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.
Topic 8 of the Edexcel International A-level biology specification is content heavy and therefore all 11 lessons included in this bundle have been planned to cover this content in an engaging and memorable way. The lessons are filled with a wide variety of tasks, including understanding and prior knowledge checks, guided discussion periods and quick quiz competitions. Answers to all of the knowledge checks are embedded into the PowerPoints to allow the students to assess their progress.
The following specification points are covered by this bundle:
8.1, 8.2, 8.3, 8.4, 8.5, 8.6, 8.8, 8.10, 8.13, 8.14, 8.18, 8.19, 8.20
If you would like to get a sense for the quality of the lessons in this bundle, then download the nervous and hormonal control, saltatory conduction and pupil reflex lessons as these have been shared for free.
This bundle of 9 lessons covers a lot of the content in Topic B9 (Ecosystems and material cycles) of the Edexcel GCSE Biology specification. The topics covered within these lessons include:
Levels of organisation in an ecosystem
Biotic and abiotic factors
Interdependence
Types of ecological relationships
Sampling techniques
Efficiency of biomass transfer
Human impacts on ecosystems
Maintaining and increasing biodiversity
The carbon cycle
The nitrogen cycle
Decomposition
The rate of decay
All of these lesson presentations and accompanying resources are detailed and engaging and contain regular progress checks to allow the students to constantly assess their understanding.
This bundle of 10 lessons covers a lot of the content in Topic B3 (Genetics) of the Edexcel GCSE Biology specification. The topics covered within these lessons include:
Advantages and disadvantages of asexual reproduction
Advantages and disadvantages of sexual reproduction
The role of meiosis
The structure of DNA
Transcription and translation
Understanding and using genetic terminology
Monohybrid inheritance
Sex determination
Sex linkage
The causes of variation
All of these lesson presentations and accompanying resources are detailed and engaging and contain regular progress checks to allow the students to constantly assess their understanding.
This lesson bundle contains 16 lessons which have been designed to cover the Pearson Edexcel A-level Biology A (Salters Nuffield) specification points which focus on the structure of DNA and RNA, their roles in replication and protein synthesis, and genetics and inheritance. The lesson PowerPoints are highly detailed, and along with their accompanying worksheets, they have been planned at length to contain a wide range of engaging tasks which cover the following A-level Biology content found in topics 2, 3 and 6 of the course:
2.5 (i): Know the basic structure of mononucleotides (deoxyribose or ribose linked to a phosphate and a base, including thymine, uracil, cytosine, adenine or guanine) and the structures of DNA and RNA (polynucleotides composed of mononucleotides linked through condensation reactions)
2.5 (ii): Know how complementary base pairing and the hydrogen bonding between two complementary strands are involved in the formation of the DNA double helix
2.6 (i): Understand the process of protein synthesis (transcription) including the role of RNA polymerase, translation, messenger RNA, transfer RNA, ribosomes and the role of start and stop codons
2.6 (ii): Understand the roles of the DNA template (antisense) strand in transcription, codons on messenger RNA and anticodons on transfer RNA
2.7: Understand the nature of the genetic code
2.8: Know that a gene is a sequence of bases on a DNA molecule that codes for a sequence of amino acids in a polypeptide chain
2.11 (i): Understand the process of DNA replication, including the role of DNA polymerase
2.12 (i): Understand how errors in DNA replication can give rise to mutations
2.12 (ii): Understand how cystic fibrosis results from one of a number of possible gene mutations
2.13 (i): Know the meaning of the terms: gene, allele, genotype, phenotype, recessive, dominant, incomplete dominance, homozygote and heterozygote
2.13 (ii): Understand patterns of inheritance, including the interpretation of genetic pedigree diagrams, in the context of monohybrid inheritance
2.14: Understand how the expression of a gene mutation in people with cystic fibrosis impairs the functioning of the gaseous exchange, digestive and reproductive systems
2.15 (i): Understand the uses of genetic screening, including the identification of carriers, pre-implantation genetic diagnosis (PGD) and prenatal testing, including amniocentesis and chorionic villus sampling
2.15 (ii): Understand the implications of prenatal genetic screening
3.8 (i): The loci is a location of genes on a chromosome
3.8 (ii): The linkage of genes on a chromosome and sex linkage
3.12: Understand how cells become specialised through differential gene expression, producing active mRNA leading to synthesis of proteins, which in turn control cell processes or determine cell structure in animals and plants, including the lac operon
3.14 (i): Phenotype is an interaction between genotype and the environment
3.15: Understand how some phenotypes are affected by multiple alleles for the same gene at many loci (polygenic inheritance) as well as the environment and how this can give rise to phenotypes that show continuous variation
6.4: Know how DNA can be amplified using the polymerase chain reaction (PCR)
6.10: Understand how one gene can give rise to more than one protein through posttranscriptional changes to messenger RNA (mRNA).
