This fully-resourced lesson describes the stages of meiosis and specifically the events which contribute to genetic variation. The detailed PowerPoint and accompanying resources have been designed to cover specification points 2.3 (iv) & (v) of the Edexcel A-level Biology B specification and includes description of crossing over, independent assortment and the production of haploid gametes In order to understand how the events of meiosis like crossing over and random assortment and independent segregation can lead to variation, students need to be clear in their understanding that DNA replication in interphase results in homologous chromosomes as pairs of sister chromatids. Therefore the beginning of the lesson focuses on the chromosomes in the parent cell and this first part of the cycle and students will be introduced to non-sister chromatids and the fact that they may contain different alleles which is important for the exchange that occurs during crossing over. Time is taken to go through this event in prophase I in a step by step guide so that the students can recognise that the result can be new combinations of alleles that were not present in the parent cell. Moving forwards, the lesson explores how the independent segregation of chromosomes and chromatids during anaphase I and II results in genetically different gametes. The final part of the lesson looks at the use of a mathematical expression to calculate the possible combinations of alleles in gametes as well as in a zygote following the random fertilisation of haploid gametes. Understanding and prior knowledge checks are interspersed throughout the lesson as well as a series of exam questions which challenge the students to apply their knowledge to potentially unfamiliar situations.

This fully-resourced lesson describes the relationship between the structure and function of the eukaryotic cell structures. The detailed and engaging PowerPoint and accompanying exam-question worksheets (which are all differentiated) have been designed to cover point 1.2 (b) of the CIE International A-level Biology specification As cells are the building blocks of living organisms, it makes sense that they would be heavily involved in all of the 19 topics in the CIE International course and intricate planning has ensured that links to previously covered topics at GCSE are made and details linking to upcoming topics are made throughout the lesson. A wide range of activities, that include exam-style questions, class discussion points and quick quiz competitions, will maintain motivation and engagement whilst covering the finer details of the following structures: nucleus nucleolus ribosomes rough endoplasmic reticulum Golgi apparatus lysosomes smooth endoplasmic reticulum mitochondria cell surface membrane centrioles vacuole chloroplasts cell wall plasmodesmata As mentioned above, all of the worksheets have been differentiated to support students of differing abilities whilst maintaining challenge Due to the detail that is included in this lesson, it is estimated that it will take in excess of 3/4 hours of allocated A-level teaching time to cover the work

This lesson describes how molecules move across the cell membrane by the passive methods of simple and facilitated diffusion. The PowerPoint and accompanying resources have been designed to cover the first part of specification point 2.1.5 (d) [i] of the OCR A-level Biology A 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 2.1.5 (b), 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 fully-resourced lesson describes the control of gene expression at a post-transcriptional level through the removal of introns during splicing. The detailed PowerPoint and accompanying resources have been designed to cover the second part of point 6.1.1 (b) as detailed in the OCR A-level Biology A specification and also explains how it’s possible for 1 gene to give rise to multiple products as a result of this post-transcriptional modification of mRNA. 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 module 2.1.3 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. At this point, the students will complete a task that acts as a prior knowledge check where they have to identify the 6 errors in the descriptive passage about the lac operon and its role in the regulation of gene expression in prokaryotes. 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 period of class discussion 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 lesson describes the formation of dipeptides & polypeptides and the different levels of protein structure with reference to specific examples in living organisms. Both the engaging PowerPoint and accompanying resources have been designed to cover specification points 2.1.2 (l) & (m) of the OCR A-level Biology A course and make continual links to previous lessons such as amino acids as well as to upcoming lessons like antibodies. 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. Students will see the differences between globular and fibrous protein and again biological examples are used to increase relevance. The lesson concludes with one final quiz round called STRUC by NUMBERS where the students have to use their understanding of the protein structures to calculate a numerical answer.

This engaging and fully-resourced lesson describes the relationship between the structure of the chloroplast and its role as the site of photosynthesis. The PowerPoint and accompanying resources have been designed to prepare the students for topic 5.1 (Photosynthesis) of the AQA A-level Biology course Students were introduced to the cell structures in eukaryotic cells in topic 2.1 so this lesson has been written to build on that knowledge. A version of the quiz show POINTLESS runs throughout the lesson and this maintains engagement whilst challenging the students to recall the parts of the chloroplast based on a description which is related to their function. The following structures are covered in this lesson: double membrane thylakoids (grana) stroma intergranal lamellae starch grains chloroplast DNA and ribosomes Once each structure has been recalled, a range of activities are used to ensure that key details are understood such as the role of the thylakoid membranes in the light-dependent reactions and the importance of ATP and reduced NADP for the reduction of GP to TP in the Calvin cycle. This lesson has been specifically written to prepare students for the upcoming lessons on the light-dependent and light-independent reactions

