This lesson looks at the detailed structure of DNA and builds on the knowledge from topic 1 to explain how this nucleic acid differs in the nucleus, mitochondria and chloroplasts of eukaryotic cells and in prokaryotic cells. Both the engaging PowerPoint and accompanying resources have been designed to cover the first part of point 6.1 (b) of the CIE International A-level Biology specification. As well as focusing on the differences between the DNA found in these two types of cells which includes the length, shape and association with histones, the various tasks will ensure that students are confident to describe how this double-stranded polynucleotide is held together by hydrogen and phosphodiester bonds. These tasks include exam-style questions which challenge the application of knowledge as well as a few quiz competitions to maintain engagement.

This engaging lesson describes the relationship between the structure, properties and functions of a phopholipid and cholesterol. The PowerPoint has been written as the second lesson in a series of two that cover specification points 2.1.2 (h), (i) & (j) of the OCR A-level Biology A course and there is a particular focus on their roles in membranes to link to module 2.1.5. In the previous lesson, the students met triglycerides and a quick quiz round called FAMILY AFFAIR is used at the start of the lesson to challenge the students on their knowledge of the structure of this macromolecule to identify the shared features in a phospholipid. This then allows the differences to be introduced, such as the presence of a phosphate group in place of the third fatty acid. Moving forwards, the students will learn that the two fatty acid tails are hydrophobic whilst the phosphate head is hydrophilic which leads into a key discussion point where the class has to consider how it is possible for the phospholipids to be arranged when both the inside and outside of a cell is an aqueous solution. The outcome of the discussion is the introduction of the bilayer which is critical for the lesson in module 2.1.5 on the fluid mosaic model. Students are briefly introduced to facilitated diffusion and reminded of active transport so they can recognise that proteins will be found in the membrane to allow for movement of large or polar molecules. The remainder of the lesson focuses on cholesterol, beginning with the structure. The hydrophobic nature of this molecule is then considered and discussed so that they can understand its role in the regulation of membrane fluidity. That just leaves one final quiz round which identifies vitamin D, testosterone and oestrogen as three substances that are formed from cholesterol

This fully-resourced lesson describes how polygenic inheritance gives rise to phenotypes that show continuous variation. The engaging PowerPoint and accompanying resources have been primarily designed to cover points 3.20 (i) & 3.21 of the Edexcel International A-level Biology specification but also includes activities to challenge the students on previous concepts in topics 3 and 2. The students begin the lesson by having to identify phenotype and species from their respective definitions so that a discussion can be encouraged where they will recognise that phenotypic variation within a species is due to both genetic and environmental factors. The main part of the the lesson focuses on these genetic factors, and describes how mutation and the events of meiosis contribute to this variation. A range of activities, which include exam-style questions and quick quiz rounds, are used to challenge the students on their knowledge and understanding of substitution mutations, deletions, insertions, the genetic code, crossing over and independent assortment. Moving forwards, the concept of multiple alleles is introduced and students will learn how the presence of more than 2 alleles at a locus increases the number of phenotypic variants. Another quick quiz round is used to introduce polygenic inheritance and the link is made between this inheritance of genes at a number of loci as an example of continuous variation. The final part of the lesson describes a few examples where environmental factors affect phenotype, such as chlorosis in plants. As this is the final lesson in topic 3, the numerous activities can be used for revision purposes and to demonstrate the links between different biological topics.

This lesson describes the relationship between the structure and function of the xylem and phloem in transport. The engaging and detailed PowerPoint and accompanying resources have been designed to cover point 4.7 (i) of the Edexcel A-level Biology B specification. The lessons begins by challenging the students to identify the substances that a plant needs for the cellular reactions, where they are absorbed and where these reactions occur in a plant. The aim of this task is to get the students to recognise that water and mineral ions are absorbed in the roots and needed in the leaves whilst the products of photosynthesis are in the leaves and need to be used all over the plant. Students will be reminded that the xylem and phloem are part of the vascular system responsible for transporting these substances and then the rest of the lesson focuses on linking structure to function. A range of tasks which include discussion points, exam-style questions and quick quiz rounds are used to describe how lignification results in the xylem as a hollow tube of xylem cells to allow water to move as a complete column. They will also learn that the narrow diameter of this vessel allows capillary action to move water molecules up the sides of the vessel. The same process is used to enable students to understand how the structures of the companion cells allows assimilates to be loaded before being moved to the sieve tube elements through the plasmodesmata.