This lesson bundle contains 16 lessons which have been designed to cover the Edexcel International A-level Biology specification points which focus on the structure of DNA and RNA, their roles in replication and protein synthesis, and genetics and inheritance. The lesson PowerPoints are highly detailed, and along with their accompanying worksheets, they have been planned at length to contain a wide range of engaging tasks which cover the following A-level Biology content found in topics 2, 3 and 6 of the course:
2.9 (i): Know the basic structure of mononucleotides (deoxyribose or ribose linked to a phosphate and a base, including thymine, uracil, adenine, cytosine or guanine) and the structures of DNA and RNA (polynucleotides composed of mononucleotides linked by condensation reactions to form phosphodiester bonds)
2.9 (ii): Know how complementary base pairing and the hydrogen bonding between two complementary strands are involved in the formation of the DNA double helix
2.10 (i): Understand the process of DNA replication, including the role of DNA polymerase
2.11: Understand the nature of the genetic code
2.12: Know that a gene is a sequence of bases on a DNA molecule that codes for a sequence of amino acids in a polypeptide chain
2.13 (i): understand the process of protein synthesis (transcription and translation), including the role of RNA polymerase, translation, messenger RNA, transfer RNA, ribosomes and the role of start and stop codons
2.13 (ii): Understand the roles of the DNA template (antisense) strand in transcription, codons on messenger RNA and anticodons on transfer RNA
2.14 (i): Understand how errors in DNA replication can give rise to mutations (substitution, insertion and deletion of bases)
2.14 (ii): Know that some mutations will give rise to cancer or genetic disorders, but that many mutations will have no observable effect
2.15 (i): Know the meaning of the terms: gene, allele, genotype, phenotype, recessive, dominant, codominance, homozygote and heterozygote
2.15 (ii): Understand patterns of inheritance, including the interpretation of genetic pedigree diagrams, in the context of monohybrid inheritance
2.15 (iii): Understand sex linkage on the X chromosome, including red-green colour blindness in humans
2.16: Understand how the expression of a gene mutation in people with cystic fibrosis impairs the functioning of the gaseous exchange, digestive and reproductive systems
2.17 (i): Understand the uses of genetic screening, including the identification of carriers, pre-implantation genetic diagnosis (PGD) and prenatal testing, including amniocentesis and chorionic villus sampling
2.17 (ii): Understand the implications of prenatal genetic screening
3.9 (i): Know that a locus is the location of genes on a chromosome
3.9 (ii): Understand the linkage of genes on a chromosome
3.18: Understand how cells become specialised through differential gene expression, producing active mRNA, leading to the synthesis of proteins which, in turn, control cell processes or determine cell structure in animals and plants
3.19: Understand how one gene can give rise to more than one protein through posttranscriptional changes to messenger RNA (mRNA).
3.20 (i): Phenotype is an interaction between genotype and the environment
3.21: Understand how some phenotypes are affected by multiple alleles for the same gene at many loci (polygenic inheritance) as well as the environment and how this can give rise to phenotypes that show continuous variation
6.17: Know how DNA can be amplified using the polymerase chain reaction (PCR)
This bundle of 9 lessons describes homeostasis in mammals and plants, explaining the content using real-world examples including osmoregulation and the control of blood glucose and the opening and closing of the stomatal apertures.
