This lesson introduces the three-domain system and describes some of the biochemical methods used in classification to overcome the problems of morphological convergence. The PowerPoint and accompanying resources have been designed to cover points [c] and [e] in AS unit 2, topic 1 of the WJEC A-level Biology specification The lesson begins with an introduction of Carl Woese and goes on to describe how he is most famous for his definition of the Archaea as a new domain of life. Students were introduced to domains and the other classification taxa in a previous lesson, so their recall of this knowledge is continually tested and built upon as details are added. Students will discover the key differences between Archaea and Bacteria that led to the splitting of the prokaryotae kingdom and the addition of this higher classification rank. Moving forwards, the rest of the lesson considers other molecules that can be compared between species for classification purposes and the primary structure of cytochrome is described and discussed. At this point in the lesson, the students are also tested on their knowledge of the nature of the genetic code and have to explain how mutations to DNA can also be used for comparative purposes. The use of DNA genetic fingerprinting is briefly introduced and this is described in greater detail in a future lesson about assessing biodiversity at a molecular level

This lesson describes the adaptations of gas exchange surfaces in single-celled organisms, insects, bony fish and dicotyledonous plants. The PowerPoint and accompanying worksheets are part of the first lesson in a series of 6 lessons that have been designed to cover the detail of point 3.2 (Gas exchange) of the AQA A-level Biology specification. The lesson has been intricately planned to challenge the students on their understanding of the surface area to volume ratio (as covered in the previous lesson) and to make direct links to upcoming lessons on gas exchange and transport systems in humans. The lesson begins by explaining that single-celled organisms are able to diffuse oxygen and carbon dioxide across their body surface but that as organisms increase in size and their SA/V ratio decreases, they need adaptations at their gas exchange surfaces to be able to obtain the oxygen to meet their metabolic demands. This leads into the next part of the lesson which describes the roles of the following structures in insects and bony fish: spiracles, tracheae, tracheoles and tracheole fluid operculum, gill arch, gill filaments and lamellae The next task challenges the students to use their knowledge of topics 1 and 2 to come up with the letters that form the key term, countercurrent flow. This is a key element of the lesson and tends to be a principle that is poorly understood, so extra time is taken to explain the importance of this mechanism. Students are shown two diagrams, where one contains a countercurrent system and the other has the two fluids flowing in the same direction, and this is designed to support them in recognising that this type of system ensures that the concentration of oxygen is always higher in the oxygenated water than in the blood in the lamellae. The final part of the lesson describes the role of the stomata and the mesophyll cells in the gas exchange of a dicotyledonous plant. Students will learn that guard cells contain chloroplasts which generate ATP and then they are challenged to order a series of statements to form a description of the events that result in the opening of the stomata. The differing structures of the spongy mesophyll and palisade mesophyll cells are then considered before the students are challenged to explain how carbon dioxide moves through the leaf after entering via the stomata and then how water vapour and oxygen leave. Clear links are made to the loss of water vapour by transpiration so students are prepared for the lessons covering this biological process later in topic 3.

This lesson describes the in situ and ex situ methods of maintaining biodiversity, and discusses the advantages and disadvantages associated with both. The engaging PowerPoint and accompanying worksheets have been primarily designed to cover point 4.2.1 (h) of the OCR A-level Biology A specification but the lesson has been carefully planned to enable links to be made to some related topics which are found later in the course such as classification, evolution through natural selection and the Founder effect. 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 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 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 different types of pathogens that can cause communicable diseases in plants and animals. The PowerPoint and accompanying worksheets have been primarily designed to cover point 4.1.1 (a) of the OCR A-level Biology specification but as this is the first lesson in module 4, it has been specifically planned to make links to upcoming topics such as phagocytosis, vaccinations and classification. viruses - HIV/AIDS, influenza, TMV bacteria - TB, cholera, ring rot protoctista - malaria fungi - athlete’s foot, black sigatoka, ringworm, The diseases shown above are covered by the detailed content of this lesson and the differing mechanisms of action of the four types of pathogens are discussed and considered throughout. For example, time is taken to describe how HIV uses a glycoprotein to attach to T helper cells whilst toxins released by bacteria damage the host tissue and the Plasmodium parasite is transmitted from one host to another by a vector to cause malaria. The accompanying worksheets contain a range of exam-style questions, including a mathematical calculation, and mark schemes are embedded into the PowerPoint to allow students to immediately assess their understanding.

This lesson describes the main stages of mitosis and explains the significance of this type of nuclear division for the daughter cells produced by the cycle. The PowerPoint and accompanying resources have been designed to cover points 6 (a & b) in topic 6 of AS unit 1 of the WJEC A-level Biology specification and the process of cytokinesis is also described. Depending upon the exam board taken at GCSE, the knowledge and understanding of mitosis will differ considerably between students and there may be a number of misconceptions. This was considered at all points during the planning of the lesson so that existing errors are addressed and key points are emphasised throughout. Their understanding of interphase is challenged at the start of the lesson to ensure that they realise that it is identical pairs of sister chromatids that enter the M phase. The main part of the lesson focuses on prophase, metaphase, anaphase and telophase and describes how the chromosomes behave in these stages. There is a focus on the centrioles and the spindle fibres that they produce which contract to drag one chromatid from each pair in opposite directions to the poles of the cell. The remainder of the lesson is a series of understanding and application questions where students have to identify the various roles of mitosis in living organisms as well as tackling a Maths in a Biology context question. The lesson concludes with a final quiz round of MITOSIS SNAP where they only shout out this word when a match is seen between the name of a phase, an event and a picture.

