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 lesson explains how negative feedback control maintains systems within narrow limits and uses biological examples to describe the meaning of positive feedback. The PowerPoint and accompanying resources have been designed to cover points 7.11 (i) and (ii) of the Pearson Edexcel A-level Biology A (Salters Nuffield) specification but have been planned to provide important 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 well as earlier in topic 7 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 an interaction of muscles, tendons, the skeleton and ligaments is needed for movement of the human body. The PowerPoint and accompanying resources have been designed to cover point 7.9 of the Edexcel International A-level Biology specification and also includes descriptions of antagonistic muscle pairs, extensors and flexors.
At the start of the lesson, the prep room skeleton is used as the example to show that bones without muscles are bones that are unable to move (unaided). Moving forwards, the students will learn that skeletal muscles are attached to bones by bundles of collagen fibres known as tendons and as they covered the relationship between the structure and function of collagen in topic 2, a task is used that challenges their recall of these details. This will allow them to recognise that the ability of this fibrous protein to withstand tension is important for the transmission of the force from the muscle to pull on the moveable bone. A series of quick quiz competitions introduce the key terms of flexion and antagonistic and then an exam-style question challenges them to recognise the structures involved in extension at the elbow. The remainder of the lesson focuses on the role of ligaments and one final example of extension at the knee joint will demonstrate how the interaction of all of the structures met over the course of the lesson is needed for movement
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
This fully-resourced lesson describes the behaviour of chromosomes during the mitotic cell cycle and explains the importance of this type of nuclear division. The PowerPoint and accompanying resources have been designed to cover points 5.1 (b) & 5.2 (a) of the CIE A-level Biology specification and make direct links to a previous lesson which covered the outline of cell cycle
Depending upon the exam board taken at iGCSE, the knowledge and understanding of mitosis will differ considerably between students and there may be a number of misconceptions. This was considered at all points during the planning of the lesson so that existing errors are addressed and key points are emphasised throughout. Their understanding of interphase is challenged at the start of the lesson to ensure that they realise that it is identical pairs of sister chromatids that enter the M phase. The main part of the lesson focuses on prophase, metaphase, anaphase and telophase and describes how the chromosomes behave in these stages. There is a focus on the centrioles and the spindle fibres that they produce which contract to drag one chromatid from each pair in opposite directions to the poles of the cell. The remainder of the lesson is a series of understanding and application questions where students have to identify the various roles of mitosis in living organisms as well as tackling a Maths in a Biology context question. The lesson concludes with a final quiz round of MITOSIS SNAP where they only shout out this word when a match is seen between the name of a phase, an event and a picture.
This lesson describes the behaviour of chromosomes during meiosis, focusing on the events which contribute to genetic variation. The detailed PowerPoint and accompanying resources have been designed to cover points 16.1 (a, d & e) of the CIE A-level Biology specification and explains how crossing over, the random assortment and the random fusion of haploid gametes leads to variation.
In order to understand how the events of meiosis like crossing over and independent assortment and independent segregation can lead to variation, students need to be clear in their understanding that DNA replication in interphase results in homologous chromosomes as pairs of sister chromatids. Therefore the beginning of the lesson focuses on the chromosomes in the parent cell and this first part of the cycle and students will be introduced to non-sister chromatids and the fact that they may contain different alleles which is important for the exchange that occurs during crossing over. Time is taken to go through this event in prophase I in a step by step guide so that the students can recognise that the result can be new combinations of alleles that were not present in the parent cell. Moving forwards, the lesson explores how the independent assortment and segregation of chromosomes and chromatids during metaphase I and II and anaphase I and II respectively results in genetically different gametes. The key events of all of the 8 phases are described and there is a focus on key terminology to ensure that students are able to describe genetic structures in the correct context. The final part of the lesson looks at the use of a mathematical expression to calculate the possible combinations of alleles in gametes as well as in a zygote following the random fertilisation of haploid gametes. Understanding and prior knowledge checks are interspersed throughout the lesson as well as a series of exam-style questions which challenge the students to apply their knowledge to potentially unfamiliar situations.
