This lesson describes how the loop of Henle acts as a countercurrent multiplier to increase the reabsorption of water. The PowerPoint and accompanying resource are part of the 2nd lesson in a series of 2 lessons which have been designed to cover point 9.9 (iii) of the Edexcel A-level biology B specification but also considers the structure of the kidney in the kangaroo rat and therefore also covers point 9.9 (v). The lesson begins by challenging the students to recognise that the glomerular filtrate entering the loop will only contain water, ions and urea if the kidneys are functioning properly. Time is then taken to look at the structure of the loop of Henle, focusing on the descending and ascending limbs, and their differing permeabilities. Students will be reminded that this part of the nephron is located in the renal medulla, before a step-by-step guide is used to describe how the transfer of ions, particularly sodium ions, from the ascending limb to the descending limb, creates a very negative water potential in this region of the kidney. This allows water to move out of the descending limb to the tissue fluid and then into the capillaries. The next part of the lesson challenges students to consider the bigger picture as they learn that this decreasing water potential in the medulla allows water to be reabsorbed from the filtrate in the collecting duct too. The remainder of the lesson uses the real-world examples of the hopping mouse and kangaroo rat to check student understanding, and there are also prior knowledge checks to encourage students to make links to relevant content from earlier topics. All answers are embedded into the PowerPoint.

This lesson describes the meaning of excretion, as well as the role of the liver, kidneys, lungs and the skin in the removal of carbon dioxide and urea. The engaging PowerPoint and accompanying resources have been designed to cover point 5.1.2 (a) of the OCR A-level Biology specification and also explains the importance of excretion for homeostasis. The lesson begins by reminding students that excretion is one of the 7 characteristics of living organisms, as introduced within MRS GREN when they were younger. An A-level worthy definition of excretion is then introduced, and time is taken to ensure that students recognise that substances must be products of metabolism to be deemed to be excreted. In line with this, the students are challenged to spot that urea and carbon dioxide need to be excreted whilst faeces is egested. Moving forwards, the role of the liver and then the kidneys in the excretion of urea are described. There is a focus on terminology, specifically prefixes and suffixes, to allow students to understand the meaning of deamination which occurs in the liver. The lesson doesn’t go into huge detail about this process and the subsequent ornithine cycle as these are both covered in an upcoming lesson about the functions of the liver. The transport of carbon dioxide is revisited and prior knowledge checks are used to allow the students to assess their recollection of hydrogen carbonate ions and carbaminohaemoglobin. All answers to these checks as well as any understanding checks are embedded into the PowerPoint. The final part of the lesson explores how the skin is involved in excretion and a link is made to the maintenance of internal conditions within narrow limits by homeostasis.

This lesson describes how an ever decreasing water potential is created in the renal medulla to enable water reabsorption in the loop of Henle and collecting duct. The PowerPoint and accompanying resource are part of the 4th lesson in a series of 5 lessons which have been designed to cover point 6.4.3 (Control of blood water potential) of the AQA A-level biology specification. The lesson begins by challenging the students to recognise that the glomerular filtrate entering the loop will only contain water, ions and urea if the kidneys are functioning properly. Time is then taken to look at the structure of the loop of Henle, focusing on the descending and ascending limbs, and their differing permeabilities. Students will be reminded that this part of the nephron is located in the renal medulla, before a step-by-step guide is used to describe how the transfer of ions, particularly sodium ions, from the ascending limb to the descending limb, creates a very negative water potential in this region of the kidney. This allows water to move out of the descending limb to the tissue fluid and then into the capillaries. The next part of the lesson challenges students to consider the bigger picture as they learn that this decreasing water potential in the medulla allows water to be reabsorbed from the filtrate in the collecting duct too. The remainder of the lesson uses the real-world examples of the hopping mouse and kangaroo rat to check student understanding, and there are also prior knowledge checks to encourage students to make links to relevant content from earlier topics. All answers are embedded into the PowerPoint.

This lesson describes succession as the gradual, progressive changes in a ecosystem, moving from colonisation by the pioneer species to a climax community. The detailed PowerPoint and accompanying resources have been designed to cover point 6.3.1 (d) of the OCR A-level Biology specification, and therefore the lesson also describes deflected succession and the formation of a plagioclimax community. As shown in the cover image, the lesson uses a step by step guide to describe primary succession, introducing the different species at each stage, and explaining the vital roles they each perform. Time is taken to explain how the initial colonisation by algae and lichens as pioneer species is critical to form soil, which wasn’t previously present on the bare ground. The real-world example of Surtsey is used to increase relevance and students will hear about the changes that have occurred on this island over the last 67 years. Understanding checks are included at regular points to allow the students to assess their progress, and prior knowledge checks challenge them to recall content from earlier modules. Answers to all of the checks are embedded in the PowerPoint. The final part of the lesson considers how many ecosystems are prevented from reaching their climax community and this is known as deflected succession. Human influences are explored and again, real examples are used.

