This detailed lesson explores how a range of methods are used to produce fragments of DNA as part of the recombinant DNA technology process. Both the engaging PowerPoint and accompanying resources have been written to cover the first part of point 8.4.1 of the AQA A-level Biology specification and also provides information that will prove useful for the other lessons in this sub-topic on the polymerase chain reaction and using transformed host cells. The lesson begins with a definition of recombinant DNA technology so that students can 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 topic 4, 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 final part of the lesson looks at the production of synthetic genes of any sequence using gene machines and a series of application questions are used to push the students to consider how this advance in technology could be utilised. 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 is a fully-resourced lesson which introduces gene mutations and then explores how these base changes affect the primary structure of a polypeptide. The engaging and detailed PowerPoint and accompanying resources have been designed to cover the second part of point 4.3 of the AQA A-level Biology specification which states that students should be able to understand how base substitutions and base deletions change the base sequence and describe how this affects the polypeptide. In order to understand how a change in the base sequence can affect the order of the amino acids, students must be confident in their understanding and application of protein synthesis which was taught in 4.2. Therefore, the start of the lesson focuses on transcription and translation and students are guided through the use of the codon table to identify amino acids. Moving forwards, a quick quiz competition is used to introduce the names of three types of gene mutation whilst challenging the students to recognise terms which are associated with the genetic code and were met in the previous lesson. The main focus of the lesson is base substitutions and how these mutations may or may not cause a change to the amino acid sequence. The students are challenged to use their knowledge of the degenerate nature of the genetic code to explain how a silent mutation can result. The rest of the lesson looks at base deletions and base insertions and students are introduced to the idea of a frameshift mutation. One particular task challenges the students to evaluate the statement that base deletions have a bigger impact on primary structure than base substitutions. This is a differentiated task and they have to compare the fact that the reading frame is shifted by a deletion against the change in a single base by a substitution.

This extensive and fully-resourced lesson describes the steps in the production of recombinant DNA in genetic technology. Both the engaging PowerPoint and accompanying resources have been written to cover all of the detailed content of topic 19.1 of the CIE International A-level Biology specification apart from the polymerase chain reaction and gel electrophoresis as these are found in other uploaded lessons. The lesson begins with a definition of 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 topic 6, 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. Due to the detail that is included in this lesson, it is estimated that it will take in excess of 3 hours to cover the points

This lesson describes how the nervous system allows effectors to respond to stimuli and also describes hormonal control in animals. The PowerPoint and accompanying resources have been primarily designed to cover points 8.2 & 8.13 of the Edexcel International A-level Biology specification but it can also be used as a revision lesson as there are numerous prior knowledge checks of muscle contraction, protein structure and the control of gene expression. The lesson begins by challenging the students to recall that a control system contains sensory receptors, a coordination centre and effectors. Sensory receptors are covered in detail later in the topic when some key examples are considered as well as those in the retina, but time is taken now to describe how these structures act like transducers, converting one form of energy into electrical energy and the Pacinian corpuscle is used as an example. The students will learn that the communication between the receptors and the coordination centre and the effectors is by cell signalling and that the effectors can be muscles which contract or glands that release chemicals. The next part of the lesson looks at the differing responses from the nervous and hormonal systems and discusses how this can be governed by the need for a rapid response or more of a long term effect. In terms of nervous control, the students are challenged on their recall of the sliding filament theory of muscle contraction as covered in topic 7. Moving forwards, the students will learn that hormones can be either peptide or steroid hormones and their action at a target cell differs based on their form. Students are tested on their knowledge of protein structure by a series of exam-style questions on insulin and glucagon. They are reminded that steroid hormones can pass directly through the cell membrane and their knowledge of the control of gene expression by transcription factors is tested through a task involving oestrogen and the ER receptor. The lesson concludes by reminding students that the control of heart rate, as covered in topic 7, is a coordinated response that involves both nervous and hormonal control.

