This lesson describes the meaning of positive feedback and explains how negative feedback control is involved in maintaining systems within narrow limits. The PowerPoint and accompanying resources have been designed to cover points 7.16 (i) and (ii) of the Edexcel International A-level Biology specification but also provide introductory details for upcoming topics such as the importance of homeostasis during exercise and the depolarisation of a neurone. The normal ranges for blood glucose concentration, blood pH and body temperature are introduced at the start of the lesson to allow students to recognise that these aspects have to be maintained within narrow limits. A series of exam-style questions then challenge their recall of knowledge from topics 1 - 6 as they have to explain why it’s important that each of these aspects is maintained within these limits. The students were introduced to homeostasis at GCSE, so this process is revisited and discussed, so that students are prepared for an upcoming lesson on exercise, as well as for the next part of the lesson on negative feedback control. Students will learn how this form of control reverses the original change and biological examples are used to emphasise the importance of this system for restoring levels to the limits (and the optimum). The remainder of the lesson explains how positive feedback differs from negative feedback as it increases the original change and the role of oxytocin in birth and the movement of sodium ions into a neurone are used to exemplify the action of this control system.

This lesson describes how the products of the light-independent reactions of photosynthesis are used by plants, animals and other organisms. The engaging and detailed PowerPoint and accompanying resources have been primarily designed to cover point 5.4 (ii) of the Edexcel International A-level Biology specification concerning the uses of GP and 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 and 2. The previous lesson described the light-independent reactions and this lesson builds on that understanding to demonstrate how the intermediates of the cycle, GP and GALP, 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 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 topic on the structure of the chloroplast and the light-dependent and light-independent reactions of photosynthesis

This fully-resourced lesson describes how cells become specialised through differential gene expression. The PowerPoint and accompanying resources have been designed to cover the details of point 3.19 of the Edexcel International A-level Biology specification. This is one of the more difficult concepts in this A-level course and therefore key points are reiterated throughout this lesson to increase the likelihood of student understanding and to support them when trying to make links to actual biological examples in living organisms. There is a clear connection to transcription and translation as covered in topic 2, so the lesson begins by reminding students that in addition to the structural gene in a transcription unit, there is the promotor region where RNA polymerase binds. Students are introduced to the idea of transcription factors and will understand how these molecules can activate or repress transcription by enabling or preventing the binding of the enzyme. At this point, students are challenged on their current understanding with a series of questions about DELLA proteins so they can see how these molecules prevent the binding of RNA polymerase. The final section of the lesson looks at one further example with oestrogen and the ER receptor and explains how the binding of this chemical results in the release of the inhibitor and the production of active mRNA.

This fully-resourced lesson describes the relationship between the structure of monosaccharides and their roles in living organisms. The detailed and engaging PowerPoint and accompanying resources have been designed to cover the second part of points 1.12 & 1.13 of the Pearson Edexcel A-level Biology A specification and looks at alpha-glucose, galactose, fructose, deoxyribose and ribose. 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. Using the molecular formula of glucose as a guide, students will be given the general formula for the monosaccharides and will learn that deoxyribose is an exception to the rule that the number of carbon and oxygen atoms are equal. Moving forwards, students have to study the displayed formula of glucose for two minutes without being able to note anything down before they are challenged to recreate what they saw in a test of their observational skills. At this point of the lesson, the idea of numbering the carbons is introduced so that the different glycosidic bonds can be understood in an upcoming lesson as well as the recognition of the different isomers of glucose. The difference between alpha and beta-glucose is provided but students do not need to consider the beta form until topic 4. The remainder of the lesson focuses on the roles of the monosaccharides and the final task involves a series of application questions where the students are challenged to suggest why ribose could be considered important for active transport and muscle contraction

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 how urea is formed in the liver by deamination and then removed from the bloodstream by ultrafiltration at the kidney. The PowerPoint and accompanying resources have been designed to cover point 9.9 (ii) of the Edexcel A-level Biology B specification. The first part of the lesson describes how deamination and the ornithine cycle forms urea. Although the students are not required to know the details of the cycle, it is important that they are aware of how the product of deamination, ammonia, is converted into urea (and why). Moving forwards, the rest of the lesson has been written to allow the students to discover ultrafiltration as a particular function and to be able to explain how the mechanisms found in the glomerulus and the Bowman’s capsule control the movement of small molecules out of the blood plasma. Key terminology is used throughout and students will learn how the combination of the capillary endothelium and the podocytes creates filtration slits that allow glucose, water, urea and ions through into the Bowman’s capsule but ensure that blood cells and plasma proteins remain in the bloodstream. A number of quiz competitions are used to introduce key terms and values in a fun and memorable way whilst understanding and prior knowledge checks allow the students to assess their understanding of the current topic and to challenge themselves to make links to earlier topics. The final task of the lesson challenges the students to apply their knowledge by recognising substances found in a urine sample that shouldn’t be present and to explain why this would cause a problem

This detailed lesson describes the pathways and explains the mechanisms by which water and mineral ions are transported from the soil to the xylem. Both the engaging PowerPoint and accompanying resource have been designed to cover the first part of point 7.2 [c] in the CIE International A-level Biology specification. The lesson begins by looking at the specialised features of the root hair cell so that students can 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. The main part of the lesson focuses on the role of the endodermis in the transport of the water and ions into the xylem. 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. This lesson has been written to tie in with the next lesson on the pathways and mechanisms by which water and mineral ions are transported to the leaves.

