This engaging and fully-resourced lesson looks at examples of stabilising, directional and disruptive selection as the three main types of selection. The PowerPoint and accompanying resources have been designed to cover the 1st part of point 6.1.2 (e) of the OCR A-level Biology specification which states that students should be able to demonstrate and apply an understanding of the factors that affect the evolution of a species. The lesson begins by making a link to a topic from module 4 as the students are challenged to use the mark, release, recapture method to calculate numbers of rabbits with different coloured fur in a particular habitat. Sketch graphs are then constructed to show the changes in the population size in this example. 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 lesson has been designed to tie in with another uploaded lesson on genetic drift which covers the second part of this specification point.

This engaging and fully-resourced lesson looks at how genetic drift can arise after a genetic bottleneck or as a result of the Founder effect. The detailed PowerPoint and accompanying resources have been designed to cover the second part of point 6.1.2 (e) of the OCR A-level Biology A specification which states that students should be able to demonstrate and apply an understanding of the factors that affect the evolution of a species. 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 lesson has been designed to tie in with another uploaded lesson on types of selection which is part of this specification point

This detailed lesson describes the role of the mRNA, tRNA, ribosomes and start and stop codons during the second stage of protein synthesis - translation. This lesson is the second in a series of two, which have been designed together to cover point 2.13 of the Edexcel International A-level Biology specification. The first lesson in this series describes transcription. Translation is a topic which is often poorly understood and so this lesson has been written to enable the students to understand how to answer the different types of questions by knowing and including the key details of the structures involved. The lesson begins by challenging the students to consider why it is so important that the amino acids are assembled in the correct order during the formation of the chain. Moving forwards, a quick quiz round called “LOST IN TRANSLATION” is used to check on their prior knowledge of the mRNA strand, the tRNA molecules, the genetic code and the ribosomes. The next task involves a very detailed description of translation that has been divided into 14 statements which the students have to put into the correct order. By giving them a passage that consists of this considerable detail, they can pick out the important parts to use in the next task where they have to answer shorter questions worth between 3 and 4 marks. These types of questions are common in the assessments and by building up through the lesson, their confidence to answer this type should increase. The final two tasks of the lesson involve another quiz, where the teams compete to transcribe and translate in the quickest time before using all that they have learnt to answer some exam-style questions which involve the genetic code and the mRNA codon table.

This lesson describes the structure and ultrastructure of plant cells to allow students to compare this structure against animal cell structure. The detailed PowerPoint and accompanying resources have been designed to cover points 4.1 (i) & (ii) in unit 2 of the Edexcel International A-level Biology specification and also describes the functions of the cell wall, chloroplast, amyloplast, vacuole, tonoplast, plasmodesmata, pits and middle lamella 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 lesson describes the chemical tests for proteins, reducing and non-reducing sugars, starch and lipids and explains how to interpret the results. The PowerPoint and accompanying resource have been designed to cover point 2.1.2 (q) of the OCR A-level Biology A specification. The lesson begins with an explanation of the difference between a qualitative and quantitative test so that the students recognise that the four tests described within this lesson indicate the presence of a substance but not how much. The students are likely to have met these tests at GCSE so this lesson has been planned to build on that knowledge and to add the knowledge needed at this level. A step by step guide walks the students through each stage of the tests for reducing and non-reducing sugars and application of knowledge questions and prior knowledge checks are included at appropriate points to ensure understanding is complete. Time is also taken to ensure that students understand the Science behind the results. The next part of the lesson focuses on the iodine test for starch and the students will learn that the colour change is the result of the movement of an ion into the amylose helix. The rest of the lesson describes the steps in the biuret test for proteins and the emulsion test for lipids. The students will learn that the addition of sodium hydroxide and then copper sulphate will result in a colour change from light blue to lilac if a protein is present and that following the addition of a sample to ethanol and then water, a cloudy emulsion is observed if a lipid is present.