This fully-resourced lesson describes the reactions of the light independent stage of photosynthesis that takes place in the chloroplast stroma. The detailed PowerPoint and accompanying resources have been designed to cover points 5.7 (iv, v & vi) of the Edexcel A-level Biology B specification and lengthy planning has ensured that links are continually made to the previous lesson on the light-dependent stage so that students can understand how the products of that stage are essential for the Calvin cycle The lesson begins with an existing knowledge check where the students are challenged to recall the names of structures, substances and reactions from the light-dependent stage in order to reveal the abbreviations of the main 3 substances in the light-independent stage. This immediately introduces RuBP, GP and GALP and students are then shown how these substances fit into the cycle. The main section of the lesson focuses on the three phases of the Calvin cycle and time is taken to explore the key details of each phase and includes: The role of RuBisCO in carbon fixation The role of the products of the light-dependent stage, ATP and reduced NADP, in the reduction of GP to GALP The use of the majority of the GALP in the regeneration of RuBP A step-by-step guide, with selected questions for the class to consider together, is used to show how 6 turns of the cycle are needed to form the GALP that will then be used to synthesise 1 molecule of glucose. A series of exam-style questions are included at appropriate points of the lesson and this will introduce limiting factors as well as testing their ability to answer questions about this stage when presented with an unfamiliar scientific investigation. The mark schemes are included in the PowerPoint so students can assess their understanding and any misconceptions are immediately addressed. This lesson has been specifically written to tie in with the previous lessons on the structure of a chloroplast and the light-dependent stage as well as upcoming lessons on the synthesis of organic molecules from GALP and limiting factors

This fully-resourced lesson describes the structure of the DNA, including the structure of the nucleotides and the bonds that form the backbone and double helix. Both the engaging PowerPoint and accompanying resources have been designed to cover specification point 1.4 (i) as detailed in the Edexcel A-level Biology B specification. As students will already have some knowledge of this nucleic acid from GCSE, the lesson has been written to build on this prior knowledge and then to add key detail. Students need to have a clear understanding of the structure of a nucleotide for this topic as well as upcoming lessons on RNA and ATP, so the start of the lesson focuses on these monomers and the three components. Time is taken to look at the bases and students will be introduced to purines and pyrimidines and are reminded of the bonds that form between the complementary base pairs. A series of exam-style questions checks on their current understanding and mark schemes are displayed to enable the students to assess their understanding and to address any misconceptions should they arise. Phosphodiester bonds are also introduced before a quick quiz competition is used to introduce the numbers 5 and 3 so that the directionality of the DNA strand can be explained.

This detailed lesson describes how the anti-sense strand of DNA is used as template to form messenger RNA (mRNA) during transcription. The PowerPoint and accompanying resource have been designed to cover the first part of point 1.4 (vi) as detailed in the Edexcel A-level Biology B specification. The lesson begins by challenging the students to recall 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 anti-sense strand and the other strand is the sense 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 as well as their own biological knowledge. 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 fully-resourced lesson describes how a triglyceride is synthesised and explains how the structure of this lipid relates to its numerous roles. The engaging PowerPoint and accompanying worksheets have been designed to cover specification points 1.2 (i), (ii and (iii) as detailed in the Edexcel A-level Biology B specification and links are also made to related future topics such as 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 a triglyceride mean that it has numerous roles in organisms including that of an energy store and source and as an insulator of heat and electricity.

This detailed lesson describes how the structure of collagen and haemoglobin are related to their function. The engaging PowerPoint and accompanying worksheet have been designed to cover specification point 1.3 (v) of the Edexcel A-level Biology B course and also introduces fibrous and globular proteins as a result. The first part of the lesson looks at the structure of haemoglobin, and describes how the presence of an iron-containing haem group on the outside of the 4 polypeptide chains explains its ability to form oxyhaemoglobin. Moving forwards, the importance of the solubility of this protein is considered and related to the direction that the hydrophobic R groups point. At this point of the lesson, the students are challenged to construct a comparison table which can be filled in as the lesson progresses and as they are given more details of collagen. The section of the lesson concerning collagen begins with the introduction of its function in the artery wall so that students can recognise how fibrous proteins have roles associated with mechanical strength. Time is taken to discuss their solubility as well as the presence of repetitive amino acid sequences. The remainder of the lesson considers four more proteins and the final task challenges the students to use their completed table to write a summary passage comparing globular and fibrous proteins.

