A Science teacher by trade, I've also been known to be found teaching Maths and PE! However, strange as it may seem, my real love is designing resources that can be used by other teachers to maximise the experience of the students. I am constantly thinking of new ways to engage a student with a topic and try to implement that in the design of the lessons.
A Science teacher by trade, I've also been known to be found teaching Maths and PE! However, strange as it may seem, my real love is designing resources that can be used by other teachers to maximise the experience of the students. I am constantly thinking of new ways to engage a student with a topic and try to implement that in the design of the lessons.
This detailed lesson describes the transport of sodium and potassium ions in the maintenance of resting potential and how an action potential is formed. The engaging PowerPoint and accompanying resources have been designed to cover the detail included in points 9.5 (i) & (ii) of the Edexcel A-level Biology B specification.
This topic is commonly assessed in the terminal exams so a lot of time has been taken to design this resource to include a wide range of activities that motivate the students whilst ensuring that the content is covered in the depth of detail that will allow them to have a real understanding. Interspersed within the activities are understanding checks and prior knowledge checks to enable the students to not only assess their progress against the current topic but also to challenge themselves on the links to earlier topics such as methods of movements across cell membranes. There are also a number of quiz competitions which are used to introduce key terms and values in a fun and memorable way and discussion points to encourage the students to consider why a particular process or mechanism occurs.
Over the course of the lesson, the students will learn and discover how the movement of ions across the membrane causes the membrane potential to change. They will see how the resting potential is maintained through the use of the sodium/potassium pump and potassium ion leakage. There is a real focus on depolarisation to allow students to understand how generator potentials can combine and if the resulting depolarisation then exceeds the threshold potential, a full depolarisation will occur. At this point in the lesson students will discover how the all or nothing response explains that action potentials have the same magnitude and that instead a stronger stimulus is linked to an increase in the frequency of the transmission. The rest of the lesson challenges the students to apply their knowledge to explain how repolarisation and hyperpolarisation result and to suggest advantages of the refractory period for nerve cells.
This fully-resourced lesson describes how enzyme and substrate concentration affect the rate of enzyme activity. The PowerPoint and accompanying resources are the last in a series of 3 lessons which cover the detail of point 1.5 (iv) of the Edexcel A-level Biology B specification.
The first part of the lesson describes how an increase in substrate concentration will affect the rate of reaction when a fixed concentration of enzyme is used. Time is taken to introduce limiting factors and students will be challenged to identify substrate concentration as the limiting factor before the maximum rate is achieved and then they are given discussion time to identify the possible factors after this point. A series of exam-style questions are used throughout the lesson and the mark schemes are displayed to allow the students to assess their understanding and for any misconceptions to be immediately addressed. Moving forwards, the students have to use their knowledge of substrate concentration to construct a graph to represent the relationship between enzyme concentration and rate of reaction and they have to explain the different sections of the graph and identify the limiting factors.
The final section of the lesson describes how the availability of enzymes is controlled in living organisms. Students will come to recognise that this availability is the result of enzyme synthesis and enzyme degradation and their recall of transcription and translation is tested through a SPOT the ERRORs task.
Please note that this lesson explains the Biology behind the effect of concentration on enzyme-controlled reactions and not the methodology involved in carrying out such an investigation as this is covered in a core practical lesson.
Each of the five lessons included in this lesson bundle are fully-resourced and have been designed to engage and motivate the students whilst covering the following points that are detailed in topic 1.4.2 of the AQA A-level Biology specification:
Each enzyme lowers the activation energy of the reaction it catalyses
The induced-fit model of enzyme action
The specificity of enzymes
The effects of temperature, pH, enzyme concentration, substrate concentration and concentration of competitive and non-competitive inhibitors on the rate of enzyme-controlled reactions
The lessons have been planned to come as a bundle and references are continually made to previous lessons in the topic to support the students in making the important links between structure, properties and actions of these globular proteins.
This fully-resourced lesson describes how enzyme and substrate concentration can affect the rate of an enzyme-controlled reaction. The PowerPoint and accompanying resources are the 4th in a series of 5 lessons which cover the detail of point 1.4.2 of the AQA A-level Biology specification. Transcription and translation are also introduced and therefore this lesson could be used in preparation for the detailed lessons in topic 4.2.
