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 revision lesson uses a 15 question multiple-choice assessment to challenge the students on their knowledge of the content of module 5.1.2. In addition to the assessment, this lesson includes a PowerPoint where the answers are revealed, a series of key points linked to the OCR A-level biology A specification, and additional questions to challenge knowledge not directly covered by the 15 multiple-choice questions.
The topics challenged by the assessment are:
The meaning of the term excretion (as opposed to egestion)
The structure of the liver
The formation of urea by the ornithine cycle
The regions of the kidney
Ultrafiltration in the glomerulus
The structure and function of the PCT
The countercurrent multiplier mechanism in the loop of Henle
Osmoregulation
Homeostasis
The use of renal dialysis
Monoclonal antibodies in diagnostic tests
This lesson guides students through the respiratory quotient calculation and explains what the different calculated values indicate. The PowerPoint and accompanying resource have been planned to cover the content of point 7.6 of the Edexcel International A-level biology specification.
The lesson begins with a recall challenge, where the students have to demonstrate their knowledge of respiration to reveal the two letters, RQ. The meaning of a quotient is provided and time allocated, where they are encouraged to discuss which two respiratory values might be used. The formula is provided and then a worked example used to model the calculation. The obtained value of 1.0 is explained as the RQ if metabolism consists entirely of carbohydrates. Two exam-style questions are then used to challenge the students to apply their understanding and they’ll reveal the value of 0.7 for lipids. A quick quiz round introduces the range for amino acids as 0.8 - 0.9 before a final task gets them to obtain another value and to recognise that more than one type of molecule is often metabolised.
The lesson is full of understanding and prior knowledge checks, and the answers are embedded into the PowerPoint to allow students to assess their progress.
This bundle contains 20 lesson PowerPoints which are highly detailed to ensure that the topic 7 content is covered at the depth required for A-level Biology. The lessons have been intricately planned to contain a wide variety of tasks that will engage and motivate the students whilst covering the current material and to make links to other lessons in this topic as well as to the previous 6 topics.
The tasks, which include exam-style questions with mark schemes, guided discussion time and quick quiz competitions, cover the following points in the respiration, muscles and the internal environment topic of the Edexcel International A-level Biology specification:
The overall reaction of aerobic respiration
The many steps of respiration are controlled and catalysed by a specific intracellular enzyme
The roles of glycolysis in aerobic and anaerobic respiration
The role of the link reaction and the Krebs cycle in the complete oxidation of glucose
The synthesis of ATP by oxidative phosphorylation
The respiratory quotient
Know the way in which muscles, tendons, the skeleton and ligaments interact in movement
The contraction of skeletal muscle in terms of the sliding filament theory
The myogenic nature of cardiac muscle
The coordination of the heartbeat
The use of ECGs in the diagnosis of abnormal heart rhythms
The calculation of cardiac output
The control of heart rate and ventilation rate by the cardiovascular control centre and the ventilation centre in the medulle oblongata
The role of adrenaline in the fight or flight response
The principle of negative feedback in maintaining systems within narrow limits
The meaning of homeostasis and the maintenance of a dynamic equilibrium in exercise
The gross and microscopic structure of the mammalian kidney
Selective reabsorption in the proximal tubule
Water reabsorption in the loop of Henle
The control of mammalian plasma concentration
Switching genes on and off by DNA transcription factors and the roles of peptide and steroid hormones
Due to the detail included in this lesson bundle, it is estimated that it will take in excess of 2 months of allocated A-level teaching time to cover the content
If you would like to sample the quality of the lessons in the bundle, then download the skeletal muscle, coordination of the heartbeat, role of adrenaline and control of mammalian plasma concentration lessons as these have been uploaded for free
The “negative and positive feedback” and “skeletal muscle” lessons are also uploaded on TES for free but haven’t been included in this bundle as the resource limit has been reached
Topic 8 of the Edexcel International A-level biology specification is content heavy and therefore all 11 lessons included in this bundle have been planned to cover this content in an engaging and memorable way. The lessons are filled with a wide variety of tasks, including understanding and prior knowledge checks, guided discussion periods and quick quiz competitions. Answers to all of the knowledge checks are embedded into the PowerPoints to allow the students to assess their progress.
