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 lesson bundle contains 16 lessons which have been designed to cover the Pearson Edexcel A-level Biology A (Salters Nuffield) specification points which focus on the structure of DNA and RNA, their roles in replication and protein synthesis, and genetics and inheritance. The lesson PowerPoints are highly detailed, and along with their accompanying worksheets, they have been planned at length to contain a wide range of engaging tasks which cover the following A-level Biology content found in topics 2, 3 and 6 of the course:
2.5 (i): Know the basic structure of mononucleotides (deoxyribose or ribose linked to a phosphate and a base, including thymine, uracil, cytosine, adenine or guanine) and the structures of DNA and RNA (polynucleotides composed of mononucleotides linked through condensation reactions)
2.5 (ii): Know how complementary base pairing and the hydrogen bonding between two complementary strands are involved in the formation of the DNA double helix
2.6 (i): Understand the process of protein synthesis (transcription) including the role of RNA polymerase, translation, messenger RNA, transfer RNA, ribosomes and the role of start and stop codons
2.6 (ii): Understand the roles of the DNA template (antisense) strand in transcription, codons on messenger RNA and anticodons on transfer RNA
2.7: Understand the nature of the genetic code
2.8: Know that a gene is a sequence of bases on a DNA molecule that codes for a sequence of amino acids in a polypeptide chain
2.11 (i): Understand the process of DNA replication, including the role of DNA polymerase
2.12 (i): Understand how errors in DNA replication can give rise to mutations
2.12 (ii): Understand how cystic fibrosis results from one of a number of possible gene mutations
2.13 (i): Know the meaning of the terms: gene, allele, genotype, phenotype, recessive, dominant, incomplete dominance, homozygote and heterozygote
2.13 (ii): Understand patterns of inheritance, including the interpretation of genetic pedigree diagrams, in the context of monohybrid inheritance
2.14: Understand how the expression of a gene mutation in people with cystic fibrosis impairs the functioning of the gaseous exchange, digestive and reproductive systems
2.15 (i): Understand the uses of genetic screening, including the identification of carriers, pre-implantation genetic diagnosis (PGD) and prenatal testing, including amniocentesis and chorionic villus sampling
2.15 (ii): Understand the implications of prenatal genetic screening
3.8 (i): The loci is a location of genes on a chromosome
3.8 (ii): The linkage of genes on a chromosome and sex linkage
3.12: Understand how cells become specialised through differential gene expression, producing active mRNA leading to synthesis of proteins, which in turn control cell processes or determine cell structure in animals and plants, including the lac operon
3.14 (i): Phenotype is an interaction between genotype and the environment
3.15: Understand how some phenotypes are affected by multiple alleles for the same gene at many loci (polygenic inheritance) as well as the environment and how this can give rise to phenotypes that show continuous variation
6.4: Know how DNA can be amplified using the polymerase chain reaction (PCR)
6.10: Understand how one gene can give rise to more than one protein through posttranscriptional changes to messenger RNA (mRNA).
This lesson bundle contains 9 lessons which have been designed to cover the Edexcel International A-level Biology specification points which focus on the structure and function of the biological molecules, including water, carbohydrates, lipids and proteins. The lesson PowerPoints are highly detailed, and along with their accompanying worksheets, they have been planned at length to contain a wide range of engaging tasks which cover the following A-level Biology content that’s found in topics 1, 2 and 4 of the course:
1.1: Understand the importance of water as a solvent in transport, including its dipole nature
1.2 (i): Know the difference between monosaccharides, disaccharides and polysaccharides, including glycogen and starch (amylose and amylopectin)
1.2 (ii): Be able to relate the structures of monosaccharides, disaccharides and polysaccharides to their roles in providing and storing energy
1.4: Know how monosaccharides join to form disaccharides (sucrose, lactose and maltose) and polysaccharides (glycogen and amylose) through condensation reactions forming glycosidic bonds, and how these can be split through hydrolysis reactions
1.5 (i): Know how a triglyceride is synthesised by the formation of ester bonds
during condensation reactions between glycerol and three fatty acids.
