This lesson describes how the expression of a gene mutation impairs the functioning of the gaseous and digestive systems in people with cystic fibrosis. The detailed PowerPoint and accompanying worksheets have primarily been designed to cover points 2.12 (ii) and 2.14 of the Pearson Edexcel A-level Biology A (Salters Nuffield) specification but also challenges the students on their knowledge of previously-covered topics including monohybrid inheritance, protein synthesis, genetic code and blood clotting as well as making links to the upcoming topics of loci, organisation of multicellular organisms and post-transcriptional changes. The main focus of the lesson is the CFTR gene and the functions of the ion channel that is synthesised when this gene is expressed. As well as explaining that this channel allows chloride ions to flow across the apical membrane of the epithelial cells, time is taken to emphasise the importance of its inhibition on the ENaC, which prevents the flow of sodium ions back into the cells. A step by step guide is then used to describe the sequence of events that result in mucus which is motile and can be moved by the wafting action of the cilia in healthy individuals. This leads into the section of the lesson which considers the inheritance of cystic fibrosis in an autosomal recessive manner and then focuses on the change in the primary structure of the channel which results from one of over 1500 different gene mutations. Again, the students are guided through the events that lead to the depletion of the apical surface liquid and the cilia being unable to move the viscous mucus. Although the majority of the lesson is described with reference to the gaseous exchange system, the impaired functioning of the digestive system in terms of the blockage of the pancreas and liver secretions is considered and discussed and the students are challenged on their understanding through a range of exam-style questions. All of the questions included in the lesson have mark schemes which are embedded into the PowerPoint and this allows the students to assess their progress. Due to the detailed content of this lesson, it is estimated that it will take in excess of 3 hours of allocated A-level teaching time to cover

A considerable amount of time has been taken to design this revision resource so that the included activities engage the students whilst containing sufficient detail to enable them to assess their understanding of the content in topic 9 (Transport in animals) of the CIE IGCSE Biology specification. This resource can be used with those students taking both the 0610 and 0970 specifications and will be examined in June and November 2020 and 2021. This topic contains a lot of key details about the workings of the human body and is therefore likely to be heavily involved in the make up of upcoming examinations. The range of activities include exam questions with answers explained, differentiated tasks and quiz competitions such as “FOUND in the PLASMA” where students have to be the 1st to name the substances that are carried in this liquid and also “Is this passage on the right PATH” where students have to analyse a passage about the pathway of blood to determine if it is 100% correct. The lesson has been written to cover as much content from both the Core and Supplement sections as possible but the following have received particular attention: The functions of the different components of blood The structure of arteries and veins and how this is related to their functions The risk factors and treatments for CHD The structure of the heart and its associated blood vessels The function of the valves found in the heart and veins The double circulatory system

This fully-resourced lesson describes the stages of meiosis and specifically the events which contribute to genetic variation. The detailed PowerPoint and accompanying resources have been designed to cover specification points 2.3 (iv) & (v) of the Edexcel A-level Biology B specification and includes description of crossing over, independent assortment and the production of haploid gametes 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.

This engaging lesson explains why viruses are described as acellular and non-living and describes the structures of virus particles. The PowerPoint and accompanying resource have been designed to cover the second part of specification point 2.1.2 of the AQA A-level Biology specification and also includes details of HIV so that students are prepared for this lesson later in topic 2. Details of the COVID-19 epidemic are included in the lesson to increase relevance and to help students to understand this biological topic in greater depth. They will understand that the lack of cell structures results in an acellular classification and the fact that it is unable to reproduce without a host is one of the additional reasons that renders it as non-living. The main focus of the lesson is the nucleic acid, the capsid and the attachment proteins that are present in these microorganisms and time is taken to explain how these structures are involved in the infection of a host cell. The lipid membrane is also introduced and links are made to the previous lessons on eukaryotic cells. The final section uses a version of BBC 1’s POINTLESS to introduce a number of viral diseases in animals and the use of a glycoprotein by HIV to attach to helper T cells is briefly introduced.