The lessons have been planned at length and are filled with a wide variety of tasks which will engage and motivate the students whilst checking on their understanding of the following points from topic 14 of the CIE A-level biology specification (for assessment in 2025-27):
14.1: 1 - 10
14.2: 1 - 4 (ALL)
The quality of the lessons can be experienced through the download of the osmoregulation lesson as this has been shared for free.
This lesson bundle contains 11 lesson PowerPoints and their accompanying resources which are filled with a wide variety of tasks to motivate and engage the students whilst covering the detailed content of topic 4 of the Pearson Edexcel A-level Biology A (Salters Nuffield) specification. Extensive planning has gone into each lesson to ensure that understanding is complete and that students are challenged to make links to previously covered topics.
The tasks include exam-style questions, differentiated tasks, guided discussion points and quick quiz competitions and together these cover the following specification points in topic 4:
The meaning of the terms biodiversity and endemism
Measuring biodiversity within a habitat using species richness and within a species by calculating the heterozygosity index
Comparing biodiversity between habitats by calculating an index of diversity
The concept of niche and examples of behavioural, anatomical and physiological adaptations
Natural selection can lead to adaptation and evolution
The Hardy-Weinberg equation can be used to see whether a change in allele frequency is occurring in a population over time
Reproductive isolation can lead to the formation of new species
Classification is built around the species concept
Critical evaluation of new data by the scientific community, which leads to new taxonomic groupings
The ultrastructure of plant cells
The structure and function of the polysaccharides starch and cellulose
The similarities and differences between the structures, position and function of sclerenchyma fibres, xylem vessels and phloem
The importance of water and inorganic ions to plants
Evaluate the methods used by zoos and seed banks in the conservation of endangered species and their genetic diversity
If you would like to sample the quality of the lessons in this bundle, then download the isolation and speciation, ultrastructure of plant cells and xylem, phloem and sclerenchyma lessons as these have been uploaded for free
As the first topic to be taught at the start at the second year of the Edexcel International A-level Biology course, topic 5 is very important and the content includes the key reaction of photosynthesis. All 11 lessons included in this bundle are highly detailed and have been filled with a wide variety of tasks which will engage and motivate the students whilst covering the following specification points:
The overall reaction of photosynthesis
The phosphorylation of ADP and the hydrolysis of ATP
The light-dependent reactions of photosynthesis
The light-independent reactions of photosynthesis
The products of the Calvin cycle
The structure of the chloroplasts and the role of this organelle in photosynthesis
The absorption spectrum and action spectrum
Separating chloroplast pigments using chromatography and identifying them using retention factor values
Be able to calculate net primary productivity
Know the relationship between NPP, GPP and R
Understand the meaning of the terms ecosystem, community, population and habitat
The numbers and distribution of organisms in a habitat are controlled by biotic and abiotic factors
The concept of niche
The effect of temperature on the rate of enzyme activity and the calculation of the Q10
Isolation reduces gene flow and leads to allopatric and sympatric speciation
If you would like to sample the quality of the lessons in this bundle, then download the products of photosynthesis and succession lessons as these have been uploaded for free
This lesson bundle contains 12 detailed lesson PowerPoints, which along with their accompanying resources, have been intricately planned to cover the majority of the content of topics 5 and 6 of the CIE A-level Biology specification. The cell cycle, mitosis and protein synthesis are topics that students tend to find difficult and therefore the planning focused on the inclusion of a wide range of tasks that would not only promote the retention of important information and secure knowledge but also maintain motivation and engagement.
The tasks include exam-style questions with displayed mark schemes which challenge the students on their current understanding and prior knowledge, guided discussion points and quick quiz competitions which introduce key terms and values.