1.5 (ii): Know the differences between saturated and unsaturated lipids
2.6 (i): Know the basic structure of an amino acid
2.6 (ii): Understand the formation of polypeptides and proteins (amino acid
monomers linked by peptide bonds in condensation reactions)
2.6 (iii): Understand the significance of a protein’s primary structure in determining its three-dimensional structure and properties (globular and fibrous proteins and the types of bonds involved in its three-dimensional structure)
4.3: Understand the structure and function of the polysaccharides starch and
cellulose, including the role of hydrogen bonds between β-glucose molecules in
the formation of cellulose microfibrils
This lesson describes and discusses the different methods of protecting endangered species. The engaging PowerPoint and accompanying worksheets have been designed to cover point 18.3 [c] of the CIE A-level Biology specification and the methods described include zoos, botanic gardens, national parks, marine conservation zones and seed banks
Hours of research has gone into the planning of this lesson to source interesting examples that increase the relevance of the biological content concerning in situ conservation, and these include the Lizard National Nature Reserve in Cornwall, 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. The main issues surrounding this method are discussed, including the fact that the impact of this conservation may not be significant if the population has lost much of its genetic diversity and that despite the management, the conditions that caused the species to become endangered may still be present. A number of quick quiz competitions are interspersed throughout the lesson to introduce key terms and values in a fun and memorable way and one of these challenges them to use their knowledge of famous scientists to reveal the surname, Fossey. Dian Fossey was an American conservationist and her years of study of the mountain gorillas is briefly discussed along with the issue that wildlife reserves can draw poachers and tourists to the area, potentially disturbing the natural habitat.
To enrich their understanding of ex situ conservation, the better 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 enables 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. As with the in situ method, the disadvantages are also discussed 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 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 that is included in the lesson.
This lesson describes the inheritance of two non-interacting unlinked genes and guides students through the calculation of phenotypic ratios. The PowerPoint and the accompanying question sheet (which is differentiated) have been designed to cover point 8.2 (iii) of the Edexcel A-level Biology B specification.
As the previous lesson described the construction of genetic crosses and pedigree diagrams, students are aware of the methods involved in writing genotypes and gametes for the inheritance of a single gene. Therefore, the start of this lesson builds on this understanding to ensure that students recognise that genotypes contain 4 alleles and gametes contain 2 alleles when two genes are inherited. The students are taken through the steps of a worked example to demonstrate the key steps in the calculation of a phenotypic ratio before 2 exam-style questions challenge them to apply their newly-acquired knowledge. Mark schemes are displayed within the PowerPoint to allow students to assess their progress. The phenotypic ratio generated as the answer to the final question is 9:3:3:1 and time is taken to explain that this is the expected ratio when two heterozygotes for two genes are crossed which they may be expected to use when meeting the chi squared test in an upcoming lesson
Each of the 3 lessons in this bundle have been planned extensively to ensure that they contain lots of engaging biological examples that will catch the interest of the students whilst covering the difficult content of topic 18.3 (Conservation) of the CIE A-level Biology specification. The lesson PowerPoints and accompanying worksheets are filled with a wide range of tasks that include guided discussion periods, exam-style questions (with mark schemes) and quick quiz competitions and these combine to cover the following specification points:
The reasons for the need to maintain biodiversity
Methods of protecting endangered species, including the roles of zoos, botanic gardens, national parks, marine conservation zones and seed banks
The roles of non-governmental organisations such as WWF and CITES in local and global conservation
If you would like to view the detailed content of this bundle, then download the “WWF, CITES and conservation” lesson as this has been uploaded for free
The 4 lessons contained within this bundle are detailed and will engage the students whilst covering the following content in topic 11.1 of the CIE A-level Biology specification:
State that phagocytes have their origin in bone marrow and describe their mode of action
Describe the modes of action of B-lymphocytes and T-lymphocytes
Explain the meaning of the term immune response, making reference to the terms antigen, self and non-self
Explain the role of memory cells in long-term immunity
Explain, with reference to myasthenia gravis, that the immune system sometimes fails to distinguish between self and non-self