This lesson describes the ring structure of alpha and beta glucose and uses these two monomers as examples of monosaccharides when introducing disaccharides and polysaccharides as well as polymers and macromolecules. The PowerPoint and accompanying worksheet have been designed to cover specification points 2.2 (a) & (b) of the CIE International A-level Biology course, and condensation and hydrolysis reactions are also introduced and their importance for biological molecules emphasised. Monomers were previously met at GCSE and so the beginning of the lesson focuses on the recall of the meaning of this key term. A made-up version of the quiz show POINTLESS gives the students the opportunity to discuss and 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. This introduces the monosaccharides as the simplest sugars before the first in a series of quiz rounds is used to introduce fructose, ribose and importantly glucose as a few examples. Using the molecular formula of glucose as a guide, students will be given the general formula for the monosaccharides and will learn that deoxyribose is an exception to the rule that the number of carbon and oxygen atoms are equal. In the next task, students have to study the displayed formula of glucose for two minutes without being able to note anything down before they are challenged to recreate what they saw in a test of their observational skills. The difference between alpha and beta-glucose is provided and students are again challenged to draw a molecule of glucose, this time for the beta form. Moving forwards, students will learn that disaccharides are formed from two monosaccharides and this is used to initiate a discussion about how monomers need to be linked together even more times to make the larger chains known as polymers. The final section of the lesson looks at the roles of condensation and hydrolysis reactions in this formation of larger molecules as well as in the break down of larger molecules into smaller molecules.

This lesson describes how the structures of the xylem vessels, sieve tube elements and companion cells relates to their functions. The PowerPoint and accompanying resources have been designed to cover points (m & q) in topic 3 of AS unit 2 of the WJEC A-level Biology specification. Please note that this lesson does not include light and electron microscope pictures, so teachers will have to source and add these in themselves. The lessons begins by challenging the students to identify the substances that a plant needs for the cellular reactions, where they are absorbed and where these reactions occur in a plant. The aim of this task is to get the students to recognise that water and mineral ions are absorbed in the roots and needed in the leaves whilst the products of photosynthesis are in the leaves and need to be used all over the plant. Students will be reminded that the xylem and phloem are part of the vascular system responsible for transporting these substances and then the rest of the lesson focuses on linking structure to function. A range of tasks which include discussion points, exam-style questions and quick quiz rounds are used to describe how lignification results in the xylem as a hollow tube of xylem cells to allow water to move as a complete column. They will also learn that the narrow diameter of this vessel allows capillary action to move water molecules up the sides of the vessel. The same process is used to enable students to understand how the structures of the companion cells allows assimilates to be loaded before being moved to the sieve tube elements through the plasmodesmata.

This fully-resourced lesson explores what happens to lactate after a period of anaerobic respiration as detailed in point 7.7 of the Pearson Edexcel A-level Biology A (Salters Nuffield) specification. Students will learn how pyruvate is converted to lactate using reduced NAD and that the reoxidation of the coenzyme allows glycolysis to continue. The lesson begins with a focus on the coenzyme, NAD, and students are challenged to recall details of its role in the oxidation of triose phosphate. Students will learn that oxidative phosphorylation in aerobic respiration allows these coenzymes to be reoxidised but that another metabolic pathway has to operate when there is no oxygen. Time is taken to go through the lactate fermentation pathway and students are encouraged to discuss the conversions before applying their knowledge to complete the diagram and passages about the pathway. Students are introduced to the oxygen debt and will learn how the volume consumed after vigorous exercise is used to catabolise lactic acid and to restore the body’s stores to normal levels.

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 explains the meaning of gene, allele, genotype, phenotype, recessive, dominant, codominance, homozygote and heterozygote. The engaging PowerPoint and accompanying resources have been designed to cover specification point 2.15 (i) of the Edexcel International A-level Biology but also covers the meaning of genome, gene locus, homologous chromosomes, multiple alleles, autosomes and sex chromosomes as a recognition of these will be useful for upcoming lessons. As some of these terms were met at GCSE, this fully-resourced lesson has been designed to include a wide range of activities that build on this prior knowledge and provide clear explanations as to their meanings as well as numerous examples of their use in both questions and exemplary answers. The main task provides the students with an opportunity to apply their understanding by recognising a dominance hierarchy in a multiple alleles characteristic and then calculating a phenotypic ratio when given a completed genetic diagram. Other tasks include prior knowledge checks, discussion points to encourage students to consider the implementation of the genetic terms and quiz competitions to introduce new terms, maintain engagement and to act as an understanding check.

