This lesson focuses on the use and explanation of key genetic terms which will support students in their understanding of the topic 16 (inherited change) of the CIE International A-level Biology specification. In this topic, students are expected to use genetic diagrams to solve problems and this is only possible with a clear understanding of the genetic terminology that will be used in related exam questions. As some of these terms were met at GCSE, this fully-resourced lesson has been designed to include a wide range of activities that build on this prior knowledge and provide clear explanations as to their meanings as well as numerous examples of their use in both questions and exemplary answers. The main task provides the students with an opportunity to apply their understanding by recognising a dominance hierarchy in a multiple alleles characteristic and then calculating a phenotypic ratio when given a completed genetic diagram. Other tasks include prior knowledge checks, discussion points to encourage students to consider the implementation of the genetic terms and quiz competitions to introduce new terms, maintain engagement and act as an understanding check. The 16 terms are genome, gene, chromosome, gene locus, homologous chromosomes, alleles, dominant, recessive, genotype, codominance, multiple alleles, autosomes, sex chromosomes, phenotype, homozygous and heterozygous

This concise, engaging revision lesson has been designed to include activities that will motivate the students whilst they assess their understanding of topic B3 (Biological molecules) of the CIE IGCSE Combined Science specification. An understanding of biological molecules is fundamental to the understanding of a lot other Biology topics and this lesson has attempted to make the links between the different areas. The range of activities which include exam questions, quick tasks and quiz competitions have been written to cover as much of the content as possible but the following topics have received particular attention: The chemical elements in carbohydrates The formation of starch and glycogen from glucose The iodine test for starch Lipids are formed of fatty acids and glycerol Investigational skills The ethanol emulsion test for lipids This resource includes a PowerPoint (27 slides) and a worksheet with a task about the digestion of milk fat so students can recognise the components of lipids

This lesson focuses on the nature of the genetic code and specifically focuses on the degenerate nature to make a link to gene mutations which is covered later in topic 2. The PowerPoint has been designed to cover point 2.7 of the Pearson Edexcel A-level Biology (Salters Nuffield) specification which states that students should understand how the descriptive terms triplet code, degenerate and non-overlapping relate to the genetic code. 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, substitutions and 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 can be understood when covered in greater detail with cystic fibrosis

This fully-resourced lesson covers the meaning of the 9 genetic terms that are detailed in point 2.13 (i) of the Pearson Edexcel A-level Biology (Salters Nuffield) specification as well as four other key terms which will need to be used later in topic 2, 3 and 8. In the following lessons, students are expected to be able to demonstrate and apply their knowledge and understanding of genetic diagrams and phenotypic ratios to show patterns of inheritance and this is only possible with a clear understanding of the genetic terminology that will be used in related exam questions. As some of these terms were met at GCSE, this lesson has been designed to build on this prior knowledge and provide clear explanations as to their meanings as well as numerous examples of their use in both questions and exemplary answers. The main task provides the students with an opportunity to apply their understanding by recognising a dominance hierarchy in a multiple alleles characteristic and then calculating a phenotypic ratio when given a completed genetic diagram. Other tasks include prior knowledge checks, discussion points to encourage students to consider the implementation of the genetic terms and quiz competitions to introduce new terms, maintain engagement and act as an understanding check. The 13 terms are genome, gene, chromosome, gene locus, homologous chromosomes, alleles, dominant, recessive, genotype, phenotype, homozygotes and heterozygotes

This fully-resourced lesson explains how gel electrophoresis is used to analyse nucleic acids and proteins and explores its applications in forensic science and medical diagnosis. The engaging and detailed PowerPoint and accompanying resource have been written to cover point 19.1 (d) of the CIE International A-level Biology specification As a whole lesson, each step of the genetic fingerprinting process is covered but with the main focus on 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 and restriction enzymes are discussed and students are challenged on their knowledge of this process and these substances as they were encountered in a previous lesson. 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 topic 19.1 as well as those from topic 6 where DNA, RNA and protein synthesis were introduced.

