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 the basic structure of mononucleotides and the resulting structural similarities and differences between DNA and RNA. The PowerPoint and accompanying resource have been designed to cover points 2.9 (i) and (ii) of the Edexcel International A-level Biology specification and makes regular links to upcoming lessons which cover DNA replication and protein synthesis. In a lesson in topic 1, the students were introduced to monosaccharides as an example of a monomer and were informed that a nucleotide was another example. In line with this, the start of the lesson challenges them to recognise the key term nucleotide when only the letters U, C and T are shown. The next part of the lesson describes the structure of a DNA nucleotide and an RNA nucleotide so that the pentose sugar and the bases adenine, cytosine and guanine can be recognised as similarities whilst deoxyribose and ribose and thymine and uracil are seen as the differences. Time is taken to discuss how a phosphodiester bond is formed between adjacent nucleotides and their prior knowledge and understanding of condensation reactions is tested through a series of questions. Students are then introduced to the purine and pyrimidine bases and this leads into the description of the double-helical structure of DNA and the hydrogen bonds between complementary bases. The final section of the lesson describes the structure of mRNA, tRNA and rRNA and students are challenged to explain why this single stranded polynucleotide is shorter than DNA In addition to the current understanding and prior knowledge checks, a number of quiz rounds have been written into the lesson to introduce key terms in a fun and memorable way and the final round acts as a final check on the structures of DNA and RNA.

This lesson describes how the primary structure determines the secondary structure, 3D structure and properties of a protein. The detailed and engaging PowerPoint and accompanying resources have been designed to cover points 2.6 (ii) & (iii) of the Edexcel International A-level Biology specification but also makes specific reference to genes and protein synthesis and therefore introduces students to processes covered later in topic 2. The start of the lesson focuses on the formation of a peptide bond during a condensation reaction so that students can understand how a dipeptide is formed and therefore how a polypeptide forms when multiple reactions occur. The main part of the lesson describes the different levels of protein structure. A step by step guide is used to demonstrate how the sequences of bases in a gene acts as a template to form a sequence of codons on a mRNA strand and how this is translated into a particular sequence of amino acids known as the primary structure. The students are then challenged to apply their understanding of this process by using three more gene sequences to work out three primary structures and recognise how different genes lead to different sequences. Moving forwards, students will learn how the order of amino acids in the primary structure determines the shape of the protein molecule, through its secondary, tertiary and quaternary structure and time is taken to consider the details of each of these. There is a particular focus on the different bonds that hold the 3D shape firmly in place and a quick quiz round then introduces the importance of this shape as exemplified by enzymes, antibodies and hormones. The lesson concludes with one final task where the students have to identify three errors in a passage about the hydrolysis of a dipeptide or polypeptide.

This engaging lesson describes the basic structure of an amino acid and introduces them as the monomers of polypeptides. The PowerPoint has been designed to cover point 2.6 (i) of the Edexcel International A-level Biology specification and has been specifically written to lead into the next lesson on dipeptides and polypeptides. The lesson begins with a prior knowledge check, where the students have to use the 1st letters of 4 answers to uncover a key term. This 4-letter key term is gene and the lesson begins with this word because it is important for students to understand that these sequences of bases on DNA determine the specific sequence of amino acids in a polypeptide as covered later in the topic. Moving forwards, the students are given time to work out that there are 64 different DNA triplets and will learn that these encode for the 20 amino acids that are common to all organisms. The main task of the lesson is an observational one, where students are given time to study the displayed formula of 4 amino acids. They are not allowed to draw anything during this time but will be challenged with 3 multiple choice questions at the end. This task has been designed to allow the students to visualise how the 20 amino acids share common features in an amine and an acid group. A quick quiz round introduces the R group and time is taken to explain how the structure of this side chain is the only structural difference, before cysteine is considered in greater detail due to the presence of sulfur atoms. Students are briefly introduced to disulfide bridges so they will recognise how particular bonds form between the R groups in the tertiary structure which is covered in the next lesson. The lesson concludes with one more quiz round called LINK TO THE FUTURE where the students will see the roles played by amino acids in the later part of the course such as translation and dipeptides.

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 osmosis as the movement of free water molecules through a partially permeable membrane, down the water potential gradient. The engaging PowerPoint and accompanying resources have been designed to cover the details of specification point 2.4 of the Edexcel International A-level Biology specification and also describes the effect of solutions of different water potentials on suspended animal and plant cells. It’s likely that students will have used the term concentration in their osmosis definitions at iGCSE, 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, down 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.

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 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 lesson describes how the eyepiece graticule and stage micrometer are used to measure the size of an object with an optical microscope. The PowerPoint and accompanying resource have been designed to cover the second part of point 2.1.3 of the AQA A-level Biology specification The main task of this concise lesson involves a step by step guide which walks students through the methodology and the use of the scale on the stage micrometer to identify the size of the divisions of the eyepiece graticule. This will need them to convert between units and as this was covered in the previous lesson, a number of prior knowledge checks will check that they are able to do this. Moving forwards, the students are challenged to apply this method to a series of exam-style questions and the mark scheme is displayed on the PowerPoint so that they can assess their understanding.

