This lesson describes how to use the magnification formula to calculate the magnification or the actual size in a range of units. The PowerPoint and accompanying resources have been designed to cover the 3rd part of point 2.1.3 of the AQA A-level Biology specification The students are likely to have met the magnification formula at GCSE so this lesson has been written to build on that knowledge and to support them with more difficult questions when they have to calculate actual size without directly being given the magnification. A step by step guide is used to walk the students through the methodology and useful tips are provided. Students could be asked to calculate the actual size in millimetres, micrometres, nanometres or picometres so time is taken to ensure that they can convert between one and another. This lesson has been written to tie in with the previous two lessons on microscopes and measuring the size of an object and the two rounds of the ongoing quiz competition take place in this lesson.

This detailed lesson describes the sequence of events that occur during the first stage of protein synthesis, which is known as transcription. The detailed lesson PowerPoint and accompanying worksheet are the first in a series of two lesson resources that have been designed to cover the details of point 2.13 of the Edexcel International A-level Biology specification and include details of the DNA template strand, RNA polymerase and messenger RNA. The lesson begins by challenging the students to work out that most of the nuclear DNA in eukaryotes does not code for polypeptides. This allows the promoter region and terminator region to be introduced, along with the structural gene. Through the use of an engaging quiz competition, students will learn that the strand of DNA involved in transcription is known as the DNA template (or antisense) strand and the other strand is the coding strand. Links to previous lessons on DNA and RNA structure are made throughout and students are continuously challenged on their prior knowledge as well as they current understanding of the lesson topic. Moving forwards, the actual process of transcription is covered in a 7 step bullet point description where the students are asked to complete each passage using the information previously provided. An exam-style question is used to check on their understanding before the final task of the lesson looks at the journey of mRNA to the ribosome for the next stage of translation. This lesson has been written to directly lead into the following lesson on translation

This fully-resourced lesson describes the process of DNA replication and includes key details of the role of DNA polymerase. The detailed PowerPoint and accompanying resources have been designed to cover point 2.10 (i) of the Edexcel International A-level Biology specification and also includes descriptions of the roles of DNA helicase and DNA ligase and an introduction of this type of replication as semi-conservative. As the main focus of this lesson is the roles of the enzymes, students will understand how DNA helicase breaks the hydrogen bonds between nucleotide bases, DNA polymerase forms the growing nucleotide strands and DNA ligase joins the nucleic acid fragments. The specification specifically mentions DNA polymerase and in line with this, extra time is taken to explain key details, such as the assembly of strands in the 5’-to-3’ direction by this enzyme, so that the continuous manner in which the leading strand is synthesised can be compared against that of the lagging strand. The students are constantly challenged to make links to previous topics such as DNA structure and hydrolysis reactions through a range of exam questions and answers are displayed so that any misconceptions are quickly addressed. The main task of the lesson asks the students to use the information provided in the lesson to order the sequence of events in DNA replication before discussing how the presence of a conserved strand and a newly built strand in each new DNA molecule shows that it is semi-conservative.

This lesson describes how molecules move across cell membranes by passive transport, as exemplified by simple and facilitated diffusion. The PowerPoint and accompanying resource have been designed to cover the first part of specification point 2.5 of the Edexcel International A-level Biology specification and the factors that increase the rate of diffusion are covered along with the limitations imposed by the phospholipid bilayer and the role of channel and carrier proteins The structure and properties of cell membranes were described in the lesson covering 2.2, so this lesson has been written to include continual references to the content of that lesson. This enables links to be made between the movement across a cell membrane with the concentration gradient, the parts of the membrane that are involved and any features that may increase the rate at which the molecules move. A quick quiz competition challenges students to recall Fick’s law of diffusion and a series of questions and tasks are used to demonstrate how a large surface area, a short diffusion distance and the maintenance of a steep concentration gradient will increase the rate of simple diffusion. Another quick quiz round is then used to introduce temperature and size of molecule as two further factors that can affect simple diffusion. The remainder of the lesson focuses on facilitated diffusion and describes how transmembrane proteins are needed to move small, polar or large molecules from a high concentration to a lower concentration across a partially permeable membrane