This fully-resourced lesson describes the roles of the T and B lymphocytes in the cellular and humoral responses and the development of immunological memory. The detailed PowerPoint and accompanying resources have been designed to cover the third part of point 2.4 of the AQA A-level Biology specification and the structure of antibodies and the roles of plasma cells and memory cells in the primary and secondary immune responses are also included. Antigen presentation was introduced at the end of the previous lesson so the task at the start of this lesson challenges students to recognise the name of this process and then they have to spot the errors in the passage that describes the details of this event. This reminds them that contact between the APC and T lymphocytes is necessary to elicit a response which they will come to recognise as the cellular response. A series of quick quiz rounds reveals key terms in a memorable way and one that is introduced is helper T cells. Time is then taken to describe the importance of cell signalling for an effective response and students will learn how the release of chemicals by these cells activates other aspects of the response. The role of the killer T cells is also described before an exam-style question is used to check on their understanding at this point of the lesson. This leads into the section of the lesson that deals with the humoral response and students will understand how this involves the antibodies that are produced by the plasma cells that are the result of clonal selection and expansion. The remainder of the lesson focuses on the structure of the antibodies and then explains how the retention of memory B cells after the primary response enables a quicker and more effective secondary response to occur if necessary. Finally, students are challenged with a series of application questions where they have to apply their knowledge to potentially unfamiliar situations.

This fully-resourced lesson describes how the mechanism of natural selection results in changes in a population that are known as adaptations. The PowerPoint and accompanying resources have been designed to cover specification points 4.2.2 (g), (h) and (i) as detailed in the OCR A-level Biology A specification and also considers how antibiotic resistance has implications for human populations. 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 as a reminder 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 which was considered in the previous sub-module. 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 and again current understanding of this topic is tested alongside prior knowledge of 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 2/3 hours of allocated A-level teaching time to deliver this lesson.

This detailed and engaging lesson will support students with their revision in the build up to their PAPER 1 & 2 mocks or final assessments. The wide range of tasks and activities will challenge students on their knowledge of topics 1 - 11 of the CIE A-level biology specification (for assessment in 2025 - 27), allowing them to identify any areas which require further attention before the examinations. Included in the range of tasks are exam-style questions and understanding checks and all answers are embedded into the PowerPoint. There are quiz rounds to maintain engagement and to encourage healthy competition, as well as guided discussion periods to provide opportunities for students to support each other. The following content is directly covered by this revision lesson: The nature of the genetic code The structure of haemoglobin and collagen Fibrous and globular proteins The roles of the heart valves in the cardiac cycle The changes in the quantity of DNA through the mitotic cell cycle The role of DNA polymerase and DNA ligase in DNA replication The behaviour of chromosomes during prophase, metaphase, anaphase and telophase The importance of mitosis for living organisms The bonds formed during translation The structure of starch and cellulose The ultrastructure of eukaryotic cells Calculating the size of an object under an optical microscope Using the image = actual x magnification formula The role of APCs and T helper cells in the immune response Pathogens which cause infectious diseases Many of the tasks have been differentiated to maintain challenge whilst providing access to all. This is an extensive lesson with multiple tasks so it is estimated that it will take over 3 hours of teaching time if covered in full, but teachers may choose to use small sections in shorter lessons to focus on a specific topic.

This detailed and engaging lesson supports students with their revision in the build up to their PAPER 2 mocks or final assessment. The wide range of tasks and activities will challenge students on their knowledge and understanding of the content of topics 1 - 4 and 8 - 10 of the Edexcel A-level biology B specification, allowing them to identify those areas which require further attention before the examinations. Included in the range of tasks are exam-style questions and understanding checks and all answers are embedded into the PowerPoint. As shown in the cover image, there are several quiz rounds to maintain engagement and to encourage healthy competition, as well as guided discussion periods to provide opportunities for students to support each other. The following content is directly covered by this revision lesson: Directional, disruptive and stabilising selection Saltatory conduction The structure of neurones Depolarisation and the initiation of an action potential Hardy-Weinberg principle The Founder effect and population bottlenecks Genetic terminology Codominance Sex linkage and autosomal linkage Chi squared test Myoglobin vs haemoglobin Succession The sympathetic and parasympathetic divisions of the ANS The control of heart rate The functions of the different parts of the brain This is an extensive lesson with many tasks so it is estimated that it will take over 3 hours of teaching time if covered in full, but teachers may choose to use sections to focus on a specific topic. If the students find this lesson useful, there is also a PAPER 1 REVISION lesson uploaded which challenges the content of topics 1 - 7.