Simple and facilitated diffusion are forms of passive transport and this lesson describes the factors that increase the rate of this movement across membranes. This fully-resourced lesson is the first in a series of two that have been designed to cover specification point 2.4 of the Pearson Edexcel A-level Biology A and the involvement of channel and carrier proteins is also described and discussed. In a number of previous lessons that covered specification points 2.1 and 2.2, students were provided with the details of gas exchange surfaces and the structure and properties of cell membranes. This lesson continually refers back to the content of these lessons so that links can be made between the movement across a cell membrane with the concentration gradient, the parts of the membrane involved and any features that may increase the rate at which the molecules move. A series of questions about the alveoli is used to demonstrate how a large surface area, a short diffusion distance and the maintenance of a steep concentration gradient will increase the rate of simple diffusion. One of two quick quiz rounds is then used to introduce temperature and size of molecule as two further factors that can affect simple diffusion. The remainder of the lesson focuses on facilitated diffusion and describes how transmembrane proteins are needed to move small, polar or large molecules from a high concentration to a lower concentration across a partially permeable membrane. The other lesson included in this series to cover specification point 2.4 describes active transport, endocytosis and exocytosis.

This lesson introduces the differences between ectotherms and endotherms and then describes the behavioural responses of an ecotherm. The PowerPoint and accompanying resource have been designed to cover specification point 9.9 (vi) of the Edexcel A-level Biology B specification which states that students should understand how ectotherms rely on the external environment for their temperature control. The main aim when designing the lesson was to support students in making sensible and accurate decisions when challenged to explain why these types of organisms have chosen to carry out a particular response. A wide range of animals are used so students are engaged in the content matter and are prepared for the unfamiliar situations that they will encounter in the terminal exam. Time is also taken to compare ectotherms against endotherms so that students can recognise the advantages and disadvantages of ectothermy when covered in the following lesson.

This lesson describes how solutes are selectively reabsorbed in the proximal tubule. The PowerPoint and accompanying resource have been designed to cover the first part of specification point 7.20 of the Edexcel International A-level Biology specification and builds on the knowledge gained in the previous lessons on the microscopic structure of the nephron and ultrafiltration. The lesson begins by challenging the students to recall the substances that are found in the glomerular filtrate so that each of them can be considered over the course of the rest of the lesson. Moving forwards, the first of the numerous discussion points which are included in the lesson is used to get students to predict the component of the filtrate which won’t be found in the urine when they are presented with pie charts from each of these situations. Upon learning that glucose is 100% reabsorbed, along with most of the ions and some of the water, the rest of the lesson focuses on describing the relationship between the structure of the PCT and the function of selective reabsorption. Again, this section begins by encouraging the students to discuss and to predict which structures they would expect to find in a section of the kidney if the function is to reabsorb. They are given the chance to see the structure (as shown in the cover image) before each feature is broken down to explain its importance. Time is taken to look at the role of the cotransporter proteins to explain how this allows glucose, along with sodium ions, to be reabsorbed from the lumen of the PCT into the epithelial cells. The final part of the lesson focuses on urea and how the concentration of this substance increases along the tubule as a result of the reabsorption of some of the water.

This lesson explains how negative feedback control maintains systems within narrow limits and uses biological examples to describe the meaning of positive feedback. The PowerPoint and accompanying resources have been designed to cover points 7.11 (i) and (ii) of the Pearson Edexcel A-level Biology A (Salters Nuffield) specification but have been planned to provide important details for upcoming topics such as the importance of homeostasis during exercise and the depolarisation of a neurone. The normal ranges for blood glucose concentration, blood pH and body temperature are introduced at the start of the lesson to allow students to recognise that these aspects have to be maintained within narrow limits. A series of exam-style questions then challenge their recall of knowledge from topics 1 - 6 as well as earlier in topic 7 to explain why it’s important that each of these aspects is maintained within these limits. The students were introduced to homeostasis at GCSE, so this process is revisited and discussed, so that students are prepared for an upcoming lesson on exercise, as well as for the next part of the lesson on negative feedback control. Students will learn how this form of control reverses the original change and biological examples are used to emphasise the importance of this system for restoring levels to the limits (and the optimum). The remainder of the lesson explains how positive feedback differs from negative feedback as it increases the original change and the role of oxytocin in birth and the movement of sodium ions into a neurone are used to exemplify the action of this control system.

