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 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 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 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 uses step by step guides to walk students through the interpretation of genetic pedigree diagrams for monohybrid inheritance. The PowerPoint and accompanying resources have been designed to cover point 2.15 (ii) of the Edexcel International A-level Biology specification and includes the inheritance when there are more than two alleles at a gene locus as well as those that demonstrate codominance. In order to minimise the likelihood of errors and misconceptions, the guides that are included within the lesson will support the students with the following: Writing parent genotypes Working out the different gametes that are made following meiosis Interpreting Punnett crosses to work out phenotypic ratios Students can often find pedigree trees the most difficult to interpret and to explain so exemplar answers are used and the worksheets are differentiated so students can seek assistance if necessary.

This fully-resourced lesson describes the inheritance of genes with loci on the X chromosomes and considers biological examples. The detailed PowerPoint and accompanying resources have been designed to cover point 2.15 (ii) of the Edexcel International A-level specification and focuses on the inheritance of red-green colour blindness and haemophilia in humans 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. In terms of humans, the lesson focuses on haemophilia and red-green colour blindness 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 task of the lesson challenge the students to apply their knowledge to an exam 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 mark schemes to allow them to assess their progress and address any misconceptions

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 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 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 lesson describes how passive transport is brought about (simple) diffusion and facilitated diffusion. The PowerPoint and accompanying resources have been designed to cover the first part of specification point 4.2 (ii) of the Edexcel A-level Biology B specification but also covers 4.2 (iii) as the relationship between the properties of a molecule and the method by which they are transported is discussed. The structure of the cell surface membrane was described in the previous lesson, 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 series of questions about the alveoli 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. One of two quick quiz rounds 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 engaging lesson describes the myogenic stimulation of the heart and focuses on the roles of the SAN, AVN and bundle of His. The PowerPoint and accompanying resources have been designed to cover the point 4.4 (iv) of the Edexcel A-level Biology B specification but also describes the role of the Purkyne fibres. The lesson begins with the introduction of the SAN 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. The lesson has been written to make clear links to the cardiac cycle and the structure of the heart and students are challenged on their knowledge of this system from earlier in the topic. 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 fully-resourced lesson describes the roles of the platelets and plasma proteins in the sequence of events that lead to blood clotting. The engaging PowerPoint and accompanying resources have been primarily designed to cover the content detailed in point 4.4 (viii) of the Edexcel A-level Biology B specification and includes descriptions of the roles of thromboplastin, thrombin and fibrin but time has also been taken to look at haemophilia as a sex-linked disease so that students are prepared for topic 8 (genetic variation). The lesson begins with the introduction of clotting factors as integral parts of the blood clotting process and explains that factor III, thromboplastin, needs to be recalled as well as the events that immediately precede and follows its release. Students will learn how damage to the lining and the exposure of collagen triggers the release of this factor and how a cascade of events then results. Quick quiz rounds and tasks are used to introduce the names of the other substances involved which are prothrombin, thrombin, fibrinogen and fibrin. In a link to the upcoming topic of proteins, students will understand how the insolubility of fibrin enables this mesh of fibres to trap platelets and red blood cells and to form the permanent clot. The final part of the lesson introduces haemophilia as a sex-linked disease and students are challenged to apply their knowledge to an unfamiliar situation as they have to write genotypes and determine phenotypes before explaining why men are more likely to suffer from this disease than women.

This engaging lesson describes how the structure of the mammalian lung is adapted for rapid gaseous exchange. The PowerPoint has been designed to cover point 2.1 (iii) of the Pearson Edexcel A-level Biology A specification and focuses on the essential features of the alveolar epithelium as well as the mechanism of ventilation to maintain a steep concentration gradient for the simple diffusion of oxygen and carbon dioxide. Gas exchange at the alveoli is a topic that was covered at GCSE and considered during the previous lessons in topic 2.1 so this lesson has been written to challenge the recall of that knowledge and then to build on it. The main focus of the first half of the lesson is the type of epithelium found lining the alveoli and students will discover that a single layer of flattened cells known as simple, squamous epithelium acts to reduce the diffusion distance. The following features of the alveolar epithelium are also covered: Surface area Moist lining Production of surfactant The maintenance of a steep concentration gradient is the role of the respiratory system and the next part of the lesson focuses on the diaphragm and intercostal muscles. As the mechanism of inhalation is a cascade of events, the details of this process are covered in a step by step format using bullet points. At each step, time is taken to discuss the key details which includes an introduction to Boyle’s law that reveals the inverse relationship between volume and pressure. It is crucial that students are able to describe how the actions of the diaphragm, external intercostal muscles and ribcage result in an increased volume of the thoracic cavity and a subsequent decrease in the pressure, which is below the pressure outside of the body. At this point, their recall of the structures of the mammalian gas exchange system is tested, to ensure that they can describe the pathway taken by air when moving into the lungs.

This lesson describes and explains the effect of an increasing temperature on the rate of an enzyme-catalysed reaction. The PowerPoint and the accompanying resource are part of the 1st lesson in a series of 4 which cover the content detailed in point 3.2 (a) of the CIE A-level Biology specification and this lesson has been specifically planned to tie in with the lesson in 3.1 where the properties of enzymes and their mechanism of action were introduced. The lesson begins by challenging the students to recognise optimum as a key term from its 6 synonyms that are shown on the board. Time is taken to ensure that the students understand that the optimum temperature is the temperature at which the most enzyme-product complexes are produced per second and therefore the temperature at which the rate of an enzyme-controlled reaction works at its maximum. The optimum temperatures of DNA polymerase in humans and in a thermophilic bacteria and RUBISCO in a tomato plant are used to demonstrate how different enzymes have different optimum temperatures and the roles of the latter two in the PCR and photosynthesis are briefly described to prepare students for these lessons in topics 19 and 13. Moving forwards, the rest of the lesson focuses on enzyme activity at temperatures below the optimum and at temperatures above the optimum. Students will understand that increasing the temperature increases the kinetic energy of the enzyme and substrate molecules, and this increases the likelihood of successful collisions and the production of enzyme-substrate and enzyme-product complexes. When considering the effect of increasing the temperature above the optimum, continual references are made to the previous lesson and the control of the shape of the active site by the tertiary structure. Students will be able to describe how the hydrogen and ionic bonds in the tertiary structure are broken by the vibrations associated with higher temperatures and are challenged to complete the graph to show how the rate of reaction decreases to 0 when the enzyme has denatured. Please note that this lesson has been designed specifically to explain the relationship between the change in temperature and the rate of reaction and not the practical skills that would be covered in a core practical lesson