The following specification points are covered by this bundle:
8.1, 8.2, 8.3, 8.4, 8.5, 8.6, 8.8, 8.10, 8.13, 8.14, 8.18, 8.19, 8.20
If you would like to get a sense for the quality of the lessons in this bundle, then download the nervous and hormonal control, saltatory conduction and pupil reflex lessons as these have been shared for free.
The biological molecules topic is incredibly important, not just because it is found at the start of the course, but also because of its detailed content which must be well understood to promote success with the other 7 AQA A-level Biology topics. Many hours of intricate planning has gone into the design of all of the 20 lessons that are included in this bundle to ensure that the content is covered in detail, understanding is constantly checked and misconceptions addressed and that engagement is high. This is achieved through the wide variety of tasks in the PowerPoints and accompanying worksheets which include exam-style questions with clear answers, discussion points, differentiated tasks and quick quiz competitions.
The following specification points are covered by the lessons within this bundle:
Monomers and polymers
Condensation and hydrolysis reactions
Common monosaccharides
Maltose, sucrose and lactose
The structure and functions of glycogen, starch and cellulose
Biochemical tests using Benedict’s solution for reducing sugars and non-reducing sugars and iodine/potassium iodide for starch
The structure and properties of triglycerides and phospholipids
The emulsion test for lipids
The structure of amino acids
The formation of dipeptides and polypeptides
The levels of protein structure
The biuret test for proteins
Enzymes act as biological catalysts
The induced-fit model of enzyme action
The properties of an enzyme
The effect of temperature on the rate of an enzyme-controlled reaction
The effect of enzyme and substrate concentration on the rate of an enzyme-controlled reaction
The effect of competitive and non-competitive inhibitors on the rate of an enzyme-controlled reaction
The structure of DNA and RNA
The semi-conservative replication of DNA
ATP as the universal energy currency
The properties of water and its importance in Biology
Inorganic ions
Due to the detail of each of these lessons, it is estimated that it will take in excess of 2 months of allocated teaching time to cover the content.
If you would like to see the quality of the lessons, download the monomers and polymers, polysaccharides, triglycerides, dipeptides and polypeptides and inorganic ions lessons as these have been shared for free
The biological molecules topic is incredibly important, not just because it is found near to the start of the course, but also because of its detailed content which must be well understood to promote success with the other 18 CIE International A-level Biology topics. Many hours of intricate planning have gone into the design of all of the 11 lessons that are included in this bundle to ensure that the content is covered in detail, understanding is constantly checked and misconceptions addressed and that engagement is high. This is achieved through the wide variety of tasks in the PowerPoints and accompanying worksheets which include exam-style questions with clear answers, discussion points, differentiated tasks and quick quiz competitions.
The following specification points are covered by the lessons within this bundle:
Tests for reducing and non-reducing sugars
The iodine test for starch
The emulsion test for lipids
The biuret test for proteins
The ring forms of alpha and beta glucose
The meaning of the terms monomer, polymer, macromolecule, monosaccharide, disaccharide and polysaccharide
The formation of a glycosidic bond by a condensation reaction
The breakage of glycosidic bonds by hydrolysis reactions
The relationship between the molecular structure and functions of a triglyceride
The relationship between the structure and functions of a phospholipid
The structure of an amino acid and the formation and breakage of a peptide bond
The meaning of the different protein structures and the types of bonding that hold these molecules in shape
The molecular structure of haemoglobin and collagen as examples of globular and fibrous proteins
The relationship between the properties and roles of water in living organisms
The lesson on the biuret test for proteins and the emulsion test for lipids also contains a section which can be used for the revision of topics 2.2 and 2.3
Due to the detail of each of these lessons, it is estimated that it will take in excess of 4 weeks of allocated teaching time to cover the content.