The PowerPoints and accompanying resources contain a wide range of tasks, which include exam-style questions, guided discussion periods and quiz competitions, and these have been designed to check on the students’ understanding of the current topic as well as previously-covered topics
This lesson describes self and non-self antigens and how a failure to distinguish between the two is the mechanism of autoimmune diseases. The PowerPoint and accompanying worksheets have been primarily designed to cover points 11.1 (d & f) of the CIE A-level Biology specification and describe examples of these diseases including myasthenia gravis, but this lesson can also be used to revise the content of the earlier topics as well as the previous lessons in topic 10 & 11 through the range of activities that are included
The first part of the lesson focuses on the antigens and explains how the failure of the immune system cells to recognise these molecules on the outside of a cell or organism elicits an immune response. Moving forwards, the students are challenged to recognise diseases from descriptions and then to use the first letters of their names to form the term, autoimmune. In doing so, the students will discover that rheumatoid arthritis, ulcerative colitis, type I diabetes mellitus, multiple sclerosis and myasthenia gravis are all examples of autoimmune diseases. The next part of the lesson focuses on the mechanism of these diseases where the immune system cells do not recognise the antigens (self-antigens) on the outside of the healthy cells, and therefore treats them as foreign antigens, resulting in the production of autoantibodies against proteins on these healthy cells and tissues. Key details of the autoimmune diseases stated above and lupus are described and links to previously covered topics as well as to future topics such as the pancreas and nervous system are made. The students will be challenged by the numerous exam-style questions, all of which have mark schemes embedded into the PowerPoint to allow for immediate assessment of progress.
This lesson describes the structure and function of synapses in nerve impulse transmission and focuses on acetylcholine as a neurotransmitter. The PowerPoint and accompanying resources have been designed to cover point 8.6 (i) of the Edexcel International A-level Biology specification, using a cholinergic synapse as the main example
The lesson begins by using a version of the WALL from “Only Connect” which asks the students to group 12 words into three groups of 4. Not only will this challenge their prior knowledge from topics earlier in this topic but it will also lead to the discovery of four of the structures that are found in a synapse. Moving forwards, students are introduced to acetylcholine as the neurotransmitter involved at cholinergic synapses and they will start to add labels to the structures found in the pre-synaptic bulb. Time is taken to focus on certain structures such as the voltage gated channels as these types of channel were met previously when looking at the depolarisation of a neurone. There is plenty of challenge and discovery as students are pushed to explain why organelles like mitochondria would be found in large numbers in the bulb. With this process being a cascade of events, a bullet point format is used to ensure that the key content is taken in by the students and again key points like exocytosis and the action of acetylcholinesterase are discussed further.
Understanding checks and prior knowledge checks are included throughout the lesson so that students can not only assess their progress against the current topic but also see whether they can make links to earlier topics.
This detailed lesson describes how recombinant DNA is produced using restriction endonucleases and DNA ligase and is inserted into other cells. The engaging PowerPoint and accompanying resources have been designed to cover points 8.18 & 8.19 of the Edexcel International A-level Biology specification.
The lesson begins with a definition of genetic engineering and recombinant DNA to allow students to begin to understand how this process involves the transfer of DNA fragments from one species to another. Links are made to the genetic code and transcription and translation mechanisms, which were met in topic 2, in order to explain how the transferred gene can be translated in the transgenic organism. Moving forwards, the method involving reverse transcriptase and DNA polymerase is introduced and their knowledge of the structure of the polynucleotides and the roles of enzymes is challenged through questions and discussion points. Restriction endonucleases are then introduced and time is taken to look at the structure of a restriction site as well as the production of sticky ends due to the staggered cut on the DNA. A series of exam-style questions with displayed mark schemes are used to allow the students to assess their current understanding.
The second half of the lesson looks at the culture of transformed host cells as an in vivo method to amplify DNA fragments. Students will learn that bacterial cells are the most commonly transformed cells so the next task challenges their recall of the structures of these cells so that plasmid DNA can be examined from that point onwards.
Time is taken to explore the finer details of each step such as the addition of the promoter and terminator regions, use of the same restriction enzyme to cut the plasmid as was used to cut the gene and the different types of marker genes.