The following specification points are covered by these 12 lessons:
Topic 5
The structure of a chromosome, limited to DNA, histone proteins, chromatids, centromere and telomere
The importance of mitosis in producing genetically identical cells, growth, cell replacement, repair of tissues and asexual reproduction
The cell cycle, including the G and S phases of interphase, mitosis and cytokinesis
Uncontrolled cell division and the formation of tumours
The behaviour of chromosomes in animal and plant cells in the mitotic cell cycle
Topic 6
The structure of nucleotides, including ATP
The structure of DNA and RNA
The semi-conservative replication of DNA during interphase
A polypeptide is coded for by a gene
Gene mutations can cause changes to the polypeptide sequence
The information in DNA is used during transcription and translation to construct polypeptides
Respiration and photosynthesis are two of the most important biological processes, which can be poorly understood by students but unsurprisingly are commonly assessed in the terminal exams. These 11 lessons have been intricately planned so that they contain a wide range of activities that will engage the students whilst covering the key detail to try to deepen their understanding and include exam-style questions so they are prepared for the assessments.
The following specification points in topic 5 of the Edexcel A-level Biology B course are covered by these 11 fully-resourced lessons:
Cellular respiration yields ATP
The different stages of aerobic respiration
The conversion of glucose to pyruvate during glycolysis
The mitochondrial matrix as the site of the Link reaction and Krebs cycle
The production of carbon dioxide, reduced NAD and ATP in the Krebs cycle
Oxidative phosphorylation
The yield of ATP from anaerobic respiration
The production of lactate in mammalian muscles
Ethanol formation in plants
The meaning of the absorption and action spectra
The reason for a variety of photosynthetic pigments in plants
The structure of the chloroplasts
The role of thylakoid membranes in the light-dependent stage
The process of cyclic and non-cyclic photophosphorylation
The use of reduced NADP and ATP in the Calvin cycle
Understand how GALP is used as a raw material in the production of monosaccharides, amino acids and other molecules
Factors that limit photosynthesis including carbon dioxide, light intensity and temperature
Due to the detail of these lessons, it is estimated that it will take in excess of a month of A-level lessons to cover these lessons
If you would like to sample the quality of the lessons, download the link reaction, Krebs cycle and light-independent stage lessons as these have been shared for free
It’s fair to say that cell structure and biological molecules are two of the most important topics in the OCR A-level Biology A course and all 19 lessons that are included in this bundle have been planned at length to cover the module 2.1.1 & 2.1.2 specification points in the detail required at this level.
The lesson PowerPoints and their accompanying resources contain a wide range of tasks as well as regular checks to allow students to assess their understanding of the current content as well as prior knowledge checks to emphasise the importance of making links to topics in other modules.
The following specification points in modules 2.1.1 (cell structure) and 2.1.2 (biological molecules) are covered by the lessons in this bundle:
2.1.1
The use of microscopy to observe and investigate different types of cell and cell structure in a range of eukaryotic organisms
The use of the eyepiece graticule and stage micrometer
The use of staining in light microscopy
The use and manipulation of the magnification formula
The difference between magnification and resolution
The ultrastructure of eukaryotic cells and the functions of the different cellular components
The interrelationship between the organelles involved in the production and secretion of proteins
The importance of the cytoskeleton
The similarities and differences between the ultrastructure of prokaryotic and eukaryotic cells
2.1.2
The properties and roles of water in living organisms
The concept of monomers and polymers and the importance of condensation and hydrolysis reactions
The chemical elements that make up biological molecules
The structure and properties of glucose and ribose
The synthesis and breakdown of a disaccharide and a polysaccharide by the formation and breakage of glycosidic bonds
The structure of starch, glycogen and cellulose molecules
The relationship between the structure, function and roles of triglycerides, phospholipids and cholesterol in living organisms
The general structure of an amino acid
The synthesis and breakdown of dipeptides and polypeptides
The levels of protein structure
The structure and function of globular proteins
The properties and functions of fibrous proteins
The key inorganic ions involved in biological processes
The chemical tests for proteins, reducing and non-reducing sugars, starch and lipids
If you would like to sample the quality of the lessons included in this bundle, then download the following lessons as they have been uploaded for free:
The use of microscopy
The importance of the cytoskeleton
Properties and roles of water
Glucose & ribose
General structure of an amino acid
Dipeptides, polypeptides and protein structure
This bundle of 15 lessons covers the majority of the content in Topic B3 (Organism level systems) of the OCR Gateway A GCSE Biology specification. The topics covered within these lessons include:
The nervous system
The eye
Hormones and the endocrine system
Adrenaline
Negative feedback loops
Thyroid gland and thyroxine
The menstrual cycle
Contraception
Using hormones to treat infertility
Plant hormones
Homeostasis
Controlling body temperature
Controlling blood glucose
Diabetes
Inside the kidney
All of these lesson presentations and accompanying resources are detailed and engaging and contain regular progress checks to allow the students to constantly assess their understanding.
