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 fully-resources lesson looks at the phenomenon known as the Bohr effect and describes and explains how an increased carbon dioxide concentration affects the dissociation of oxyhaemoglobin. The PowerPoint has been designed to cover the second part of point 3.1.2 (j) of the OCR A-level Biology A specification and continually ties in with the previous lesson on the role of haemoglobin. The lesson begins with a terminology check to ensure that the students can use the terms affinity, oxyhaemoglobin and dissociation. In line with this, they are challenged to draw the oxyhaemoglobin dissociation curve and are reminded that this shows how oxygen associates with haemoglobin but how it dissociates at low partial pressures. Moving forwards, a quick quiz is used to introduce Christian Bohr and the students are given some initial details of his described effect. This leads into a series of discussions where the outcome is the understanding that an increased concentration of carbon dioxide decreases the affinity of haemoglobin for oxygen. The students will learn that this reduction in affinity is a result of a decrease in the pH of the cell cytoplasm which alters the tertiary structure of the haemoglobin. Opportunities are taken at this point to challenge students on their prior knowledge of protein structures as well as the bonds in the tertiary structure. The lesson finishes with a series of questions where the understanding and application skills are tested as students have to explain the benefit of the Bohr effect for an exercising individual. These questions are differentiated to allow students of differing abilities to access the work and to be challenged

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

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 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 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 describes how DNA is replicated during interphase of the cell cycle and explains why it is known as semi-conservative replication. Both the detailed PowerPoint and accompanying resources have been designed to cover the details of point 2.1.3 (e) of the OCR A-level Biology A specification and the occurrence of spontaneous mutations is also discussed in the latter part of the lesson. As detailed in the specification, the focus of this lesson is the role of the enzymes DNA helicase and polymerase and students are also introduced to DNA ligase to enable them to understand how this enzyme functions to join the nucleic acid fragments. Time is taken to explain key details such as the assembly of strands in the 5’-to-3’ direction so that the continuous manner in which the leading strand is synthesised can be compared against that of the lagging strand. The students are constantly challenged to make links to previous topics such as DNA structure, phosphorylated nucleotides and hydrolysis reactions through a range of exam questions and answers are displayed so any misconceptions are quickly addressed. The final part of the lesson focuses on the occurrence of mistakes by DNA polymerase and also on the quantity of DNA in the cell following replication so that future links can be made to the cell cycle (as covered in module 2.1.6)

This is an engaging lesson that looks at the structures and actions of the two parts of the autonomic nervous system (ANS) and shows students where this particular system fits into the whole organisation of the nervous system. The lesson begins by introducing the students to the idea that motor neurones are not simply somatic motor neurones but will actually be classified as autonomic motor neurones if they innervate the involuntary muscles. A range of tasks, progress checks and quick competitions are used during the lesson to engage the students in this topic and show them how it relates to other topics such as motor neurones and neurotransmitters. Key terminology is used throughout, such as ganglions, so that students can recognise and access the marks if an exam question on this topic arises. This lesson has been written for A-level students

This lesson focuses on the structure of RNA and specifically the similarities and differences between this nucleic acid and DNA so that students are prepared for the upcoming lessons on transcription and translation. The engaging and detailed PowerPoint and accompanying resource have been designed to cover part 1 of point 2.1.3 (g) of the OCR A-level Biology A specification which states that students should be able to describe the structure of molecules of messenger RNA, transfer RNA and ribosomal RNA. Students were introduced to nucleotides and the detailed structure of DNA in previous lessons, so this lesson is written to tie in with those and continuously challenge prior knowledge as well as understanding of the current topic. The lesson begins by reminding students that RNA is a member of the family of nucleic acids and therefore has a number of structural features that are commonly shared with 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 fully-resourced lesson looks at the effects of nervous mechanisms on the heart rate. The engaging and detailed PowerPoint and accompanying resources have been designed to cover the part of point 5.1.5 (k) 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 control of the heart rate by the cardiovascular centre in the medulla oblongata This lesson begins with a prior knowledge check where students have to identify and correct any errors in a passage about the conduction system of the heart. This allows the SAN to be recalled as this structure play an important role as the effector in this control system. Moving forwards, the three key parts of a control system are recalled as the next part of the lesson will specifically look at the range of sensory receptors, the coordination centre and the effector. Students are introduced to chemoreceptors and baroreceptors and time is taken to ensure that the understanding of the stimuli detected by these receptors is complete and that they recognise the result is the conduction of an impulse along a neurone to the brain. A quick quiz is used to introduce the medulla oblongata as the location of the cardiovascular centre. The communication between this centre and the SAN through the autonomic nervous system can be poorly understood so detailed explanations are provided and the sympathetic and parasympathetic divisions compared. The final task challenges the students to demonstrate and apply their understanding by writing a detailed description of the control and this task has been differentiated three ways to allow differing abilities to access the work