As well as understanding and prior knowledge checks, quick quiz competitions are used throughout the lesson to introduce key terms such as cDNA and EcoR1 in a fun and hopefully memorable way
This lesson explains how a nerve impulse (action potential) is conducted along an axon and focuses on the role of the sodium and potassium ions. The PowerPoint and accompanying resources have been designed to cover point 8.4 of the Edexcel International A-level Biology specification and contains detailed descriptions of resting potential, depolarisation, repolarisation, hyperpolarisation and the refractory period.
This topic is commonly assessed in the terminal exams so extensive planning ensures that this resource includes a wide range of activities to motivate and engage the students whilst ensuring that the content is covered in the depth of detail that will allow them to have a real understanding. Interspersed within the activities are understanding checks and prior knowledge checks to enable the students to not only assess their progress against the current topic but also to challenge themselves on the links to earlier topics such as methods of movements across cell membranes. There are also a number of quiz competitions which are used to introduce key terms and values in a fun and memorable way and discussion points to encourage the students to consider why a particular process or mechanism occurs.
Over the course of the lesson, the students will learn and discover how the movement of ions across the membrane causes the membrane potential to change. They will see how the resting potential is maintained through the use of the sodium/potassium pump and potassium ion leakage. There is a real focus on depolarisation to allow students to understand how generator potentials can combine and if the resulting depolarisation then exceeds the threshold potential, a full depolarisation will occur. At this point in the lesson students will discover how the all or nothing response explains that action potentials have the same magnitude and that instead a stronger stimulus is linked to an increase in the frequency of the transmission. The rest of the lesson challenges the students to apply their knowledge to explain how repolarisation and hyperpolarisation result and to suggest advantages of the refractory period for nerve cells.
This lesson describes the main stages of meiosis and has a specific focus on those events which contribute to genetic variation. The detailed PowerPoint and accompanying resources have been designed to cover point (d) in topic 6 of AS unit 1 of the WJEC A-level Biology specification and includes description of crossing over, independent assortment, independent segregation and the production of haploid gametes
In order to understand how the events of meiosis like crossing over and independent 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 assortment and segregation of chromosomes and chromatids during metaphase I and II and anaphase I and II respectively results in genetically different gametes. The key events of all of the 8 phases are described and there is a focus on key terminology to ensure that students are able to describe genetic structures in the correct context. 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-style questions which challenge the students to apply their knowledge to potentially unfamiliar situations.
This lesson has been specifically planned to lead on from the previous two lessons on the cell cycle and the main stages of mitosis and constant references are made throughout to encourage students to make links and also to highlight the differences between the two types of nuclear division
This lesson describes how tissue fluid is formed and reabsorbed in order to emphasise its importance as the link between the blood and cells. The PowerPoint and accompanying resources have been designed to cover point (h) in topic 3 of AS unit 2 of the WJEC A-level Biology specification and explains how a combination of the effects of hydrostatic pressure and oncotic pressure results in the formation of tissue fluid in animals.
