A Science teacher by trade, I've also been known to be found teaching Maths and PE! However, strange as it may seem, my real love is designing resources that can be used by other teachers to maximise the experience of the students. I am constantly thinking of new ways to engage a student with a topic and try to implement that in the design of the lessons.
A Science teacher by trade, I've also been known to be found teaching Maths and PE! However, strange as it may seem, my real love is designing resources that can be used by other teachers to maximise the experience of the students. I am constantly thinking of new ways to engage a student with a topic and try to implement that in the design of the lessons.
This fully-resourced lesson describes the effects of enzyme and substrate concentration on enzyme activity. The PowerPoint and accompanying resources are the third in a series of 3 lessons which cover the details of point 2.1.4 (d) [i] of the OCR A-level Biology A specification and students are also challenged on their recall of the details of transcription and translation as covered in module 2.1.3.
The first part of the lesson describes how an increase in substrate concentration will affect the rate of reaction when a fixed concentration of enzyme is used. Time is taken to introduce limiting factors and students will be challenged to identify substrate concentration as the limiting factor before the maximum rate is attained and then they are given discussion time to identify the possible factors after this point. A series of exam-style questions are used throughout the lesson and the mark schemes are displayed to allow the students to assess their understanding and for any misconceptions to be immediately addressed. Moving forwards, the students have to use their knowledge of substrate concentration to construct a graph to represent the relationship between enzyme concentration and rate of reaction and they have to explain the different sections of the graph and identify the limiting factors.
The final section of the lesson describes how the availability of enzymes is controlled in living organisms. Students will come to recognise that this availability is the result of enzyme synthesis and enzyme degradation and a SPOT THE ERRORS task is used to challenge their recall of protein synthesis.
Please note that this lesson explains the Biology behind the effect of concentration on enzyme activity and not the methodology involved in carrying out such an investigation as this is covered in the lessons designed in line with point 2.1.4 (d) [ii]
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
Normally the first topic to be taught in the second year of the AQA A-level Biology course, topic 5 contains some very important biological processes which include photosynthesis, respiration and energy transfer between organisms. All of the 13 lessons that are included in this bundle are highly detailed and have been planned at length to ensure that students remain motivated and engaged whilst being constantly challenged on their current understanding. Links to previously-covered topics are also made throughout the lessons.
The following specification points are covered in these lessons:
TOPIC 5.1
The light-dependent reaction of photosynthesis
The use of reduced NADP and ATP from the light-dependent reaction in the light-independent reaction
The light-independent reaction of photosynthesis
Environmental factors that limit the rate of photosynthesis
TOPIC 5.2
Respiration produces ATP
Glycolysis as the first stage of aerobic and anaerobic respiration
The conversion of pyruvate to lactate or ethanol in the anaerobic pathways
The link reaction and the Krebs cycle
Synthesis of ATP by oxidative phosphorylation
Other respiratory substrates
TOPIC 5.3
Gross primary production and net primary production
The net production of consumers
Farming practices designed to increase the efficiency of energy transfer
If you would like to sample the quality of the lessons in this bundle, then download the chloroplast structure, anaerobic respiration, oxidative phosphorylation and GPP lessons as these have been uploaded for free
It’s fair to say that cell structure and biological molecules are two of the most important topics in the OCR A-level Biology A course and all 19 lessons that are included in this bundle have been planned at length to cover the module 2.1.1 & 2.1.2 specification points in the detail required at this level.
The lesson PowerPoints and their accompanying resources contain a wide range of tasks as well as regular checks to allow students to assess their understanding of the current content as well as prior knowledge checks to emphasise the importance of making links to topics in other modules.