This lesson guides students through the stages of the nitrogen cycle, focusing on the vital roles performed by microorganisms in this cycle. The detailed PowerPoint and accompanying resources are part of the 1st lesson in a series of 3 lessons which have been planned to cover point 5.4 (nutrient cycles) of the AQA A-level biology specification. The lesson begins by challenging students to recall two monomers containing nitrogen that were met in topic 1, allowing them to recognise that this chemical element is a key component of nucleotides in DNA and amino acids, which are needed to synthesise proteins. Moving forwards, they will learn that despite the high % of nitrogen in the Earth’s atmosphere, it cannot be used directly by plants, and therefore plants need a supply of “fixed” nitrogen. A diagram is constantly updated and displayed as new information is introduced and this supports their understanding. The students will discover that microorganisms are involved in nitrogen fixation, decomposition and ammonification, nitrification, and denitrification. As each of these biological actions is introduced, time is spent considering key details and understanding checks are used to allow the students to assess their progress. There are also several prior knowledge checks, where students are encouraged to make links to content met in topics 1 - 4. Answers to all questions are embedded into the PowerPoint.

This lesson describes the pathway by which the translation of mRNA into proteins can be prevented by siRNA and miRNA molecules. The engaging and detailed PowerPoint and accompanying resources are part of the final lesson in a series of 4 lessons that cover the detail of point 8.2.2 of the AQA A-level biology specification. The lesson begins with an exisiting knowledge check, as the students are challenged to recognise the processes of DNA methylation and histone acetylation, before RNA interference is introduced as another way by which gene expression is controlled in eukaryotes. Moving forwards, a quick quiz round introduces small interfering RNA (siRNA) and students will learn how this double-stranded, non-coding RNA is normally just 21 base pairs long. A step by step guide then describes the action of siRNA in preventing translation, through the cutting of the target mRNA into fragments which are then degraded. Time is taken to consider the possible application of siRNA molecules in the treatment of HIV and then cystic fibrosis, and the latter involves a series of exam-style questions which challenge the students on their understanding of this topic as well as the recall of content from the other 7 AQA topics. The remainder of the lesson focuses on microRNA (miRNA) and students will understand how this molecule is produced and how its action differs to that of siRNA in mammalian cells.

This lesson describes how only part of a cell’s DNA is translated and explains how the potency of a stem cell determines its ability to specialise. The engaging and detailed PowerPoint and accompanying resources have been planned to cover all of the content in point 8.2.1 of the AQA A-level biology specification. The lesson begins by challenging the students to recall any existing knowledge of stem cells, to check that they remember that these cells differentiate, before the concept of cell potency is introduced to allow them to recognise that not all cells can differentiate into the same amount of cell types. A quick quiz is used to introduce pluripotency, unipotency, totipotency and multipotency before they are challenged to use their understanding of language to order these along the potency continuum. Beginning with totipotency, time is taken to go through details of each of these cell types, including where these cells are located. During the section of the lesson considering pluripotency, induced pluripotent stem cells are discussed and their potential for use in regenerative medicine is explored. Understanding checks through exam-based questions are embedded throughout the lesson (as well as the answers) to allow students to assess their current understanding and to address any gaps immediately. There are also prior knowledge checks so students can link to other topics from the specification and there is a maths in biology question so their mathematical skills are challenged in line with that element of the course.

This detailed lesson describes the processes of PCR and electrophoresis to allow students to understand how gene sequencing can be used. The engaging PowerPoint and accompanying resource have been planned to cover the content of point 7.1 of the Edexcel A-level biology B specification. The lesson begins by comparing the number of genes in the genome with the number of base pairs, to allow students to learn that the bases in the genes only accounts for about 1.5% of the genome. This challenges them to recall that most is non-coding DNA, and the importance and usefulness of these sections are explored during the lesson. Moving forward, a step-by-step guide describes the key steps in the polymerase chain reaction, and time is taken at each step to qualify the fine details such as the use of Taq polymerase instead of human DNA polymerase. The remainder of the lesson focuses on the various uses of these DNA samples once they’ve been amplified by the PCR. The steps of the electrophoresis process are described and students will see how DNA profiling can be used in forensic science to identify criminals and for paternity tests. Understanding and prior knowledge checks are found throughout the lesson, along with the answers, to allow students to assess their grasp of the current topic as well as their ability to identify the links with previously covered topics.