If you would like to see the quality of the lessons, download the alpha and beta glucose, phospholipids and haemoglobin and collagen lessons as these have been shared for free
As the first topic to be taught at the start at the second year of the Pearson Edexcel A-level Biology A (Salters Nuffield) course, topic 5 is very important and the content includes the key reaction of photosynthesis. All 10 lessons included in this bundle are highly detailed and have been filled with a wide variety of tasks which will engage and motivate the students whilst covering the following specification points:
Understand the terms ecosystem, community, population and habitat
The numbers and distribution of organisms in a habitat are controlled by biotic and abiotic factors
The concept of niche
The stages of succession from colonisation to climax community
The overall reaction of photosynthesis
The phosphorylation of ADP and the hydrolysis of ATP
The light-dependent reactions of photosynthesis
The light-independent reactions of photosynthesis
The products of the Calvin cycle
The structure of the chloroplasts and the role of this organelle in photosynthesis
Be able to calculate net primary productivity
Know the relationship between NPP, GPP and R
The effect of temperature on the rate of enzyme activity
Isolation reduces gene flow and leads to allopatric and sympatric speciation
If you would like to sample the quality of the lessons in this bundle, then download the light-independent reactions and isolation and speciation lessons as these have been uploaded for free
Some of the key biological topics are covered in topic 2 of the Pearson Edexcel A-level Biology A (Salters Nuffield) course and include the transport of materials across cell membranes, DNA structure and replication, protein synthesis and monohybrid inheritance. In line with this, many hours of intricate planning have gone into the design of all of the 19 lessons that are included in this bundle to ensure that the content is covered in detail, understanding is constantly checked to immediately address misconceptions and that engagement is high. This is achieved through the wide variety of tasks in the PowerPoints and accompanying worksheets which include exam-style questions with clear answers, discussion points, differentiated tasks and quick quiz competitions.
The following specification points are covered by the lessons within this bundle:
The properties of gas exchange surfaces in living organisms
Understand how the rate of diffusion is dependent on these properties and can be used in the calculation of the rate of diffusion by Fick’s law
Adaptations of the mammalian lung for rapid gaseous exchange
Structure and properties of cell membranes
Simple and facilitated diffusion as methods of passive transport
The involvement of ATP and carrier proteins in active transport, endocytosis and exocytosis
The basic structure of mononucleotides
The structures of DNA and RNA
The process of protein synthesis
The roles of the template strand, mRNA and tRNA
The nature of the genetic code
A gene is a sequence of bases on DNA that codes for the amino acid sequence of a polypeptide
The basic structure of an amino acid
The formation of polypeptides and proteins
The primary, secondary, tertiary and quaternary structure of proteins
Globular and fibrous proteins using haemoglobin and collagen as examples
The mechanism of action and the specificity of enzymes
Enzymes are biological catalysts that reduce activation energy
The process of DNA replication
Errors in DNA replication can give rise to mutations
The meaning of key genetic terms
Patterns of inheritance, in the context of monohybrid inheritance
Understand how the expression of a gene mutation in people with cystic fibrosis impairs the functioning of the gaseous exchange, digestive and reproductive systems
Understand the uses and implications of genetic screening and prenatal testing
Due to the detail included in each of these lessons, it is estimated that it will take in excess of 2 months of allocated teaching time to cover the content.
If you would like to see the quality of the lessons, download the gas exchange surfaces, cell membranes, transcription, globular and fibrous proteins, monohybrid inheritance and cystic fibrosis lessons as these have been shared for free
This lesson bundle contains 9 lesson PowerPoints and their accompanying resources which have been intricately planned to deliver the detailed content of topic 6 of the Pearson Edexcel A-level Biology A (Salters Nuffield) specification and to make links to the 5 previously covered topics. In addition to the detailed content, each lesson contains exam-style questions with mark schemes embedded into the PowerPoint, differentiated tasks, guided discussion points and quick quiz competitions to introduce key terms and values in a fun and memorable way.
The following specification points are covered by the lessons in this bundle:
DNA can be amplified using the PCR
Comparing the structure of bacteria and viruses
Understand how Mycobacterium tuberculosis and human immunodeficiency virus infact human cells
The non-specific responses of the body to infection
The roles of antigens and antibodies in the body’s immune response
The differences in the roles of the B and T cells in the body’s immune response
Understand how one gene can give rise to more than one protein
The development of immunity
The major routes that pathogens may take when entering the body
The role of barriers in protecting the body from infection
The difference between bacteriostatic and bactericidal antibiotics
If you would like to sample the quality of the lessons in this bundle, then download the immune response and post-transcriptional changes lessons as these have been uploaded for free
This detailed and engaging lesson looks at the culture of transformed host cells as an in vivo method to amplify DNA fragments. Both the PowerPoint and accompanying resources have been designed to cover the third part of point 8.4.1 of the AQA A-level Biology specification and ties in with the previous two lessons in this sub-topic on producing DNA fragments and the polymerase chain reaction.