This fully-resourced lesson describes how enzymes function intracellularly and extracellularly and explains their mode of action. The engaging PowerPoint and accompanying resources have been designed to cover points 3.1 (a, b & c) and considers the details of Fischer’s lock and key hypothesis and Koshland’s induced-fit model and explains how an enzyme’s specificity is related to their 3D structure and enables them to act as biological catalysts. The lesson has been planned to tie in with topic 2.3, and to challenge the students on their knowledge of protein structure and globular proteins. This prior knowledge is tested through a series of exam-style questions along with current understanding and mark schemes are included in the PowerPoint so that students can assess their answers. Students will learn that enzymes are large globular proteins which contain an active site that consists of a small number of amino acids. Emil Fischer’s lock and key hypothesis is introduced to enable students to recognise that their specificity is the result of an active site that is complementary in shape to a single type of substrate. Time is taken to discuss key details such as the control of the shape of the active site by the tertiary structure of the protein. The induced-fit model is described so students can understand how the enzyme-susbtrate complex is stabilised and then students are challenged to order the sequence of events in an enzyme-controlled reaction. The lesson finishes with a focus on ATP synthase and DNA polymerase so that students are aware of these important intracellular enzymes when learning about the details of respiration and DNA replication before they are challenged on their knowledge of carbohydrates, lipids and proteins from topics 1.2 - 1.4 as they have to recognise some extracellular digestive enzymes from descriptions of their biological molecule substrates.

This lesson describes how enzymes can be immobilised in calcium alginate and compares their activity against enzymes that are free in solution. The PowerPoint and the accompanying resources have been designed to cover point 3.2 (d) of the CIE A-level Biology specification. The lesson has been planned to challenge the students on their ability to apply knowledge to a potentially unfamiliar situation. A series of exam-style questions which include “suggest” and “describe and explain” questions are used throughout the lesson and these will allow the students to recognise the advantages and disadvantages of a particular method. Although the alginate method is the only one referenced in this specification point, the adsorption and covalent bonding methods are introduced and then briefly analysed to allow students to understand that a matrix doesn’t involve these bonds which could disrupt the active site. The remainder of the lesson introduces some actual examples of the use of immobilised enzymes with the aim of increasing the relevance. Please note that this lesson has been written to explain the effect of immobilisation on enzyme activity. The practical element of carrying out the investigation is described in a separate lesson.

This lesson describes and explains how increasing the temperature affects the rate of an enzyme-controlled reaction. The PowerPoint and the accompanying resource have been designed to cover the second part of point 1.4.2 of the AQA A-level Biology specification and ties in directly with the previous lesson on the properties of enzymes and their mechanism of action. The lesson begins by challenging the students to recognise optimum as a key term from its 6 synonyms that are shown on the board. Time is taken to ensure that the students understand that the optimum temperature is the temperature at which the most enzyme-product complexes are produced per second and therefore the temperature at which the rate of an enzyme-controlled reaction works at its maximum. The optimum temperatures of DNA polymerase in humans and in a thermophilic bacteria and RUBISCO in a tomato plant are used to demonstrate how different enzymes have different optimum temperatures and the roles of the latter two in the PCR and photosynthesis are briefly described to prepare students for these future lessons. Moving forwards, the rest of the lesson focuses on enzyme activity at temperatures below the optimum and at temperatures above the optimum. Students will understand that increasing the temperature increases the kinetic energy of the enzyme and substrate molecules, and this increases the likelihood of successful collisions and the production of enzyme-substrate and enzyme-product complexes. When considering the effect of increasing the temperature above the optimum, continual references are made to the previous lesson and the control of the shape of the active site by the tertiary structure. Students will be able to describe how the hydrogen and ionic bonds in the tertiary structure are broken by the vibrations associated with higher temperatures and result in an active site that is no longer complementary to the substrate. Key terminology such as denaturation is used throughout. Please note that this lesson has been designed specifically to explain the relationship between the change in temperature and the rate of reaction and not the practical skills that would be covered in a core practical lesson

This detailed lesson describes the the structure and function of the motor neurones that form the autonomic nervous system and is responsible for automatic responses. The engaging PowerPoint and accompanying resource have been designed to cover point 9.4 (v) of the Edexcel A-level Biology B specification and describes the sympathetic and parasympathetic divisions and how they act antagonistically. The lesson begins with a focus on the types of effectors that will be connected to the CNS by autonomic motor neurones. Students will learn that effectors which are not under voluntary control such as cardiac muscle, smooth muscle and glands will be innervated by these neurones. Moving forwards, a quick quiz competition is used to introduced ganglia as a structure which connects the two or more neurones involved in the cell signalling between the CNS and the effector. This leads into the discovery of the two divisions and students will begin to recognise the differences between the sympathetic and parasympathetic systems based on function but also structure. The remainder of the lesson looks at the differing effects of these two systems. This lesson has been written to tie in with the lesson on the organisation of the mammalian nervous system which was covered earlier in this topic