This fully-resourced lesson looks at the structures that make up the gross anatomy of the heart and also covers the calculation of cardiac ouput. The engaging and detailed PowerPoint and accompanying resources have been designed to cover the 4th part of point 3.4.1 of the AQA A-level Biology specification which states that students should be able to describe the gross structure of the human heart and be able to use the equation stroke volume x heart rate to calculate cardiac output. As this topic was covered at GCSE, the lesson has been planned to build on this prior knowledge whilst adding the key details which will enable students to provide A-level standard answers. The primary focus is the identification of the different structures of the heart but it also challenges their ability to recognise the important relationship to function. For example, time is taken to ensure that students can explain why the atrial walls are thinner than the ventricular walls and why the right ventricle has a thinner wall than the left ventricle. Opportunities are taken throughout the lesson to link this topic to the others found in topic 3.4.1 such as blood circulation and the cardiac cycle. Moving forwards, the students are introduced to the stroke volume and meet normative values for this and for resting heart rate. This will lead into the calculation for cardiac output and a series of questions are used to test their ability to apply this equation as well as percentage change.

A fully resourced revision lesson which uses a range of exam questions (with explained answers), quick tasks and quiz competitions to enable the students to assess their understanding of the topics found within module 4 (Biodiversity, evolution and disease) of the OCR A-level Biology specification. The topics tested within this lesson include: Communicable diseases, biodiversity, classification and evolution Student will enjoy the range of tasks and quiz rounds whilst crucially being able to recognise any areas which require further attention

An engaging lesson presentation (81 slides) and associated worksheets that uses a combination of exam questions, quick tasks and quiz competitions to help the students to assess their understanding of the topics found within Topic 7 (Animal coordination and homeostasis) of the EDEXCEL GCSE Biology specification The topics that are tested within the lesson include: The endocrine system Thyroxine The menstrual cycle Hormonal and barrier methods of contraception Homeostasis Thermoregulation Osmoregulation Control of blood glucose concentration DIabetes Students will be engaged through the numerous activities including quiz rounds like “Have they got the right BALANCE?" and the “B7 ABBREVIATIONS” whilst crucially being able to recognise those areas which need further attention

An engaging lesson presentation (75 slides) and associated worksheets that uses a combination of exam questions, quick tasks and quiz competitions to help the students to assess their understanding of the topics found within unit B7(Ecology) of the AQA GCSE Biology specification (specification unit B4.7). The topics that are tested within the lesson include: Communities Abiotic factors Biotic factors Levels of organisation Recycling materials Decomposition Deforestation Global warming Trophic levels Pyramids of biomass Transfer of biomass Students will be engaged through the numerous activities including quiz rounds like “Number CRAZY" whilst crucially being able to recognise those areas which need further attention

This fully-resourced lesson focuses on the events of meiosis which specifically contribute to genetic variation. The detailed PowerPoint and accompanying resources have been designed to cover the 4th and final part of point 4.3 of the AQA A-level Biology specification which states that students should be able to describe how meiosis produces daughter cells that are genetically different from each other. In order to understand how the events of meiosis like crossing over and random assortment and independent segregation can lead to variation, students need to be clear in their understanding that DNA replication in interphase results in homologous chromosomes as pairs of sister chromatids. Therefore the beginning of the lesson focuses on the chromosomes in the parent cell and this first part of the cycle and students will be introduced to non-sister chromatids and the fact that they may contain different alleles which is important for the exchange that occurs during crossing over. Time is taken to go through this event in prophase I in a step by step guide so that the students can recognise that the result can be new combinations of alleles that were not present in the parent cell. Moving forwards, the lesson explores how the independent segregation of chromosomes and chromatids during anaphase I and II results in genetically different gametes. The final part of the lesson looks at the use of a mathematical expression to calculate the possible combinations of alleles in gametes as well as in a zygote following the random fertilisation of haploid gametes. Understanding and prior knowledge checks are interspersed throughout the lesson as well as a series of exam questions which challenge the students to apply their knowledge to potentially unfamiliar situations. Due to the detail of this lesson, it is estimated that this will take about 2 hours of A-level teaching time to deliver