This lesson describes the effect that treaties such as CITES have had on global diversity. The PowerPoint and accompanying worksheets have been primarily designed to cover point 10.4 (ii) of the Edexcel A-level Biology B specification but has been planned to constantly challenge them on their knowledge of topic 3.3 (biodiversity) as a local conservation agreement is also considered Many hours of research have gone into the planning of this lesson to ensure that a range of interesting biological examples are included, with the aim of fully engaging the students in the material to increase its relevance. The students will learn that the Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES) was first agreed in 1973 and that 35000 species are currently found in appendix I, II or III. Time is taken to go through the meaning of each appendix and then the following animal and plant species are used to explain the finer details of the agreement: Tree pangolin, eastern black rhino for CITES appendix I Darwin’s orchid for CITES appendix II Four-horned antelope for CITES appendix III Exam-style questions are used to check on their understanding of the current topic as well as to challenge their knowledge of previously-covered topics such as the functions of keratin, when considering the structure of the rhino horn. Each of these questions has its own markscheme which is embedded in the PowerPoint and this allows the students to constantly assess their progress. The final part of the lesson considers the Countryside Stewardship Scheme as a local conservation agreements and discusses the reasons behind some of the key points. Students are told that farmers, woodland owners, foresters and land managers can apply for funding for a range of options including hedgerow management, low input grassland, buffer strips, management plans and soil protection options. The importance of the hedgerows for multiple species is discussed, and again a real-life example is used with bats to increase the likelihood of retention. The last task challenges them to use their overall knowledge of biodiversity to explain why buffer strips consisting of multiple types of vegetation are used and to explain why these could help when a farmer is using continuous monoculture.

This lesson describes the inheritance of two non-interacting unlinked genes and guides students through the calculation of phenotypic ratios. The PowerPoint and the accompanying question sheet (which is differentiated) have been designed to cover point 8.2 (iii) of the Edexcel A-level Biology B specification. As the previous lesson described the construction of genetic crosses and pedigree diagrams, students are aware of the methods involved in writing genotypes and gametes for the inheritance of a single gene. Therefore, the start of this lesson builds on this understanding to ensure that students recognise that genotypes contain 4 alleles and gametes contain 2 alleles when two genes are inherited. The students are taken through the steps of a worked example to demonstrate the key steps in the calculation of a phenotypic ratio before 2 exam-style questions challenge them to apply their newly-acquired knowledge. Mark schemes are displayed within the PowerPoint to allow students to assess their progress. The phenotypic ratio generated as the answer to the final question is 9:3:3:1 and time is taken to explain that this is the expected ratio when two heterozygotes for two genes are crossed which they may be expected to use when meeting the chi squared test in an upcoming lesson

This lesson describes a range of methods that can be used to assess the distribution and abundance of organisms in a local area. The PowerPoint and accompanying worksheets have been designed to cover points [c] and [d] of topic 18.1 of the CIE A-level Biology specification and describe the use of frame quadrats, line and belt transects, and the mark-release-recapture method. Due to the substantial mathematical content of the A-level Biology exams, as well as descriptions of the different methods, there is a focus on the range of calculations that are used to estimate the population of either sessile or motile species. As shown by the image, step by step guides are used to walk the students through the key stages in these calculations before exam-style questions challenge them to apply their understanding and mark schemes are included in the lesson to allow them to immediately assess their progress. The precautions and assumptions associated with the mark-release-recapture method are discussed and links are made to stabilising selection as covered in topic 17 when considering how the number of species have changed over time.

