) of the Edexcel A-level Biology B specification and it closely ties in with the previous lesson on in situ conservation. To enrich their understanding of ex situ conservation, the well-known examples of ZSL London zoo, Kew Gardens and the Millennium Seed Bank Project in Wakehurst are used. Students will understand how conserving animal species outside of their natural habitat enables human intervention that ensures the animals are fed and given medical assistance when needed as well as reproductive assistance to increase the likelihood of the successful breeding of endangered species. As with the in situ method in the previous lesson, the issues are also discussed and there is a focus on the susceptibility of captive populations to diseases as a result of their limited genetic diversity. The final part of the lesson considers how seed banks can be used to ensure that plant species avoid extinction and how the plants can be bred asexually to increase plant populations quickly.

This lesson describes and discusses the different methods of protecting endangered species. The engaging PowerPoint and accompanying worksheets have been designed to cover point 18.3 [c] of the CIE A-level Biology specification and the methods described include zoos, botanic gardens, national parks, marine conservation zones and seed banks Hours of research has gone into the planning of this lesson to source interesting examples that increase the relevance of the biological content concerning in situ conservation, and these include the Lizard National Nature Reserve in Cornwall, the Lake Télé Community reserve in the Republic of Congo and the marine conservation zone in the waters surrounding Tristan da Cunha. Students will learn how this form of active management conserves habitats and species in their natural environment, with the aim of minimising human impact whilst maintaining biodiversity. The main issues surrounding this method are discussed, including the fact that the impact of this conservation may not be significant if the population has lost much of its genetic diversity and that despite the management, the conditions that caused the species to become endangered may still be present. A number of quick quiz competitions are interspersed throughout the lesson to introduce key terms and values in a fun and memorable way and one of these challenges them to use their knowledge of famous scientists to reveal the surname, Fossey. Dian Fossey was an American conservationist and her years of study of the mountain gorillas is briefly discussed along with the issue that wildlife reserves can draw poachers and tourists to the area, potentially disturbing the natural habitat. To enrich their understanding of ex situ conservation, the better known examples of ZSL London zoo, Kew Gardens and the Millennium Seed Bank Project in Wakehurst are used. Students will understand how conserving animal species outside of their natural habitat enables human intervention that ensures the animals are fed and given medical assistance when needed as well as reproductive assistance to increase the likelihood of the successful breeding of endangered species. As with the in situ method, the disadvantages are also discussed and there is a focus on the susceptibility of captive populations to diseases as a result of their limited genetic diversity. The final part of the lesson considers how seed banks can be used to ensure that plant species avoid extinction and how the plants can be bred asexually to increase plant populations quickly. Due to the extensiveness of this lesson, it is estimated that it will take in excess of 2/3 hours of allocated A-level teaching time to cover the tasks and content that is included in the lesson.

This lesson describes how the standard deviation and the t-test are used to analyse data. The detailed PowerPoint and accompanying resources are part of the first lesson in a series of 2 lessons that have been designed to cover point 10.1 (vi) of the Edexcel A-level Biology B specification. The next lesson, which uses skills covered in this lesson and has also been uploaded, describes how to analyse data using the Spearman rank correlation coefficient A step by step guide walks the students through each stage of the calculation of the standard deviation and gets them to complete a worked example with the class before applying their knowledge to another set of data. This data looks at the birth weights of humans on one day in the UK and this is used again later in the lesson to compare against the birth weights of babies in South Asia when using the student’s t-test. The null hypothesis is re-introduced, as it will encountered when considering the chi squared test in topic 8, and students will learn to accept or reject this based upon a comparison of their value against one taken from the table based on the degrees of freedom.

This lesson describes the inheritance of two non-interacting unlinked genes and guides students through the calculation of phenotypic ratios. The PowerPoint and the accompanying question sheet (which is differentiated) have been designed to cover point 8.2 (iii) of the Edexcel A-level Biology B specification. As the previous lesson described the construction of genetic crosses and pedigree diagrams, students are aware of the methods involved in writing genotypes and gametes for the inheritance of a single gene. Therefore, the start of this lesson builds on this understanding to ensure that students recognise that genotypes contain 4 alleles and gametes contain 2 alleles when two genes are inherited. The students are taken through the steps of a worked example to demonstrate the key steps in the calculation of a phenotypic ratio before 2 exam-style questions challenge them to apply their newly-acquired knowledge. Mark schemes are displayed within the PowerPoint to allow students to assess their progress. The phenotypic ratio generated as the answer to the final question is 9:3:3:1 and time is taken to explain that this is the expected ratio when two heterozygotes for two genes are crossed which they may be expected to use when meeting the chi squared test in an upcoming lesson

