This fully-resourced lesson describes the blood clotting process and includes the release of thromboplastin and the subsequent conversions to thrombin and fibrin. The engaging PowerPoint and accompanying worksheets have been primarily designed to cover the content detailed in point 1.6 of the Pearson Edexcel A-level Biology A specification but time has been taken to look at haemophilia as a sex-linked disease so that students are prepared for sex-linkage when covered in topic 3. The lesson begins with the introduction of clotting factors as integral parts of the blood clotting process and explains that factor III, thromboplastin, needs to recalled as well as the events that immediately precede and follows its release. Students will learn how damage to the lining and the exposure of collagen triggers the release of this factor and how a cascade of events then results. Quick quiz rounds and tasks are used to introduce the names of the other substances involved which are prothrombin, thrombin, fibrinogen and fibrin. In a link to the upcoming topic of proteins, students will understand how the insolubility of fibrin enables this mesh of fibres to trap platelets and red blood cells and to form the permanent clot. In the previous lessons, students described the events in atherosclerosis and a link is made to the role of blood clotting in CVD. The final part of the lesson introduces haemophilia as a sex-linked disease and students are challenged to apply their knowledge to an unfamiliar situation as they have to write genotypes and determine phenotypes before explaining why men are more likely to suffer from this disease than women.

This fully-resourced lesson describes how genes can be switched on and off by DNA transcription factors, including hormones. The PowerPoint and accompanying resources have been designed to cover point 7.16 as detailed in the Pearson Edexcel A-level Biology A specification but also links to topic 3 when the lac operon was described in relation to differential gene expression. This is one of the more difficult concepts in this A-level course and therefore key points are reiterated throughout this lesson to increase the likelihood of student understanding and to support them when trying to make links to actual biological examples in living organisms. There is a clear connection to transcription and translation as covered in topic 2, so the lesson begins by reminding students that in addition to the structural gene in a transcription unit, there is the promotor region where RNA polymerase binds. Students are introduced to the idea of transcription factors and will understand how these molecules can activate or repress transcription by enabling or preventing the binding of the enzyme. At this point, students are challenged on their current understanding with a series of questions about DELLA proteins so they can see how these molecules prevent the binding of RNA polymerase. Their remainder of the lesson looks at the ER receptor and students will learn that this factor is normally inactive due to an inhibitor being attached. This will then introduce oestrogen as the hormone which binds to the receptor, causing the inhibitor to be released and activating the factor. The main task then challenges them to order statements containing the detailed events that follow the binding of oestrogen. The lesson in topic 3 on gene expression which describes the lac operon has also been uploaded for free.

This detailed lesson describes how changes in ventilation rate are brought about to allow for the delivery of oxygen and the removal of carbon dioxide. The engaging PowerPoint and accompanying resources have been designed to cover the second part of point 7.9 (ii) in the Pearson Edexcel A-level Biology A specification. The previous lesson described the control of heart rate so this lesson has been written to tie in with this and to use this knowledge to further the students understanding of the control of ventilation rate. The lesson begins with a focus on the muscles involved in ventilation, specifically the diaphragm and external intercostal muscles, so that students can understand how their contraction results in an increase in the volume of the thoracic cavity. Boyle’s law is briefly introduced to allow students to recognise the relationship between volume and pressure so that the movement of air with the pressure gradient can be described. Time is then taken to consider the importance of inhalation and an exam-style question challenges the students to explain that a constant supply of oxygen to the alveoli is needed to maintain a steep concentration gradient with the surrounding capillaries. The students are then tasked with writing a description of exhalation at rest using the description of inhalation as their guide. The rest of the lesson focuses on the mechanisms involved in increasing the rate and depth of breathing during exercise. Students will use their knowledge of the control of heart rate to recall that chemoreceptors detect changes in oxygen and carbon dioxide and blood pH and that the medulla oblongata processes the sensory information that it receives before coordinating a response. The final task challenges them to use the information provided in this lesson and the previous one to order 10 detailed descriptions so they can form a complete passage about this control system.