This is a highly detailed and engaging lesson that covers the detail of the 2nd part of specification point 6.2.1 of the AQA A-level Biology specification which states that students should be able to describe the establishment of resting potential, the changes in membrane potential that lead to depolarisation and the importance of the refractory period. This topic is commonly assessed in the terminal exams so a lot of time has been taken to design this resource to include a wide range of activities that motivate the students whilst ensuring that the content is covered in the depth of detail that will allow them to have a real understanding. Interspersed within the activities are understanding checks and prior knowledge checks to enable the students to not only assess their progress against the current topic but also to challenge themselves on the links to earlier topics such as methods of movements across cell membranes and saltatory conduction. There are also a number of quiz competitions which are used to introduce key terms and values in a fun and memorable way and discussion points to encourage the students to consider why a particular process or mechanism occurs. Over the course of the lesson, the students will learn and discover how the movement of ions across the membrane causes the membrane potential to change. They will see how the resting potential is maintained through the use of the sodium/potassium pump and potassium ion leakage. There is a real focus on depolarisation to allow students to understand how generator potentials can combine and if the resulting depolarisation then exceeds the threshold potential, a full depolarisation will occur. At this point in the lesson students will discover how the all or nothing response explains that action potentials have the same magnitude and that instead a stronger stimulus is linked to an increase in the frequency of the transmission. The rest of the lesson challenges the students to apply their knowledge to explain how repolarisation and hyperpolarisation result and to suggest advantages of the refractory period for nerve cells. This lesson has been designed for students studying the AQA A-level Biology course and ties in nicely with other uploaded lessons on mammalian sensory receptors and the structures and functions of the neurones.

This fully-resourced lesson is highly detailed and in combination with the uploaded lesson on the causes of diabetes type I and II, it covers all of specification point 6.4.2 of the AQA A-level Biology specification which states that students should be able to describe the homeostatic control of blood glucose concentration using negative feedback mechanisms that release insulin or glucagon. A wide range of activities will maintain motivation and engagement whilst the content is covered in detail to enable the students to explain how the receptors in the pancreas detect the concentration change and how the hormones attaching to receptor sites on the liver triggers a series of events in this effector organ. This is a topic which has a huge amount of difficult terminology so time is taken to look at all of the key words, especially those which begin with the letter G so students are able to use them accurately in the correct context. The action of adrenaline is also considered and linked to the breakdown of glycogen to glucose during glycogenolysis. This lesson has been written for students studying on the AQA A-level Biology course and ties in with the already mentioned lesson on diabetes but also with the other uploaded lessons on topic 6 such as nerve impulses and kidney function

This fully-resourced lesson describes how the structure of the xylem tissue allows water to be transported in the stem and leaves. Written for AQA A-level Biology, the engaging and detailed PowerPoint and the accompanying worksheets cover the 1st part of specification point 3.4.2 (mass transport in plants) and includes a detailed description of the cohesion-tension theory. The first part of the lesson focuses on the relationship between the structure and function of the xylem tissue. A number of quiz competitions have been included in the lesson to maintain engagement and to introduce key terms. The 1st round does just that and results in the introduction of lignin which leads into the explanation of how the impregnation of this substance in the cell walls result in the death and subsequent decay of the cell structures. Students are encouraged to discuss how the formation of this hollow tube enables the transport of water to be effective. Moving forwards, other structures such as the bordered pits are introduced and an understanding of their function is tested later in the lesson. The remainder of the lesson focuses on the transport of water in the stem and leaves by root pressure and the transpiration pull, which includes cohesion, tension and adhesion. The lesson has been designed to make links to information covered earlier in the lesson as well to topics from earlier in the specification such as cell structures and biological molecules Due to the extensiveness of this lesson, it is estimated that it will take in excess of 2/3 A-level teaching hours to cover the detail included in this lesson.

This lesson describes how the primary structure determines the secondary structure, 3D structure and properties of a protein. The detailed and engaging PowerPoint and accompanying resources have been designed to cover points 2.6 (ii) & (iii) of the Edexcel International A-level Biology specification but also makes specific reference to genes and protein synthesis and therefore introduces students to processes covered later in topic 2. The start of the lesson focuses on the formation of a peptide bond during a condensation reaction so that students can understand how a dipeptide is formed and therefore how a polypeptide forms when multiple reactions occur. The main part of the lesson describes the different levels of protein structure. A step by step guide is used to demonstrate how the sequences of bases in a gene acts as a template to form a sequence of codons on a mRNA strand and how this is translated into a particular sequence of amino acids known as the primary structure. The students are then challenged to apply their understanding of this process by using three more gene sequences to work out three primary structures and recognise how different genes lead to different sequences. Moving forwards, students will learn how the order of amino acids in the primary structure determines the shape of the protein molecule, through its secondary, tertiary and quaternary structure and time is taken to consider the details of each of these. There is a particular focus on the different bonds that hold the 3D shape firmly in place and a quick quiz round then introduces the importance of this shape as exemplified by enzymes, antibodies and hormones. The lesson concludes with one final task where the students have to identify three errors in a passage about the hydrolysis of a dipeptide or polypeptide.