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

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 is a fast-paced lesson which uses a range of tasks and quick competitions to compare the diagnosis, symptoms and treatment of Diabetes mellitus Type I and II. Students are continually challenged throughout the lesson to build and deepen their knowledge of these conditions and consider how they can be controlled through hormone injections or lifestyle changes. Clear links are made to related topics such as auto-immune diseases and the endocrine system and progress checks have been written into the lesson to allow students to assess their understanding of all of these topics. The final part of the lesson involves the students writing a letter to an individual who has type II, explaining how this diagnosis was done, giving details of the condition and recommending lifestyle changes. This task is differentiated so that students who are finding it difficult can still access the learning. This lesson has been written for A-level students. If you are looking for a lesson for younger students on this topic, then my other upload “Diabetes Type I and II” will be more suitable.

This lesson focuses on the nature of the genetic code in terms of being near universal, non-overlapping and degenerate and specifically focuses on this latter term to explain how a mutation may not result in a change to the sequence of amino acids. The PowerPoint has been designed to cover point 2.1.3 (f) of the OCR A-level Biology A specification and there are clear links to gene mutations which students will meet in module 6. The lesson begins by introducing the terms near universal and non-overlapping in addition to degenerate. A quick quiz competition is used to generate the number 20 so that the students can learn that there are 20 proteinogenic amino acids in the genetic code. This leads into a challenge, where they have to use their prior knowledge of DNA to calculate the number of different DNA triplets (64) and the mismatch in number is then discussed and related back to the lesson topic. Moving forwards, base substitutions and base deletions are briefly introduced so that they can see how although one substitution can change the primary structure, another will change the codon but not the encoded amino acid. The lesson concludes with a brief look at the non-overlapping nature of the code so that the impact of a base deletion (or insertion) can be understood when covered in greater detail in module 6.

This lesson explains the principles of the polymerase chain reaction (PCR) and the PowerPoint has been designed to cover point 6.1.3 (d) of the OCR A-level Biology A specification A quick quiz competition is used to introduce the PCR abbreviation before students are encouraged to discuss the possible identity of the enzyme involved and to recall the action of this enzyme. Students will learn that this reaction involves cyclical heating and cooling to a range of temperatures so the next part of this lesson focuses on each temperature and specifically the reasons behind the choice. Time is taken to examine the key points in detail, such as why Taq polymerase has to be used as it is not denatured at the high temperature as well as the involvement of the primers. This process is closely linked to other techniques like electrophoresis which is covered in a later lesson and ties are continuously made throughout the lesson This process is mentioned in other uploaded lessons in this module such as electrophoresis and genetic engineering to allow students to understand how it is critical for DNA analysis

This fully-resourced lesson explores the contributions of chromosome mutations to genetic variation. The engaging PowerPoint and accompanying worksheets have been designed and written to cover the part of point 6.1.2 (a) 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 contribution of genetic factors to phenotypic variation Over the course of the lesson, students will encounter a number of chromosome mutations and see the conditions which they cause. Time is taken to look at non-disjunction and how this can result in Down, Turner’s and Klinefelter’s syndromes. Students are guided through a description of the formation of gametes and zygotes with abnormal numbers of chromosomes before being challenged to describe the formation of a zygote with Turner’s syndrome. Moving forwards, translocation and polyploidy are also discussed. Progress checks are written into the lesson at regular intervals, that not only check the learning from this lesson but also from related topics (such as meiosis) and this enables the students to constantly assess their understanding.

This is an engaging and informative lesson that looks at the properties of water and challenges students to be able to explain how these properties are related to the numerous functions of this biological molecule. This lesson focuses on the link between properties and functions which is the area where students commonly struggle. A range of tasks and activities, including a quick competition are used to introduce the different properties and the key terms and then time is taken to look at how this property enables water to be used for a range of functions. Students will learn that water has both a high specific heat capacity and a high latent heat of vaporisation and be able to explain why this is important. Water is a crucial solvent which enables it to perform many roles in living organisms and these are explored. Progress checks are written into the lesson at regular intervals so that students can constantly assess their understanding and build on any knowledge that was there from GCSE.