This lesson describes the characteristic features of the three domains and explains why viruses are not included in this classification. The PowerPoint and accompanying resources have been primarily designed to cover points 18.2 (b) & 18.2 (d) of the CIE A-level Biology specification but also contains tasks that challenge the students on their knowledge of taxonomic hierarchy from this topic and the features of virus from topic 1. The lesson begins with an introduction of the microbiologist 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 the last 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 and will understand that it wasn’t until 13 years after the discovery that it was adopted. Moving forwards, the rest of the lesson explains why viruses are not included in this classification and outlines how they are classified, according to the ICTV, through the type of nucleic acid they contain and whether this is single-stranded or double-stranded

This lesson describes the uses and implications of pre-implantation genetic diagnosis, amniocentesis and chorionic villus sampling. The lesson PowerPoint and accompanying worksheets have been primarily designed to cover point 2.15 of the Pearson Edexcel A-level Biology A (Salters Nuffield) specification but regular links are made to the earlier content of topics 1 & 2, and their knowledge of topics including the heart and circulation, monohybrid inheritance and cystic fibrosis are tested. The lesson begins by challenging them to use this prior knowledge of topic 2 to identify the letters in the abbreviations PGD and CVS. The involvement of IVF to obtain the embryos (or oocytes) is then discussed and a series of exam-style questions are used to get them to understand how this method screens embryos prior to implantation, so that those identified as having genetic diseases or being carriers are not inserted into the female’s uterus. Mark schemes for all of the questions included in this lesson are embedded into the PowerPoint so students can constantly assess their progress. Moving forwards, Down syndrome (trisomy 21) is used as an example of a chromosomal abnormality that can be tested for using CVS or amniocentesis. Time is taken to describe the key details of both of these procedures so students have a clear understanding of the implications and the invasiveness to the female being tested. The link between amniocentesis and an increased risk of miscarriage is considered and the results of a 2006 study are used to challenge them on their data skills.

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 detailed lesson describes each of the 4 stages of aerobic respiration and explains how this cellular reaction yields ATP and generates heat. The engaging PowerPoint and accompanying resource have been designed to cover points 5.1 (i) and (ii) of the Edexcel A-level Biology B specificaiton and acts as a clear introduction for the upcoming lessons where the finer details of glycolysis, the Link reaction and Krebs cycle and oxidative phosphorylation are described 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 is not present. This stage involves 10 reactions and an opportunity is taken to explain how each of these reactions is catalysed by a different, specific intracellular enzyme. 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 and that these stages produce the waste product of carbon dioxide. 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 and the the formation of water when oxygen acts as the final electron acceptor.

This detailed lesson describes the relationship between the structure and function of starch and cellulose. The engaging PowerPoint and accompanying resource have been designed to cover point 4.9 of the Pearson Edexcel A-level Biology A specification and focuses on the importance of the glycosidic and hydrogen bonds for the structure of these polysaccharides. The structure of amylose and amylopectin was described during a lesson in topic 1, so the start of this lesson challenges the students on their recall of these details. They have to complete a comparison table for these two polysaccharides by identifying the monomer and type of glycosidic bonds that are found in each of the structures. Time is taken to explain how the greater resistance to digestion of amylose means that this carbohydrate is important for plant energy storage whereas the multiple chain ends in the branched amylopectin means that this polysaccharide can be hydrolysed quickly when energy is needed. The rest of the lesson describes the structure of cellulose and focuses on the link between the structure and the need for this polysaccharide to support the plant cell as well as the whole plant. Students will see how every other beta glucose monomer is rotated by 180 degrees and will learn that hydrogen bonds form between these molecules on the same chain as well as between adjacent chains in a cellulose microfibril. The lesson concludes with a quick quiz competition where the students have to compete to open a safe using a combination made up of key values associated with glycogen, starch and cellulose.