This lesson has been specifically planned to link to the two lessons on the cell cycle and the main stages of mitosis as covered in topic 5 and constant references are made throughout to encourage students to make links and also to highlight the differences between the two types of nuclear division
This lesson bundle contains 3 lessons which have been intricately planned to build on the knowledge acquired in the previous lesson and in earlier topics of the course to allow students to gain a deep understanding of classification. The lesson PowerPoints and accompanying resources contain a wide range of tasks which will engage and motivate the students whilst all of the content of topic 18.2 of the CIE A-level Biology specification is covered as detailed below:
Describe the classification of species into the taxonomic hierarchy of domain, kingdom, phylum, class, order, family, genus and species
The characteristic features of the three domains
The characteristic features of the kingdoms
The classification of viruses, separate to the three-domain model of classification of cellular organisms
If you would like to sample the quality of the lessons in this bundle, then download the “features of the kingdoms” lesson as this has been shared for free
The detailed content, exam-style questions, guided discussion points and quiz competitions that are found in each of the 16 paid lessons that are included in this bundle (as well as the 5 free lessons which are named at the bottom) cover the following specification points in module 4 of the OCR A-level Biology A specification:
Module 4.1.1
The different types of pathogen that can cause communicable diseases in plants and animals
The means of transmission of animal and plant communicable pathogens
The primary non-specific defences against pathogens in animals
The structure and mode of action of phagocytes
The structure, different roles and modes of action of B and T lymphocytes in the specific immune response
The primary and secondary immune responses
The structure and general functions of antibodies
An outline of the action of opsonins, agglutinins and anti-toxins
The differences between active and passive immunity, and between natural and artificial immunity
Autoimmune diseases
The principles of vaccination
Module 4.2.1
How biodiversity can be considered at different levels
The random and non-random sampling strategies that are carried out to measure the biodiversity of a habitat
How to measure species richness and species evenness
The use and interpretation of Simpson’s Index of Diversity
How genetic biodiversity may be assessed
The ecological, economic and aesthetic reasons for maintaining biodiversity
In situ and ex situ methods of maintaining biodiversity
International and local conservation agreements made to protect species and habitats
4.2.2
The biological classification of species
The binomial system of naming species and the advantage of such a system
The features used to classify organisms into the five kingdoms
The evidence that has led to new classification systems
The different types of variation
Using the standard deviation to measure the spread of a set of data
Using the Student’s t-test to compare means of data values of two populations
Using the Spearman’s rank correlation coefficient to consider the relationship of the data
The different types of adaptations to their environment
The mechanism by which natural selection can affect the characteristics of a population over time
How evolution in some species has an impact on human populations
If you would like to get an idea of the quality of the lessons that are included in this bundle, then download the following five OCR A lessons which have been uploaded for free:
Immunity & vaccinations
Reasons for maintaining biodiversity
Taxonomic hierarchy and the binomial naming system
Adaptations and natural selection
Transmission of animal and plant pathogens
The 3 lessons contained within this lesson bundle cover the content as detailed in topic 4.5 of the Edexcel A-level Biology B specification. The lesson PowerPoints and accompanying worksheets are filled with lots of different tasks that cover the specification points shown below whilst engaging and motivating the students with exam-style questions, guided discussion periods and quiz competitions.
TOPIC 4.5: Transport of gases in blood
The structure of haemoglobin in relation to its role in the transport of respiratory gases, including the Bohr effect
Understand the oxygen dissociation curve of haemoglobin
Understand the similarities and differences between the structures and functions of haemoglobin and myoglobin
Understand the significance of the oxygen affinity of foetal haemoglobin as compared to adult haemoglobin
This lesson describes how tissue fluid is formed and reabsorbed and also describes the role of the lymphatic system in the return of fluid to the blood. The detailed PowerPoint and accompanying resources have been designed to cover points 4.6 (i & ii) of the Edexcel A-level Biology B specification and explains how a combination of the effects of hydrostatic pressure and oncotic pressure results in the formation of tissue fluid in animals.
The lesson begins with an introduction to the arteriole and venule end of a capillary as these will need to be considered as separate entities when describing the formation of tissue fluid. A quick quiz competition introduces a value for the hydrostatic pressure at the arteriole end and students are challenged to first predict some parts of the blood will move out of the capillary as a result of the push from the hydrostatic pressure and this allows oncotic pressure to be initially explored. The main part of the lesson uses a step by step guide to describe how the net movement is outwards at the arteriole end before students will use this guidance to describe what happens at the venule end. In the concluding part of the lesson, students will come to recognise oedema as a condition where tissue fluid accumulates and they again are challenged to explain how this occurs before they finally learn how the fluid is returned to the circulatory system as lymph.
This lesson describes how to calculate the relative formula mass from simple chemical formulae and for those that include brackets. The PowerPoint and the accompanying worksheet have been designed to cover point 1.43 of the Edexcel GCSE Chemistry specification and also covers that point in the Chemistry section of the Combined Science course.