This lesson describes the meaning of the term stem cell and the differences between totipotent, pluripotent and multipotent stem cells. The PowerPoint and accompanying worksheets have been designed to cover points 7.3 (i) and (ii) of the Edexcel A-level Biology B specification meaning that this lesson also contains discussion periods about the potential opportunities to use stem cells from embryos in medicine. The lesson begins with a knowledge recall of the structure of eukaryotic cells and the students have to use the first letters of each of the four answers to reveal the key term, stem cell. Time is then taken to consider the meaning of cellular differentiation, and this leads into the key idea that not all stem cells are equal when it comes to the number of cell types that they have the potential to differentiate into. A quick quiz round introduces the five degrees of potency, and then the students are challenged to use their understanding of terminology to place totipotency, pluripotency, multipotency, oligopotency and unipotency in the correct places on the potency continuum. Although the latter two do not have to be specifically known based on the content of specification point 7.3 (i), an understanding of their meaning was deemed helpful when planning the lesson as it should assist with the retention of knowledge about totipotency, pluripotency and multipotency. These three highest degrees of potency are the main focus of the lesson, and key details are emphasised such as the ability of totipotent cells to differentiate into any extra-embroyonic cell, which the pluripotent cells are unable to do. The morula, and inner cell mass and trophoblast of the blastocyst are used to demonstrate these differences in potency. The final part of the lesson discusses the decisions that the scientific community have to make about the use of pluripotent embryonic stem cells, adult stem cells and also multipotent foetal stem cells As there is a heavy mathematical content in the current A-level Biology exams, a Maths in a Biology context question is included in the lesson (when introducing the morula) to ensure that students continue to be prepared for the numerous calculations that they will have to tackle in the terminal exams. This resource has been differentiated two ways to allow students of differing abilities to access the work

This lesson describes the effect that treaties such as CITES have had on global diversity. The PowerPoint and accompanying worksheets have been primarily designed to cover point 10.4 (ii) of the Edexcel A-level Biology B specification but has been planned to constantly challenge them on their knowledge of topic 3.3 (biodiversity) as a local conservation agreement is also considered Many hours of research have gone into the planning of this lesson to ensure that a range of interesting biological examples are included, with the aim of fully engaging the students in the material to increase its relevance. The students will learn that the Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES) was first agreed in 1973 and that 35000 species are currently found in appendix I, II or III. Time is taken to go through the meaning of each appendix and then the following animal and plant species are used to explain the finer details of the agreement: Tree pangolin, eastern black rhino for CITES appendix I Darwin’s orchid for CITES appendix II Four-horned antelope for CITES appendix III Exam-style questions are used to check on their understanding of the current topic as well as to challenge their knowledge of previously-covered topics such as the functions of keratin, when considering the structure of the rhino horn. Each of these questions has its own markscheme which is embedded in the PowerPoint and this allows the students to constantly assess their progress. The final part of the lesson considers the Countryside Stewardship Scheme as a local conservation agreements and discusses the reasons behind some of the key points. Students are told that farmers, woodland owners, foresters and land managers can apply for funding for a range of options including hedgerow management, low input grassland, buffer strips, management plans and soil protection options. The importance of the hedgerows for multiple species is discussed, and again a real-life example is used with bats to increase the likelihood of retention. The last task challenges them to use their overall knowledge of biodiversity to explain why buffer strips consisting of multiple types of vegetation are used and to explain why these could help when a farmer is using continuous monoculture.

This lesson describes a range of methods that can be used to assess the distribution and abundance of organisms in a local area. The PowerPoint and accompanying worksheets have been designed to cover points [c] and [d] of topic 18.1 of the CIE A-level Biology specification and describe the use of frame quadrats, line and belt transects, and the mark-release-recapture method. Due to the substantial mathematical content of the A-level Biology exams, as well as descriptions of the different methods, there is a focus on the range of calculations that are used to estimate the population of either sessile or motile species. As shown by the image, step by step guides are used to walk the students through the key stages in these calculations before exam-style questions challenge them to apply their understanding and mark schemes are included in the lesson to allow them to immediately assess their progress. The precautions and assumptions associated with the mark-release-recapture method are discussed and links are made to stabilising selection as covered in topic 17 when considering how the number of species have changed over time.