This fully-resourced lesson explores the relationship between the structure of arteries, arterioles and veins and their respective functions. The engaging and detailed PowerPoint and accompanying resources have been designed to cover the 6th part of point 3.4.1 of the AQA A-level Biology specification which states that students should be able to describe the structure of these blood vessels in relation to their function. This lesson has been written to build on any prior knowledge from GCSE or earlier in this topic to enable students to fully understand why a particular type of blood vessel has particular features. Students will be able to make the connection between the narrow lumen and elastic tissue in the walls of arteries and the need to maintain the high pressure of the blood. A quick version of the GUESS WHO game is used to introduce smooth muscle and collagen in the tunica media and externa and again the reason for their presence is explored and explained. Moving forwards, the importance of the arterioles as a transition between the artery and capillary is discussed and students will see how the smooth muscle in the walls of this blood vessel allows for the redistribution of blood during exercise. The final part of the lesson considers the structure of the veins and students are challenged to explain how the differences to those observed in arteries is due to the lower blood pressure found in these vessels. It is estimated that it will take about 2 hours of allocated A-level Biology teaching time to cover the detail included in this lesson

This fully-resourced lesson describes the principles and limitations of optical, transmission electron and scanning electron microscopes. The engaging PowerPoint and accompanying resources have been designed to cover the specification details at the start of topic 2.1.3 of the AQA A-level Biology course and also explains the difference between magnification and resolution. When designing all four of the lessons to cover the detail of 2.1.3, I was conscious that microscopes and the methods of studying cells is a topic that doesn’t always attract the full attention of the students. In line with this, I aimed to plan lessons that encouraged engagement so that the likelihood of knowledge retention and understanding was increased. An ongoing quiz competition runs across the 4 lessons and in this particular lesson, rounds such as YOU DO THE MATH and IT’S TIME FOR ACTION will introduce key terms and values in a fun and memorable way. Time is taken to look at the key details of each of the types of microscope and students will be able to describe how light or the transmission of electrons through or across a specimen will form an image. Students will come to recognise the difference between magnification and resolution and examples are provided and exam-style questions used to check on understanding. As well as current understanding checks, prior knowledge checks challenge the students to make links to other biological topics which include specialised cells and tissues, cell structures and biological molecules. As detailed above, this lesson has been written to be the first in a series of 4 lessons and the others, which are uploaded are: Measuring the size of an object viewed under an optical microscope Use of the magnification formula Cell fractionation and ultracentrifugation

This lesson describes the role of plant hormones in stomatal closure, leaf loss in deciduous plants and seed germination. The extensive and detailed PowerPoint and accompanying resources have been planned to cover the content of point b of module 5.1.5 of the OCR A-level biology A specification. The start of the lesson challenges the students to identify three leaf cells in the list of 11 leaf structures. This introduces guard cells and then the opening between them, the stomatal aperture. Time is taken to go through the process by which the apertures are opened to allow carbon dioxide to diffuse into the leaf for photosynthesis. This provides students with an insight into the movement of potassium ions and water when they are challenged about the closure of these openings in response to water stress. Students will meet abscisic acid and understand how this acts as the first messenger, before calcium ions act as the second messenger to trigger events on the inside of the guard cells. Moving forwards, the role of ethene and auxins in leaf loss and gibberellins in seed germination are described and explained. Multiple opportunities are taken to challenge students on their prior knowledge as well as their current understanding and all answers are embedded into the PowerPoint. This lesson is extensive and it is estimated that it will take 2-3 hours of teaching time to go through all of the tasks and content.

This lesson will support students with their revision in the build up to the AQA A-level biology PAPER 1 mocks or final assessments. The lesson includes a wide variety of tasks and activities which will engage and motivate students whilst challenging their knowledge and understanding of the content of topics 1 - 4, allowing them to identify any gaps so they can be addressed before the assessments. These tasks include exam-style questions and understanding checks and all answers are embedded into the PowerPoint. Several of these questions challenge their mathematical skills, to prepare them for the volume of marks that will be assigned to this aspect of the course. There are also quick quiz rounds and guided discussion periods to allow students to support each other, and some of the accompanying resources have been differentiated to allow access to the content for all. The following content is directly covered by this revision lesson: The nature of the genetic code Classification hierarchy The structure of proteins Cardiac output The roles of enzymes in DNA replication The events of meiosis which contribute to genetic variation The relationship between structure and function in plant polysaccharides The structure and function of organelles Cell fractionation Calculating the size of an object under an optical microscope Using the image = actual x magnification formula Types of immunity Understanding whether data is significantly different or not The role of macrophages in the immune response The evolution of antibiotic resistance The lesson finishes with a round of BLOCKBUSTERS, where students are challenged to recognise 17 key terms from across topics 1 - 4, which weren’t directly covered by the earlier part of the lesson. If you are happy with the quality of this revision lesson, a lesson challenging content from topics 5 - 8 for PAPER 2 has also been uploaded.