This fully-resourced lesson explores the inheritance of genetic characteristics that involve multiple alleles and codominant alleles. The engaging and detailed PowerPoint and differentiated worksheets have been designed to cover the part of point 6.1.2 (b[i]) which states that students should be able to demonstrate and apply their knowledge and understanding of genetic diagrams to show patterns of inheritance including multiple and codominant alleles. The main part of the lesson uses the inheritance of the ABO blood groups to demonstrate how the three alleles that are found at the locus on chromosome 9 and the codominance of the A and B alleles affects the phenotypes. Students are guided through the construction of the different genotypes and how to interpret the resulting phenotype. They are challenged to use a partially completed pedigree tree to determine the blood group for some of the family members and to explain how they came to their answer. To further challenge their ability to apply their knowledge, a series of questions about multiple alleles and codominance in animals that are not humans are used. The final part of the lesson makes a link back to module 4 and the correlation between a high proportion of polymorphic gene loci and an increase in genetic diversity. Students will be expected to make links between module 4 and 6 as part of papers 2 and 3, so this demonstrates how exam questions can do just that

This is an extensive and fully-resourced lesson that guides students through drawing genetic diagrams to show the inheritance of one or two genes in order to calculate the phenotypic ratio. The engaging PowerPoint and accompanying worksheets have been designed to cover the part of module 6.1.2 (b[i]) which states that students should be able to demonstrate and apply an understanding of the patterns for both monogenic and dihybrid inheritance As you can see from the cover image, this lesson uses a step by step guide to go through each important stage of drawing the genetic cross. Extra time is taken over step 2 which involves writing out the different possible gametes that a parent can produce. This is the step where students most commonly make mistakes so it is critical that the method is understood. Helpful hints are also given throughout, such as only writing out the different possible gametes in order to avoid creating unnecessary work. Students are shown how to answer an example question so that they can visualise how to set out their work before they are challenged to try two further questions. This first of these is differentiated so that even those students who find this very difficult are able to access the learning. The final question will enable the students to come up with the ratio 9:3:3:1 and they will be shown how they can recognise when this should be the expected ratio as this links to the chi-squared test.

This is a fast-paced lesson which goes through the main steps of selective breeding and looks at the potential risks of this process. The lesson begins by looking at the characteristics of a number of organisms that would be selected. Time is taken to ensure that students understand that selective breeding is not a new thing and has been going on for a very long time and therefore some of the problems associated with this are now being experienced. The actual process is reduced down into 5 steps which can be recalled and applied to questions. The remainder of the lesson looks at the potential issues with selective breeding. The reduction in the nose size of pugs is explored as an example of the health problems which bred animals may face. This lesson has been written for GCSE students.

This lesson uses the example of the genetic engineering of bacteria to produce insulin to walk students through the steps involved in this process. It has been written for GCSE students and therefore includes the detail required at this level, such as the involvement of restriction enzymes and the sticky ends that their cut produces. The lesson begins by challenging students to recognise that insulin is being described by a series of clues. Some further details of this hormone are recalled to test their previous knowledge of the endocrine system and also to lead into the genetic engineering of bacteria to make this protein. Moving forwards, time is taken to go through the details of plasmids and how they act as vectors as well as the enzymes, restriction and ligase. The main task of the lesson uses a series of descriptions to go through the steps involved in the process. Words or phrases are missing from each description so students have to use the terms they’ve encountered in this lesson as well as their prior knowledge to complete the step. Discussion-provoking questions are added to encourage the students to consider why certain parts of the process occur. The lesson concludes by the consideration of other organisms which have been genetically engineered as well as some of the risks of the process, which students are asked to complete for homework. As detailed above, this lesson has been designed for GCSE students but could be used with students taking A-level Biology, who are struggling to understand the detail found at this level and need to revisit the foundations.