This fully-resourced lesson describes genetic biodiversity as the number of genes in a population and considers how it can be assessed. The engaging PowerPoint and accompanying differentiated resources have been primarily designed to cover point 4.2.1 (e) of the OCR A-level Biology A specification but also introduces inheritance and codominance so that students are prepared for these genetic topics when they are covered in module 6.1.2 In order to understand that 2 or more alleles can be found at a gene loci, students need to be confident with genetic terminology. Therefore the start of the lesson focuses on key terms including gene, locus, allele, recessive, genotype and phenotype. A number of these will have been met at GCSE, as well as during the earlier lessons in module 2.1.3 when considering meiosis, so a quick quiz competition is used to check on their recall of the meanings of these terms. The CFTR gene is then used as an example to demonstrate how 2 alleles results in 2 different phenotypes and therefore genetic diversity. Moving forwards, students will discover that more than 2 alleles can be found at a locus and they are challenged to work out genotypes and phenotypes for a loci with 3 alleles (shell colour in snails) and 4 alleles (coat colour in rabbits). Two calculations are provided to the students that can calculate the % of loci with more than one allele and the proportion of polymorphic gene loci. At this point, the students are introduced to codominance and again they are challenged to apply their understanding to a new situation by working out the number of phenotypes in the inheritance of blood groups. The lesson concludes with a brief consideration of the HLA gene loci, which is the most polymorphic loci in the human genome, and students are challenged to consider how this sheer number of alleles can affect the chances of tissue matches in organ transplantation

This lesson describes the steps in the emulsion test for lipids and then uses a range of tasks to challenge the students on their knowledge of topic 1.3. The engaging PowerPoint and accompanying resource are part of the last lesson in a series of 3 lessons which have been designed to cover the content of point 1.3 (lipids) of the AQA A-level Biology specification. The first part of the lesson describes the key steps in the emulsion test for lipids, and states the positive result for this test. There is a focus on the need to mix the sample with ethanol, which is a distinctive difference to the tests for reducing sugars and starch. The remainder of the lesson uses exam-style questions with mark schemes embedded in the PowerPoint, understanding checks, guided discussion points and quick quiz competitions to challenge the following specification points: The structure of a triglyceride The relationship between triglyceride property and function The hydrophilic and hydrophobic nature of the phospholipid The phospholipid bilayer of the cell membrane Cholesterol is also introduced so that students are prepared for this molecule when it is met in topic 2.3 (cell membranes)

A fully resourced lesson which includes an informative lesson presentation (25 slides) and an associated worksheet that show students how to give answers to a certain number of significant figures. The answers to questions in Science are often required to be given in significant figures and this lesson guides students through this process, including the rules of rounding that must be applied for success to be likely. This lesson has been designed for GCSE students but is suitable for KS3

A detailed lesson which looks at the type of cell division known as mitosis and aims to ensure that students understand that it leads to the production of genetically identical daughter cells. In order to understand this type of cell division and any related topic such as meiosis, students have to be confident with the use of terms like diploid. In addition to this, time is taken to introduce them to a way of considering the quantity of DNA within a cell in terms of n. If they are able to use this correctly, then no matter the organism which is involved in a mitosis exam question, they will be able to answer successfully. Discussion points and progress checks are written into the lesson at regular intervals so their understanding can be assessed. The last part of the lesson provides the students with an opportunity to apply their knowledge of mitosis to a range of exam questions and they can assess against the displayed mark schemes. This lesson has been designed for GCSE students (14 - 16 year olds in the UK) but is also appropriate for older students who want to recap on the key details of the division before extended knowledge is added.

An engaging and detailed lesson presentation (31 slides) that looks at how nitrogen is cycled and focuses on the different bacteria who play key roles in this cycle. The lesson begins by exploring why nitrogen is so critical for living organisms for the synthesis of DNA and proteins. Students are introduced to nitrogen-fixing bacteria to start and challenged to use their knowledge of interdependence to state the type of ecological relationship that is formed between them and the leguminous plant that they live on. Each stage of the cycle is complimented by a diagram highlighting that part so students are able to visualise how the cycle comes together. Time is taken to ensure that students recognise that any non-leguminous plants can only absorb nitrogen when it is nitrates form from the soil. Moving forwards, students will meet decomposers and nitrifying bacteria and again be shown where their function fits into the cycle. As the final part of the learning, students are challenged to consider what else is needed in order for this to be a cycle and will meet the denitrifying bacteria as a result. Progress checks, in a range of forms, have been written into this lesson at regular intervals so that students can assess their understanding and any misconceptions can be immediately addressed. This lesson has been written for GCSE students, but could be used with A-level students who want to have a recap before extending their knowledge further.