This detailed lesson has been intricately planned to support student revision in the build up to their PAPER 2 mocks or final assessment. The wide range of tasks and activities will challenge students on their knowledge of topics 1 - 4, 7 & 8 of the Pearson Edexcel A-level biology A specification, allowing them to recognise those areas which require further attention before the examinations. Included in the range of tasks are exam-style questions and understanding checks and all answers are embedded into the PowerPoint. There are quiz rounds to maintain engagement and to encourage healthy competition, as well as guided discussion periods to provide opportunities for students to support each other. The following content is directly covered by this revision lesson: Allopatric and sympatric speciation Saltatory conduction The structure of neurones Depolarisation and the initiation of an action potential Hardy-Weinberg principle Genetic terminology Sex linkage and autosomal linkage Aerobic respiration The lower yield of ATP from anaerobic respiration The sliding filament model of muscle contraction The ultrastructure of skeletal muscle Slow and fast twitch muscle fibres The control of heart rate The functions of the different parts of the brain Calculating cardiac output Gene expression as demonstrated by the lac operon The events of atherosclerosis Epigenetics This is an extensive lesson with many tasks so it is estimated that it will take over 3 hours of teaching time if covered in full, but teachers may choose to use sections to focus on a specific topic.

This fully-resourced lesson explores the effect of geographical and reproductive isolation on the evolution of a new species. The engaging PowerPoint and accompanying resources have been designed to cover point 6.1.2 (g) of the OCR A-level Biology A specification which states that students should be able to demonstrate and apply an understanding of the effect of these isolating mechanisms on the evolution of a new species by either allopatric or sympatric speciation. The lesson begins by using the example of a hinny, which is the hybrid offspring of a horse and a donkey, to challenge students to recall the biological classification of a species. Moving forwards, students are introduced to the idea of speciation and the key components of this process, such as isolation and selection pressures, are covered and discussed in detail. Understanding and prior knowledge checks are included throughout the lesson to allow the students to not only assess their progress against the current topic but also to make links to earlier topics in the specification. Time is taken to look at the details of allopatric speciation and how the different mutations that arise in the isolated populations and genetic drift will lead to genetic changes. The example of allopatric speciation in wrasse fish because of the isthmus of Panama is used to allow the students to visualise this process. The final part of the lesson considers sympatric speciation and again a wide variety of tasks are used to enable a deep understanding to be developed. This lesson has been written to tie in with the other uploaded lessons on topic 6.1.2 (patterns of inheritance).

This fully-resourced lesson covers part #1 of specification point 6.2.1 of the AQA A-level Biology specification which states that students should know the structure of a myelinated motor neurone and be able to explain why saltatory conduction enables a faster conduction along with the effect of axon diameter and temperature. A wide range of activities have been written into this resource to maintain the motivation of the students whilst ensuring that the detail is covered in real depth. Interspersed with the activities are understanding checks and prior knowledge checks to allow the students to not only assess their understanding of the current topic but also challenge themselves to make links to earlier topics such as the movement of ions across membranes and biological molecules. Time at the end of the lesson is also given to future knowledge such as the involvement of autonomic motor neurones in the stimulation of involuntary muscles. Over the course of the lesson, students will learn and discover how the structure of a motor neurone is related to its function over conducting impulses from the CNS to the effector. There is a focus on the myelin sheath and specifically how the insulation is not complete all the way along which leaves gaps known as the nodes of Ranvier which allow the entry and exit of ions. Saltatory conduction is poorly explained by a lot of students so time is taken to look at the way that the action potential jumps between the nodes and this is explained further by reference to local currents. The rest of the lesson focuses on the other two factors which are axon diameter and temperature and students are challenged to discover these two by focusing on the vampire squid. This lesson has been designed for students studying the AQA A-level Biology course