The lesson begins with an introduction to the arteriole and venule end of a capillary as these will need to be considered as separate entities when describing the formation of tissue fluid. A quick quiz competition introduces a value for the hydrostatic pressure at the arteriole end and students are challenged to first predict some parts of the blood will move out of the capillary as a result of the push from the hydrostatic pressure and this allows oncotic pressure to be initially explored. The main part of the lesson uses a step by step guide to describe how the net movement is outwards at the arteriole end before students will use this guidance to describe what happens at the venule end. In the concluding part of the lesson, students will come to recognise oedema as a condition where tissue fluid accumulates and they again are challenged to explain how this occurs before they finally learn how the fluid is returned to the circulatory system as lymph
This lesson bundle contains 4 lessons, which are fully-resourced and are filled with a range of tasks to engage and motivate the students whilst covering the following specification points in topic 10 of the CIE A-level Biology specification:
10.1
[a]: Define the term disease and explain the difference between an infectious disease and a non-infectious disease
[b]: State the name and type of causative organism of cholera, malaria, TB, HIV/AIDS, smallpox and measles
[c]: Explain how cholera, malaria, TB and HIV are transmitted
10.2
[a]: Outline how penicillin acts on bacteria and why antibiotics do not affect viruses
[b]: Explain in outline how bacteria becomes resistant to antibiotics with reference to mutation and selection
[c]: Discuss the consequences of antibiotic resistance and the steps that can be taken to reduce its impact
Included in the tasks are exam-style questions, and the mark schemes for each of these are embedded into the PowerPoint to allow the students to assess their progress
This lesson describes the structure and function of the human heart and names the blood vessels associated with this organ . The PowerPoint and accompanying resources are part of the first lesson in a series of 2 lessons that have been designed to cover point (b) in topic 3 of AS unit 2 of the WJEC A-level Biology specification
As this topic was covered at GCSE, the lesson has been planned to build on this prior knowledge whilst adding the key details which will enable students to provide A-level standard answers. The primary focus is the identification of the different structures of the heart but it also challenges their ability to recognise the important relationship to function. For example, time is taken to ensure that students can explain why the atrial walls are thinner than the ventricular walls and why the right ventricle has a thinner wall than the left ventricle. Opportunities are taken throughout the lesson to link this topic to the others found in topic 3 including those which have already been covered like circulatory systems as well as those which are upcoming such as the initiation of heart action. There is also an application question where students have to explain why a hole in the ventricular septum would need to be repaired if it doesn’t naturally close over time.
This lesson describes the roles of the SAN and Purkyne fibres in the coordination of the three stages of the cardiac cycle. The PowerPoint and accompanying resources are part of the first lesson in a series of 2 lessons that have been designed to cover point [c] in topic 3 of AS unit 2 of the WJEC A-level Biology specification and has a specific focus on the pressure changes that occur in each stage of the cycle
The start of the lesson introduces the cardiac cycle as well as the key term systole, so that students can immediately recognise that the three stages of the cycle are atrial and ventricular systole followed by diastole. Students are challenged on their prior knowledge of the structure of the heart as they have to name and state the function of an atrioventricular and semi-lunar valve from an internal diagram. This leads into the key point that pressure changes in the chambers and the major arteries results in the opening and closing of these sets of valves. Students are given a description of the pressure change that results in the opening of the AV valves and shown where this would be found on the graph detailing the pressure changes of the cardiac cycle. They then have to use this as a guide to write descriptions for the closing of the AV valve and the opening and closing of the semi-lunar valves and to locate these on the graph. By providing the students with this graph, the next part of the lesson can focus on explaining how these changes come about. Students have to use their current and prior knowledge of the chambers and blood vessels to write 4 descriptions that cover the cardiac cycle.
This rest of the lesson focuses on the roles of the SAN and Purkyne fibres as well as the AVN and the bundle of His in the coordination of the heartbeat, continually linking back to the work on the cycle. The SAN is introduced as the natural pacemaker and then time is given to study each step of the conduction of the impulse as it spreads away from the myogenic tissue in a wave of excitation. Moving forwards, students are encouraged to consider why a delay would occur at the AVN and then they will learn that the impulse is conducted along the Bundle of His to the apex so that the contraction of the ventricles can happen from the bottom upwards. The structure of the cardiac muscle cells is discussed and the final task of the lesson challenges the students to describe the conducting tissue, with an emphasis on the use of key terminology.
This lesson describes how the structure of arteries, arterioles, capillaries, venules and veins in the mammalian circulatory system relate to their functions. The PowerPoint and accompanying resources are part of the second lesson in a series of 2 lessons which have been designed to cover specification point (b) of topic 3 in AS unit 2 of the WJEC A-level Biology A specification. The first lesson in this series covers the structure and function of the human heart and its associated blood vessels
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, it is quite likely that some students will not be aware of the transition vessels that are the arterioles. This section begins with an understanding of the need for these vessels because the structural and functional differences between arteries and capillaries is too significant. The action of the smooth muscle in the walls of these vessels is discussed and students will be challenged to describe a number of situations that would require blood to be redistributed. The middle part of the lesson looks at the role of the capillaries in exchange and links are made to diffusion to ensure that students can explain how the red blood cells pressing against the endothelium results in a short diffusion distance. The remainder 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.
