This lesson describes the nervous pathways of a range of reflex actions, including spinal reflex arcs and a cranial reflex, and their survival value is explored. The PowerPoint and accompanying resources have been planned to cover the content of point 5.1.5 (i) of the OCR A-level biology A specification. The lesson begins with a challenge, where the students have to spot the connections between 3 groups of 3 terms, and this will introduce different neurones, muscle tissues and reflexes for reference throughout. There are prior knowledge checks throughout the lesson, and one is immediately used to check on the students’ knowledge of the functions of the different structures in a nervous pathway and the order they are involved. The spinal reflex after an individual presses on a sharp pin is used to check that they can apply their knowledge to a real biological example. At this point, the potential for a reflex to be overridden if an unmyelinated relay neurone is involved is introduced and this is explained in detail later in the lesson. The knee jerk reflex is then discussed and students will understand that this is the choice for a reflex test because of the direct communication between the sensory and motor neurone. The final part of the lesson describes the corneal reflex as a cranial reflex and students will learn how it can be inhibited through conscious control by the higher part of the brain, as happens when an individual puts contact lenses on.

This fully-resourced lesson describes the inheritance of genes with loci on the X chromosomes and considers biological examples. The detailed PowerPoint and accompanying resources have been designed to cover point 2.15 (ii) of the Edexcel International A-level specification and focuses on the inheritance of red-green colour blindness and haemophilia in humans 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. 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 task of the lesson challenge the students to apply their knowledge to an exam 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 mark schemes to allow them to assess their progress and address any misconceptions

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 the structure of DNA as a double-stranded polymer coiled into a double helix and focuses on nucleotides as the monomers. The PowerPoint and accompanying resources have been designed to cover the detail of point 3.4 of the Edexcel GCSE Biology & Combined Science specifications. The lesson begins with a reveal of the acronym DNA and students will learn that this stands for deoxyribonucleic acid. There is a focus on the use and understanding of key terminology throughout the lesson so time is taken to look at the meanings of the prefixes poly and mono as well as the suffix -mer. This leads into the description of DNA as a polymer which is made up of many monomers known as nucleotides. Students will be introduced to the three components of a DNA nucleotide and will learn that four different bases can be attached to the sugar. An observational task is used to get them to recognise that DNA consists of two strands and that complementary bases are joined by hydrogen bonds. Understanding checks are interspersed throughout the lesson along with mark schemes so that students can assess their progress

A detailed lesson presentation (37 slides) and associated worksheets that looks at the different pieces of evidence that scientists use to support evolution and discusses how these support the theory. The lesson begins by challenging students to decide which piece of evidence is the key piece in supporting evolution (fossils). Students will then have to arrange a number of statements to describe how a fossil is formed. Students are introduced to the fossil record and questions are used to check that they understand where the oldest fossils would be found. Moving forwards, students are given three pieces of evidence that would be observed in the fossil record and they are challenged to explain how each of these supports the theory of evolution. Quick competitions are then used to get the students to see some extinct organisms in the Dodo and Woolly Mammoth and again they are questioned on how extinct animals support the theory of evolution. Further evidence in rapid changes in species and molecular comparison is discussed. There are regular progress checks throughout the lesson so that students can assess their understanding and there is a set homework included.

This is a highly-detailed and fully-resourced lesson which covers the detail of specification point 5.1.2 (d) of the OCR A-level Biology A specification which states that students should be able to demonstrate and apply an understanding of the roles of the hypothalamus, posterior pituitary, ADH and the collecting duct in the control of the water potential of the blood. Students learnt about the principles of homeostasis and negative feedback in an earlier module, so this lesson acts to build on that knowledge and challenges them to apply their knowledge. A wide range of activities have been included in the lesson to maintain motivation and engagement whilst the understanding and prior knowledge checks will allow the students to assess their progress as well as challenge themselves to make links to other Biology topics. The lesson begins with a discussion about how the percentage of water in urine can and will change depending on the blood water potential. Students will quickly be introduced to osmoregulation and they will learn that the osmoreceptors and the osmoregulatory centre are found in the hypothalamus. A considerable amount of time is taken to study the cell signalling between the hypothalamus and the posterior pituitary gland by looking at the specialised neurones (neurosecretory cells). Links are made to the topics of neurones, nerve impulses and synapses and the students are challenged to recall the cell body, axon and vesicles. The main section of the lesson forms a detailed description of the body’s detection and response to a low blood water potential. The students are guided through this section as they are given 2 or 3 options for each stage and they have to use their knowledge to select the correct statement. The final task asks the students to write a detailed description for the opposite stimulus and this task is differentiated so those who need extra assistance can still access the work. This lesson has been written for students studying on the OCR A-level Biology A course and ties in nicely with the other uploaded lessons in module 5.1.2 which include the structure of the nephron, ultrafiltration and selective reabsorption.