This resource contains a detailed and engaging PowerPoint and accompanying worksheets, all of which have been designed to cover point 2.14 of the Edexcel GCSE Biology or Combined Science specification. This specification point states that students should be able to explain the structure and function of a reflex arc including sensory, relay and motor neurones. The lesson builds on the knowledge from point 2.13 where students learnt about the structures in the nervous system. The lesson begins by challenging the students to come up with the word reflex having been presented with 5 other synonyms of the word automatic. This leads into a section of discovery and discussion where students are encouraged to consider how a reflex arc can be automatic and rapid despite the fact that the impulse is conducted into the CNS like any other reaction. Students will be introduced to the relay neurone and will learn how this provides a communication between the sensory neurone and the motor neurone and therefore means that these arcs do not involve processing by the brain. Moving forwards, the main task of the lesson challenges the students to write a detailed description of a reflex arc. Assistance is given on the critical section which involves the relay neurone in the spinal cord before they have to use their knowledge of nervous reactions to write a paragraph before and after to complete the description. As a final task, students will have to compare the structure and functions of the three neurones. This lesson contains a wide range of activities which include quiz competitions to introduce key terms and values in a fun and memorable way as well as understanding and prior knowledge checks so that students can assess their grasp of the critical content. It has been written for students studying the Edexcel GCSE Biology or Combined Science courses but is also suitable for younger students looking at the nervous system or A-level students who need to recall the key details and structures

This lesson describes the principles of homeostasis and the differences between negative feedback and positive feedback. The PowerPoint and accompanying resources have been designed to cover point 5.1.1 [c] of the OCR A-level Biology A specification and explains how this feedback control maintains systems within narrow limits but has also been planned to provide important details for upcoming topics such as osmoregulation, thermoregulation and the depolarisation of a neurone. The normal ranges for blood glucose concentration, blood pH and body temperature are introduced at the start of the lesson to allow students to recognise that these aspects have to be maintained within narrow limits. A series of exam-style questions then challenge their recall of knowledge from topics 1-8 to explain why it’s important that each of these aspects is maintained within these limits. The students were introduced to homeostasis at GCSE, so this process is revisited and discussed, to ensure that students are able to recall that this is the maintenance of a state of dynamic equilibrium. A quick quiz competition is used to reveal negative feedback as a key term and students will learn how this form of control reverses the original change and biological examples are used to emphasise the importance of this system for restoring levels to the limits (and the optimum). The remainder of the lesson explains how positive feedback differs from negative feedback as it increases the original change and the role of oxytocin in birth and the movement of sodium ions into a neurone are used to exemplify the action of this control system.

This is a fully-resourced REVISION lesson which challenges the students on their knowledge of the content in TOPIC B4 (Natural selection and genetic modification) of the Edexcel GCSE Combined Science specification. The lesson uses an engaging PowerPoint (65 slides) and accompanying worksheets to motivate students whilst they assess their understanding of this topic. A range of exam questions, differentiated tasks and quiz competitions are used to test the following sub-topics: The discovery of key fossils and their implications for human evolution The dating of stone tools Evolution by natural selection Antibiotic resistance in bacteria as evidence for natural selection The domain and kingdom classification methods Genetic engineering of bacteria to produce human insulin The benefits and risks of genetic engineering and selective breeding The mathematical element of the course is also tested throughout the lesson and students are given helpful hints on exam techniques and how to structure answers. This resource is suitable for use at the end of topic B4 or in the lead up to mocks or the actual GCSE exams.

This lesson has been designed to cover the content as detailed in points 2.1, 2.2 and 2.3 (Mitosis as part of the cell cycle) of the Edexcel GCSE Biology & Combined Science specifications. Consisting of a detailed and engaging PowerPoint (44 slides) and an accompanying worksheet, the range of activities will motivate the students whilst ensuring that the content is covered in detail. Students will learn how interphase, the 4 phases of mitosis and cytokinesis result in the production of genetically identical diploid daughter cells. Time is taken to go through each of the three stages of the cell cycle in detail so students can recognise how the key events of each stage allow this important form of “copying” cell division to occur. Progress checks are included throughout the lesson so that students can assess their understanding of the content and any misconceptions can be addressed whilst quiz competitions, like The Big REVEAL and YOU DO THE MATH, are used to introduce new terms and important values in a fun and memorable way. This lesson has been written for GCSE-aged students who are studying the Edexcel GCSE Biology or Combined Science specifications but can be used with older students who need to know the key details of the cell cycle for their A level course before taking it to greater depths

This lesson explains why large organisms with a low surface area to volume ratio need specialised gas exchange surfaces and a mass transport system. The PowerPoint and accompanying worksheets have been designed to cover points 4.1 (i & ii) of the Edexcel A-level Biology B specification and have been specifically planned to prepare students for the upcoming lessons on gas exchange (4.3) and circulation (4.4) 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. The final part of the lesson considers how a mass transport system is needed alongside the specialised gas exchange surface to allow the oxygen to be delivered to the respiring cells to enable them to continue to carry out aerobic respiration to generate ATP.