The lesson contains a wide range of tasks, understanding checks and quick quiz competitions to guide students through calculating the relative formula mass for substances with a range of chemical formulae. The relative formula mass is required in a lot of calculations, such as those that involve moles, so it is an important skill to get right. Worked examples are used throughout the lesson to visualise the metho for the students. Initially, students will learn how to calculate the mass from simple formulae before helpful hints are provided for harder formulae such as those that contain a bracket. Students are given the chance to apply their knowledge by proving that mass is conserved in a reaction and this prepares them for an upcoming lesson.
This lesson has been written for GCSE students but could be used with higher ability KS3 students in lessons that are looking to push knowledge forward
This lesson describes the similarities and differences between the structure and function of haemoglobin and myoglobin. The PowerPoint and accompanying resource have been designed to cover point 4.5 (iii) of the Edexcel A-level Biology B specification
Students have already covered the structure and function of haemoglobin in topics 1.3 and 4.5, so this concise lesson has been planned to challenge that knowledge. Students are introduced to myoglobin and will learn that this is an oxygen-binding protein found in the skeletal muscle tissue. Therefore the first part of the lesson focuses on slow twitch muscle fibres, where the content of myoglobin is high, and this presents an opportunity for links to be made to respiration, mitochondria and capillaries. The main part of the lesson challenges the students to compare the two proteins on structure and function including the number of polypeptide chains and affinity for oxygen and students can assess their understanding through use of the displayed mark schemes to the series of exam-style questions.
This lesson describes the differing properties of metals and non-metals and also relates this to their position in the Periodic Table. The lesson PowerPoint has been designed to cover points 1.18, 1.40 & 1.42 of the Edexcel GCSE Chemistry specification and this also covers those same points on the Combined Science course.
The lesson contains a range of tasks including guided discussion points and quick quiz competitions which will engage and motivate the students whilst introducing key properties such as malleability and the ability to conduct electricity. Time is also taken to consider where the metallic and non-metallic elements are found in the Periodic Table and a series of progress checks will challenge the students to link together properties with position.
This lesson bundle contains 17 detailed and fully-resourced lessons which cover the following specification points in topic 3 of the AQA A-level Biology specification:
Topic 3.1
The relationship between the size of an organism or structure and its surface area to volume ratio
The development of systems in larger organisms as adaptations that facilitate exchange as this ratio reduces
Topic 3.2
Adaptations of gas exchange surfaces as shown by gas exchange in single-celled organisms, insects, bony fish and the leaves of dicotyledonous plants
The gross structure of the human gas exchange system
The essential features of the alveolar epithelium as a surface over which gas exchange takes place
The mechanism of breathing to include the role of the diaphragm and the intercostal muscles
Topic 3.3
During digestion, large molecules are hydrolysed to smaller molecules
Digestion in mammals by amylases, disaccharidases, lipase, endopeptidases, exopeptidases and dipeptidases
Mechanisms for the absorption of the products of digestion by cells lining the ileum of mammals
Topic 3.4.1
The structure and role of haemoglobin in the loading, transport and unloading of oxygen
The effects of carbon dioxide concentration on the dissociation of oxyhaemoglobin
The general pattern of blood circulation in a mammal
The gross structure of the human heart
Pressure and volume changes and valve movements during the cardiac cycle
The structure of the arteries, arterioles and veins
The formation of tissue fluid and its return to the circulatory system
Topic 3.4.2
Xylem as the tissue that transports water
The cohesion-tension theory of water transport
Phloem as the tissue that transports organic substances in plants
The mass flow hypothesis for the mechanism of translocation in plants
If you would like to sample the quality of the lessons included in this bundle, then download the following lessons which have been uploaded for free
Alveolar epithelium
Absorption in the ileum
Arteries, arterioles and veins
Formation of tissue fluid
Translocation
This lesson describes the principle components of the plasma membrane, focusing on the phospholipid bilayer and membrane proteins. The detailed PowerPoint and accompanying worksheets have been designed to cover the detail in point (a) of AS unit 1, topic 3 of the WJEC A-level Biology specification and clear links are made to Singer and Nicholson’s fluid mosaic model
The fluid mosaic model is introduced at the start so that it can be referenced at appropriate points throughout the lesson. Students were introduced to phospholipids in topic 1 and so an initial task challenges them to spot the errors in a passage describing the structure and properties of this molecule. This reminds them of the bilayer arrangement, with the hydrophilic phosphate heads protruding outwards into the aqueous solutions on the inside and the outside of the cell. In a link to some upcoming lessons on the transport mechanisms, the students will learn that only small, non-polar molecules can move by simple diffusion and that this is through the tails of the bilayer. This introduces the need for transmembrane proteins to allow large or polar molecules to move into the cell by facilitated diffusion and active transport. Proteins that act as receptors as also introduced and an opportunity is taken to make a link to an upcoming topic so that students can understand how hormones or drugs will bind to target cells in this way. Moving forwards, the structure of cholesterol is covered and students will learn that this hydrophobic molecule sits in the middle of the tails and therefore acts to regulate membrane fluidity. The final part of the lesson challenges the students to apply their newly-acquired knowledge to a series of questions where they have to explain why proteins may have moved when two cells are used and to suggest why there is a larger proportion of these proteins in the inner mitochondrial membrane than the outer membrane.