This fully-resourced lesson describes the ultrastructure of eukaryotic cells and the role of the RER and Golgi apparatus in protein transport. The engaging and detailed PowerPoint and accompanying exam-question worksheets (which are all differentiated) have been primarily designed to cover point 3.2 of the Pearson Edexcel A-level Biology A (Salters Nuffield) specification but also covers 3.1 which states that students should know that living organisms are made of cells, sharing some common features As cells are the building blocks of living organisms, it makes sense that they would be heavily involved in all of the 8 topics in the Edexcel course and intricate planning has ensured that these links to previously covered topics as well as upcoming ones are made throughout the lesson. A wide range of activities, that include exam-style questions, class discussion points and quick quiz competitions, will maintain motivation and engagement whilst covering the finer details of the following structures: nucleus nucleolus centrioles ribosomes rough endoplasmic reticulum Golgi apparatus lysosomes smooth endoplasmic reticulum mitochondria cell surface membrane As mentioned above, all of the worksheets have been differentiated to support students of differing abilities whilst maintaining challenge Due to the detail that is included in this lesson, it is estimated that it will take in excess of 3 hours of allocated A-level teaching time to go through all of the tasks

This fully-resourced lesson describes the ultrastructure of plant cells and includes the cell walls, chloroplasts, amyloplasts, vacuole, tonoplast, plasmodesmata, pits and middle lamella. The detailed PowerPoint and accompanying resources have been designed to cover point 4.7 of the Pearson Edexcel A-level Biology specification and also compares this structure against animal cells that was covered at the beginning of topic 3. The lesson begins with a task called REVERSE GUESS WHO which will challenge the students to recognise a particular organelle from a description of its function. This will remind students that plant cells are eukaryotic and therefore contain a cell-surface membrane, a nucleus (+ nucleolus), a mitochondria, a Golgi apparatus, ribosomes and rough and smooth endoplasmic reticulum like the animal cells. Moving forwards, the next part of the lesson focuses on the relationship between the structure and function of the vacuole, chloroplast, plasmodesmata and cellulose cell wall. When considering the vacuole, key structures such as the tonoplast are described as well as critical functions including the maintenance of turgor pressure. A detailed knowledge of the structure of the chloroplast at this early stage of their A-level studies will increase the likelihood of a clear understanding of photosynthesis when covered in topic 5. For this reason, time is taken to consider the light-dependent and light-independent reactions and to explain how these stages are linked. Students will learn that chloroplasts and amyloplasts can contain stores of starch so an opportunity is taken to challenge them on their knowledge of this polysaccharide as it was covered in topic 1. The final task challenges them to recognise descriptions of the cell wall, chloroplast, amyloplasts, vacuole, tonoplast and plasmodesmata which will leave 2 remaining which describe the pits and middle lamella.

This fully-resourced lesson describes the ultrastructure of a prokaryotic cell including the cell wall, capsule,plasmid, flagellum, pili, ribosomes, mesosomes and circular DNA. The engaging PowerPoint and accompanying resources have been designed to cover the specification point 3.4 that is detailed in the Pearson Edexcel A-level Biology A specification but also makes continual references to eukaryotic cells as covered in 3.1 - 3.3 so that comparisons can be made. A clear understanding of terminology is important for A-level Biology so this lesson begins with a challenge, where the students have to come up with a 3-letter prefix that they believe will translate as before or in front of . This leads into the discovery of the meaning of prokaryote as before nucleus which acts to remind students that these types of cell lack this cell structure. Links to the previous lessons on the eukaryotic cells are made throughout the lesson and at this particular point, the students are asked to work out why the DNA would be described as naked and to state where it will be found in the cell. Moving forwards, the students will discover that these cells also lack membrane bound organelles and a quick quiz competition challenges them to identify the specific structure that is absent from just a single word. In addition to the naked DNA, students will learn that there are also ribosomes in the cytoplasm and will discover that these are smaller than those found in the cytoplasm of an eukaryotic cell (but the same size as those in chloroplasts and mitochondria). The remainder of the lesson focuses on the composition of the cell wall, the additional features of prokaryotic cells such as plasmids and there is also the introduction of binary fission as the mechanism by which these organisms reproduce so that students can recognise that prokaryotic cells do not contain centrioles