The first part of the lesson describes how an increase in substrate concentration will affect the rate of reaction when a fixed concentration of enzyme is used. Time is taken to introduce limiting factors and students will be challenged to identify substrate concentration as the limiting factor before the maximum rate is achieved and then they are given discussion time to identify the possible factors after this point. A series of exam-style questions are used throughout the lesson and the mark schemes are displayed to allow the students to assess their understanding and for any misconceptions to be immediately addressed. Moving forwards, the students have to use their knowledge of substrate concentration to construct a graph to represent the relationship between enzyme concentration and rate of reaction and they have to explain the different sections of the graph and identify the limiting factors.
The final section of the lesson describes how the availability of enzymes is controlled in living organisms. Students will recognise that this availability is the result of enzyme synthesis and enzyme degradation and a number of prior knowledge checks challenge students on their knowledge of proteins as covered in topic 1.4.1
Please note that this lesson explains the Biology behind the effect of concentration on enzyme-controlled reactions and not the methodology involved in carrying out such an investigation as this is covered in a core practical lesson.
Carbohydrates, lipids and proteins are the key biological molecules and the specification points covering the relationship between their structures and functions are found in the very first three topics of Edexcel A-level Biology B course. With this in mind, hours of intricate planning has gone into each of the 9 lessons that are included in this bundle to ensure that students are continually engaged whilst the detailed content is covered by the variety of tasks. These tasks include exam-style questions with accompanying mark schemes so that students can assess their understanding, guided discussion periods and quiz competitions to introduce key values and terminology in a memorable way
This lesson describes and explains how temperature affects enzyme activity. The PowerPoint and the accompanying resource are part of the 1st lesson in a series of 3 which cover the content detailed in point 1.5 (iv) of the Edexcel A-level Biology B specification and this lesson has been specifically planned to tie in with the previous lesson covering 1.5 (i, ii & iii) where the structure, properties and mechanism of action of enzymes 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 7 and 5.
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 enzyme activity in a reaction and not the practical skills that would be covered in a core practical lesson
This lesson describes the structure of enzymes and explains how their specificity enables them to act as catalysts intracellularly and extracellularly. The engaging PowerPoint and accompanying resources have been designed to cover points 1.5 (i), (ii), (iii) & (vii) of the Edexcel A-level Biology B specification and describes Fischer’s lock and key hypothesis and Koshland’s induced-fit model to deepen student understanding of the mechanism of enzyme action
The lesson has been specifically planned to tie in with topic 1.3 where protein structure and globular proteins were covered. 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, DNA helicase and DNA polymerase and students are challenged on their recall of DNA replication with an exam question before they are challenged on their knowledge of carbohydrates, lipids and proteins from topics 1.1 - 1.3 as they have to recognise some extracellular digestive enzymes from descriptions of their substrates.
This bundle contains 11 fully-resourced lessons which will engage and motivate the students whilst covering the following specification points in topics 7 and 8 of the CIE A-level Biology specification:
TOPIC 7
The structure of xylem vessel elements, phloem sieve tube elements and companion cells
The relationship between the structure and function of xylem vessel elements, phloem sieve tube elements and companion cells
Explain how hydrogen bonding of water molecules is involved with the movement in the xylem by cohesion-tension in transpiration pull and adhesion to cell walls
The pathways and mechanisms by which water and mineral ions are transported from the soil to the xylem and from roots to leaves
Assimilates move between sources and sinks between phloem sieve tubes
The mechanism by which sucrose is loaded into the phloem
The mass flow of phloem sap down a hydrostatic pressure gradient
TOPIC 8
The double, closed circulatory system of a mammal
The relationship between the structure and function of arteries, veins and capillaries
The role of haemoglobin in carrying oxygen and carbon dioxide
The significance of the oxygen dissociation curve of adult haemoglobin at different carbon dioxide concentrations
The external and internal structure of the heart
The cardiac cycle
The role of the SAN, AVN and Purkyne tissue in the initiation and conduction of the heart action
The lesson PowerPoints and accompanying resources contain a wide range of tasks which include exam-style questions with mark schemes, discussion points and quiz competitions that will check on current understanding as well as making links to previously covered topics.