This lesson has been written for GCSE students with a focus on the key processes and reactions involved in the carbon cycle as well as discussions centering around how the levels of carbon dioxide alter during the day and over longer periods of time. A number of quick competitions have been written into the lesson to introduce key terms or to challenge students to recognise key reactions that they will have already met in their Biology lessons. As each stage of the cycle is encountered, time is taken to discuss the potential impacts and the organisms involved. The remainder of the lesson looks at carbon dioxide levels. Initially, students are challenged to explain why the levels would change during the course of a day. Students are already likely to be aware that carbon dioxide levels have increased over the last 100/200 years but not necessarily how much. Time is taken to focus on the mathematical skills which could be challenged on this topic and the percentage change equation is shown to the students so they can quantify their answers. As a class, deforestation and its effect on the carbon cycle and atmospheric levels are discussed so that students can mirror this in a homework task about combustion of fossil fuels. Progress checks are written into the lesson at regular intervals so that students are constantly assessing their understanding.

This fully-resourced lesson describes the relationship between the structure and function of globular proteins, specifically focusing on haemoglobin, insulin and pepsin. The detailed and engaging PowerPoint and accompanying resources have been primarily designed to cover specification point 2.1.2 (n) of the OCR A-level Biology A course but due to the detailed coverage of haemoglobin, the start of this lesson could also be used when teaching lessons that cover specification points 3.1.2 (i) and (j). By the end of the lesson, students will be able to describe that the interactions of the hydrophobic and hydrophilic R groups results in a spherical shape that is soluble in water and be able to explain the importance of this property with reference to the individual functions of these three globular proteins. They will also be able to name key individual details for each protein, such as haemoglobin being a conjugated protein, insulin being linked by numerous disulfide bridges and pepsin’s low number of basic R groups meaning it is stable in the acidic environment of the stomach. Extra time has gone into the planning of this lesson to ensure that links are continuously made to previous topics such as amino acids and the levels of protein structure as well as to upcoming topics like the control of blood glucose concentration that is covered in module 5.1.4.

This fully-resourced lesson describes the components of the chloroplast, focusing on the grana and stroma as the sites of photosynthesis. The engaging PowerPoint and accompanying resources have been designed to cover point 5.2.1 (b) of the OCR A-level Biology A specification and has been specifically designed to introduce students to the light-dependent and light-independent stages before they are covered in detail in upcoming lessons. Students were introduced to eukaryotic cells and their organelles structures in module 2.1.1 so this lesson has been written to test and to build on that knowledge. A version of the quiz show POINTLESS runs throughout the lesson and this maintains engagement whilst challenging the students to recall the parts of the chloroplast based on a description which is related to their function. The following structures are covered in this lesson: double membrane thylakoids (grana) stroma intergranal lamellae starch grains chloroplast DNA and ribosomes Once each structure has been recalled, a range of activities are used to ensure that key details are understood such as the role of the thylakoid membranes in the light-dependent reactions and the importance of ATP and reduced NADP for the reduction of GP to TP in the Calvin cycle. Links to other topics are made throughout and this is exemplified by the final task of the lesson where students are challenged on their recall of the structure, properties and function of starch (as originally covered in module 2.1.2)