This lesson describes the effects of pH on enzyme activity. The PowerPoint and accompanying resources are part of the first lesson in a series of 3 lessons which have been designed to cover the content of point 2.1.4 (d)(i)of the OCR A-level Biology A specification. The lesson begins with a short discussion, where the students are challenged to identify how the stomach and the small intestine differ in terms of a particular condition and to explain why the conditions in these neighbouring digestive organs are so important. This introduces pepsin and trypsin and these protease enzymes play a key role throughout the lesson as they are good examples of how different extracellular enzymes have different optimum pH values (which are not necessarily 7.0). Moving forwards, students will discuss how the rate of an enzyme-controlled reaction will change if there are small or large changes in pH, and then time is taken to ensure that students can explain these changes with reference to tertiary structure bonds and the shape of the active site. Through the use of a quick quiz competition, the students will be reminded of the key term “buffer” and a series of questions are used to challenge their understanding of how these substances could be used in a practical investigation. They will also learn how buffers are found in blood plasma as well as in red blood cells in the form of haemoglobin. With there being such a considerable proportion of marks for Maths in a Biology context questions in the A-level assessments, the remainder of the lesson challenges the students to use a given formula to calculate the pH of blood when given the hydrogen ion concentration and to calculate percentage decrease. These questions have been differentiated to give assistance to those that need the support Please note that this is a lesson which describes the effect on enzyme activity, as described in 2.1.4 (d)(i), and not the details of the practical investigation which is covered in a later lesson

This lesson describes how maltose, sucrose and lactose are synthesised during condensation reactions and broken down during hydrolysis reactions. The PowerPoint and accompanying question sheet have been designed to cover point 1.1 (iii) of the Edexcel A-level Biology B specification but also make links to the previous lesson on monosaccharides when considering the different components of these three disaccharides. The first section of the lesson focuses on a prefix and a suffix so that the students can recognise that the names of the common disaccharides end in -ose. In line with this, a quick quiz round is used to introduce maltose, sucrose and lactose before students are challenged on their prior knowledge as they have to describe how condensation reactions and the formation of glycosidic bonds were involved in the synthesis of each one. The main task of the lesson again challenges the students to recall details of a previous lesson as they have to identify the monomers of each disaccharide when presented with the displayed formula. Time is taken to show how their knowledge of these simple sugars will be important in later topics such as enzymes, translocation in the phloem and the lac operon in the control of gene expression. The lesson finishes with two exam-style questions where students have to demonstrate and apply their newly acquired knowledge

This engaging lesson acts as an introduction to topic 1.3 (proteins) by introducing the general structure of an amino acid. The PowerPoint lesson has been designed to cover point 1.3 (i) as detailed in the Edexcel A-level Biology B specification and provides a clear introduction to the following lesson on the formation of polypeptides, protein structures and globular and fibrous proteins. The lesson begins with a prior knowledge check, where the students have to use the 1st letters of 4 answers to uncover a key term. This 4-letter key term is gene and the lesson begins with this word because it is important for students to understand that these sequences of bases on DNA determine the specific sequence of amino acids in a polypeptide. Moving forwards, students are given discussion time to work out that there are 64 different DNA triplets and will learn that these encode for the 20 amino acids that are common to all organisms. The main task of the lesson is an observational one, where students are given time to study the displayed formula of 4 amino acids. They are not allowed to draw anything during this time but will be challenged with 3 multiple choice questions at the end. This task has been designed to allow the students to visualise how the 20 amino acids share common features in an amine and an acid group. A quick quiz round introduces the R group and time is taken to explain how the structure of this side chain is the only structural difference, before cysteine is considered in greater detail due to the presence of sulfur atoms. Students are briefly introduced to disulfide bridges so they will recognise how particular bonds form between the R groups in the tertiary structure which is covered in the next lesson. One more quiz round called LINK TO THE FUTURE is used to conclude the lesson and demonstrates the range of roles performed by amino acids in the latter part of the course including translation at the ribosomes.