This lesson describes how energy is transferred between trophic levels using the terms net and gross primary productivity and calculates the efficiency of this transfer. The PowerPoint and accompanying resources have been designed to cover points 10.2 (i) and (ii) of the Edexcel A-level Biology B specification and the content of the lesson also accounts for the loss of energy between different levels and describes the farming practices that act to reduce these losses. Due to the fact that the productivity of plants is dependent on photosynthesis, a series of exam-style questions have been written into the lesson which challenge the students to explain how the structure of the leaf as well as the light-dependent and light-independent reactions are linked to GPP. All of the exam questions have mark schemes that are included in the PowerPoint to allow students to immediately assess their understanding. A number of quick quiz competitions as well as guided discussion points are used to introduce the formulae that calculate NPP and N and to recognise the meaning of the components. Once again, this is immediately followed with an opportunity to apply their understanding to selected questions and the students will have to calculate the efficiency of energy transfer. The remainder of the lesson focuses on the ways that energy is lost at each trophic level and the biology behind the following farming practices are discussed: raising herbivores to reduce the number of trophic levels in a food chain intensely rearing animals to reduce respiratory losses in human food chains the use of fungicides, insecticides and herbicides the addition of artificial fertilisers The ethical issues raised by these practices are also considered and alternative methods discussed such as the addition of natural predators and the use of organic fertilisers like manure

This lesson describes the role of the posterior pituitary gland and ADH in the homeostatic balance of blood water potential. The PowerPoint and accompanying resources have been designed to cover specification points (f & g) in topic 7 of A2 unit 3 of the WJEC A-level Biology specification. Students learnt about the principles of homeostasis and negative feedback in an earlier lesson in this topic, so this lesson acts to build on that knowledge and challenges them to apply their knowledge. A wide range of activities have been included in the lesson to maintain motivation and engagement whilst the understanding and prior knowledge checks will allow the students to assess their progress as well as challenge themselves to make links to other Biology topics. The lesson begins with a discussion about how the percentage of water in urine can and will change depending on the blood water potential. Students will quickly be introduced to osmoregulation and they will learn that the osmoreceptors and the osmoregulatory centre are found in the hypothalamus. A considerable amount of time is taken to study the cell signalling between the hypothalamus and the posterior pituitary gland by looking at the specialised neurones (neurosecretory cells). Links are made to the topics of neurones, nerve impulses and synapses and the students are challenged to recall the cell body, axon and vesicles. The main section of the lesson forms a detailed description of the body’s detection and response to a low blood water potential. The students are guided through this section as they are given 2 or 3 options for each stage and they have to use their knowledge to select the correct statement. The final task asks the students to write a detailed description for the opposite stimulus

This lesson describes how the structures of the xylem vessels, sieve tube elements and companion cells relates to their functions. The PowerPoint and accompanying resources have been designed to cover points (m & q) in topic 3 of AS unit 2 of the WJEC A-level Biology specification. Please note that this lesson does not include light and electron microscope pictures, so teachers will have to source and add these in themselves. 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 fully-resourced lesson guides students through the principles of monohybrid inheritance, focusing on the importance of alleles. The PowerPoint and accompanying resources have been designed to cover points (a & b) in topic 3 of A2 unit 4 of the WJEC A-level Biology specification and includes the inheritance of alleles that demonstrate codominance. In order to minimise the likelihood of errors and misconceptions, step by step guides have been included throughout the lesson to support the students with the following: Writing parent genotypes Working out the different gametes that are made following meiosis Interpreting Punnett crosses to work out phenotypic ratios Students can often find pedigree trees the most difficult to interpret and to explain so exemplar answers are used as well as differentiated worksheets provided to support those students who need extra assistance

This lesson describes the key events of the eukaryotic cell cycle and specifically focuses on those that occur in interphase. The PowerPoint and accompanying resources have been designed to cover point (a) in topic 6 of AS unit 1 of the WJEC A-level Biology specification and also introduces the stages of mitosis and cytokinesis to prepare students for the upcoming lesson on the significance of this type of cell division. The students were introduced to the cell cycle at GCSE so this lesson has been planned to build on that knowledge and to emphasise that the M phase which includes mitosis (nuclear division) only occupies a small part of the cycle. The students will learn that interphase is the main stage and that this is split into three phases, G1, S and G2. A range of tasks which include exam-style questions, guided discussion points and quick quiz competitions are used to introduce key terms and values and to describe the main processes that occur in a very specific order. Extra time is taken to ensure that key terminology is included and understood, such as sister chromatid and centromere, and this focus helps to show how it is possible for genetically identical daughter cells to be formed at the end of the cycle.