This bundle contains 9 fully-resourced and detailed lessons that have been designed to cover the content of topic 15.1 of the CIE A-level Biology specification (for assessment in 2025-27) which concerns the control and coordination in mammals. The wide range of activities included in each lesson will engage the students whilst the detailed content is covered and the understanding and prior knowledge checks allow them to assess their progress on the current topic as well as challenging them to make links to other related topics. Many of the tasks are differentiated to allow differing abilities to access the work and be challenged.
Topic 15.1 specification points 1, 3, 4, 5, 6, 7, 9, 10, 11, and 12 are covered by these lessons
If you want to see the quality of the lessons before purchasing then download the lessons on sensory, morot and intermediate neurones and the structure and role of the cholinergic synapse as these have been shared for free.
All 10 lessons included in this bundle are highly detailed and are fully-resourced. The lesson PowerPoints and their accompanying worksheets contain a wide range of tasks that will engage and motivate the students whilst covering the following specification points as set out in topic 4 of the Edexcel International A-level Biology specification:
The structure and ultrastructure of plant cells
The function of the organelles in plant cells
The structure and function of starch and cellulose
The similarities and differences between the structures, position and functions of sclerenchyma, xylem and phloem
The importance of water and inorganic ions in plants
Understand that classification is a means of organising the variety of life based on relationships between organisms
New taxonomic groupings
The meaning of the terms biodiversity and endemism
Know how biodiversity can be measured within a habitat and within a species
Comparing biodiversity between habitats using the index of diversity
The adaptations of organisms to their environment
Use of the Hardy-Weinberg equation
Changes in allele frequency are the result of mutation and natural selection
Evaluate the methods used by zoos and seed banks in the conservation of endangered species and their genetic diversity
If you would like to sample the quality of lessons in this bundle then download the cellulose & starch and modern-day classification lessons as these have been uploaded for free
Each of the 20 revision lessons included in this bundle has been designed to motivate and engage the students whilst they are challenged on their knowledge of the content of the OCR A-Level Biology A specification. The detailed PowerPoints contain a wide range of activities which include exam questions with explained answers, differentiated tasks and quiz competitions that are supported by the accompanying worksheets.
The modules covered in this bundle are:
Module 2.1.1: Cell structure
Module 2.1.2: Biological molecules
Module 2.1.3: Nucleotides and nucleic acids
Module 2.1.4: Enzymes
Module 2.1.5: Biological membranes
Module 2.1.6: Cell division, cell diversity and cellular organisation
Module 3.1.2: Transport in animals
Module 3.1.3: Transport in plants
Module 4.1.1: Communicable diseases, disease prevention and the immune system
Module 4.2.1: Biodiversity
Module 4.2.2: Classification and evolution
Module 5.1.2: Excretion as an example of homeostatic control
Module 5.1.3: Neuronal communication
Module 5.1.4: Hormonal communication
Module 5.1.5: Plant and Animal responses
Module 5.2.1: Photosynthesis
Module 5.2.2: Respiration
Module 6.1.1: Cellular control
Module 6.1.2: Pattens of inheritance
Module 6.1.3: Manipulating genomes
Helpful hints are provided throughout the lessons to help the students with exam technique and in structuring their answers. These lessons are suitable for use throughout the course and can be used for revision purposes at the end of a module or in the lead up to mocks or the actual A LEVEL exams
This lesson bundle has been formed from the 13 detailed lesson PowerPoints and their accompanying resources that have been uploaded to cover a lot of the content in modules 2.1.4, 2.1.5 and 2.1.6 of the OCR A-level Biology A specification.