The lesson begins with the introduction of the terms transgenic and transformed. 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. A quick quiz competition is used to introduce the key term, vector, and then the rest of the lesson looks at the details of the five steps involved in the transformation of the host cell:
Remove and prepare the plasmid to act as a vector
Insert the DNA fragment into the vector
Transfer the recombinant plasmid into the host cell
Identify the cells which have taken up the recombinant plasmid
All the transformed host cells to replicate and express the novel gene
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. Links are continuously made to the previous lessons in this topic so that students feel confident to answer assessment questions which bring in knowledge from all of the sections.
This detailed lesson describes how the structure of a prokaryotic cell differs from the structure of an eukaryotic cell. The engaging PowerPoint and accompanying resources have been designed to cover the first part of point 2.1.2 of the AQA A-level Biology specification and describes how the size and cell structures differ and also covers the additional features that are found in some prokaryotic cells.
A clear understanding of terminology is important for A-level Biology so this lesson begins with a challenge, where the students have to add an additional prefix to their prefix and suffix table which they believe will translate as before or in front of. This leads into the discovery of the meaning of prokaryote as before nucleus and this acts to remind students that these types of cell lack this cell structure. Links to the previous lessons on the eukaryotic cells are made throughout the lesson and at this particular point, the students are asked to work out why the DNA would be described as naked and to state where it will be found in the cell. Moving forwards, the students will discover that these cells also lack membrane bound organelles and a quick quiz competition challenges them to identify the specific structure that is absent from just a single word. In addition to the naked DNA, students will learn that there are also ribosomes in the cytoplasm and will discover that these are smaller than those found in the cytoplasm of an eukaryotic cell (but the same size as those in chloroplasts and mitochondria). The remainder of the lesson focuses on the composition of the cell wall, the additional features of prokaryotic cells such as plasmids and there is also the introduction of binary fission as the mechanism by which these organisms reproduce.
This detailed lesson describes the key structural features of a prokaryotic cell and compares these against the structures of an eukaryotic cell. The engaging PowerPoint and accompanying resources have been designed to cover specification points 1.2 (d) & (e) as detailed in the CIE International A-level Biology specification and describes how the size and cell structures differ as well as the additional features that are found in some prokaryotic cells and briefly introduces binary fission.
A clear understanding of terminology is important for A-level Biology so this lesson begins with a challenge, where the students have to recognise a prefix that they believe translates as before or in front of . This leads into the discovery of the meaning of prokaryote as before nucleus and this acts to remind students that these types of cell lack this cell structure. Links to the previous lessons on the eukaryotic cells are made throughout the lesson and at this particular point, the students are asked to work out why the DNA would be described as naked and to state where it will be found in the cell. Moving forwards, the students will discover that these cells also lack membrane bound organelles and a quick quiz competition challenges them to identify the specific structure that is absent from just a single word. In addition to the naked DNA, students will learn that there are also ribosomes in the cytoplasm and will discover that these are smaller than those found in the cytoplasm of an eukaryotic cell (but the same size as those in chloroplasts and mitochondria). The remainder of the lesson focuses on the composition of the cell wall, the additional features of prokaryotic cells such as plasmids and there is also the introduction of binary fission as the mechanism by which these organisms reproduce
All 4 of the lessons that are included in this bundle are fully-resourced and contain a wide range of activities that will motivate and engage the students whilst covering the content as detailed in topic 4 of the CIE A-level Biology specification (Cell membranes and transport).
Exam-style questions which check on current and prior understanding, differentiated tasks, discussion points and quick quiz competitions cover the following specification points:
The fluid mosaic model of membrane structure
The roles of phospholipids, cholesterol, glycoproteins and proteins
The roles of channel and carrier proteins
Simple diffusion
Facilitated diffusion
Active transport, endocytosis and exocytosis
Osmosis and the effect of the movement of water on animal and plant cells
If you would like to sample the quality of these lessons, download the active transport lesson as this has been uploaded for free
This detailed lesson describes how the movement of water between solutions and cells has differing effects on animal and plant cells. Both the PowerPoint and accompanying resources have been designed to cover specification points 4.2 (a) and (f) as detailed in the CIE International A-level Biology specification.
It’s likely that students will have used the term concentration in their osmosis definitions at GCSE, so the aim of the starter task is to introduce water potential to allow students to begin to recognise osmosis as the movement of water molecules from a high water potential to a lower potential, with the water potential gradient. Time is taken to describe the finer details of water potential to enable students to understand that 0 is the highest value (pure water) and that this becomes negative once solutes are dissolved. Exam-style questions are used throughout the lesson to check on current understanding as well as prior knowledge checks which make links to previously covered topics such as the lipid bilayer of the cell membrane. The remainder of the lesson focuses on the movement of water when animal and plant cells are suspended in hypotonic, hypertonic or isotonic solutions and the final appearance of these cells is described, including any issues this may cause.