This fully-resourced lesson describes the relationship between the properties and functions of the fibrous proteins, collagen, keratin and elastin. The detailed PowerPoint and accompanying resources have been designed to cover point 2.1.2 (o) of the OCR A-level Biology A specification but also make links to upcoming topics such as blood vessel structure and the immune system as well as constantly challenging students on their knowledge of proteins from earlier in this module. The lesson begins by challenging the students to recognise 7 structures found in animals from their descriptions and once they’ve written feathers, cartilage, bones, arteries, tendons, callus and skin into the right places, they will reveal the term fibrous and learn that these types of protein are found in these structures. Using their knowledge of the properties of globular proteins, they will learn that the insolubility of fibrous proteins allows them to form fibres, which perform structural functions. The rest of the lesson focuses on the functions of collagen, keratin and elastin and time is taken to discuss the key details and to make links to future topics so that students can recognise the importance of cross-modular based answers. A series of exam-style questions are used to challenge their knowledge of protein structure as well as their ability to apply their knowledge to an unfamiliar situation when learning that elastin is found in the walls of the urinary bladder. All of the questions have mark schemes embedded into the PowerPoint to allow them to immediately assess their understanding. This lesson has been specifically planned to tie in with the previous lesson on globular proteins as well as the one preceding that on the structures of proteins

This lesson describes how the surfaces in insects, fish and mammals are adapted for gas exchange. The PowerPoint and accompanying worksheets have been designed to cover the detail of point 4.3 (i) of the Edexcel A-level Biology B specification. The lesson has been intricately planned to challenge the students on their understanding of the surface area to volume ratio (as covered in topic 4.1) and to make direct links to upcoming lessons on the transport systems in humans. The lesson begins by explaining that single-celled organisms are able to diffuse oxygen and carbon dioxide across their body surface but that as organisms increase in size and their SA/V ratio decreases, they need adaptations at their gas exchange surfaces to be able to obtain the oxygen to meet their metabolic demands. This leads into the next part of the lesson which describes the roles of the following structures in insects and bony fish: spiracles, tracheae, tracheoles and tracheole fluid operculum, gill arch, gill filaments and lamellae The next task challenges the students to use their knowledge of topics 1, 2 and 3 to come up with the letters that form the key term, countercurrent flow. This is a key element of the lesson and tends to be a principle that is poorly understood, so extra time is taken to explain the importance of this mechanism. Students are shown two diagrams, where one contains a countercurrent system and the other has the two fluids flowing in the same direction, and this is designed to support them in recognising that this type of system ensures that the concentration of oxygen is always higher in the oxygenated water than in the blood in the lamellae. As the alveoli as a structure of gas exchange was introduced at GCSE, this final part of the lesson has been written to challenge the recall of that knowledge and to build on it. The main focus is the type of epithelium found lining the alveoli and students will discover that a single layer of flattened cells known as simple, squamous epithelium acts to reduce the diffusion distance. Again, students will have met this in a lesson in topic 2 on specialised cells (and tissues) so a number of prior knowledge checks are used alongside current understanding checks. The following features of the alveolar epithelium are also covered: Surface area Moist lining Production of surfactant The maintenance of a steep concentration gradient As a constant ventilation supply is critical for the maintenance of the steep concentration gradient, the final task considers the mechanism of ventilation

This fully-resourced lesson describes the structure and general properties of slow and fast skeletal muscle fibres. The detailed PowerPoint and accompanying resources are the second in a series of 2 lessons that cover the content detailed in point 6.3 of the AQA A-level Biology specification and due to the obvious links, this lesson also challenges the students on their knowledge of respiration, cell structures and biological molecules like glycogen and haemoglobin The following structure and properties are covered over the course of this lesson: Reliance on the aerobic or anaerobic pathways to generate ATP Resistance to fatigue mitochondrial density capillary density myoglobin content (and colour) fibre diameter phosphocreatine content glycogen content A wide variety of tasks are used to cover this content and include knowledge recall and application of knowledge exam-style questions with fully-displayed mark schemes as well as quick quiz competitions to maintain motivation and engagement. This lesson has been specifically planned to tie in with the previous lesson in topic 6.3, titled “Contraction of skeletal muscles”, and this lesson has been uploaded for free