The following specification points in modules 2.1.1 (cell structure) and 2.1.2 (biological molecules) are covered by the lessons in this bundle:
2.1.1
The use of microscopy to observe and investigate different types of cell and cell structure in a range of eukaryotic organisms
The use of the eyepiece graticule and stage micrometer
The use of staining in light microscopy
The use and manipulation of the magnification formula
The difference between magnification and resolution
The ultrastructure of eukaryotic cells and the functions of the different cellular components
The interrelationship between the organelles involved in the production and secretion of proteins
The importance of the cytoskeleton
The similarities and differences between the ultrastructure of prokaryotic and eukaryotic cells
2.1.2
The properties and roles of water in living organisms
The concept of monomers and polymers and the importance of condensation and hydrolysis reactions
The chemical elements that make up biological molecules
The structure and properties of glucose and ribose
The synthesis and breakdown of a disaccharide and a polysaccharide by the formation and breakage of glycosidic bonds
The structure of starch, glycogen and cellulose molecules
The relationship between the structure, function and roles of triglycerides, phospholipids and cholesterol in living organisms
The general structure of an amino acid
The synthesis and breakdown of dipeptides and polypeptides
The levels of protein structure
The structure and function of globular proteins
The properties and functions of fibrous proteins
The key inorganic ions involved in biological processes
The chemical tests for proteins, reducing and non-reducing sugars, starch and lipids
If you would like to sample the quality of the lessons included in this bundle, then download the following lessons as they have been uploaded for free:
The use of microscopy
The importance of the cytoskeleton
Properties and roles of water
Glucose & ribose
General structure of an amino acid
Dipeptides, polypeptides and protein structure
This lesson describes how an interaction of muscles, tendons, the skeleton and ligaments is needed for movement of the human body. The PowerPoint and accompanying resources have been designed to cover point 7.9 of the Edexcel International A-level Biology specification and also includes descriptions of antagonistic muscle pairs, extensors and flexors.
At the start of the lesson, the prep room skeleton is used as the example to show that bones without muscles are bones that are unable to move (unaided). Moving forwards, the students will learn that skeletal muscles are attached to bones by bundles of collagen fibres known as tendons and as they covered the relationship between the structure and function of collagen in topic 2, a task is used that challenges their recall of these details. This will allow them to recognise that the ability of this fibrous protein to withstand tension is important for the transmission of the force from the muscle to pull on the moveable bone. A series of quick quiz competitions introduce the key terms of flexion and antagonistic and then an exam-style question challenges them to recognise the structures involved in extension at the elbow. The remainder of the lesson focuses on the role of ligaments and one final example of extension at the knee joint will demonstrate how the interaction of all of the structures met over the course of the lesson is needed for movement
This lesson describes how muscles, tendons, the skeleton and ligaments interact to enable movement. The PowerPoint and accompanying resources have been designed to cover point 7.1 of the Pearson Edexcel A-level Biology A (Salters Nuffield) specification and also includes descriptions of antagonistic muscle pairs, extensors and flexors.
At the start of the lesson, the prep room skeleton is used as the example to show that bones without muscles are bones that are unable to move (unaided). Moving forwards, the students will learn that skeletal muscles are attached to bones by bundles of collagen fibres known as tendons and as they covered the relationship between the structure and function of collagen in topic 2, a task is used that challenges their recall of these details. This will allow them to recognise that the ability of this fibrous protein to withstand tension is important for the transmission of the force from the muscle to pull on the moveable bone. A series of quick quiz competitions introduce the key terms of flexion and antagonistic and then an exam-style question challenges them to recognise the structures involved in extension at the elbow. The remainder of the lesson focuses on the role of ligaments and one final example of extension at the knee joint will demonstrate how the interaction of all of the structures met over the course of the lesson is needed for movement
This lesson bundle contains 11 detailed lesson PowerPoints, which along with their accompanying resources, have been intricately planned to cover the majority of the content of topics 5 and 6 of the CIE A-level Biology specification. The cell cycle, mitosis and protein synthesis are topics that students tend to find difficult and therefore the planning focused on the inclusion of a wide range of tasks that would not only promote the retention of important information and secure knowledge but also maintain motivation and engagement.
The tasks include exam-style questions with displayed mark schemes which challenge the students on their current understanding and prior knowledge, guided discussion points and quick quiz competitions which introduce key terms and values.