This lesson explains the need for specialised exchange surfaces and uses examples to describe the features of an efficient exchange surface. The PowerPoint and accompanying worksheets have been designed to cover points 3.1.1 (a & b) of the OCR A-level Biology A specification and also have been specifically planned to prepare the students for the upcoming lessons in module 3 on gas exchange and mass transport in animals.
The students are likely to have been introduced to the surface area to volume ratio at GCSE, but understanding of its relevance tends to be mixed. Therefore, real life examples are included throughout the lesson that emphasise the importance of this ratio in order to increase this relevance. A lot of students worry about the maths calculations that are associated with this topic so a step by step guide is included at the start of the lesson that walks them through the calculation of the surface area, the volume and then the ratio. Through worked examples and understanding checks, SA/V ratios are calculated for cubes of increasing side length and living organisms of different size. These comparative values will enable the students to conclude that the larger the organism or structure, the lower the surface area to volume ratio. A differentiated task is then used to challenge the students to explain the relationship between the ratio and the metabolic demands of a single-celled and multicellular organisms and this leads into the next part of the lesson, where the adaptations of large organisms to increase this ratio at the exchange surfaces are covered. The students will calculate the SA/V ratio of a human alveolus (using the surface area and volume formulae for a sphere) and will see the significant increase that results from the folding of the membranes. In addition to the ratio, time is taken to discuss and describe how the maintenance of a steep concentration gradient and a thin membrane are important for the rate of diffusion and again biological examples are used in humans and other organisms to increase the understanding. Fick’s law of diffusion is also introduced as a mechanism to help the students to recall that surface area, concentration difference and thickness of membrane govern the rate of simple diffusion.
As well as making links to upcoming topics, prior knowledge checks are used to challenge the students on their knowledge of previously-covered modules which include inorganic ions, organelles, cell membrane transport and tissues.
This lesson describes the characteristic features of the Animalia, Plantae, Fungi, Protoctista and Prokaryotae kingdoms. The engaging PowerPoint and accompanying resources have been designed to cover point (d) in AS unit 2, topic 1 of the WJEC A-level Biology specification
This lesson begins with a knowledge recall as students have to recognise that prior to 1990, kingdom was the highest taxa in the classification hierarchy. Moving forwards, they will recall the names of the five kingdoms and immediately be challenged to split them so that the prokaryotae kingdom is left on its own. An opportunity is taken at this point to check on their prior knowledge of the structure of a bacterial cell as covered in unit 1, topic 2. These prior knowledge checks are found throughout the lesson (along with current understanding checks) as students are also tested on their knowledge of the structure and function of cellulose. This is found in the section of the lesson where the main constituent of the wall can be used to distinguish between plantae, fungi and prokaryotae. Quick quiz competitions, such as YOU DO THE MATH and SAY WHAT YOU SEE are used to introduce key values and words in a fun and memorable way. The final part of the lesson looks at the protoctista kingdom and students will come to understand how these organisms tend to share a lot of animal or plant-like features.