This fully-resourced lesson explains how an enzyme’s specificity is related to their 3D structure and enables them to act as biological catalysts. The engaging PowerPoint and accompanying resources have been designed to cover the first parts of specification point 1.4.2 and considers the details of Fischer’s lock and key hypothesis and Koshland’s induced-fit model to deepen student understanding of the mechanism of enzyme action The lesson has been specifically planned to tie in with related topics that were previously covered such as protein structure and globular proteins. This prior knowledge is tested through a series of exam-style questions along with current understanding and mark schemes are included in the PowerPoint so that students can assess their answers. Students will learn that enzymes are large globular proteins which contain an active site that consists of a small number of amino acids. Emil Fischer’s lock and key hypothesis is introduced to enable students to recognise that their specificity is the result of an active site that is complementary in shape to a single type of substrate. Time is taken to discuss key details such as the control of the shape of the active site by the tertiary structure of the protein. The induced-fit model is described so students can understand how the enzyme-susbtrate complex is stabilised and then students are challenged to order the sequence of events in an enzyme-controlled reaction. The lesson finishes with a focus on ATP synthase and DNA polymerase so that students are aware of these important intracellular enzymes when learning about the details of respiration and DNA replication before they are challenged on their knowledge of carbohydrates, lipids and proteins from topics 1.2 - 1.4 as they have to recognise some extracellular digestive enzymes.

This fully-resourced lesson describes the role of barriers in protecting the body from infection by pathogens when entering the body by the major routes. The engaging and detailed PowerPoint and accompanying resources have been designed to cover points 6.11 (i) & (ii) of the Pearson Edexcel A-level Biology A (Salters Nuffield) specification and describe the following barriers: skin key steps of the blood clotting process mucous membranes stomach acid vaginal and skin flora There are clear links to topics 1, 2 and 3 in each of these barriers, so time is taken to consider these during the descriptions. For example, the presence of keratin in the cytoplasm of the skin cells allows the student knowledge of the properties of this fibrous protein to be checked. Other topics that are revisited during this lesson include blood clotting, protein structure, key terminology and the epithelium that lines the different parts of the airways. All of the exam-style questions and tasks have mark schemes that are embedded in the PowerPoint and a number of them have been differentiated to allow students of differing abilities to access the work.

This lesson describes how tissue fluid is formed and reabsorbed and also describes the role of the lymphatic system in the return of fluid to the blood. The detailed PowerPoint and accompanying resources have been designed to cover points 4.6 (i & ii) of the Edexcel A-level Biology B specification and explains how a combination of the effects of hydrostatic pressure and oncotic pressure results in the formation of tissue fluid in animals. The lesson begins with an introduction to the arteriole and venule end of a capillary as these will need to be considered as separate entities when describing the formation of tissue fluid. A quick quiz competition introduces a value for the hydrostatic pressure at the arteriole end and students are challenged to first predict some parts of the blood will move out of the capillary as a result of the push from the hydrostatic pressure and this allows oncotic pressure to be initially explored. The main part of the lesson uses a step by step guide to describe how the net movement is outwards at the arteriole end before students will use this guidance to describe what happens at the venule end. In the concluding part of the lesson, students will come to recognise oedema as a condition where tissue fluid accumulates and they again are challenged to explain how this occurs before they finally learn how the fluid is returned to the circulatory system as lymph.