This lesson describes and explains how temperature affects enzyme activity. The PowerPoint and the accompanying resource are part of the 1st lesson in a series of 3 which cover the content detailed in point 1.5 (iv) of the Edexcel A-level Biology B specification and this lesson has been specifically planned to tie in with the previous lesson covering 1.5 (i, ii & iii) where the structure, properties and mechanism of action of enzymes were introduced. The lesson begins by challenging the students to recognise optimum as a key term from its 6 synonyms that are shown on the board. Time is taken to ensure that the students understand that the optimum temperature is the temperature at which the most enzyme-product complexes are produced per second and therefore the temperature at which the rate of an enzyme-controlled reaction works at its maximum. The optimum temperatures of DNA polymerase in humans and in a thermophilic bacteria and RUBISCO in a tomato plant are used to demonstrate how different enzymes have different optimum temperatures and the roles of the latter two in the PCR and photosynthesis are briefly described to prepare students for these lessons in topics 7 and 5. Moving forwards, the rest of the lesson focuses on enzyme activity at temperatures below the optimum and at temperatures above the optimum. Students will understand that increasing the temperature increases the kinetic energy of the enzyme and substrate molecules, and this increases the likelihood of successful collisions and the production of enzyme-substrate and enzyme-product complexes. When considering the effect of increasing the temperature above the optimum, continual references are made to the previous lesson and the control of the shape of the active site by the tertiary structure. Students will be able to describe how the hydrogen and ionic bonds in the tertiary structure are broken by the vibrations associated with higher temperatures and are challenged to complete the graph to show how the rate of reaction decreases to 0 when the enzyme has denatured. Please note that this lesson has been designed specifically to explain the relationship between the change in temperature and the rate of enzyme activity in a reaction and not the practical skills that would be covered in a core practical lesson

This fully-resourced lesson describes how enzyme and substrate concentration affect the rate of enzyme activity. The PowerPoint and accompanying resources are the last in a series of 3 lessons which cover the detail of point 1.5 (iv) of the Edexcel A-level Biology B specification. The first part of the lesson describes how an increase in substrate concentration will affect the rate of reaction when a fixed concentration of enzyme is used. Time is taken to introduce limiting factors and students will be challenged to identify substrate concentration as the limiting factor before the maximum rate is achieved and then they are given discussion time to identify the possible factors after this point. A series of exam-style questions are used throughout the lesson and the mark schemes are displayed to allow the students to assess their understanding and for any misconceptions to be immediately addressed. Moving forwards, the students have to use their knowledge of substrate concentration to construct a graph to represent the relationship between enzyme concentration and rate of reaction and they have to explain the different sections of the graph and identify the limiting factors. The final section of the lesson describes how the availability of enzymes is controlled in living organisms. Students will come to recognise that this availability is the result of enzyme synthesis and enzyme degradation and their recall of transcription and translation is tested through a SPOT the ERRORs task. Please note that this lesson explains the Biology behind the effect of concentration on enzyme-controlled reactions and not the methodology involved in carrying out such an investigation as this is covered in a core practical lesson.

This lesson describes the development and spread of antibiotic resistance in bacteria and discusses the difficulties in controlling this spread. The PowerPoint and accompanying worksheet have been designed to cover specification points 6.4 (i & ii) of the Edexcel A-level Biology B 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 spread of MRSA and to try to prevent the development of resistance in other strains.

This engaging lesson describes how chromosome mutations result in changes to the number or structure of chromosomes and focuses on Downs and Turner’s syndrome. The PowerPoint and accompanying resources have been designed to cover specification points 2.3 (vi) and (vii) as detailed in the Edexcel A-level Biology B specification. A human karyotype which has not been altered by a mutation is studied at the start of the lesson to allow students to recall the usual number of chromosomes as well as the sex chromosomes. They are then challenged to identify the differences when presented with the karyotypes of sufferers of Downs, Turner’s and Klinefelter’s syndrome. Students will learn that in the majority of cases, these conditions are the result of non-disjunction and having been assisted in the explanation of the outcome for Downs and Klinefelters, they have to form their own for Turner’s. The remainder of the lesson looks at other types of mutations, including translocation, and students will also see how whole sets of chromosomes can be duplicated in polyploidy.

This lesson reminds students of the meaning of homeostasis and describes the how thermoregulation maintains the body in dynamic equilibrium during exercise. The PowerPoint has been designed to cover point 7.17 of the Edexcel International A-level Biology specification. Students were introduced to homeostasis at GCSE and this lesson has been written to build on that knowledge and to add the key detail needed at this level. Focusing on the three main parts of a homeostatic control system, the students will learn about the role of the internal and peripheral thermoreceptors, the thermoregulatory centre in the hypothalamus and the range of effectors which bring about the responses to restore optimum levels. The following responses are covered in this lesson: Vasodilation Increased sweating Body hairs In each case, time is taken to challenge students on their ability to make links to related topics such as the arterioles involved in the redistribution of blood and the high specific latent heat of vaporisation of water.