This lesson describes self and non-self antigens and how a failure to distinguish between the two is the mechanism of autoimmune diseases. The PowerPoint and accompanying worksheets have been primarily designed to cover points 11.1 (d & f) of the CIE A-level Biology specification and describe examples of these diseases including myasthenia gravis, but this lesson can also be used to revise the content of the earlier topics as well as the previous lessons in topic 10 & 11 through the range of activities that are included The first part of the lesson focuses on the antigens and explains how the failure of the immune system cells to recognise these molecules on the outside of a cell or organism elicits an immune response. Moving forwards, the students are challenged to recognise diseases from descriptions and then to use the first letters of their names to form the term, autoimmune. In doing so, the students will discover that rheumatoid arthritis, ulcerative colitis, type I diabetes mellitus, multiple sclerosis and myasthenia gravis are all examples of autoimmune diseases. The next part of the lesson focuses on the mechanism of these diseases where the immune system cells do not recognise the antigens (self-antigens) on the outside of the healthy cells, and therefore treats them as foreign antigens, resulting in the production of autoantibodies against proteins on these healthy cells and tissues. Key details of the autoimmune diseases stated above and lupus are described and links to previously covered topics as well as to future topics such as the pancreas and nervous system are made. The students will be challenged by the numerous exam-style questions, all of which have mark schemes embedded into the PowerPoint to allow for immediate assessment of progress.

This lesson describes the action of bactericidal and bacteriostatic antibiotics, as illustrated by penicillin and tetracycline. The engaging PowerPoint and accompanying resources have been designed to cover point 6.3 (i) of the Edexcel A-level Biology B specification but it has been specifically planned to make continual links to earlier lessons in topic 6 and to protein synthesis as covered in topic 1 The lesson begins by challenging the students to use their general biological knowledge and any available sources 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. Time is then taken to describe the action of penicillin and students will learn how inhibitors and modified versions of this antibiotic are used to overcome those bacteria who have resistance. 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 these different types of antibiotics from descriptions.

This lesson describes why a disease would be deemed to be an autoimmune disease and describes the mechanisms involved in a few examples. The PowerPoint and accompanying worksheets have been primarily designed to cover point 4.1.1 (k) of the OCR A-level Biology A specification, but this lesson can also be used to revise the content of modules 2 and 3 and the previous lessons in 4.1.1 through the range of activities included The lesson begins with a challenge, where the students have to recognise diseases from descriptions and use the first letters of their names to form the term, autoimmune. In doing so, the students will immediately learn that rheumatoid arthritis, ulcerative colitis, type I diabetes mellitus, multiple sclerosis and myasthenia gravis are all examples of autoimmune diseases. The next part of the lesson focuses on the mechanism of these diseases where the immune system cells do not recognise the antigens (self-antigens) on the outside of the healthy cells, and therefore treats them as foreign antigens, resulting in the production of autoantibodies against proteins on these healthy cells and tissues. Key details of the autoimmune diseases stated above and lupus are described and links to previously covered topics as well as to future topics such as the nervous system are made. The students will be challenged by numerous exam-style questions, all of which have mark schemes embedded into the PowerPoint to allow for immediate assessment of progress.

This lesson outlines how penicillin acts on bacteria and why antibiotics do not affect viruses. The PowerPoint and accompanying resources have been designed to cover point 10.2 (a) of the CIE A-level Biology specification and also introduces the concept of bactericidal and bacteriostatic antibiotics, as illustrated by penicillin and tetracycline. The lesson begins with an engaging task, where the students have to identify the surnames of famous scientists from their descriptions to reveal the surname Fleming. This introduces Sir Alexander Fleming as the microbiologist who discovered penicillin in 1928. Time is taken to describe penicillin as a group of antibiotics that contain a beta-lactam ring in their molecular structure. Using this information and their knowledge of bacterial cell structure from topic 1, the students have to complete a passage describing how penicillin inhibits the formation of cross links in cell wall synthesis. A series of exam-style questions are then used to make links to the upcoming topic of antibiotic resistance. The next part of the lesson focuses on the differences between bactericidal and bacteriostatic antibiotics and the students will learn that penicillin is bactericidal as the weakening of the cell wall leads to lysis and death. Tetracycline is used as the example of a bacteriostatic antibiotic and students will discover that it is the prevention of the binding of tRNA that inhibits protein synthesis and that this reduction and prevention of growth and reproduction is synonymous with these antimicrobial agents. Students are challenged on their knowledge of translation and will also be given time for a class discussion to understand that these antibiotics work in tandem the body’s immune system to overcome the pathogen The final part of the lesson explains why antibiotics are ineffective against viruses.