A deep understanding of the topic of cells is crucial for the success of any A-level Biologist and these lessons not only provide the depth of detail needed at this level but also make links to the upcoming 18 topics in the CIE course.
Contained within the 4 lesson PowerPoints and multiple resources that are included in this bundle are a wide range of activities to motivate and engage the students whilst they cover the content as detailed in topic 1.2 of the CIE A-level Biology specification. The majority of the resources are differentiated to allow students of differing abilities to access the work and to be challenged at all times.
The following specification points are covered in this bundle:
The relationship between the structure and function of the structures of eukaryotic cells
The structure and role of ATP in cells
The structural features of prokaryotic cells
Comparing eukaryotic and prokaryotic cells
The key features of viruses as non-cellular structures
If you would like to sample the quality of these lessons, then download the eukaryotic cell structures and functions and viruses lessons as these have been shared for free
This is a fully-resourced revision lesson that uses a combination of exam questions, understanding checks, quick tasks and quiz competitions to enable students to assess their understanding of the content found within Module 2.1.1 (Cell structure) of the OCR A-level Biology A specification.
The sub-topics and specification points that are tested within the lesson include:
The use of microscopy to observe and investigate different types of cells
The use and manipulation of the magnification formula
The difference between magnification and resolution
The ultrastructure of eukaryotic cells and the function of the different cellular components
Interpretation of electron microscope images
The interrelationship between the organelles involved in the production and secretion of proteins
The similarities and differences in the structure and ultrastructure of prokaryotic and eukaryotic cells
Students will be engaged through the numerous quiz rounds such as “It doesn’t HURT to CONVERT” and “Word association game” whilst crucially being able to recognise those areas which require their further attention during general revision or during the lead up to the actual A-level terminal exams
This fully-resourced lesson describes how the eukaryotic cells of complex multicellular organisms become specialised for specific functions. The detailed and engaging PowerPoint and accompanying resources have been designed to cover the 3rd part of point 2.1.1 of the AQA A-level Biology specification and also describes how these specialised cells are organised into tissues, organs and organ systems.
The start of the lesson focuses on the difference in the SA/V ratio of an amoeba and a human in order to begin to explain why the process of differentiation is critical for multicellular organisms. Students will discover that a zygote is a stem cell which can express all of the genes in its genome and divide by mitosis. Time is then taken to introduce gene expression as this will need to be understood in the later topics of the course. Moving forwards, the lesson uses the process of haematopoiesis from haematopoietic stem cells to demonstrate how the red blood cell and neutrophil differ significantly in structure despite arising from the same cell along the same cell lineage. A series of exam-style questions will not only challenge their knowledge of structure but also their ability to apply this knowledge to unfamiliar situations. These differences in cell structure is further exemplified by the epithelial cells of the respiratory tract and students will understand why the shape and arrangement of these cells differ in the trachea and alveoli in line with function. The link between specialised cells and tissues is made at this point of the lesson with these examples of epithelium and students will also see how tissues are grouped into organs and then into organ systems.
The remainder of the lesson focuses on specialised plant cells and the differing shapes and features of the palisade and spongy mesophyll cells and the guard cells are covered at length and in detail. Step by step guides will support the students so that they can recognise the importance of the structures and links are made to upcoming topics such as diffusion, active transport and osmosis so that students are prepared for these when covered in the future.
This lesson has been written to continually tie in with the previous two lessons in this specification point which are uploaded under the titles of the structure of eukaryotic animal and plant cells.