This concise lesson describes the essential features of the alveolar epithelium as a surface over which gas exchange takes place. The engaging PowerPoint has been designed to cover the fourth part of point 3.2 of the AQA A-level Biology specification and also includes an introduction to ventilation which is covered in the following lesson. Gas exchange at the alveoli is a topic that was covered at GCSE so this lesson has been written to challenge the recall of that knowledge and to build on it. The main focus 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. Again, students will have met this in a lesson in topic 2 on specialised cells (and tissues) so a number of prior knowledge checks are used alongside current understanding checks. The following features of the alveolar epithelium are also covered: Surface area Moist lining Production of surfactant The maintenance of a steep concentration gradient As a constant ventilation supply is critical for the maintenance of the steep concentration gradient, the final part of the lesson considers the mechanism of ventilation to prepare the students for the next lesson.

This detailed lesson describes the differences between monosaccharides, disaccharides and polysaccharides. The PowerPoint and accompanying resource have been designed to cover point 1.1 (i) that’s detailed in the Edexcel A-level Biology B specification and the aim of this lesson is to provide the students with key details to prepare them for the upcoming lessons on the carbohydrate groups. The lesson begins with a made-up round of the quiz show POINTLESS, where students have to try to identify four answers to do with carbohydrates. In doing so, they will learn or recall that these molecules are made from carbon, hydrogen and oxygen, that they are a source of energy which can sometimes be rightly or wrongly associated with obesity and that the names of the three main groups is derived from the Greek word sakkharon. A number of quick quiz rounds have been written into the lesson to introduce key terms in a fun and memorable way and the first round allows the students to meet some of common monosaccharides. Moving forwards, students will learn that a disaccharide is formed when two of these monomers are joined together and they are then challenged on their knowledge of condensation reactions which were originally encountered during the lesson on water. Students will understand how multiple reactions and multiple glycosidic bonds will result in the formation of a polysaccharide and glycogen and starch are introduced as well as amylose and amylopectin as components of this latter polymer. The final part of the lesson considers how hydrolysis reactions allow polysaccharides and disaccharides to be broken back down into monosaccharides.

This fully-resourced lesson describes the beneficial, neutral and harmful effects of gene mutations on the primary structure of a polypeptide. The engaging and detailed PowerPoint and accompanying resources have been designed to cover point 6.1.1 (a) of the OCR A-level Biology A specification which states that students should be able to understand how substitutions, deletions and insertions change the base sequence and describe how this affects protein production and function. In order to understand how a change in the base sequence can affect the order of the amino acids, students must be confident in their understanding and application of protein synthesis which was covered in module 2.1.3. Therefore, the start of the lesson focuses on transcription and translation and students are guided through the use of the codon table to identify amino acids. Moving forwards, a task called known as THE WALL is used to introduce to the names of three types of gene mutation whilst challenging the students to recognise terms which are associated with the genetic code and were met back in 2.1.3. The main focus of the lesson is base substitutions and how these mutations may or may not cause a change to the amino acid sequence. The students are challenged to use their knowledge of the degenerate nature of the genetic code to explain how a silent mutation can result. The rest of the lesson looks at base deletions and base insertions and students are introduced to the idea of a frameshift mutation. One particular task challenges the students to evaluate the statement that base deletions have a bigger impact on primary structure than base substitutions. This is a differentiated task and they have to compare the fact that the reading frame is shifted by a deletion against the change in a single base by a substitution

This fully-resourced lesson describes the key events that occur during the three stages of the cardiac cycle and relates these to the structure of the mammalian heart. The engaging and detailed PowerPoint and accompanying resources have been designed to cover point 1.8 of the Edexcel International A-level Biology specification As the structure of the heart was covered at iGCSE, the lesson has been planned to build on this prior knowledge whilst adding the key details which will enable students to provide A-level standard answers. The primary focus is the identification of the different structures of the heart but it also challenges their ability to recognise the important relationship to function. For example, time is taken to ensure that students can explain why the atrial walls are thinner than the ventricular walls and why the right ventricle has a thinner wall than the left ventricle. Opportunities are taken throughout the lesson to link this topic to the others found in topic 1 including those which have already been covered like the blood vessels. There is also an application question where students have to explain why a hole in the ventricular septum would need to be repaired if it doesn’t naturally close over time. The next part of the lesson introduces the cardiac cycle through the use of quick quiz competition which generates the key term systole. Students will learn that there are three stages in the cycle are atrial and ventricular systole followed by cardiac diastole and that the uni-directional movement of blood during these stages is maintained by the atrioventricular and semi-lunar valves. This leads into the emphasis of the key point that pressure changes in the chambers and the major arteries is the cause of the opening and closing of these sets of valves. Students are given a description of the pressure change that results in the opening of the AV valves and shown where this would be found on the graph detailing the pressure changes of the cardiac cycle. They then have to use this as a guide to write descriptions for the closing of the AV valve and the opening and closing of the semi-lunar valves and to locate these on the graph. By providing the students with this graph, the rest of the lesson can focus on explaining how these changes come about. Students have to use their current and prior knowledge of the chambers and blood vessels to write 4 descriptions that cover the cardiac cycle. The final part of the lesson covers the changes in the volume of the ventricle. It is estimated that it will take in excess of 2 hours of allocated A-level teaching time to cover the detail included in this lesson as required by this specification point