This clear and concise lesson covers the Link reaction and its site in the cell as detailed in point 5.2.2 (d) of the OCR A-level Biology A specification. The PowerPoint explains how the product of glycolysis, pyruvate, is decarboxylated and dehydrogenated and combined with coenzyme A to form acetyl coenzyme A which will then enter the Krebs cycle. The lesson begins with a challenge, where the students have to recall the details of glycolysis in order to form the word matrix. This introduces the key point that this stage occurs in this part of the mitochondria and time is taken to explain why the reactions occur in the matrix as opposed to the cytoplasm like glycolysis. Moving forwards, the Link reaction is covered in 5 detailed bullet points and students have to add the key information to these points using their prior knowledge as well as knowledge provided in terms of NAD. The students will recognise that this reaction occurs twice per molecule of glucose and a quick quiz competition is used to test their understanding of the numbers of the different products of this stage. This is just one of the range of methods that are used to check understanding and all answers are explained to allow students to assess their progress. This lesson has been written to tie in with the other uploaded lessons on glycolysis and the Krebs cycle and oxidative phosphorylation.

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 detailed lesson explains how the process of transcription results in the production of mRNA. Both the detailed PowerPoint and accompanying question worksheet have been designed to cover the first part of points 2.5 (i) & (ii) of the Pearson Edexcel A-level Biology A specification The lesson begins by challenging the students to work out that most of the nuclear DNA in eukaryotes does not actually 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 template (or anti-sense) strand and the other strand is the coding (or sense) strand. Links to previous lesson on the structure of DNA and RNA are made throughout and students are continuously challenged on their prior knowledge as well as their 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 protein synthesis, translation.

This lesson describes the vascular system of mammals as a double circulatory system to allow comparisons with those in earthworms, insects and fish. The PowerPoint and accompanying resources have been designed to cover the final content of specification point (a) in topic 3 (Adaptations for transport) of AS unit 2 in the WJEC A-level Biology specification and there is a primary focus 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 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.

Disaccharides are formed from the condensation of two monosaccharides and this lesson describes the formation of maltose, sucrose and lactose. The concise PowerPoint and accompanying question sheet have been designed to cover the third part of points 1.12 & 1.13 of the Pearson Edexcel A-level Biology A specification but also continually links to the previous lesson on monosaccharides when considering the different components of these three disaccharides. The first section of the lesson focuses on a prefix and a suffix so that the students can recognise that the names of the common disaccharides end in -ose. In line with this, a quick quiz round is used to introduce maltose, sucrose and lactose before students are challenged on their prior knowledge as they have to describe how condensation reactions and the formation of glycosidic bonds were involved in the synthesis of each one. The main task of the lesson again challenges the students to recall details of a previous lesson as they have to identify the monomers of each disaccharide when presented with the displayed formula. Time is taken to show how their knowledge of these simple sugars will be important in later topics such as extracellular enzymes, translocation in the phloem and the control of gene expression as exemplified by the Lac Operon. The lesson finishes with two exam-style questions where students have to demonstrate and apply their newly acquired knowledge

This fully-resourced lesson describes the structure of the glucose and ribose as monosaccharides and considers their roles in living organisms. The detailed and engaging PowerPoint and accompanying resources have been designed to cover point 1.1 (ii) as detailed in the Edexcel A-level Biology B specification and also considers the structure of galactose, fructose and deoxyribose. Students were introduced to carbohydrates and monosaccharides in the previous lesson so this lesson builds on that initial understanding and adds key details to their knowledge of this simplest group. Using the molecular formula of glucose as a guide, students will be given the general formula for the monosaccharides and will learn that deoxyribose is an exception to the rule that the number of carbon and oxygen atoms are equal. Moving forwards, students have to study the displayed formula of glucose for two minutes without being able to note anything down before they are challenged to recreate what they saw in a test of their observational skills. At this point of the lesson, the idea of numbering the carbons is introduced so that the different glycosidic bonds can be understood in an upcoming lesson as well as the recognition of the different isomers of glucose. The difference between alpha and beta-glucose is provided and students are again challenged to draw a molecule of glucose, this time for the beta form. The remainder of the lesson focuses on the roles of the 6 monosaccharides and the final task involves a series of application questions where the students are challenged to suggest why ribose could be considered important for active transport and muscle contraction

This lesson explains how to calculate the net primary productivity by subtracting a plant’s respiratory losses from the gross primary productivity. The PowerPoint and accompanying resources have been designed to cover points 5.9 (i) and (ii) of the Edexcel International A-level Biology specification. Due to the fact that the productivity of plants is dependent on photosynthesis, a series of exam-style questions have been written into the lesson which challenge the students to explain how the structure of the leaf as well as the light-dependent and light-independent reactions are linked to GPP. All of the exam questions have displayed mark schemes which are included in the PowerPoint to allow students to immediately assess their understanding. A number of quick quiz competitions as well as guided discussion points are used to introduce the formulae to calculate NPP and N and to recognise the meaning of the components. Once again, this is immediately followed by the opportunity to apply their understanding to selected questions