This is a fully-resourced and engaging REVISION LESSON which challenges the students on their knowledge and understanding of the topic 2 content (Biological molecules) of the CIE International A-level Biology specification. This topic isn’t always well understood by students so the lesson has been designed to include a wide range of activities that include differentiated exam questions, quick tasks and quiz competitions which will engage the students whilst they assess their progress. It has been designed to cover as much of the specification as possible but the following sub-topics have received particular attention: Formation of polysaccharides by glycosidic bonds between monomers Recognising monosaccharides, disaccharides and polysaccharides The structure of starch and glycogen in relation to their function as stores and providers of energy Water as a solvent with a high specific heat capacity and a high specific latent heat of vaporisation Structure and bonding in proteins The structure of globular and fibrous proteins as demonstrated by haemoglobin and collagen The structure and function of cellulose Links are made to other topics so that students are able to see how questions can include parts from different Biological concepts.

This lesson describes the vascular system of mammals as a double circulatory system to allow comparisons with those in earthworms, insects and fish. The PowerPoint and accompanying resources have been designed to cover the final content of specification point (a) in topic 3 (Adaptations for transport) of AS unit 2 in the WJEC A-level Biology specification and there is a primary focus on the differences in pressure between the pulmonary and systemic circulation. The lesson begins with a focus on the meaning of a double circulatory system and checks that students are clear in the understanding that the blood passes through the heart twice per cycle of the body. Beginning with the pulmonary circulation, students will recall that the pulmonary artery carries the blood from the right ventricle to the lungs. An opportunity is taken at this point to check on their knowledge of inhalation and the respiratory system as well as the gas exchange between the alveoli and the capillary bed. A quick quiz is used to introduce arterioles and students will learn that these blood vessels play a crucial role in the changes in blood pressure that prevent the capillaries from damage. When looking at the systemic circulation, time is taken to look at the coronary arteries and renal artery as students have to be aware of these vessels in addition to the ones associated with the heart. In the final part of the lesson, students are challenged to explain how the structure of the heart generates a higher pressure in the systemic circulation and then to explain why the differing pressures are necessary.

This is a fully-resourced REVISION lesson which challenges the students on their knowledge of the content in TOPIC B4 (Natural selection and genetic modification) of the Edexcel GCSE Combined Science specification. The lesson uses an engaging PowerPoint (65 slides) and accompanying worksheets to motivate students whilst they assess their understanding of this topic. A range of exam questions, differentiated tasks and quiz competitions are used to test the following sub-topics: The discovery of key fossils and their implications for human evolution The dating of stone tools Evolution by natural selection Antibiotic resistance in bacteria as evidence for natural selection The domain and kingdom classification methods Genetic engineering of bacteria to produce human insulin The benefits and risks of genetic engineering and selective breeding The mathematical element of the course is also tested throughout the lesson and students are given helpful hints on exam techniques and how to structure answers. This resource is suitable for use at the end of topic B4 or in the lead up to mocks or the actual GCSE exams.

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 7.1 of the AQA A-level specification which states that students should be able to use fully-labelled genetic diagrams to predict or interpret the results of crosses involving 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. The lesson has been designed to tie in with the other uploaded lessons on the topic of inheritance (7.1), so if you like the quality of this lesson please take a moment to look at these too

This lesson describes the effects of gene mutations can have on amino acid sequences, as illustrated by sickle cell anaemia. The engaging and detailed PowerPoint and accompanying resources are part of the first lesson in a series of 2 lessons which have been designed to cover point (f) in topic 3 of A2 unit 4 of the WJEC A-level Biology specification and includes substitutions, deletions and insertions In order to understand how a change in the base sequence can affect the order of the amino acids, students must be confident in their understanding and application of protein synthesis which was covered earlier in this topic. Therefore, the start of the lesson focuses on transcription and translation and students are guided through the use of the codon table to identify amino acids. Moving forwards, a task called known as THE WALL is used to introduce to the names of three types of gene mutation whilst challenging the students to recognise three terms which are associated with the genetic code. The main focus of the lesson is substitutions and how these mutations may or may not cause a change to the amino acid sequence. The students are challenged to use their knowledge of the degenerate nature of the genetic code to explain how a silent mutation can result. Students will learn that a substitution is responsible for the new allele that causes sickle cell anaemia and they are tested on their understanding through an exam-style question. As with all of the questions, a mark scheme is included in the PowerPoint which can be displayed to allow the students to assess their understanding. The rest of the lesson looks at base deletions and base insertions and students are introduced to the idea of a frameshift mutation. One particular task challenges the students to evaluate the statement that base deletions have a bigger impact on primary structure than base substitutions. This is a differentiated task and they have to compare the fact that the reading frame is shifted by a deletion against the change in a single base by a substitution

This fully-resourced lesson describes how DNA is replicated during interphase and explains why it is semi-conservative replication. Both the detailed PowerPoint and accompanying resources have been designed to cover the details of point 6.1 © of the CIE International A-level Biology specification The main focus of this lesson is the roles of DNA helicase in breaking the hydrogen bonds between nucleotide bases and DNA polymerase incorporating the phosphorylated nucleotides into the sequence. 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 main task of the lesson asks the students to use the information provided in the lesson to order the sequence of events in DNA replication before discussing how the presence of a conserved strand and a newly built strand in each new DNA molecule shows that it is semi-conservative.