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 point 2.1 (vi) of the Edexcel A-level Biology B specification and the importance of specimen staining is also briefly introduced so that students are prepared for the next lesson. 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 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.

This lesson describes how the hydrolysis of ATP provides energy for biological processes such as active transport and endocytosis and exocytosis. The PowerPoint and accompanying resources have been designed to cover points 4.2 (iv), (v) & (vi) of the Edexcel A-level Biology B specification The start of the lesson focuses on the structure of this energy currency and challenges the students to use their knowledge of nucleotides and specifically RNA nucleotides to recognise the components of ATP. As a result, they will learn that this molecule consists of adenine, ribose and three phosphate groups. In order to release the stored energy, ATP must be broken down and students will be given time to discuss which reaction will be involved as well as the products of this reaction. Time is taken to describe how the hydrolysis of ATP can be coupled to energy-requiring reactions and this leads into a series of exam-style questions where students are challenged on their knowledge of simple and facilitated diffusion to recognise that ATP is needed for active transport. These questions also challenge them to 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 and in the release of ADH from the pituitary gland during osmoregulation.

This fully-resourced lesson describes the advantages of the double circulatory system that is found in mammals. The engaging PowerPoint and accompanying resources have been designed to cover point 4.4 (ii) of the Edexcel A-level Biology B specification and focuses on the differences in pressure between the pulmonary and systemic circulation. The lesson begins with a focus on the meaning of a double circulatory system and checks that students are clear in the understanding that the blood passes through the heart twice per cycle of the body. Beginning with the pulmonary circulation, students will recall that the pulmonary artery carries the blood from the right ventricle to the lungs. An opportunity is taken at this point to check on their knowledge of inhalation and the respiratory system as well as the gas exchange between the alveoli and the capillary bed. A quick quiz is used to introduce arterioles and students will learn that these blood vessels play a crucial role in the changes in blood pressure that prevent the capillaries from damage. When looking at the systemic circulation, time is taken to look at the coronary arteries and renal artery as students have to be aware of these vessels in addition to the ones associated with the heart. In the final part of the lesson, students are challenged to explain how the structure of the heart generates a higher pressure in the systemic circulation and then to explain why the differing pressures are necessary.

This fully-resourced lesson describes the conversion of Calvin cycle intermediates to carbohydrates, lipids and amino acids. The engaging and detailed PowerPoint and accompanying resources have been primarily designed to cover point 13.1 (h) of the CIE A-level Biology specification concerning the uses of GP and TP 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 2. The previous lesson described the three stages of the Calvin cycle and this lesson builds on that understanding to demonstrate how the intermediates of the cycle, GP and TP, are 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 TP 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 TP 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 topic on the structure of the chloroplast, the light-dependent stage of photosynthesis and the Calvin cycle.

This detailed lesson describes how water can be moved through plant cells by the apoplastic and symplastic pathways. The engaging PowerPoint and accompanying resource have been designed to cover point 4.7 (ii) of the Edexcel A-level Biology B specification and includes a description of the movement from the endodermis to the xylem to tie in with the following lesson on the cohesion-tension model. The lesson begins by looking at the specialised features of the root hair cell to allow students to understand how these epidermal cells absorb water and mineral ions from the soil. Moving forwards, students are introduced to key terminology such as epidermis and root cortex before time is taken to look at the different pathways that water and minerals use to transverse across the cortex. Discussion points are included throughout the lesson to encourage the students to think about each topic in depth and challenges them to think about important questions such as why the apoplastic pathway is needed for the water carrying the ions. Students will be introduced to the Casparian strip and will learn how this layer of cells blocks the apoplastic pathway. A step by step method using class questions and considered answers is used to guide them through the different steps and to support them when writing the detailed description.