This is a fully-resourced lesson that has been written for GCSE students and focuses on the meaning of the term, potential difference, and guides students through using this factor in calculations. A range of student-led tasks will challenge the students to recognise how a voltmeter needs to be set up to measure the potential difference and then gets them to use the readings to calculate other factors. Their mathematical skills will be tested throughout and students will be asked to analyse their answers and study a series circuit to learn the key rule about potential difference in these types of circuits. Progress checks have been written into the lesson at regular intervals so students are constantly assessing their understanding.

This is a fun and engaging lesson that uses a range of quick competitions and tasks to ensure that the students recognisethe electrical symbols for the essential components and can describe the functions for each of these. Competitions such as SNAP and SAY WHAT YOU SEE will introduce the students to the components and their symbols. This lesson has been written for GCSE students and looks to build on what they should know from KS3 - however, it could be used with higher ability students at that level.

This is a fully-resourced lesson that is written for GCSE students and focuses on the calculations associated with the numerous equations that electrical power is found in. The lesson includes a fast-paced lesson presentation and a series of questions on a worksheet which has been differentiated two ways. Over the course of the lesson, the students will meet the different equations which include the factor of electrical power. Their whole range of mathematical skills will be tested, including rearranging the formula, conversion between units and simplifying two equations into one. The understanding of each of these skills and equations is checked through a range of tasks, each of which has a displayed mark scheme and explanation at the end so that students can self-assess their understanding. Students are encouraged to discuss and come up with insightful questions and answers.

This fully-resourced lesson explains how gel electrophoresis is used to separate DNA fragments or proteins and explores its applications in genetic fingerprinting. The engaging and detailed PowerPoint and accompanying resources have been written to cover point 6.1.3 (e) of the OCR A-level Biology A specification The steps of the genetic fingerprinting process is covered the whole lesson but the main focus is the use of gel electrophoresis within this process. Students will be introduced to STRs and will come to recognise their usefulness in human identification as a result of the variability between individuals. Moving forwards, the involvement of the PCR is discussed and students are challenged on their knowledge of this process as it was encountered in a previous lesson. A brief outline of the role of restriction enzymes is provided to support students when these key gene technology enzymes are met in more detail later in the module. The main section of the lesson focuses on the use of gel electrophoresis to separate DNA fragments (as well as proteins) and the key ideas of separation due to differences in base pair length or molecular mass are discussed and explained. As well as current understanding checks, an application question involving Huntington’s disease is used to challenge their ability to apply their knowledge of the process to an unfamiliar situation. The remainder of the lesson describes how the DNA is transferred to a membrane and hybridisation probes are used to create a pattern on the X-ray film. Time has been taken to make continuous links to the previous lessons in module 6.1.3 as well as those from module 2.1.3 where DNA, RNA and protein synthesis were introduced.

This lesson describes the active loading of assimilates like sucrose at the source and the translocation along the phloem to the sink. Both the detailed PowerPoint and accompanying resources have been designed to cover point 3.1.3 (f) of the OCR A-level Biology A specification. The lesson begins by challenging the students to recognise the key term translocation when it is partially revealed and then the rest of the lesson focuses on getting them to understand how this process involves the mass flow of assimilates down the hydrostatic pressure gradient from the source to the sink. It has been written to tie in with 3.1.3 (b) where the structure of the phloem tissue was initially introduced and the students are continually challenged on this prior knowledge. A step-by-step guide is used to describe how sucrose is loaded into the phloem at the source by the companion cells. Time is taken to discuss key details such as the proton pumping to create the proton gradient and the subsequent movement back into the cells by facilitated diffusion using co-transporter proteins. Students will learn that the hydrostatic pressure at the source is high, due to the presence of the water and sucrose as cell sap, and that this difference when compared to the lower pressure at the sink leads to the movement along the phloem. A number of quick quiz rounds are included in the lesson to maintain engagement and to introduce key terms and the lesson concludes with a game of SOURCE or SINK as students have to identify whether a particular plant structure is one or the other (or both)

This extensive and fully-resourced lesson describes the principles and explains the techniques used in the production of recombinant DNA in genetic engineering. Both the engaging PowerPoint and accompanying resources have been written to cover points 6.1.3 (f) (i & ii) of the OCR A-level Biology A 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 module 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 enzymes 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. The following key steps are described and explained: • Remove and prepare the plasmid to act as a vector • Insert the DNA fragment into the vector • Transfer the recombinant plasmid into the host cell • Identify the cells which have taken up the recombinant plasmid • Allow the transformed host cells to replicate and express the novel gene 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 memorable way.

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 epistasis. The detailed and engaging PowerPoint and associated resources have been designed to cover the part of point 6.1.2 (b[ii]) of the OCR A-level Biology A specification which states that students should be able to demonstrate and apply their knowledge and understanding of the use of phenotypic ratios to identify epistasis. 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 epistasis 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 as well as recognising the different types of epistasis.

This is an informative lesson that builds on the knowledge that students gained at GCSE on the topic of inheritance to enable them to carry out genetic crosses for the inheritance of a single gene at A-level. The start of the lesson focuses on the terminology that is associated with this topic which has to be recognised and understood if students are going to be able to begin a cross. Time is taken to go over key points such as the genotypes and working out the different possible gametes that would be produced by meiosis. Students can save time by only showing the different gametes so assistance is given on this. As can be seen from the cover image, a step by step guide is used to go through a number of examples so that students can visualise how to set out their diagrams in order to maximise the marks gained. There are progress checks written into the lesson throughout so that assessment is constant. This lesson can be taught alongside another upload called “understanding genetic trees”

This engaging lesson looks at the role of haemoglobin in transporting oxygen and carbon dioxide and compares the dissociation curves for foetal and adult haemoglobin. The detailed PowerPoint has been designed to cover points 3.1.2 (i & j) of the OCR A-level Biology A specification and includes references to the role of carbonic anhydrase and the formation of haemoglobinic acid and carbaminohaemoglobin. The lesson begins with a version of the quiz show Pointless to introduce haemotology as the study of the blood conditions. Students are told that haemoglobin has a quaternary structure and are challenged to use their prior knowledge of biological molecules to determine what this means for the protein. They will learn that each of the 4 polypeptide chains contains a haem group with an iron ion attached and that it is this group which has a high affinity for oxygen. Time is taken to discuss how this protein must be able to load (and unload) oxygen as well as transport the molecules to the respiring tissues. Students will plot the oxyhaemoglobin dissociation curve and the S-shaped curve is used to encourage discussions about the ease with which haemoglobin loads each molecule. At this point, foetal haemoglobin and its differing affinity of oxygen is introduced and students are challenged to predict whether this affinity will be higher or lower than adult haemoglobin and to represent this on their dissociation curve. The remainder of the lesson looks at the different ways that carbon dioxide is transported around the body that involve haemoglobin. Time is taken to look at the dissociation of carbonic acid into hydrogen ions so that students can understand how this will affect the affinity of haemoglobin for oxygen in an upcoming lesson on the Bohr effect. It is estimated that it will take in excess of 2 hours of A-level teaching time to cover the detail of these two specification points as covered in this lesson