This lesson outlines how bacteria become resistant to antiobiotics and discusses its consequences and the steps taken to reduce its impact. The PowerPoint and accompanying worksheet have been designed to cover specification points 10.2 (b & c) of the CIE A-level Biology specification President Trump’s error ridden speech about antibiotics is used at the beginning of the lesson to remind students that this is a treatment for bacterial infections and not viruses as he stated. Moving forwards, 2 quick quiz competitions are used to introduce MRSA and then to get the students to recognise that they can use this abbreviation to remind them to use mutation, reproduce, selection (and survive) and allele in their descriptions of the development of resistance by evolution through natural selection. The main task of the lesson challenges the students to form a description to explain how this strain of bacteria developed resistance to methicillin, making use of the five key terms emphasised above. Moving forwards, there is a focus on the hospital as the common location for MRSA infections and students will recognise that this opportunistic pathogen can infect through open wounds to cause sepsis and potentially death. Figures from infections and deaths in hospitals in the US are used to increase the relevance and students will learn how a MRSA prevention program in VHA facilities includes screening of surgery patients to try to reduce its impact. The lesson concludes with a discussion about other methods that can be used by hospitals and general practitioners to reduce the impact of MRSA and to try to prevent the development of resistance in other strains.

This lesson guides students through the use of the chi-squared test to determine the significance of the difference between observed and expected results. It is fully-resourced with a detailed PowerPoint and differentiated worksheets that have been designed to cover point 8.2 (vi) of the Edexcel A-level Biology B specification The lesson includes a step-by-step guide to demonstrates how to carry out the test in small sections. At each step, time is taken to explain any parts which could cause confusion and helpful hints are provided to increase the likelihood of success in exam questions on this topic. Students will understand how to use the phenotypic ratio to calculate the expected numbers and then how to find the critical value in order to compare it against the chi-squared value. A worked example is used to show the working which will be required to access the marks and then the main task challenges the students to apply their knowledge to a series of questions of increasing difficulty. This is the final lesson of topic 8.2 (transfer of genetic information) and links are made throughout the lesson to earlier parts of this topic such as dihybrid inheritance as well as to earlier topics like meiosis

This detailed lesson describes how changes in ventilation rate are brought about to allow for the delivery of oxygen and the removal of carbon dioxide. The engaging PowerPoint and accompanying resources have been designed to cover the second part of point 7.9 (ii) in the Pearson Edexcel A-level Biology A specification. The previous lesson described the control of heart rate so this lesson has been written to tie in with this and to use this knowledge to further the students understanding of the control of ventilation rate. The lesson begins with a focus on the muscles involved in ventilation, specifically the diaphragm and external intercostal muscles, so that students can understand how their contraction results in an increase in the volume of the thoracic cavity. Boyle’s law is briefly introduced to allow students to recognise the relationship between volume and pressure so that the movement of air with the pressure gradient can be described. Time is then taken to consider the importance of inhalation and an exam-style question challenges the students to explain that a constant supply of oxygen to the alveoli is needed to maintain a steep concentration gradient with the surrounding capillaries. The students are then tasked with writing a description of exhalation at rest using the description of inhalation as their guide. The rest of the lesson focuses on the mechanisms involved in increasing the rate and depth of breathing during exercise. Students will use their knowledge of the control of heart rate to recall that chemoreceptors detect changes in oxygen and carbon dioxide and blood pH and that the medulla oblongata processes the sensory information that it receives before coordinating a response. The final task challenges them to use the information provided in this lesson and the previous one to order 10 detailed descriptions so they can form a complete passage about this control system.

This fully-resourced lesson describes the modes of action of the T and B lymphocytes in the immune response. The detailed PowerPoint and accompanying resources have been designed to cover point 2.4 of the CIE A-level Biology specification and the structure of antibodies and the roles of memory cells is also briefly introduced. Antigen presentation was introduced at the end of the previous lesson so the task at the start of this lesson challenges students to recognise the name of this process and then they have to spot the errors in the passage that describes the details of this event. This reminds them that contact between the APC and T lymphocytes is necessary to elicit a response which they will come to recognise as the cellular response. A series of quick quiz rounds reveals key terms in a memorable way and one that is introduced is helper T cells. Time is then taken to describe the importance of cell signalling for an effective response and students will learn how the release of chemicals by these cells activates other aspects of the response. The role of the killer T cells is also described before an exam-style question is used to check on their understanding at this point of the lesson. This leads into the section of the lesson that deals with the humoral response and students will understand how this involves the antibodies that are produced by the plasma cells that are the result of clonal selection and expansion. The remainder of the lesson focuses on the role of the antibodies and the attachment of phagocytes to opsonins.