This fully-resourced lesson describes the control of gene expression at a post-transcriptional level through the removal of introns during splicing. The detailed PowerPoint and accompanying resources have been designed to cover the second part of point 6.1.1 (b) as detailed in the OCR A-level Biology A specification and also explains how it’s possible for 1 gene to give rise to multiple products as a result of this post-transcriptional modification of mRNA. The lesson begins with a knowledge recall as the students have to recognise the definition of a gene as a sequence of bases on a DNA molecule that codes for a sequence of amino acids in a polypeptide chain. This description was introduced in module 2.1.3 and the aim of the start of the lesson is to introduce the fact that despite this definition, most of the nuclear DNA in eukaryotes doesn’t actually code for proteins. A quick quiz competition is then used to introduce exons as the coding regions within a gene before students are challenged to predict the name of the non-coding regions and then to suggest a function for these introns. At this point, the students will complete a task that acts as a prior knowledge check where they have to identify the 6 errors in the descriptive passage about the lac operon and its role in the regulation of gene expression in prokaryotes. Moving forwards, pre-mRNA as a primary transcript is introduced and students will learn that this isn’t the mature strand that moves off to the ribosome for translation. Instead, a process called splicing takes place where the introns are removed and the remaining exons are joined together. Another quick quiz round leads to an answer of 20000 and students will learn that this is the number of protein-coding genes in the human genome. Importantly, the students are then told that the number of proteins that are synthesised is much higher than this value and a period of class discussion encourages them to come up with biological suggestions for this discrepancy between the two numbers. The lesson concludes with a series of understanding and application questions where students will learn that alternative splicing enables a gene to produce more than a single protein and that this natural phenomenon greatly increases biodiversity

This fully-resourced lesson describes the regulatory mechanisms that control gene expression at a transcriptional level. The detailed PowerPoint and accompanying resources have been designed to cover the first part of point 6.1.1 (b) as detailed in the OCR A-level Biology A specification which states that the students knowledge should include the lac operon and examples of transcription factors in eukaryotes. . This is one of the more difficult concepts in this A-level course and therefore key points are reiterated throughout this lesson to increase the likelihood of student understanding and to support them when trying to make links to actual biological examples in living organisms. There is a clear connection to transcription and translation as covered in module 2.1.3, so the lesson begins by reminding students that in addition to the structural gene in a transcription unit, there is the promotor region where RNA polymerase binds. Students are introduced to the idea of transcription factors and will understand how these molecules can activate or repress transcription by enabling or preventing the binding of the enzyme. At this point, students are challenged on their current understanding with a series of questions about DELLA proteins so they can see how these molecules prevent the binding of RNA polymerase. Their understanding is then tested again with another example with oestrogen and the ER receptor. The final and main section of the lesson focuses on the lac operon and immediately an opportunity is taken to challenge their knowledge of biological molecules with a task where they have to spot the errors in a passage describing the formation and breakdown of this disaccharide. Students will be able to visualise the different structures that are found in this operon and time is taken to go through the individual functions. A step by step guide is used to walk students through the sequence of events that occur when lactose is absent and when it is present before they are challenged to apply their understanding to an exam question.

This fully-resourced lesson describes the beneficial, neutral and harmful effects of gene mutations on the primary structure of a polypeptide. The engaging and detailed PowerPoint and accompanying resources have been designed to cover point 6.1.1 (a) of the OCR A-level Biology A specification which states that students should be able to understand how substitutions, deletions and insertions change the base sequence and describe how this affects protein production and function. 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 in module 2.1.3. 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 terms which are associated with the genetic code and were met back in 2.1.3. 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 fully-resourced lesson describes the movement of molecules by active transport, endocytosis and exocytosis, which are all active process that require ATP. The PowerPoint and accompanying worksheets have been designed to cover the second part of point 2.1.5 (d) [i] of the OCR A-level Biology A specification. The first part of this specification point, concerning simple and facilitated diffusion, was covered in the previous lesson. The start of the lesson challenges the students to use their prior knowledge of biological molecules to come up with the abbreviation ATP. Students were introduced to this molecule in module 2.1.3, so a series of prior knowledge questions are used to check on their recall of the structure and properties of ATP. Students are also reminded that the hydrolysis of ATP can be coupled to energy-requiring reactions within the cell and the rest of the lesson focuses on the use of this energy input for active transport, endocytosis and exocytosis. Students are challenged to answer a series of questions which compare active transport against the forms of passive transport and to use data from a bar chart to support this form of transport. In answering these questions they will discover that carrier proteins are specific to certain molecules and time is taken to look at the exact mechanism of these transmembrane proteins. A quick quiz round introduces endocytosis and the students will see how vesicles are involved along with the energy source of ATP to move large substances in or out of the cell. The lesson concludes with a link to a future topic as the students are shown how exocytosis is involved in a synapse.