The following specification points are covered by these 11 lessons:
Topic 5
The structure of a chromosome, limited to DNA, histone proteins, chromatids, centromere and telomere
The importance of mitosis in producing genetically identical cells, growth, cell replacement, repair of tissues and asexual reproduction
The cell cycle, including theh G and S phases of interphase, mitosis and cytokinesis
The behaviour of chromosomes in animal and plant cells in the mitotic cell cycle
Topic 6
The structure of nucleotides, including ATP
The structure of DNA and RNA
The semi-conservative replication of DNA during interphase
A polypeptide is coded for by a gene
Gene mutations can cause changes to the polypeptide sequence
The information in DNA is used during transcription and translation to construct polypeptides
This lesson describes how to use the Spearman’s rank correlation coefficient to consider the relationship between two sets of data. The PowerPoint and accompanying exam-style question are part of the final lesson in a series of 3 which have been designed to cover point 4.2.2 (f) of the OCR A-level Biology A specification. The previous two lessons described the different types of variation and explained how to calculate the standard deviation and how to use the Student’s t-test to compare two means.
As with the previous lesson, a step by step guide is used to walk the students through the use of the formula to generate the rank coefficient and to determine whether there is a positive correlation, no correlation or a negative correlation. The students are also reminded of the null hypothesis and will be shown how to accept or reject this hypothesis and to determine significance. The students will work through an example with the class and then are given the opportunity to apply their newly-acquired knowledge to an exam-style question. The mark scheme is displayed on the PowerPoint so they can assess their understanding
Photosynthesis and respiration are two of the most commonly assessed topics in A-level exams but are often poorly understood by students. These 9 lessons have been intricately planned to contain a wide range of activities that will engage and motivate the students whilst covering the key detail to try to deepen their understanding and includes exam-style questions so they are fully prepared for these assessments.
The following specification points in topics 5 and 7 of the Pearson Edexcel A-level Biology A (Salters Nuffield) specification are covered by these lessons:
Understand the overall reaction of photosynthesis
Understand the light-dependent reactions of photosynthesis including the role of these electrons in generating ATP, reducing NADP in photophosphorylation and producing oxygen through photolysis of water
Understand the light-independent reactions as reduction of carbon dioxide using the products of the light-dependent reactions
Know that the products are simple sugars that are used by plants, animals and other organisms in respiration and the synthesis of new biological molecules
Understand the structure of chloroplasts in relation to their role in photosynthesis
Understand the overall reaction of aerobic respiration
Understand that respiration is a many-stepped process with each step controlled and catalysed by a specific intracellular enzyme
Understand the roles of glycolysis in aerobic and anaerobic respiration
Understand the role of the link reaction and the Krebs cycle in the complete oxidation of glucose and formation of carbon dioxide, ATP, reduced NAD and reduced FAD
Understand how ATP is synthesised by oxidative phosphorylation
Understand what happens to lactate after a period of anaerobic respiration in animals
If you would like to sample the quality of the lessons in this bundle then download the light independent reactions, the link reaction and Krebs cycle and the fate of lactate lessons as these have been shared for free
This lesson explains the need for specialised exchange surfaces and uses examples to describe the features of an efficient exchange surface. The PowerPoint and accompanying worksheets have been designed to cover points 3.1.1 (a & b) of the OCR A-level Biology A specification and also have been specifically planned to prepare the students for the upcoming lessons in module 3 on gas exchange and mass transport in animals.
The students are likely to have been introduced to the surface area to volume ratio at GCSE, but 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 this 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 that walks 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 a single-celled and multicellular organisms and this leads into the next part of the lesson, where the adaptations of large organisms to increase this ratio at the exchange surfaces are 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. In addition to the ratio, time is taken to discuss and describe how the maintenance of a steep concentration gradient and a thin membrane are important for the rate of diffusion and again biological examples are used in humans and other organisms to increase the understanding. Fick’s law of diffusion is also introduced as a mechanism to help the students to recall that surface area, concentration difference and thickness of membrane govern the rate of simple diffusion.
As well as making links to upcoming topics, prior knowledge checks are used to challenge the students on their knowledge of previously-covered modules which include inorganic ions, organelles, cell membrane transport and tissues.
This lesson describes the gross structure of the human gas exchange system, including the trachea, bronchi, bronchioles and lungs. The PowerPoint and accompanying resources are part of the third lesson in a series of 6 which have been designed to cover the detail of topic 3.2 in the AQA A-level Biology specification which is titled gas exchange and this lesson has been specifically planned to prepare students for the next lesson where the essential features of the alveoli are described.