This lesson describes the structure and function of synapses in nerve impulse transmission and focuses on acetylcholine as a neurotransmitter. The PowerPoint and accompanying resources have been designed to cover point 8.6 (i) of the Edexcel International A-level Biology specification, using a cholinergic synapse as the main example The lesson begins by using a version of the WALL from “Only Connect” which asks the students to group 12 words into three groups of 4. Not only will this challenge their prior knowledge from topics earlier in this topic but it will also lead to the discovery of four of the structures that are found in a synapse. Moving forwards, students are introduced to acetylcholine as the neurotransmitter involved at cholinergic synapses and they will start to add labels to the structures found in the pre-synaptic bulb. Time is taken to focus on certain structures such as the voltage gated channels as these types of channel were met previously when looking at the depolarisation of a neurone. There is plenty of challenge and discovery as students are pushed to explain why organelles like mitochondria would be found in large numbers in the bulb. With this process being a cascade of events, a bullet point format is used to ensure that the key content is taken in by the students and again key points like exocytosis and the action of acetylcholinesterase are discussed further. Understanding checks and prior knowledge checks are included throughout the lesson so that students can not only assess their progress against the current topic but also see whether they can make links to earlier topics.

This detailed lesson describes how recombinant DNA is produced using restriction endonucleases and DNA ligase and is inserted into other cells. The engaging PowerPoint and accompanying resources have been designed to cover points 8.18 & 8.19 of the Edexcel International A-level Biology specification. The lesson begins with a definition of genetic engineering and recombinant DNA to allow students to begin to understand how this process involves the transfer of DNA fragments from one species to another. Links are made to the genetic code and transcription and translation mechanisms, which were met in topic 2, in order to explain how the transferred gene can be translated in the transgenic organism. Moving forwards, the method involving reverse transcriptase and DNA polymerase is introduced and their knowledge of the structure of the polynucleotides and the roles of enzymes is challenged through questions and discussion points. Restriction endonucleases are then introduced and time is taken to look at the structure of a restriction site as well as the production of sticky ends due to the staggered cut on the DNA. A series of exam-style questions with displayed mark schemes are used to allow the students to assess their current understanding. The second half of the lesson looks at the culture of transformed host cells as an in vivo method to amplify DNA fragments. Students will learn that bacterial cells are the most commonly transformed cells so the next task challenges their recall of the structures of these cells so that plasmid DNA can be examined from that point onwards. Time is taken to explore the finer details of each step such as the addition of the promoter and terminator regions, use of the same restriction enzyme to cut the plasmid as was used to cut the gene and the different types of marker genes. As well as understanding and prior knowledge checks, quick quiz competitions are used throughout the lesson to introduce key terms such as cDNA and EcoR1 in a fun and hopefully memorable way

This lesson explains how a nerve impulse (action potential) is conducted along an axon and focuses on the role of the sodium and potassium ions. The PowerPoint and accompanying resources have been designed to cover point 8.4 of the Edexcel International A-level Biology specification and contains detailed descriptions of resting potential, depolarisation, repolarisation, hyperpolarisation and the refractory period. This topic is commonly assessed in the terminal exams so extensive planning ensures that this resource includes a wide range of activities to motivate and engage the students whilst ensuring that the content is covered in the depth of detail that will allow them to have a real understanding. Interspersed within the activities are understanding checks and prior knowledge checks to enable the students to not only assess their progress against the current topic but also to challenge themselves on the links to earlier topics such as methods of movements across cell membranes. There are also a number of quiz competitions which are used to introduce key terms and values in a fun and memorable way and discussion points to encourage the students to consider why a particular process or mechanism occurs. Over the course of the lesson, the students will learn and discover how the movement of ions across the membrane causes the membrane potential to change. They will see how the resting potential is maintained through the use of the sodium/potassium pump and potassium ion leakage. There is a real focus on depolarisation to allow students to understand how generator potentials can combine and if the resulting depolarisation then exceeds the threshold potential, a full depolarisation will occur. At this point in the lesson students will discover how the all or nothing response explains that action potentials have the same magnitude and that instead a stronger stimulus is linked to an increase in the frequency of the transmission. The rest of the lesson challenges the students to apply their knowledge to explain how repolarisation and hyperpolarisation result and to suggest advantages of the refractory period for nerve cells.