This detailed lesson describes the fluid mosaic model of membrane structure and also describes the roles of its components. The detailed and engaging PowerPoint and accompanying worksheets have been designed to cover specification point 2.1.5 (b) of the OCR A-level Biology A specification and clear links are made to related topics such as the binding of peptide hormones The fluid mosaic model is introduced at the start of the lesson so that it can be referenced at appropriate points throughout the lesson. Students were introduced to phospholipids in module 2.1.2 and an initial task challenges them to spot the errors in a passage describing the structure and properties of this molecule. This reminds them of the bilayer arrangement, with the hydrophilic phosphate heads protruding outwards into the aqueous solutions on the inside and the outside of the cell. In a link to some upcoming lessons on the transport mechanisms, the students will learn that only small, non-polar molecules can move by simple diffusion and that this is through the tails of the bilayer. This introduces the need for transmembrane proteins to allow large or polar molecules to move into the cell by facilitated diffusion and active transport. Proteins that act as receptors as also introduced and an opportunity is taken to make a link to an upcoming topic so that students can understand how hormones or drugs will bind to target cells in this way. Moving forwards, the structure of cholesterol is covered and students will learn that this hydrophobic molecule sits in the middle of the tails and therefore acts to regulate membrane fluidity. The final part of the lesson challenges the students to apply their newly-acquired knowledge to a series of questions where they have to explain why proteins may have moved when two cells are used and to suggest why there is a larger proportion of these proteins in the inner mitochondrial membrane than the outer membrane.

This lesson describes how molecules move across the cell membrane by the passive methods of simple and facilitated diffusion. The PowerPoint and accompanying resources have been designed to cover the first part of specification point 2.1.5 (d) [i] of the OCR A-level Biology A specification and the factors that increase the rate of diffusion are covered along with the limitations imposed by the phospholipid bilayer and the role of channel and carrier proteins. The structure and properties of cell membranes were described in the lesson covering 2.1.5 (b), so this lesson has been written to include continual references to the content of that lesson. This enables links to be made between the movement across a cell membrane with the concentration gradient, the parts of the membrane that are involved and any features that may increase the rate at which the molecules move. A series of questions about the alveoli are 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

This detailed lesson describes how the movement of water molecules by osmosis can affect both plant and animal cells. Both the PowerPoint and accompanying resources have been designed to cover specification point 2.1.5 (e) [i] as detailed in the OCR A-level Biology A specification and there is a particular focus on solutions of different water potentials. It’s likely that students will have used the term concentration in their osmosis definitions at GCSE, so the aim of the starter task is to introduce water potential to allow students to begin to recognise osmosis as the movement of water molecules from a high water potential to a lower potential, with the water potential gradient. Time is taken to describe the finer details of water potential to enable students to understand that 0 is the highest value (pure water) and that this becomes negative once solutes are dissolved. Exam-style questions are used throughout the lesson to check on current understanding as well as prior knowledge checks which make links to previously covered topics such as the lipid bilayer of the cell membrane. The remainder of the lesson focuses on the movement of water when animal and plant cells are suspended in hypotonic, hypertonic or isotonic solutions and the final appearance of these cells is described, including any issues this may cause. This lesson has been specifically written to tie in with the previous two lessons covering 2.1.5 (b) & (d) where the cell membrane, diffusion and active transport were described.