The lesson is filled with a range of activities such as guided discussion periods, exam-style questions (with markschemes) and quiz competitions and these run alongside the slides containing the detailed A-level Biology content to cover the following features:
The incomplete rings of cartilage, ciliated pseudostratified columnar epithelium and goblet cells in the trachea
The narrowing airways of the primary, secondary and tertiary bronchi
The elastic fibres and smooth muscle in the terminal and respiratory bronchioles
The pleural cavity and fluid of the lungs
When describing the production of mucus by the goblet cells in the trachea, time is taken to consider cystic fibrosis and the inheritance of this autosomal recessive disorder. Students will be supported in working out genotypes from a pedigree tree to prepare them for the topic of inheritance (7.1)
This lesson describes how biodiversity is generated through natural selection and leads to behavioural, anatomical and physiological adaptations. The PowerPoint and accompanying resources have been designed to cover specification points (m) & (n) in AS unit 2, topic 1 of the WJEC A-level Biology specification
President Trump’s error ridden speech about antibiotics is used at the beginning of the lesson to remind students that this is a treatment for bacterial infections and not viruses as he stated. Moving forwards, 2 quick quiz competitions are used to introduce MRSA and then to get the students to recognise that they can use this abbreviation to remind them to use mutation, reproduce, selection (and survive) and allele in their descriptions of evolution through natural selection. The main task of the lesson challenges the students to form a description that explains how this strain of bacteria developed resistance to methicillin to enable them to see the principles of natural selection. This can then be used when describing how the anatomy of the modern-day giraffe has evolved over time. The concept of convergent evolution is introduced and links are made to the need for modern classification techniques as covered earlier in topic 1. Moving forwards, students will understand how natural selection leads to adaptations and a quick quiz competition introduces the different types of adaptation and a series of tasks are used to ensure that the students can distinguish between anatomical, behavioural and physiological adaptations. The Marram grass is used to test their understanding further, before a step by step guide describes how the lignified cells prevent a loss of turgidity. Moving forwards, the students are challenged to explain how the other adaptations of this grass help it to survive in its environment. A series of exam-style questions on the Mangrove family will challenge them to make links to other topics such as osmosis and the mark schemes are displayed to allow them to assess their understanding. The final part of the lesson focuses on the adaptations of the anteater but this time links back to the topic of taxonomy and students have to answer questions about species and classification hierarchy.
Due to the extensiveness of this lesson and the detail contained within the resources, it is estimated that it will take in excess of 2 hours of allocated A-level teaching time to deliver this lesson.
This lesson explains the meaning of biodiversity and describes how it can be assessed in a habitat, in a species level at a genetic level and at a molecular level. The engaging PowerPoint and accompanying resources have been designed to cover points (h-l) in AS unit 2, topic 1 of the WJEC A-level Biology specification but as a lot of genetic content is covered when considering diversity within a species, this lesson can be used as an introduction to the upcoming topics of inheritance
A quiz competition called BIOLOGICAL TERMINOLOGY SNAP runs over the course of the lesson and this will engage the students whilst challenging them to recognise key terms from their definitions. This quiz introduces biodiversity, loci, allele and recessive and each of these terms is put into context once introduced. Once biodiversity has been revealed, the students will learn that they are expected to be able to assess the biodiversity within a habitat and within a species and at a molecular level.
The variety of alleles in the gene pool of a population increases the genetic diversity so a number of examples are used to demonstrate how the number of phenotypes increases with the number of alleles at a locus. The CFTR gene is used 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).
Moving forwards, a step by step guide to complete a worked example to calculate a value of D using Simpson’s index of diversity. Students are challenged with a range of exam-style questions where they have to apply their knowledge and all mark schemes are displayed and clearly explained within the PowerPoint to allow students to assess their understanding and address any misconceptions if they arise.
The final part of the lesson considers how DNA fingerprinting can be used to assess biodiversity at a molecular level and again a series of exam-style questions are used to challenge the students to apply their newly-acquired knowledge to an unfamiliar situation.