This fully-resourced lesson describes the movement of molecules by active transport, endocytosis and exocytosis. The PowerPoint and accompanying worksheets have been designed to cover the second part of specification points 2.5 (i) & (ii) of the Edexcel International A-level Biology specification and describes the role of ATP as an immediate source of energy as well as the role of the carrier proteins. ATP is introduced at the start of the lesson and students will learn that this molecule is a phosphorylated nucleotide so they are able to make appropriate links when they cover the structure of DNA and RNA later in topic 2. Students will learn that adenosine triphosphate is the universal energy currency and that the hydrolysis of this molecule can be coupled to energy-requiring reactions within the cell and the rest of the lesson focuses on the use of this energy input for active transport, endocytosis and exocytosis. Students are challenged to answer a series of questions which compare active transport against the forms of passive transport and to use data from a bar chart to support this form of transport. In answering these questions they will discover that carrier proteins are specific to certain molecules and time is taken to look at the exact mechanism of these transmembrane proteins. A quick quiz round introduces endocytosis and the students will see how vesicles are involved along with the energy source of ATP to move large substances in or out of the cell. The lesson concludes with a link to a future topic as the students are shown how exocytosis is involved in a synapse.

This detailed lesson describes the structure and properties of the cell membrane, focusing on the phospholipid bilayer, cholesterol and membrane proteins. The detailed PowerPoint and accompanying resources have been designed to cover the details of point 2.2 (i) of the Edexcel International A-level Biology specification and clear links are made to Singer and Nicholson’s fluid mosaic model which is covered in the following lesson Students met triglycerides in topic 1 and so a quick quiz competition at the start of the lesson challenges their recall of the structure of these lipids so that they can recognise the similarities and differences to the structure of phospholipids. Time is taken to look at the differing properties of the phosphate head and the fatty acid tails in terms of water and the class is challenged to work out how the phospholipids must be arranged when there’s an aqueous solution on the inside and outside of the cell. This introduces 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 fused and to suggest why there is a larger proportion of these proteins in the inner mitochondrial membrane than the outer membrane.

This detailed lesson describes the role of the mRNA, tRNA, ribosomes and start and stop codons during the second stage of protein synthesis - translation. This lesson is the second in a series of two, which have been designed together to cover point 2.13 of the Edexcel International A-level Biology specification. The first lesson in this series describes transcription. Translation is a topic which is often poorly understood and so this lesson has been written to enable the students to understand how to answer the different types of questions by knowing and including the key details of the structures involved. The lesson begins by challenging the students to consider why it is so important that the amino acids are assembled in the correct order during the formation of the chain. Moving forwards, a quick quiz round called “LOST IN TRANSLATION” is used to check on their prior knowledge of the mRNA strand, the tRNA molecules, the genetic code and the ribosomes. The next task involves a very detailed description of translation that has been divided into 14 statements which the students have to put into the correct order. By giving them a passage that consists of this considerable detail, they can pick out the important parts to use in the next task where they have to answer shorter questions worth between 3 and 4 marks. These types of questions are common in the assessments and by building up through the lesson, their confidence to answer this type should increase. The final two tasks of the lesson involve another quiz, where the teams compete to transcribe and translate in the quickest time before using all that they have learnt to answer some exam-style questions which involve the genetic code and the mRNA codon table.