This fully-resourced lesson describes how selection pressures act on a gene pool and cause stabilising, directional and disruptive selection. The PowerPoint and accompanying resources have been designed to cover point 8.3 (i) of the Edexcel A-level Biology B specification which states that students should be able to identify each type of selection by its effect on different phenotypes. The lesson begins with an introduction to the mark, release, recapture method to calculate numbers of rabbits with different coloured fur in a particular habitat. This shows changes in numbers of the organisms and sketch graphs are then constructed to show these changes in the population size. A quick quiz competition is used to engage the students whilst introducing the names of the three main types of selection before a class discussion point encourages the students to recognise which specific type of selection is represented by the rabbits. Key terminology including intermediate and extreme phenotypes and selection pressure are used to emphasise their importance during explanations. A change in the environment of the habitat and a change in the numbers of the rabbits introduces directional selection before students will be given time to discuss and to predict the shape of the sketch graph for disruptive selection. Students are challenged to apply their knowledge in the final task of the lesson by choosing the correct type of selection when presented with details of a population and answer related questions.

This fully-resourced lesson guides students through the use of the Hardy-Weinberg equation to monitor changes in allele frequencies in a population. The detailed PowerPoint and differentiated practice questions worksheets have been designed to cover point 8.3 (iv) of the Edexcel A-level Biology B specification The lesson begins with a focus on the equation to ensure that the students understand the meaning of each of the terms. The recessive condition, cystic fibrosis, is used as an example so that students can start to apply their knowledge and assess whether they understand which genotypes go with which term. Moving forwards, a step-by-step guide is used to show students how to answer a question. Tips are given during the guide so that common misconceptions and mistakes are addressed immediately. The rest of the lesson gives students the opportunity to apply their knowledge to a set of 3 questions, which have been differentiated so that all abilities are able to access the work and be challenged

This engaging and fully-resourced lesson explores how genetic drift can arise after a population bottleneck or as a result of the Founder effect. The detailed PowerPoint and accompanying resources have been designed to cover points 8.3 (ii) & (iii) of the Edexcel A-level Biology B specification A wide range of examples are used to show the students how a population that descends from a small number of parents will have a reduction in genetic variation and a change in the frequency of existing alleles. Students are encouraged to discuss new information to consider key points and understanding checks in a range of forms are used to enable them to check their progress and address any misconceptions. Students are provided with three articles on Huntington’s disease in South Africa, the Caribbean lizards and the plains bison to understand how either a sharp reduction in numbers of a new population beginning from a handful of individuals results in a small gene pool. Links to related topics are made throughout the lesson to ensure that a deep understanding is gained.

This fully-resourced lesson guides students through the construction of genetic crosses and pedigree diagrams for the inheritance of a single gene. The clear PowerPoint and accompanying resources have been designed to cover point 8.2 (ii) of the Edexcel A-level Biology B specification and includes the inheritance of multiple allele characteristics as well as those 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 fully-resourced lesson describes the inheritance of genes that are carried on the X chromosome and includes a particular focus on haemophilia in humans. The detailed PowerPoint and associated differentiated resources have been designed to cover specification point 8.2 (v) as detailed in the Edexcel A-level Biology B specification. Key genetic terminology is used throughout and the lesson begins with a check on their ability to identify the definition of homologous chromosomes. Students will recall that the sex chromosomes are not fully homologous and that the smaller Y chromosome lacks some of the genes that are found on the X. This leads into one of the numerous discussion points, where students are encouraged to consider whether females or males are more likely to suffer from sex-linked diseases and they will be challenged to find evidence to support this decision later in the lesson. In terms of humans, the lesson focuses on haemophilia and red-green colour blindness and a step-by-step guide is used to demonstrate how these specific genetic diagrams should be constructed and how the phenotypes should then be interpreted. The final tasks of the lesson challenge the students to carry out a dihybrid cross that involves a sex-linked disease and an autosomal disease before applying their knowledge to a question about chickens and how the rate of feather production in chicks can be used to determine gender. All of the tasks are differentiated so that students of differing abilities can access the work and all exam questions have fully-explained, visual markschemes to allow them to assess their progress and address any misconceptions

This fully-resourced lesson has been written to support students to develop a clear understanding of 16 key genetic terms, including the 8 that are detailed in specification point 8.2 (i) of the Edexcel A-level Biology B specification. 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. 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 to act as an understanding check.