Respiration and photosynthesis are two of the most commonly-assessed topics in the terminal A-level exams but are often poorly understood by students. These 16lessons have been intricately planned to contain a wide range of activities that will engage and motivate the students whilst covering the key detail to try to deepen their understanding and includes exam-style questions so they are fully prepared for these assessments.
The following specification points in topics 12 and 13 of the CIE A-level Biology course are covered by these lessons:
The need for energy in living organisms
The features of ATP
The synthesis of ATP by substrate-level phosphorylation in glycolysis and the Krebs cycle
The roles of the coenzymes in respiration
The synthesis of ATP through the electron transport chain in the mitochondria and chloroplasts
The relative energy values of carbohydrates, lipids and proteins as respiratory substrates
Determining the respiratory quotient from equations for respiration
The four stages of aerobic respiration
An outline of glycolysis
When oxygen is available, pyruvate is converted into acetyl CoA in the link reaction
The steps of the Krebs cycle
Oxidative phosphorylation
The relationship between the structure and function of the mitochondrion
Distinguish between aerobic and anaerobic respiration in mammalian tissue and in yeast cells
Anaerobic respiration generates a small yield of ATP and builds up an oxygen debt
The products of the light-dependent stage are used in the Calvin cycle
The structure of a chloroplast and the sites of the light-dependent and light-independent stages of photosynthesis
The role of the chloroplast pigments
Absorption and action spectra
Using chromatography to separate the chloroplast pigments
The light-dependent stage of photosynthesis
The three stages of the Calvin cycle
The conversion of Calvin cycle intermediates to carbohydrates, lipids and amino acids
Explain the term limiting factor in relation to photosynthesis
Explain the effects of changes in light intensity, carbon dioxide concentration and temperature on the rate of photosynthesis
Explain how an understanding of limiting factors is used to increase crop yields in protected environments
Due to the detail of these lessons, it is estimated that it will take up to 2 months of allocated A-level teaching time to cover the detail included in the slides of these lessons
If you would like to sample the quality of the lessons, download the roles of the coenzymes, the Krebs cycle and the products of the Calvin cycle lessons as these have been shared for free
This bundle contains 7 fully-resourced lessons which are highly detailed and will engage and motivate the students whilst covering the content of topic 13 of the CIE A-level Biology specification (for assessment in 2025 - 27). The following specification points are covered:
Topic 13.1: points 1 - 12
Topic 13.2: points 1 & 2
The lesson PowerPoints and accompanying resources contain a wide range of tasks which include exam-style questions, whole class discussion periods and quiz competitions which are designed to introduce key terms and values in a memorable way.
If you would like to get an idea of the quality of these lessons, then download the Calvin cycle intermediates lesson as this has been shared for free.
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 (12) of topic 13.1 of the CIE A-level Biology specification (for assessment in 2025 - 2027) 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 fully-resourced lesson describes the three main stages of the Calvin cycle as fixation, reduction and regeneration. The detailed PowerPoint and accompanying resources have been designed to cover the content of point (11) of topic 13.1 of the CIE A-level Biology specification (for assessment in 2025-27) and detailed planning ensures that continual links are made to the previous lesson on the light-dependent stage so that students understand how the products of that stage, ATP and reduced NADP, 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 Calvin cycle. This immediately introduces RuBP, GP and TP 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 TP
The use of the majority of the TP in the regeneration of RuBP
A step-by-step guide, with discussion points where the class are given time to discuss the answer to selected questions, is used to show how 6 turns of the cycle are needed to form the TP 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 describes the light-dependent stage, focusing on the production of ATP by photophosphorylation and reduced NADP. The detailed PowerPoint and accompanying resources have been designed to cover the details of points 7, 8, 9 and 10 of topic 13.1 of the CIE A-level Biology specification.
The light-dependent stage of photosynthesis is a process which students can find difficult to understand in the necessary detail so this lesson has been planned to walk them through all of the key details. Time is taken to describe the roles of the major protein complexes that are embedded in the thylakoid membrane and this includes the two photosystems, the cytochrome proton pump and ATP synthase. A series of exam-style questions have been written that link to other biological topics in this course such as eukaryotic cell structures and membrane transport as well as application questions to challenge them to apply their understanding. Some of these resources have been differentiated to allow students of differing abilities to access the work and to be pushed at the same time. Students will learn that there are two pathways that the electron can take from PSI and at the completion of the two tasks which describe each of these pathways, they will understand how ATP is generated in non-cyclic and cyclic photophosphorylation. The final task of the lesson asks them to compare these two forms of photophosphorylation to check that they understand when photolysis is involved and reduced NADP is formed.