This fully-resourced lesson describes how polygenic inheritance gives rise to phenotypes that show continuous variation. The engaging PowerPoint and accompanying resources have been primarily designed to cover points 3.20 (i) & 3.21 of the Edexcel International A-level Biology specification but also includes activities to challenge the students on previous concepts in topics 3 and 2. The students begin the lesson by having to identify phenotype and species from their respective definitions so that a discussion can be encouraged where they will recognise that phenotypic variation within a species is due to both genetic and environmental factors. The main part of the the lesson focuses on these genetic factors, and describes how mutation and the events of meiosis contribute to this variation. A range of activities, which include exam-style questions and quick quiz rounds, are used to challenge the students on their knowledge and understanding of substitution mutations, deletions, insertions, the genetic code, crossing over and independent assortment. Moving forwards, the concept of multiple alleles is introduced and students will learn how the presence of more than 2 alleles at a locus increases the number of phenotypic variants. Another quick quiz round is used to introduce polygenic inheritance and the link is made between this inheritance of genes at a number of loci as an example of continuous variation. The final part of the lesson describes a few examples where environmental factors affect phenotype, such as chlorosis in plants. As this is the final lesson in topic 3, the numerous activities can be used for revision purposes and to demonstrate the links between different biological topics.

This fully-resourced lesson describes how a triglyceride is synthesised and describes the differences between saturated and unsaturated lipids. The engaging PowerPoint and accompanying resources have been designed to cover specification points 1.5 (i) & (ii) as detailed in the Edexcel International A-level Biology specification and links are also made to related future topics such as the use of lipids as a substrate for respiration and the importance of the myelin sheath for the conduction of an electrical impulse. The lesson begins with a focus on the basic structure and roles of lipids, including the elements that are found in this biological molecule and some of the places in living organisms where they are found. Moving forwards, the students are challenged to recall the structure of the carbohydrates from earlier in topic 1 so that the structure of a triglyceride can be introduced. Students will learn that this macromolecule is formed from one glycerol molecule and three fatty acids and have to use their understanding of condensation reactions to draw the final structure. Time is taken to look at the difference in structure and properties of saturated and unsaturated fatty acids and students will be able to identify one from the other when presented with a molecular formula. The final part of the lesson explores how the various properties of lipids mean that these molecules have numerous roles in organisms including that of an energy store and source and as an insulator of heat and electricity.

This fully-resourced lesson describes how magnification and resolution can be achieved using light and electron microscopy. The engaging PowerPoint and accompanying resources have been designed to cover the content of points 3.7 (i) & (ii) of the Edexcel International A-level Biology specification and also considers how specimens are stained. To promote engagement and focus throughout this lesson, the PowerPoint contains a quiz competition with 7 rounds. The quiz rounds found in this lesson will introduce the objective lens powers, the names of the parts of a light microscope and emphasise some of the other key terms such as resolution. The final round checks on their understanding of the different numbers that were mentioned in the lesson, namely the differing maximum magnifications and resolutions. Time is taken to explain the meaning of both of these microscopic terms so that students can recognise their importance when considering the organelles that were met earlier in topic 3. By the end of the lesson, the students will be able to explain how a light microscope uses light to form an image and will understand how electrons transmitted through a specimen or across the surface will form an image with a TEM or a SEM respectively.

This fully-resourced lesson describes the role of mitosis and the cell cycle in producing genetically identical daughter cells. The detailed PowerPoint and accompanying resources have been designed to cover point 3.14 of the Edexcel International A-level Biology specification and explains the importance of these cells for growth and asexual reproduction. In an earlier lesson covering meiosis (3.10), students were introduced to the different phases and structures involved in the cycle so this lesson builds on that by providing greater detail of the key events in each phase. Beginning with a focus on interphase, the importance of DNA replication is explained so that students can initially recognise that there are pairs of identical sister chromatids and then can understand how they are separated later in the cycle. A quiz competition has been written into the lesson and this runs throughout, challenging the students to identify the quantity of DNA in the cell (in terms of n) at different points of the cycle. The main part of the lesson focuses on prophase, metaphase, anaphase and telophase and describes how the chromosomes behave in these stages. Students will understand how the cytoplasmic division that occurs in cytokinesis results in the production of genetically identical daughter cells. This leads into a series of understanding and application questions where students have to identify the various roles of mitosis in living organisms as well as tackling a Maths in a Biology context question. The lesson concludes with a final round of MITOSIS SNAP where they only shout out this word when a match is seen between the name of a phase, an event and a picture.