Each lesson contains a wide range of tasks, which include exam-style questions (with mark schemes), guided discussion points, and quick quiz competitions, that will engage and motivate the students whilst covering the following specification points:
Module 2.1.4: Enzymes
The role of enzymes in catalysing reactions that affect metabolism at a cellular and whole organism level
The role of enzymes in catalysing both intracellular and extracellular reactions
The mechanism of enzyme action
The effect of pH on enzyme activity
The effect of temperature on enzyme activity
The calculation of the temperature coefficient
The effect of enzyme and substrate concentration on enzyme activity
The need for coenzymes, cofactors and prosthetic groups in some enzyme-controlled reactions
Module 2.1.5: Biological membranes
The fluid mosaic model of membrane structure and the roles of its components
Simple and facilitated diffusion as forms of passive transport
Active transport, endocytosis and exocytosis as processes requiring ATP as an immediate source of energy
The movement of water across membranes by osmosis and the effects that solutions of different water potential can have on plant and animal cells
Module 2.1.6: Cell division, cell diversity and cellular organisation
The cell cycle
How the cell cycle is regulated
The main stages of mitosis
The significance of mitosis in life cycles
The significance of meiosis in life cycles
The main stages of meiosis
How cells of multicellular organisms are specialised for particular functions
The organisation of cells into tissues, organs and organ systems
The production of erythrocytes and neutrophils from stem cells in bone marrow
If you would like to sample the quality of the lessons in this bundle, then download the following lessons as they have been uploaded for free:
The roles of enzymes and mechanism of action
Simple and facilitated diffusion
Cell specialisation and organisation
This bundle of 10 lessons covers a lot of the content in Topic B5 (Health, disease and development of medicines) of the Edexcel GCSE Biology specification. The topics covered within these lessons include:
Health
The difference between communicable and non-communicable diseases
Pathogens
Common infections
The spread of diseases and the prevention
The spread of STIs
Plant defences
Identification of plant diseases
The physical and chemical defences of the human body
The use of antibiotics
Developing new medicines
Monoclonal antibodies
Non-communicable diseases
Treating cardiovascular disease
All of these lesson presentations and accompanying resources are detailed and engaging and contain regular progress checks to allow the students to constantly assess their understanding.
This bundle contains 13 detailed lesson PowerPoints, which together with their accompanying resources, have been planned to include a wide variety of tasks that will engage and motivate the students whilst covering the content of topic 3 of the Pearson Edexcel A-level Biology A (Salters Nuffield) specification. The voice of the genome topic content includes key biological concepts such as eukaryotic cells, cell division and genetics and the following specification points are covered by these lessons:
All living organisms are made of cells, sharing common features
The ultrastructure of eukaryotic cells and the role of the organelles
The role of the rER and the Golgi body in protein transport
The relationship between the features of the mammalian gametes and their functions
The loci is the location of a gene on a chromosome
The linkage of genes on a chromosome and sex linkage
The role of meiosis in ensuring genetic variation
The role of mitosis and the cell cycle
The meaning of the terms stem cell, pluripotency and totipotency
The decisions about the use of stem cells in medical therapies
The specialisation of cells through differential gene expression
Understand how the cells of multicellular organisms are organised into tissues, tissues into organs and organs into systems
Phenotype is the interaction between genotype and the environment
Epigenetic changes can modify the activation of certain genes
Some phenotypes are affected by multiple alleles for the same gene at many loci as well as the environment and this gives rise to continuous variation
If you would like to sample the quality of lessons in this bundle, then download the ultrastructure of eukaryotic cells, mitosis and the cell cycle and gene expression lessons as these have been uploaded for free
This bundle of 9 lessons covers the majority of the content in Topic B1 of the OCR Gateway A GCSE Combined Science specification. The topics covered within these lessons include:
Animal and plant cells
Prokaryotic cells
Light and electron microscopy
DNA
Enzymes
Enzyme activity
Aerobic respiration
Anaerobic respiration
Photosynthesis
All of these lesson presentations and accompanying resources are detailed and engaging and contain regular progress checks to allow the students to constantly assess their understanding. It is estimated that this bundle would cover about 6 week’s worth of lessons.
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