This lesson describes the Krebs cycle as a stage of aerobic respiration that liberates energy to produce ATP and reduced NAD and releases carbon dioxide. The PowerPoint and accompanying resource have been designed to cover specification point [c] in topic 3 of A2 unit 3 of the WJEC A-level Biology specification.
The lesson begins with a version of the Impossible game where students have to spot the connection between 8 of the 9 terms and will ultimately learn that this next stage is called the Krebs cycle. The main part of the lesson challenges the students to use descriptions of the main steps of the cycle to continue their diagram of the reactions. Students are continually exposed to key terminology such as decarboxylation and dehydrogenation and they will learn where carbon dioxide is lost and reduced NAD and FAD are generated. They will also recognise that ATP is synthesised by substrate level phosphorylation. The final task challenges them to apply their knowledge of the cycle to work out the numbers of the different products and to calculate the number of ATP that must be produced in the next stage
This lesson has been designed to tie in with the other uploaded lessons on glycolysis and the electron transport chain (in oxidative phosphorylation).
This bundle of 6 lessons has been designed to cover the following specification points in topic 3 of A2 unit 4 of the WJEC A-level Biology specification:
[a]: alleles as different forms of the same gene
[b]: the principles of monohybrid Mendelian inheritance including simple crosses involving codominance
[c]: the principles of dihybrid Mendelian inheritance including simple crosses involving linkage
[d]: the use of the chi squared test
[e]: sex linkage as illustrated by haemophilia and Duchenne muscular hypertrophy
[f]: gene mutation as illustrated by sickle cell anaemia and chromosome mutations as illustrated by Down syndrome
Each of the lessons is fully-resourced and contains a wide range of tasks that will engage and motivate the students whilst covering the detailed content of this topic. Any exam questions that are found in the resources have markschemes embedded into the PowerPoint
If you would like to see the quality of lessons included in this bundle, then download the alleles & monohybrid inheritance and gene mutation lessons as these have been shared for free
This lesson describes sex linkage, focusing on the the inheritance of genes on the X chromosome that lead to haemophilia and Duchenne muscular dystrophy. The PowerPoint and accompanying resources have been designed to cover specification point [e] in topic 3 of A2 unit 4 of the WJEC A-level Biology specification.
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 and they will be challenged to find evidence to support this decision later in the lesson. In terms of humans, the lesson focuses on haemophilia 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 tasks of the lesson challenge the students to carry out a dihybrid cross that involves a sex-linked disease and an autosomal disease before applying their knowledge to a 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 markschemes to allow them to assess their progress and address any misconceptions
This lesson describes the effects of pH on the rate of an enzyme-catalysed reaction. The PowerPoint and accompanying resources are part of the second lesson in a series of 4 lessons which have been designed to cover the content of point 3.2 (a) of the CIE A-level Biology specification.
The lesson begins with a short discussion, where the students are challenged to identify how the stomach and the small intestine differ in terms of a particular condition and to explain why the conditions in these neighbouring digestive organs are so important. This introduces pepsin and trypsin and these protease enzymes play a key role throughout the lesson as they are good examples of how different extracellular enzymes have different optimum pH values (which are not necessarily 7.0). Moving forwards, students will discuss how the rate of an enzyme-controlled reaction will change if there are small or large changes in pH, and then time is taken to ensure that students can explain these changes with reference to tertiary structure bonds and the shape of the active site. Through the use of a quick quiz competition, the students will be reminded of the key term “buffer” and a series of questions are used to challenge their understanding of how these substances could be used in a practical investigation. They will also learn how buffers are found in blood plasma as well as in red blood cells in the form of haemoglobin. As there is a considerable proportion of marks for Maths in a Biology context questions in the A-level assessments, the remainder of the lesson challenges the students to use a given formula to calculate the pH of blood when given the hydrogen ion concentration and to calculate percentage decrease. These questions have been differentiated to give assistance to those that need the support