Due to the detail included in this lesson, it is estimated that it will take up to 3 hours of allocated A-level teaching time to complete.
This lesson describes the relationship between the structure of the chloroplast and the functions related to photosynthesis . This fully-resourced lesson, which consists of an engaging PowerPoint and accompanying resources, has been designed to cover points (1, 2 and 3) of topic 13.1 of the CIE A-level Biology specification. The lesson introduces students to the grana and stroma as the site of the light-dependent and light-independent stages respectively before they are covered in greater detail in the lessons that are taught later in topic 13.1.
Students were introduced to eukaryotic cells and their organelles in topic 1 so this lesson has been written to test and 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. Links to other topics are made throughout and this is exemplified by the final task of the lesson where students are challenged on their recall of the structure, properties and function of starch, as originally covered in topic 2.2
It’s no coincidence that cell structure and biological molecules find themselves as topics 1 and 2 of the CIE A-level Biology course, because a clear understanding of their content is absolutely critical to promote success with the 17 topics that follow.
Hours and hours of intricate planning has gone into the 18 lessons included in this bundle to ensure that the detailed content is relevant and can be understood and that links are made to related sections of topics 3 - 19. The lesson PowerPoints and accompanying resources contain a wide range of activities that include:
differentiated exam-style questions with clear mark schemes
directed discussion points
quiz competitions to introduce key terms and values
current understanding and prior knowledge checks
Due to the detail included in these lessons, it is estimated that it will take in excess of 2 months of allocated teaching time to cover the content of the resources
A number of the resources have been shared for free so these can be downloaded in order to sample the quality of the lessons
This lesson bundle contains 6 fully-resourced lessons which have been designed to engage and motivate the students whilst covering the detailed content of topic 3 (Enzymes) in the CIE A-level Biology specification. These globular proteins catalyse biological reactions throughout living organisms so a deep understanding of this topic is important for all of the other 18 topics in this course.
The wide range of activities that are included within the lesson PowerPoints and accompanying resources will cover the following specification points:
Enzymes are globular proteins that catalyse reactions
The mode of action of enzymes
The lock and key hypothesis and the induced-fit model
The effect of temperature on the rate of an enzyme-catalysed reaction
The effect of pH on the rate of an enzyme-catalysed reaction
The effect of enzyme and substrate concentration on the rate of an enzyme-catalysed reaction
The effect of inhibitor concentration on the rate of an enzyme-catalysed reaction
The effect of competitive and non-competitive inhibitors on enzyme activity
Immobilising an enzyme in alginate
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 concentration of inhibitors affects the rate of an enzyme-catalysed reaction. The PowerPoint and accompanying resource are the last in a series of 4 lessons which cover the content detailed in point 3.2 (a) of the CIE A-level Biology specification but this lesson also covers point 3.2 [c] as competitive and non-competitive inhibitors are introduced and their differing effects on enzyme activity described and explained.
The lesson begins with a made up round of the quiz show POINTLESS called “Biology opposites” and this allows students to recognise that inhibition is the opposite of stimulation. This introduces inhibitors as substances that reduce the rate of a reaction and students are challenged to use their general knowledge of enzymes to identify that inhibitors prevent the formation of the enzyme-substrate complex. Moving forwards, a quick quiz competition generates the abbreviation EIC (representing enzyme-inhibitor complex) and this introduces competitive inhibitors as substances that occupy the active site. The students are asked to apply their knowledge to a new situation to work out that these inhibitors must have a similar shape to the enzyme’s substrate molecule. A series of exam-style questions are used throughout the lesson and at this point, the students are challenged to work out that an increase in the substrate concentration would reduce the effect of a fixed concentration of a reversible competitive inhibitor. The rest of the lesson focuses on non-competitive inhibitors and time is taken to ensure that key details such as the disruption of the tertiary structure is understood and biological examples are used to increase the relevance. Again, students will learn that increasing the concentration of the inhibitor results in a greater inhibition and a reduced rate of reaction but that increasing the substrate concentration cannot reduce the effect as was observed with competitive inhibitors.
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.