This detailed lesson describes the structure and properties of the cell membrane, focusing on the phospholipid bilayer and membrane proteins. Fully resourced, the PowerPoint and accompanying worksheets have been designed to cover the first part of point 2.3 of the AQA A-level Biology specification and clear links are made to Singer and Nicholson’s fluid mosaic model
The fluid mosaic model is introduced at the start of the lesson so that it can be referenced at appropriate points throughout the lesson. Students were introduced to phospholipids in topic 1 and so an initial task challenges them to spot the errors in a passage describing the structure and properties of this molecule. This reminds them of the bilayer arrangement, with the hydrophilic phosphate heads protruding outwards into the aqueous solutions on the inside and the outside of the cell. In a link to some upcoming lessons on the transport mechanisms, the students will learn that only small, non-polar molecules can move by simple diffusion and that this is through the tails of the bilayer. This introduces the need for transmembrane proteins to allow large or polar molecules to move into the cell by facilitated diffusion and active transport. Proteins that act as receptors as also introduced and an opportunity is taken to make a link to an upcoming topic so that students can understand how hormones or drugs will bind to target cells in this way. Moving forwards, the structure of cholesterol is covered and students will learn that this hydrophobic molecule sits in the middle of the tails and therefore acts to regulate membrane fluidity. The final part of the lesson challenges the students to apply their newly-acquired knowledge to a series of questions where they have to explain why proteins may have moved when two cells are used and to suggest why there is a larger proportion of these proteins in the inner mitochondrial membrane than the outer membrane.
The locus and linkage, meiosis, differential gene expression and protein transport within cells lessons have been uploaded for free and by downloading these, you will be able to observe the detail of planning that has gone into all of the lessons that are included in this bundle. This intricate planning ensures that the students are engaged and motivated whilst the detailed content of topic 3 (Cell structure, Reproduction and Development) of the Edexcel International A-level Biology specification is covered.
The 14 lesson PowerPoints and accompanying resources contain a wide range of activities which cover the following topic 3 specification points:
All living organisms are made of cells
Cells of multicellular organisms are organised into tissues, organs and organ systems
The ultrastructure of eukaryotic cells
The function of the organelles in eukaryotic animal cells
The role of the RER and Golgi apparatus in protein transport within cells
The ultrastructure of prokaryotic cells
Magnification and resolution in light and electron microscopes
The gene locus is the location of a gene on a chromosome
The linkage of genes on a chromosome
The role of meiosis in ensuring genetic variation
Understand how the mammalian gametes are specialised for their functions
The role of mitosis and the cell cycle in growth and asexual reproduction
Calculation of mitotic indices
The meaning of the terms stem cell, pluripotent, totipotent, morula and blastocyst
The decisions that have to be made about the use of stem cells in medical therapies
Cells become specialised through differential gene expression
One gene can give rise to more than one protein through post-transcriptional changes to mRNA
Phenotype is the interaction between genotype and the environment
Epigenetic modifications can alter the activation of certain genes
Some phenotypes are affected by multiple alleles or by polygenic inheritance
Due to the detail included in all of these lessons, it is estimated that it will take in excess of 6 weeks of allocated A-level teaching time to complete the teaching of the bundle
This detailed lesson introduces the 3 main principles of the cell theory and describes how cells are organised into tissues, organs and organ systems. The engaging PowerPoint and accompanying resources have been designed to cover points 2.1 (i) & (ii) of the Edexcel A-level Biology B specification.
The cell theory is introduced at the start of the lesson and the 1st principle is immediately discussed to ensure that students are aware that all living organisms are made of cells. This principle is discussed with relation to viruses to enable students to understand that the lack of cell structure in a virus is one of the reasons that they are not considered to be living. The second principle states that the cell is the basic unit of structure and organisation and this leads into the main part of the lesson where specialised cells and their groupings into tissues are considered. Students are challenged to compare an amoeba against a human to get them to focus on the difference in the SA/V ratio. This acts as an introduction into the process of differentiation and a recognition of its importance for multicellular organisms. Students will discover that a zygote is a stem cell which can express all of the genes in its genome and divide by mitosis. Time is then taken to introduce gene expression as this will need to be understood in the later topics of the course. Moving forwards, the lesson uses the process of haematopoiesis from haematopoietic stem cells to demonstrate how the red blood cell and neutrophil differ significantly in structure despite arising from the same cell along the same cell lineage. A series of exam-style questions will not only challenge their knowledge of structure but also their ability to apply this knowledge to unfamiliar situations. These differences in cell structure is further exemplified by the epithelial cells of the respiratory tract and students will understand why the shape and arrangement of these cells differ in the trachea and alveoli in line with function. The link between specialised cells and tissues is made at this point of the lesson with these examples of epithelium and students will also see how tissues are grouped into organs and then into organ systems. The third principle states that cells arise from pre-existing cells and this will be demonstrated later in topic 2 with mitosis and meiosis.