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

This lesson describes how to use the magnification formula to calculate the actual sizes of specimens in a range of units. The PowerPoint and accompanying resources have been designed to cover point 1.1 (e) of the CIE A-level Biology specification but can also be used as a revision tool on the content of the previous two lessons as prior knowledge checks are included along with current understanding checks. The students are likely to have met the magnification formula at iGCSE 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. The final quiz round of the competition that has run over the course of these 3 lessons will challenge them to convert between units so they are confident when challenged to present actual size in millimetres, micrometres or nanometres.

This fully-resourced lesson describes the differences between resolution and magnification, with reference to light and electron microscopy and the engaging PowerPoint and accompanying resources have been designed to cover the content of point 1.1 (d) of the CIE A-level Biology specification. To promote engagement and focus throughout these 3 lessons in topic 1.1 (The microscope in cell studies), the PowerPoint includes an ongoing quiz competition and a score sheet is found within the resources to keep track of the cumulative scores. 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 will understand their importance when looking at the cell structures in topic 1.2. 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. As detailed above, this lesson has been written to tie in with the previous lesson on measuring cells and units as well as the next lesson on calculating actual size.

This lesson describes how the eyepiece graticule and stage micrometer are used in the measurement of cells. The engaging PowerPoint and accompanying resources have been designed to cover point 1.1 [c] of the CIE A-level Biology specification and also includes a number of tasks that have been written to ensure that students are able to recognise the millimetre, micrometre and nanometre as units of size and that they are able to convert between them. As this content is part of topic 1.1, it is likely that this lesson on the measurement of cells and the units of size will be one of the first that students will encounter in this A-level course. With this in mind, this lesson and the next two on microscopes and calculating actual size have been specifically written to contain a wide variety of tasks, including an ongoing quiz competition. This will act to maintain engagement in a topic that can sometimes discourage students at this early stage of the course whilst ensuring that the key content is covered and understanding is constantly checked. A step by step guide walks them through the use of the scale on the stage micrometer to identify the size of the divisions of the eyepiece graticule and then they are challenged to apply this method to a series of questions. Useful hints are provided throughout the lesson and students will be able to confidently convert between metres, millimetres, micrometres and nanometres by the end of the lesson A quiz scoresheet is included with the lesson so that teachers can keep track of the points won in the different rounds and add them to those won in the upcoming lessons in topic 1.1

This fully-resourced lesson describes how carbon dioxide, light intensity and temperature limit the rate of photosynthesis. The PowerPoint and accompanying resources have been designed to cover point 5.7 (viii) of the Edexcel A-level Biology B specification The lesson has been specifically written to tie in with the four previous lessons in this topic which covered the structure of the chloroplast, the light-dependent and light-independent stages and GALP as a raw material. Exam-style questions are included throughout the lesson and these require the students to explain why light intensity is important for both reactions as well as challenging them on their ability to describe how the relative concentrations of GP, GALP and RuBP would change as carbon dioxide concentration decreases. There are also links to previous topics such as enzymes when they are asked to explain why an increase in temperature above the optimum will limit the rate of photosynthesis. Step by step guides are included to support them to form some of the answers and mark schemes are always displayed so that they can quickly assess their understanding and address any misconceptions

This fully-resourced lesson describes how GALP is used as a raw material in the production of monosaccharides, amino acids and other molecules. The engaging and detailed PowerPoint and accompanying resources have been primarily designed to cover point 5.7 (vii) of the Edexcel A-level Biology B specification concerning the uses of GALP but as the lesson makes continual references to biological molecules, it can act as a revision tool for a lot of the content of topic 1. The previous lesson covered the light-independent stage and this lesson builds on that understanding to demonstrate how the product of the Calvin cycle, glyceraldehyde phosphate, is used. The start of the lesson challenges the students to identify two errors in a diagram of the cycle so that they can recall that most of the GALP molecules are used in the regeneration of ribulose bisphosphate. A quiz version of Pointless runs throughout the lesson and this is used to challenge the students to recall a biological molecule from its description. Once each molecule has been revealed, time is taken to go through the details of the formation and synthesis of this molecule from GALP or from GP in the case of fatty and amino acids. The following molecules are considered in detail during this lesson: glucose (and fructose and galactose) sucrose starch and cellulose glycerol and fatty acids amino acids nucleic acids A range of activities are used to challenge their prior knowledge of these molecules and mark schemes are always displayed for the exam-style questions to allow the students to assess their understanding. As detailed above, this lesson has been specifically written to tie in with the earlier lessons in this module on the structure of the chloroplast and the light-dependent and light-independent stages of photosynthesis.