This lesson evaluates the methods used by zoos and seed banks in the conservation of endangered species. The PowerPoint and accompanying resources have been primarily designed to cover point 4.16 of the Pearson Edexcel A-level Biology A (Salters Nuffield) specification but as this is potentially the last lesson in this topic, lots of questions and activities have been included that will challenge the students on their knowledge of topic 4 (Biodiversity and Natural Resources).
Hours of research went into the planning of this lesson to source interesting examples to increase the relevance of the biological content and although the main focus of the lesson is the two ex situ conservation methods, the lesson begins with a consideration of the importance of the in situ methods that are used in the Lake Télé Community reserve in the Republic of Congo and the marine conservation zone in the waters surrounding Tristan da Cunha. Students will learn how this form of active management conserves habitats and species in their natural environment, with the aim of minimising human impact whilst maintaining biodiversity.
To enrich their understanding of ex situ conservation, the well-known examples of ZSL London zoo, Kew Gardens and the Millennium Seed Bank Project in Wakehurst are used. Students will understand how conserving animal species outside of their natural habitat allows for human intervention that ensures the animals are fed and given medical assistance when needed as well as reproductive assistance to increase the likelihood of the successful breeding of endangered species. An emphasis is placed on the desire to reintroduce the species into the wild and the example of some initial successes with the mountain chicken frog in Dominica and Montserrat is discussed. As stated in the specification point, these methods must be evaluated and therefore the issues are also considered and there is a focus on the susceptibility of captive populations to diseases as a result of their limited genetic diversity. The final part of the lesson considers how seed banks can be used to ensure that plant species, which may contain the molecules for medicine development, avoid extinction, and how the plants can be bred asexually to increase plant populations quickly.
Due to the extensiveness of this lesson, it is estimated that it will take in excess of 2/3 hours of allocated A-level teaching time to cover the tasks and content included in the lesson and as explained above, it can also be used as revision of topic 4 content
This lesson explains that autosomal linkage results from the presence of alleles on the same chromosome and uses biological examples to demonstrate this concept. The PowerPoint and accompanying worksheets have been designed to cover point 8.2 (iv) of the Edexcel A-level Biology B specification and supports students in the formation of their descriptions of how these results of these crosses can be explained by the events of meiosis (crossing over)
This is a difficult topic which can be poorly understood by students so extra time was taken during the planning to split the concept into small chunks. There is a clear focus on using the number of parent phenotypes and recombinants in the offspring as a way to determine linkage and suggest how the loci of the two genes compare. Important links to other topics such as crossing over in meiosis are made to enable students to understand how the random formation of the point of contact (chiasma) determines whether new phenotypes will be seen in the offspring or not. Linkage is an important cause of variation and the difference between observed and expected results and this is emphasised on a number of occasions and a link to the chi squared test which is covered in an upcoming lesson is also made. The main task of the lesson act as understanding check where students are challenged to analyse the results of genetic crosses involving the inheritance of the ABO blood group gene and the nail-patella syndrome gene n humans and also the inheritance of body colour and wing length in Drosophila.
This lesson explains the difference between non-infectious and infectious diseases and names the pathogens that cause examples of the latter. The PowerPoint and accompanying worksheets have been primarily designed to cover points 10.1 (a & b) of the CIE A-level Biology specification but as this is the first lesson in topic 10, links to upcoming topics such as the immune response and vaccinations are introduced.
The lesson begins with a challenge where the students have to use descriptions to recognise CHD, HIV and TB as diseases that are commonly referred to by their abbreviations. This leads into a description of the meaning of disease before the students are challenged to use any prior knowledge of this topic to recognise that CHD is an examples of a non-infectious disease whereas HIV and TB are examples of infectious diseases. Specification point 10.1 (a) states that students should know about sickle cell anaemia and lung cancer so the next section of the lesson focuses on the key details of these diseases and when considering the former, their knowledge of gene mutations, protein synthesis and haemoglobin is tested.
viruses - HIV/AIDS, influenza, measles, smallpox
bacteria - TB, cholera,
protoctista - malaria
The infectious diseases shown above are covered by the remainder of this lesson and the differing mechanisms of action of these three types of pathogens are discussed and considered throughout. For example, time is taken to describe how HIV uses a glycoprotein to attach to T helper cells whilst toxins released by bacteria damage the host tissue and the Plasmodium parasite is transmitted from one host to another by a vector to cause malaria.