Both of the accompanying resources have been differentiated to allow students of differing abilities to access the work and this lesson has been written to tie in with the previously uploaded lesson on classification and the binomial naming system
This lesson introduces the three-domain system and describes some of the biochemical methods used in classification to overcome the problems of morphological convergence. The PowerPoint and accompanying resources have been designed to cover points [c] and [e] in AS unit 2, topic 1 of the WJEC A-level Biology specification
The lesson begins with an introduction of Carl Woese and goes on to describe how he is most famous for his definition of the Archaea as a new domain of life. Students were introduced to domains and the other classification taxa in a previous lesson, so their recall of this knowledge is continually tested and built upon as details are added. Students will discover the key differences between Archaea and Bacteria that led to the splitting of the prokaryotae kingdom and the addition of this higher classification rank. Moving forwards, the rest of the lesson considers other molecules that can be compared between species for classification purposes and the primary structure of cytochrome is described and discussed. At this point in the lesson, the students are also tested on their knowledge of the nature of the genetic code and have to explain how mutations to DNA can also be used for comparative purposes. The use of DNA genetic fingerprinting is briefly introduced and this is described in greater detail in a future lesson about assessing biodiversity at a molecular level
This lesson bundle contains 5 lesson PowerPoints and together with their accompanying worksheets, they will engage and motivate the students whilst covering the following specification points in module 3.1.1 (Exchange surfaces) of the OCR A-level Biology A specification:
The need for specialised exchange surfaces
The features of an efficient exchange surface
The structures and functions of the components of the mammalian gaseous exchange system
The mechanism of ventilation in mammals
The mechanisms of ventilation and gas exchange in bony fish and insects
Found interspersed within the detailed A-level Biology content in the slides are current understanding and prior knowledge checks and these are followed by displayed mark schemes to allow students to assess their progress. There are also differentiated tasks, guided discussion periods and quiz competitions that introduce key values and terms in a fun and memorable way
If you would like to see the quality of lessons included in this bundle, then download the mammalian gaseous exchange system and ventilation and gas exchange in insects lessons as these have been uploaded for free
This lesson describes the levels of organisation, including the aggregation of cells into tissues, tissues into organs and organs into organ systems. The detailed and engaging PowerPoint and accompanying resources have been designed to cover point (d) of AS unit 1, topic 2 of the WJEC A-level Biology specification and focuses on the levels of organisation in humans and plants. Please note that the lesson does not contain prepared slides of tissue as this is covered in a later lesson.
The lesson begins by using the process of haematopoiesis from haematopoietic stem cells to demonstrate how the red blood cell and neutrophil differ significantly in structure despite arising from the same cell along the same cell lineage. A series of exam-style questions will not only challenge their knowledge of structure but also their ability to apply this knowledge to unfamiliar situations. These differences in cell structure is further exemplified by the epithelial cells of the respiratory tract and students are challenged to remember how the shape and arrangement of these cells differ in the trachea and alveoli in relation to their function. The link between specialised cells and tissues is made at this point of the lesson so students are reminded that a tissue is a group of cells that work together to perform a specific function or set of functions. Moving forwards, a quick quiz competition will challenge the students to recognise the liver, kidney, spinal cord and pancreas from a brief functional description and this leads into a series of questions that links back to topics 1 and earlier in topic 2 where proteins, organelles and carbohydrates were originally covered. These prior knowledge checks are found throughout the lesson, along with current understanding checks, and all of the mark schemes are embedded into the PowerPoint to allow students to assess their progress. In terms of organ systems, a quick task challenges them to recognise 8 of the 11 that are found in humans from descriptions and this leaves them to identify the gaseous exchange, digestive and reproductive systems as the remaining 3.
The remainder of the lesson focuses on specialised plant cells and the differing shapes and features of the palisade and spongy cells in the mesophyll layer and the guard cells are covered at length and in detail. The cells found in the xylem and phloem tissue are also discussed.
This lesson describes how the cells of multicellular organisms are organised into tissues, tissues into organs and organs into systems. The detailed and engaging PowerPoint and accompanying resources have been designed to cover point 3.13 of the Pearson Edexcel A-level Biology A (Salters Nuffield) specification and focuses on the levels of organisation in humans and plants
The lesson begins by using the process of haematopoiesis from haematopoietic stem cells to demonstrate how the red blood cell and neutrophil differ significantly in structure despite arising from the same cell along the same cell lineage. A series of exam-style questions will not only challenge their knowledge of structure but also their ability to apply this knowledge to unfamiliar situations. These differences in cell structure is further exemplified by the epithelial cells of the respiratory tract and students are challenged to remember how the shape and arrangement of these cells differ in the trachea and alveoli in relation to their function. The link between specialised cells and tissues is made at this point of the lesson so students are reminded that a tissue is a group of cells that work together to perform a specific function or set of functions. Moving forwards, a quick quiz competition will challenge the students to recognise the liver, kidney, spinal cord and pancreas from a brief functional description and this leads into a series of questions that links back to topics 1 and 2 and earlier in topic 3 where blood clotting, proteins, osmosis, organelles, methods of transport, carbohydrates and enzymes were originally covered. These prior knowledge checks are found throughout the lesson, along with current understanding checks, and all of the mark schemes are embedded into the PowerPoint to allow students to assess their progress. In terms of organ systems, a quick task challenges them to recognise 8 of the 11 that are found in humans from descriptions and this leaves them to identify the gaseous exchange, digestive and reproductive systems as the remaining 3. This leads into a section about cystic fibrosis as this genetic disorder impairs the functioning of these systems.
The remainder of the lesson focuses on specialised plant cells and the differing shapes and features of the palisade and spongy cells in the mesophyll layer and the guard cells are covered at length and in detail. The cells found in the xylem and phloem tissue are also discussed.