This fully-resourced lesson describes how the functional differences of the retinal rod and cone cells is related to their structures. The detailed PowerPoint and accompanying resources are part of the 2nd in a series of 2 lessons that have been designed to cover the details included in point 6.1.2 of the AQA A-level Biology specification. However, as explained at the start of the lesson, it has been specifically planned to be taught after the lessons in topic 6.3, so that students are aware and understand the meaning of terms such as depolarisation and hyperpolarisation. It is likely that students will be aware that the human retina contains rod and cone cells, so this lesson builds on that knowledge and adds the detail needed at this level. Over the course of the lesson, students will learn that these cells contain different optical pigments and that this feature along with their differing connectivity to the bipolar neurones means that they have different sensitivities to light, colour perception and visual acuity. Exam-style questions are interspersed throughout to check on current understanding and also make links to previously covered topics. For example, students are challenged to recognise a description of the mitochondria so they can discover that this cell structure is found in the inner segment where it is responsible for generating the ATP needed to pump sodium ions out of the cells. As detailed above, this lesson ties in closely with topic 6.3 and students will be expected to make links to synapses and to the changes in membrane potential that occur when sodium ions move in or out of a cell

This lesson describes how the recent use of similarities in biological molecules and other genetic evidence has led to new classification systems. The PowerPoint and accompanying resources have been designed to cover point 4.2.2 [c] (i) of the OCR A-level Biology A specification and focuses on the introduction of the three-domain system following Carl Woese’s detailed study of the ribosomal RNA gene. The lesson begins with an introduction of Woese and goes on to describe how he is most famous for his definition of the Archaea as a new domain of life. Students were introduced to domains and the other classification taxa in a previous lesson, so their recall of this knowledge is continually tested and built upon as details are added. Students will discover the key differences between Archaea and Bacteria that led to the splitting of the prokaryotae kingdom and the addition of this higher classification rank. Moving forwards, the rest of the lesson considers other molecules that can be compared between species for classification purposes and the primary structure of cytochrome is described and discussed. At this point in the lesson, the students are also tested on their knowledge of the nature of the genetic code and have to explain how mutations to DNA can also be used for comparative purposes.

This lesson describes why a disease would be deemed to be an autoimmune disease and describes the mechanisms involved in a few examples. The PowerPoint and accompanying worksheets have been primarily designed to cover point 4.1.1 (k) of the OCR A-level Biology A specification, but this lesson can also be used to revise the content of modules 2 and 3 and the previous lessons in 4.1.1 through the range of activities included The lesson begins with a challenge, where the students have to recognise diseases from descriptions and use the first letters of their names to form the term, autoimmune. In doing so, the students will immediately learn that rheumatoid arthritis, ulcerative colitis, type I diabetes mellitus, multiple sclerosis and myasthenia gravis are all examples of autoimmune diseases. The next part of the lesson focuses on the mechanism of these diseases where the immune system cells do not recognise the antigens (self-antigens) on the outside of the healthy cells, and therefore treats them as foreign antigens, resulting in the production of autoantibodies against proteins on these healthy cells and tissues. Key details of the autoimmune diseases stated above and lupus are described and links to previously covered topics as well as to future topics such as the nervous system are made. The students will be challenged by numerous exam-style questions, all of which have mark schemes embedded into the PowerPoint to allow for immediate assessment of progress.

This fully-resourced lesson describes the differences between continuous and discontinuous variation and intraspecific and interspecific variation. The engaging PowerPoint and accompanying resources have been designed to cover the first part of point 4.2.2 (f) of the OCR A-level Biology A specification but also acts as a revision tool as a number of activities challenge the students on their knowledge of the genetic code and meiosis from modules 2.1.3 and 2.1.6. The students begin the lesson by having to identify phenotype and species from their respective definitions so that a discussion can be encouraged where they will recognise that phenotypic variation between members of the same species is due to both genetic and environmental factors and that this is known as intraspecific variation. The next part of the the lesson focuses on these genetic factors, and describes how mutation and the events of meiosis contribute to this variation. A range of activities, which include exam-style questions and quick quiz rounds, are used to challenge the students on their knowledge and understanding of substitution mutations and deletions, the degenerate and non-overlapping genetic code, crossing over and independent assortment. Another quick quiz round is used to introduce polygenic inheritance and the link is made between this inheritance of genes at a number of loci as an example of continuous variation. In the following task, the students have to determine whether a statement or example represents discontinuous or continuous variation. The final part of the lesson describes a few examples where environmental factors affect phenotype, such as chlorosis in plants.