The accompanying worksheets contain a range of exam-style questions, including a mathematical calculation, and mark schemes are embedded into the PowerPoint to allow students to immediately assess their understanding.
This bundle of 7 lessons covers the majority of the content in Topic B1 (Key concepts in Biology) of the Edexcel GCSE Combined Science specification. The topics covered within these lessons include:
Animal cells
Plant cells
Bacterial cells
Specialised cells
Changes in microscopic technology
Number, size and scale
The relationship between quantitative units
Enzyme properties and action
Enzyme activity
Osmosis
Active transport
All of these lesson presentations and accompanying resources are detailed and engaging and contain regular progress checks to allow the students to constantly assess their understanding.
This engaging lesson describes how chromosome mutations result in changes to the number or structure of chromosomes and focuses on Downs and Turner’s syndrome. The PowerPoint and accompanying resources have been designed to cover specification points 2.3 (vi) and (vii) as detailed in the Edexcel A-level Biology B specification.
A human karyotype which has not been altered by a mutation is studied at the start of the lesson to allow students to recall the usual number of chromosomes as well as the sex chromosomes. They are then challenged to identify the differences when presented with the karyotypes of sufferers of Downs, Turner’s and Klinefelter’s syndrome. Students will learn that in the majority of cases, these conditions are the result of non-disjunction and having been assisted in the explanation of the outcome for Downs and Klinefelters, they have to form their own for Turner’s. The remainder of the lesson looks at other types of mutations, including translocation, and students will also see how whole sets of chromosomes can be duplicated in polyploidy.
This lesson guides students through the use of the chi-squared test to determine the significance of the difference between observed and expected results. It is fully-resourced with a detailed PowerPoint and differentiated worksheets that have been designed to cover point 8.2 (vi) of the Edexcel A-level Biology B specification
The lesson includes a step-by-step guide to demonstrates how to carry out the test in small sections. At each step, time is taken to explain any parts which could cause confusion and helpful hints are provided to increase the likelihood of success in exam questions on this topic. Students will understand how to use the phenotypic ratio to calculate the expected numbers and then how to find the critical value in order to compare it against the chi-squared value. A worked example is used to show the working which will be required to access the marks and then the main task challenges the students to apply their knowledge to a series of questions of increasing difficulty.
This is the final lesson of topic 8.2 (transfer of genetic information) and links are made throughout the lesson to earlier parts of this topic such as dihybrid inheritance as well as to earlier topics like meiosis
This detailed lesson describes how changes in ventilation rate are brought about to allow for the delivery of oxygen and the removal of carbon dioxide. The engaging PowerPoint and accompanying resources have been designed to cover the second part of point 7.9 (ii) in the Pearson Edexcel A-level Biology A specification.
The previous lesson described the control of heart rate so this lesson has been written to tie in with this and to use this knowledge to further the students understanding of the control of ventilation rate. The lesson begins with a focus on the muscles involved in ventilation, specifically the diaphragm and external intercostal muscles, so that students can understand how their contraction results in an increase in the volume of the thoracic cavity. Boyle’s law is briefly introduced to allow students to recognise the relationship between volume and pressure so that the movement of air with the pressure gradient can be described. Time is then taken to consider the importance of inhalation and an exam-style question challenges the students to explain that a constant supply of oxygen to the alveoli is needed to maintain a steep concentration gradient with the surrounding capillaries. The students are then tasked with writing a description of exhalation at rest using the description of inhalation as their guide. The rest of the lesson focuses on the mechanisms involved in increasing the rate and depth of breathing during exercise. Students will use their knowledge of the control of heart rate to recall that chemoreceptors detect changes in oxygen and carbon dioxide and blood pH and that the medulla oblongata processes the sensory information that it receives before coordinating a response. The final task challenges them to use the information provided in this lesson and the previous one to order 10 detailed descriptions so they can form a complete passage about this control system.