This lesson uses the example of the genetic engineering of bacteria to produce insulin to walk students through the steps involved in this process. It has been written for GCSE students and therefore includes the detail required at this level, such as the involvement of restriction enzymes and the sticky ends that their cut produces. The lesson begins by challenging students to recognise that insulin is being described by a series of clues. Some further details of this hormone are recalled to test their previous knowledge of the endocrine system and also to lead into the genetic engineering of bacteria to make this protein. Moving forwards, time is taken to go through the details of plasmids and how they act as vectors as well as the enzymes, restriction and ligase. The main task of the lesson uses a series of descriptions to go through the steps involved in the process. Words or phrases are missing from each description so students have to use the terms they’ve encountered in this lesson as well as their prior knowledge to complete the step. Discussion-provoking questions are added to encourage the students to consider why certain parts of the process occur. The lesson concludes by the consideration of other organisms which have been genetically engineered as well as some of the risks of the process, which students are asked to complete for homework. As detailed above, this lesson has been designed for GCSE students but could be used with students taking A-level Biology, who are struggling to understand the detail found at this level and need to revisit the foundations.

This engaging lesson covers the final details of specification point 6.4.2 of the AQA A-level Biology specification which states that students should be able to describe the causes and control of diabetes mellitus type I and II. The lesson has been designed to take place in a diabetes clinic where students will be challenged to perform a number of roles such as diagnosing a patient with either type I or II and to write a letter to this patient explaining how the disease was caused and any treatments that will be recommended to control the disease. It has been planned to build on the knowledge that they will have of these diseases from GCSE and links are made to other A-level topics such as the beta cells of the pancreas which they considered during the lesson on the control of blood glucose concentration. This lesson has been designed for students taking the AQA A-level Biology course and runs alongside the uploaded lesson on the control of blood glucose concentration as well as the other lessons that have been added on topic 6

This lesson describes how epigenetic changes like DNA methylation and histone modification can modify the activation of certain genes. The PowerPoint and accompanying resources have been planned to cover points 3.14 ii & iii of the Pearson Edexcel A-level biology (Salters-Nuffield) specification. The lesson begins by introducing the prefix epi- as meaning on or above in Greek to allow students to recognise that epigenetics refers to changes in gene function due to factors beyond the genetic code. Moving forwards, they will learn that DNA methylation involves the attachment of a methyl group to cytosine and will come to understand how this inhibits transcription. They are challenged to recognise the pathogenesis of atherosclerosis through a variety of tasks before reading through a source detailing the results of a study between this cardiovascular condition and DNA methylation. The remainder of the lesson considers how the acetylation of histone proteins affects the expression of genes. Understanding and prior knowledge checks are embedded throughout the lesson (along with the answers) to allow the students to assess their progress on this topic and to encourage them to make links to the content of topics 1 - 2.