This lesson looks at the structure of the DNA that is found in the nucleus, mitochondria and chloroplasts of eukaryotic cells and in prokaryotic cells. Both the engaging PowerPoint and accompanying resources have been designed to cover point 2.1.3 (d)(i) of the OCR A-level Biology A specification. As students will already have some knowledge of this nucleic acid from GCSE and from the earlier A-level topics, the lesson has been written to build on this prior knowledge and then to add key detail. As well as focusing on the differences between the DNA found in these two types of cells which includes the length, shape and association with histones, the various tasks will ensure that students are confident to describe how this double-stranded polynucleotide is held together by hydrogen and phosphodiester bonds. This knowledge of phosphodiester bonds means that specification point 2.1.3 © is also covered during this lesson. These tasks include exam-style questions which challenge the application of knowledge as well as a few quiz competitions to maintain engagement.

This detailed lesson describes the role of the mRNA, tRNA, rRNA and amino acids during the second stage of protein synthesis - translation. Both the PowerPoint and accompanying resources have been designed to cover the second part of point 2.1.3 (g) of the OCR A-level Biology A specification and continually links back to the previous lessons in this module on the structure of DNA and RNA and the genetic code Translation is a topic which is often poorly understood and so this lesson has been written to enable the students to understand how to answer the different types of questions by knowing and including the key details of the structures involved. The lesson begins by challenging the students to consider why it is so important that the amino acids are assembled in the correct order during the formation of the chain. Moving forwards, a quick quiz round called “LOST IN TRANSLATION” is used to check on their prior knowledge of the mRNA strand, the tRNA molecules, the genetic code and the ribosomes. The next task involves a very detailed description of translation that has been divided into 14 statements which the students have to put into the correct order. By giving them a passage that consists of this considerable detail, they can pick out the important parts to use in the next task where they have to answer shorter questions worth between 3 and 4 marks. These types of questions are common in the assessments and by building up through the lesson, their confidence to answer this type should increase. The final two tasks of the lesson involve another quiz, where the teams compete to transcribe and translate in the quickest time before using all that they have absorbed to answer some questions which involve the genetic code and the mRNA codon table

This REVISION resource has been written with the aim of motivating the students whilst they are challenged on their knowledge of the content in Biology TOPIC 8 (Exchange and transport in animals) of the Edexcel GCSE Combined Science specification. The resource contains an engaging and detailed PowerPoint (90 slides) and accompanying worksheets, most of which are differentiated to allow all abilities to access the work. The wide range of activities, which include exam questions and quiz competitions, have been designed to cover as much of topic 8 as possible but the following sub-topics have been given a particular focus: Surface area to volume ratio Gas exchange at the alveoli The structure of the blood vessels The gross structure of the heart and the major blood vessels Calculating the cardiac output The functions of the components of the blood Aerobic vs anaerobic respiration There is a large emphasis on mathematical skills in the new specification and these are tested throughout the lesson. This resource is suitable for use at the end of topic 8, in the lead up to mocks or in the preparation for the final GCSE exams.

This revision resource includes a range of activities that will act to engage and motivate the students whilst they assess their understanding of the Animal nutrition content (topic B6) of the CIE IGCSE Combined Science specification for examination in June and November 2020 and 2021. There are exam questions with explained answers as well as quick tasks and quiz competitions such as “Have you got the right BALANCE” where students are challenged to recognise whether a statement about the balanced diet is accurate or not. The lesson was designed to cover as much content as possible but the following topics have received particular attention: Mechanical digestion Chemical digestion by digestive enzymes Amylase and the break down of starch The adaptations of the small intestine to allow absorption The roles of the hydrochloric acid in gastric juice The break down of lipids in the small intestine The components of a balanced diet This resource includes a detailed and engaging PowerPoint (51 slides) and a worksheet which is differentiated two ways. Efforts have been made to make links to other topics such as enzymes (B4) so students can see the importance of being able to make connections in their answers