This engaging lesson describes how chromosome mutations result in changes to the number or structure of chromosomes The PowerPoint and accompanying resources are part of the second lesson in a series of 2 lessons that have been designed to cover specification points (f) in topic 3 of A2 unit 4 of the WJEC A-level Biology specification, and there is a key focus on Down syndrome A human karyotype which has not been altered by a mutation is studied at the start of the lesson to allow students to recall the usual number of chromosomes as well as the sex chromosomes. They are then challenged to identify the differences when presented with the karyotypes of sufferers of Down, Turner’s and Klinefelter’s syndrome. Students will learn that in the majority of cases, these conditions are the result of non-disjunction and having been assisted in the explanation of the outcome for Down and Klinefelters, they have to form their own for Turner’s. The remainder of the lesson looks at other types of mutations, including translocation, and students will also see how whole sets of chromosomes can be duplicated in polyploidy

This resource has been designed to cover the higher tier content of specification point 5.3.6 as detailed in the AQA GCSE Biology & Combined Science specifications. The lesson takes the format of a day at a fertility clinic and students will see how three couples, who are at different stages of their currently unsuccessful journey to getting pregnant, are advised and the treatments that could be on offer to them. Discussion points are included throughout the lesson to encourage the students to talk about the Biology and to allow any misconceptions to be addressed if and when they arise. In addition, previous knowledge checks are regular so that the links between this topic and earlier ones such as the hormones in human reproduction and contraception can be made. Students will learn how a fertility drug may be made available and will be challenged to explain why FSH and LH would be the reproductive hormones contained in these substances. The main focus of the lesson is IVF treatment and this main task culminates with students gaining a number of key points in the for and against argument before being challenged to continue this as a set homework in the form of an evaluation. Quiz competitions are used to introduce key terms in a fun and memorable way and the final task is a mathematical skills check where students will be able to compare the high number of multiple births that are associated with this treatment as compared to the number from natural births. This lesson has been designed for students studying the AQA GCSE Biology or Combined Science course but is suitable for older students who are looking at this topic.

This fully-resourced lesson is highly detailed and in combination with the uploaded lesson on the causes of diabetes type I and II, it covers all of specification point 6.4.2 of the AQA A-level Biology specification which states that students should be able to describe the homeostatic control of blood glucose concentration using negative feedback mechanisms that release insulin or glucagon. A wide range of activities will maintain motivation and engagement whilst the content is covered in detail to enable the students to explain how the receptors in the pancreas detect the concentration change and how the hormones attaching to receptor sites on the liver triggers a series of events in this effector organ. This is a topic which has a huge amount of difficult terminology so time is taken to look at all of the key words, especially those which begin with the letter G so students are able to use them accurately in the correct context. The action of adrenaline is also considered and linked to the breakdown of glycogen to glucose during glycogenolysis. This lesson has been written for students studying on the AQA A-level Biology course and ties in with the already mentioned lesson on diabetes but also with the other uploaded lessons on topic 6 such as nerve impulses and kidney function

This lesson describes the structure of messenger and transfer RNA and compares this against the structure of DNA. The engaging and detailed PowerPoint and accompanying resource have been designed to cover points 1.4 (iv) and (v) as detailed in the Edexcel A-level Biology B specification which states that students should be able to describe the structure of the two forms of this nucleic acid. Students were introduced to the detailed structure of a nucleotide and DNA in the first lesson of topic 1.4, so this lesson is written to tie in with those and continuously challenge prior knowledge as well as the understanding of the current topic. The lesson begins with the introduction of RNA as a member of the family of nucleic acids and this enables students to recognise that this polynuclotide shares a number of structural features that were previously seen in DNA. A quiz round called “A FAMILY AFFAIR” is used to challenge their knowledge of DNA to recognise those features that are also found on RNA such as the chain of linked nucleotides, pentose sugars, nitrogenous bases and phosphodiester bonds. The next task pushes them to consider features that have not been mentioned and therefore are differences as they answer a structured exam-style question on how RNA differs from DNA. Students will learn that RNA is shorter than DNA and this leads into the final part of the lesson where mRNA and tRNA are introduced and again they are challenged to use the new information explain the difference in size. Brief details of transcription and then translation are provided so that students are prepared for the upcoming lessons on protein synthesis

This lesson describes how the eyepiece graticule and stage micrometer are used in the measurement of cells. The engaging PowerPoint and accompanying resources have been designed to cover point 1.1 [c] of the CIE A-level Biology specification and also includes a number of tasks that have been written to ensure that students are able to recognise the millimetre, micrometre and nanometre as units of size and that they are able to convert between them. As this content is part of topic 1.1, it is likely that this lesson on the measurement of cells and the units of size will be one of the first that students will encounter in this A-level course. With this in mind, this lesson and the next two on microscopes and calculating actual size have been specifically written to contain a wide variety of tasks, including an ongoing quiz competition. This will act to maintain engagement in a topic that can sometimes discourage students at this early stage of the course whilst ensuring that the key content is covered and understanding is constantly checked. A step by step guide walks them through the use of the scale on the stage micrometer to identify the size of the divisions of the eyepiece graticule and then they are challenged to apply this method to a series of questions. Useful hints are provided throughout the lesson and students will be able to confidently convert between metres, millimetres, micrometres and nanometres by the end of the lesson A quiz scoresheet is included with the lesson so that teachers can keep track of the points won in the different rounds and add them to those won in the upcoming lessons in topic 1.1