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 structure of the mammalian liver, focusing on the blood vessels and bile canaliculi, as well as the hepatocytes. The PowerPoint and accompanying resources are part of the 1st lesson in a series of 2 lessons which cover point 5.1.2 (b) of the OCR A-level biology A specification. As shown on the cover image, the lesson begins with a challenge, where the students have to recognise that the liver is supplied with oxygenated blood by the hepatic artery. Three editions of the quiz “SAY WHAT YOU SEE” are used to introduce three key terms in an engaging and memorable fashion which are hepatic portal vein, sinusoids, and bile canaliculi. Following the introduction of the hepatic portal vein and sinusoids, the students will understand that the liver is supplied by two vessels and that the blood mixes in the sinusoids. Time is then taken to focus on the hepatocytes, through 3 exam-style questions that consider the type of epithelium these liver cells are found in, the microvilli on their surface and the organelles which are abundant based on function. Moving forwards, the lesson discusses the function of the stellate cells that are found in the space of Disse, before a task challenges their recall of content from a previous lesson to reveal the name of the cells that move within the sinusoids, the Kupffer cells. Students will learn that these macrophages breakdown the haemoglobin in old erythrocytes to form bilirubin. This reminds them that liver cells produce bile and the remainder of the lesson discusses how this fluid flows along the bile canaliculi to the ductules which form the common hepatic duct. The 2nd lesson in this 2-part series describes the functions of the mammalian liver.

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 the structure, actions and function of the loop of Henle in the kidney is pivotal in the production of urine. The PowerPoint and accompanying resource are part of a series of 4 lessons which have been designed to cover point 5.1.2 [c] of the OCR A-level biology A specification, which is titled "the structure, mechanisms of action and functions of the mammalian kidney. 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 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 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 how the movement of growth factors regulates growth in response to directional stimuli, focusing on gravitropism and phototropism. The PowerPoint and accompanying resources are part of the 1st lesson in a series of 3, which have been designed to cover point 6.1.1 (Survival and response) of the AQA A-level biology specification. The lesson begins with a prior knowledge check, where the students have to identify key terms encountered in topics 1 - 4, and use their 1st letters to form the term, stimuli. Students are reminded of the meaning of a stimulus, and this introduces the need for organisms to detect and respond to stimuli, to increase their chances of survival. This lesson focuses on these responses in flowering plants, and builds on any knowledge they may have gained at GCSE. They should have met auxins at this previous level, but will now be introduced to IAA, and will complete several tasks which check that they understand the key features of these chemicals, such as their location of production and method by which they move through the shoots and roots. The students are guided through the movement of IAA to the shaded side in a shoot during phototropism, and will learn how this uneven distribution leads to uneven growth. An exam-style question presents them with two further scenarios, where the tip of the shoot has been cut off or is covered, and the students need to describe and explain what will happen to the appearance of the shoot after a week. Moving forwards, the students will learn how the pumping of hydrogen ions into the cell wall and the activation of expansin proteins are involved in the cell elongation. The remainder of the lesson discusses the response to gravity and explains how shoots and roots respond differently. The lesson is full of understanding and prior knowledge checks and all answers are embedded into the PowerPoint. The other two lessons in this series of 3 covering 6.1.1 describe taxes and kineses and the protective effect of a simple reflex.

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 main characteristics of benign and malignant tumours. The PowerPoint and accompanying resource are part of the 1st lesson in a series of 2 lessons which have been planned to cover the content of point 8.2.3 of the AQA A-level biology specification. This lesson begins by challenging the students to recognise the process of mitosis from a single clue. This single clue is “a controlled process” and has been designed to remind them that mitosis is a process controlled by genes. A quick quiz round challenges their recall of the details of the mitotic cell cycle to reveal the key term, tumour, and this introduces the idea that a mutation to one of the genes leads to uncontrolled cell division and the formation of tumours. Moving forwards, the lesson considers the features of benign tumours, beginning with the key point that these masses of cells are not cancerous. Students will learn that their growth rate is slower than malignant tumours, and due to a covering of fibrous connective tissue, the cells do not invade neighbouring tissues. However, the lesson points out that due to mass effect, benign tumours can cause secondary pathological effects such as organ damage. This leads into a task where the students are challenged on their knowledge of osmoregulation, digestion and blood glucose regulation to identify the tissues which are impacted. The rest of the lesson describes the features of malignant tumours and time is spent considering how the ability of these cells to metastasise makes them so dangerous.

This lesson explains how labelled DNA probes can be used to screen patients for heritable conditions, their responses to drugs and to identify health risks. The PowerPoint and accompanying resources have been designed to cover the content of point 8.4.2 of the AQA A-level biology specification. The lesson begins by introducing the BRCA genes, and the students will learn how faulty alleles of these two genes can increase an individual’s risk of developing breast cancer. Therefore, there is a need to be able to locate specific alleles like these, and this function is performed by DNA probes. The students are challenged to use the function of the probes to predict their structure and will understand that they are short lengths of single stranded DNA that have a base sequence complementary to the base sequence of part of the target allele. As shown in the cover image, a quick quiz round is used to introduce hybridisation as key term, to ensure that students recognise that the probe will bind if the complementary base sequence is encountered. Moving forwards, a DNA microarray is introduced to show that it’s possible to screen for multiple genes. The remainder of the lesson considers how the DNA probes are used to screen for heritable conditions and drug responses, and real-life examples are used to increase relevance. Prior knowledge checks are embedded throughout the lesson to encourage the students to make links to content from earlier topics including inheritance and genetic drift.

This revision lesson uses a multiple-choice assessment to challenge the students on their understanding of topic 8, the control of gene expression. In addition to the 20 question assessment, this lesson includes a PowerPoint where the answers are revealed and additional questions are posed about the content of topic 8 which isn’t directly challenged in the questions. The PowerPoint also contains prior knowledge checks on content from topics 1, 3, 4 and 6. Revision lessons of this format which challenge topics 1 - 7 are also uploaded.

This revision lesson provides students with the opportunity to assess their understanding of the transport in mammals topic (topic 8). The lesson includes a multiple-choice assessment of 10 questions and a PowerPoint containing the answers, where each answer slide shows the exact specification code to enable students to note the areas which may require extra attention. The PowerPoint also contains additional questions to challenge content from topic 8 of the CIE A-level biology specification (2025 - 2027 update) that isn’t directly covered by the 10 questions. This lesson has been designed to be used at the end of topic 8, and in the build up to mocks and the final A-level examinations.

This revision lesson provides students with the opportunity to assess their understanding of energy transfers in and between organisms (topic 5). The lesson includes a multiple-choice assessment of 20 questions, challenging photosynthesis, respiration, energy and ecosystems, and nutrient cycles, and a PowerPoint containing the answers, where each answer slide shows the exact specification code to enable students to note the areas which may require extra attention. The PowerPoint also contains additional questions to challenge content from topic 5 of the AQA A-level biology specification that isn’t directly covered by the 20 questions, and prior knowledge checks to encourage students to make links to related content from topics 1 - 4. This lesson has been designed to be used at the end of topic 5, and in the build up to mocks and the final A-level examinations.