This fully-resourced lesson describes the structure of HIV, its replication inside helper T cells and EXPLAINS how it causes the symptoms of AIDS. The PowerPoint and accompanying resources are part of the 5th lesson in a series of 7 that cover the details of point 2.4 of the AQA A-level Biology specification. The structure of viruses was covered during the lessons in topic 2.1, so this lesson starts by challenging the students to recall the capsid, genetic material in the form of viral RNA and the lipid envelope. At this point, the students are introduced to gp120, the glycoprotein which is exposed on the surface of the lipid envelope, as this structure is critical for the entry of the virus into host cells. Students will annotate a basic diagram of HIV with these four structures which also has gp41 labelled. A quick quiz competition introduces the names of the enzymes found inside the capsid and the students will learn that integrase allows the viral DNA to be integrated into the host’s genome whilst reverse transcriptase catalyses the reaction to form DNA from RNA. A prior knowledge check challenges the students to identify the helper T cells from a description of their function and they are informed that these immune cells have the CD4 glycoprotein on their surface. Moving forwards, the main part of the lesson describes how HIV binds to the helper T cells, injects its capsid and integrates its DNA into the host’s genome in order to replicate to form virus particles (virions). Students are guided through the formation of a detailed answer about the mechanism of HIV and have to input key terms and structures where information is missing. Students will learn that the increase in the number of virus particles and a decrease in helper T cells and other immune cells results in infections like TB and by opportunistic pathogens and that this stage is recognised as AIDS The final part of the lesson challenges the students to explain why antibiotics are ineffective against viruses through a series of exam-style questions and the final task gets them to work as a class where they have to study the replication process once more to suggest drug actions that might be used to treat HIV

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.

A fully-resourced lesson which is designed for GCSE students and includes an informative lesson presentation (29 slides) and question worksheets. This lesson explores the theory of evolution by natural selection. The lesson begins with a fun challenge which gets students to come up with the name Charles Darwin but also the phrase “survival of the fittest”. The main focus of the next part of the lesson is to take students through this tag line, adding detail and keywords which they will be able to use in their answers later in the lessons. Students are continually encouraged to discuss key questions on this topic, such as “are all mutations harmful”? They will recognise how these random changes in DNA can lead to advantageous phenotypes and how this can convey a survival edge to organisms. Moving forwards, students are guided through the well-known example of the peppered moths in order to show them to how to use variation, advantage, survival, reproduction and offspring in their answers on this topic. The remainder of the lesson involves students testing their new-found knowledge as they have to apply it to explain how resistance in bacteria and longer necks in giraffes have evolved. Progress checks are written into this lesson at regular intervals so that students can constantly assess their understanding and any misconceptions can be immediately addressed.

This lesson guides students through the use of the chi-squared test to test the significance of differences between observed and expected results. It is fully-resourced with a detailed PowerPoint and differentiated task worksheets that have been designed to cover point 16.2 (d) of the CIE International A-level Biology specification which states that students should be able to use this statistical test to determine the significance. The lesson has been written to include a step-by-step guide that 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 lesson describes how to use the Spearman’s rank correlation to analyse the relationships between the distribution of species and abiotic and biotic factors. The PowerPoint and accompanying exam-style question are the first lesson in a series of 2 which have been designed to cover point 18.1 (e) of the CIE A-level Biology specification and challenges the students on their knowledge of the t-test as covered in topic 17 as well as preparing students for the next lesson on the use of the Pearson’s linear correlation formula. As with the lessons on the t-test and Simpson’s index of diversity, a step by step guide is used to walk the students through the use of the formula to generate the rank coefficient and to determine whether there is a positive correlation, no correlation or a negative correlation. The students are also reminded of the null hypothesis and will be shown how to accept or reject this hypothesis and to determine significance. The students will work through an example with the class and then are given the opportunity to apply their newly-acquired knowledge to an exam-style question which assesses whether there is a relationship between light intensity and % plant cover in a habitat. The mark scheme is displayed on the PowerPoint so the students can assess their understanding and address any misconceptions that may arise