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 fully-resourced lesson looks at the structure of genes and explores their role as a base sequence on DNA that codes for the amino acid sequence of a polypeptide. Both the PowerPoint and accompanying resource have been designed to cover the second part of point 4.1 of the AQA A-level Biology specification and has been written to specifically tie in with the previous lesson on DNA in prokaryotes and eukaryotes. The lesson begins with a prior knowledge check as the students have to recognise the key term chromosome from a description involving DNA and histones. This allows genes, as sections of a chromosome, to be introduced and the first of a number of quiz rounds is then used to get the students to meet the term locus so that they can understand how each gene has a specific location on a chromosome. Whenever possible, opportunities are taken to make links to the other parts of the AQA specification and this is utilised here as students are reminded that alternative versions of a gene (alleles) can be found at the locus. Moving forwards, students will learn that 3 DNA bases is a triplet and that each triplet codes for a specific amino acid. At this point, the genetic code is introduced and students are challenged to explain how the code contains 64 different triplets. By comparing this number against the number of different amino acids in proteins, students will see how each amino acid is encoded for by more than one triplet and how this explains the degenerate nature of the genetic code. Again, an opportunity is taken to link to gene mutations. Finally, the students are told that most of the nuclear DNA in a eukaryote doesn’t code for a polypetptide and that even within a gene, there are coding and non-coding regions known as exons and introns respectively. The last section of the lesson uses a quiz round to check on all of the key terms which have been met in the two lessons on DNA, genes and chromosomes.

This lesson describes how Fick’s law of diffusion is governed by the three main properties of gas exchange surfaces in living organisms. The PowerPoint and accompanying worksheets have been designed to cover points 2.1 (i & ii) of the Edexcel International A-level Biology specification and there is a particular focus on the relationship between the size of an organism or structure and its surface to volume ratio. Adolf Fick is briefly introduced at the start of the lesson and the students will learn that his law of diffusion governs the diffusion of a gas across a membrane and is dependent on three properties. The students are likely to know that surface area is one of these properties but although they may have been introduced to the surface area to volume ratio at iGCSE, their understanding of its relevance tends to be mixed. Therefore, real life examples are included throughout the lesson that emphasise the importance of this ratio in order to increase the relevance. A lot of students worry about the maths calculations that are associated with this topic so a step by step guide is included at the start of the lesson to walk them through the calculation of the surface area, the volume and then the ratio. Through worked examples and understanding checks, SA/V ratios are calculated for cubes of increasing side length and living organisms of different size. These comparative values will enable the students to conclude that the larger the organism or structure, the lower the surface area to volume ratio. A differentiated task is then used to challenge the students to explain the relationship between the ratio and the metabolic demands of an organism and this leads into the next part of the lesson, where the adaptations of a human to increase the ratio at the gas exchange surface is covered. The students will calculate the SA/V ratio of a human alveolus (using the surface area and volume formulae for a sphere) and will see the significant increase that results from the folding of the membranes. The remainder of the lesson introduces concentration difference and thickness of membrane as the other two properties in Fick’s law of diffusion and students are reminded that the maintenance of a steep concentration gradient and a reduction in the diffusion distance are critical for this transport mechanism. This lesson has been specifically planned to prepare students for the next lesson which describes how the structure of the mammalian lung is adapted for rapid gas exchange (specification point 2.1 [iii])

This lesson describes how the structure of the mammalian lung is adapted for rapid gaseous exchange. The engaging PowerPoint has been designed to cover point 2.1 (iii) of the Edexcel International A-level Biology specification and focuses on the essential features of the alveolar epithelium as well as the mechanism of ventilation to maintain a steep concentration gradient for the simple diffusion of oxygen and carbon dioxide. Gas exchange at the alveoli is a topic that was covered at GCSE and considered during the previous lessons in topic 2.1 so this lesson has been written to challenge the recall of that knowledge and to build on it. The main focus of the first half of the lesson 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. The following features of the alveolar epithelium are also covered: Surface area Moist lining Production of surfactant The maintenance of a steep concentration gradient is the role of the respiratory system and the next part of the lesson focuses on the diaphragm and intercostal muscles. As the mechanism of inhalation is a cascade of events, the details of this process are covered in a step by step format using bullet points. At each step, time is taken to discuss the key details which includes an introduction to Boyle’s law that reveals the inverse relationship between volume and pressure. It is crucial that students are able to describe how the actions of the diaphragm, external intercostal muscles and ribcage result in an increased volume of the thoracic cavity and a subsequent decrease in the pressure, which is below the pressure outside of the body. At this point, their recall of the structures of the mammalian gas exchange system is tested, to ensure that they can describe the pathway the air takes on moving into the lungs.