This fully-resourced lesson describes how post-transcriptional changes to mRNA enable 1 gene to give rise to multiple proteins. The detailed PowerPoint and accompanying resources have been designed to cover point 3.19 of the Edexcel International A-level Biology specification. The lesson begins with a knowledge recall as the students have to recognise the definition of a gene as a sequence of bases on a DNA molecule that codes for a sequence of amino acids in a polypeptide chain. This description was introduced in topic 2 and the aim of the start of the lesson is to introduce the fact that despite this definition, most of the nuclear DNA in eukaryotes doesn’t actually code for proteins. A quick quiz competition is then used to introduce exons as the coding regions within a gene before students are challenged to predict the name of the non-coding regions and then to suggest a function for these introns. Moving forwards, pre-mRNA as a primary transcript is introduced and students will learn that this isn’t the mature strand that moves off to the ribosome for translation. Instead, a process called splicing takes place where the introns are removed and the remaining exons are joined together. Another quick quiz round leads to an answer of 20000 and students will learn that this is the number of protein-coding genes in the human genome. Importantly, the students are then told that the number of proteins that are synthesised is much higher than this value and a class discussion period encourages them to come up with biological suggestions for this discrepancy between the two numbers. The lesson concludes with a series of understanding and application questions where students will learn that alternative splicing enables a gene to produce more than a single protein and that this natural phenomenon greatly increases biodiversity.

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.

This fully-resourced lesson describes the ultrastructure of a prokaryotic cell including the nucleoid, plasmid, 70S ribosomes and cell wall. The engaging PowerPoint and accompanying resources have been designed to cover specification point 2.1 (iii) of the Edexcel A-level Biology B specification but has been specifically designed to be taught after the lesson on the ultrastructure of eukaryotic cells, specification point 2.1 (v), so that comparisons can be drawn. A clear understanding of terminology is important for A-level Biology so this lesson begins with a challenge, where the students have to come up with a 3-letter prefix that they believe will translate as before or in front of . This leads into the discovery of the meaning of prokaryote as before nucleus which 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 so that students can recognise that prokaryotic cells do not contain centrioles

This fully-resourced lesson describes the structure of the cell surface membrane and references Singer and Nicholson’s fluid mosaic model. The detailed and engaging PowerPoint and accompanying resources have been designed to cover specification point 4.2 (i) of the Edexcel A-level Biology B specification and also makes clear links are made to related topics such as the binding of hormones as covered in topic 9 and the electron transport chain as covered in topic 5. 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 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 topic 9 so that students can understand how hormones or drugs will bind to target cells in this way and cause the release of cAMP on the interior of the cell. 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.

This revision resource has been written to include a range of activities that motivate the students whilst they assess their understanding of the content found in module 2.1.5 (Biological membranes) of the OCR A-level Biology A specification. The resource includes a detailed and engaging Powerpoint (71 slides) and associated worksheets The range of activities have been designed to cover as much of the content as possible but the following sub-topics have been given particular attention: The movement of molecules by active transport which requires ATP as an immediate source of energy The movement of molecules by passive processes The use of membrane-spanning proteins in facilitated diffusion and active transport Factors that increase the rate of simple diffusion The movement of water across membranes by osmosis The effects that solutions of different water potentials can have on animal and plant cells The fluid mosaic model of membrane structure The roles of the components of the plasma cell membrane In addition to these topics, some topics from other modules such as organelles, synapses and autoimmune diseases are tested in order to challenge the students on their ability to make links between the modules. The range of activities include exam questions and understanding checks as well as quiz competitions to maintain student engagement.