pptx, 2.54 MB
pptx, 2.54 MB

This engaging lesson describes how the structure of the mammalian lung is adapted for rapid gaseous exchange. The PowerPoint has been designed to cover point 2.1 (iii) of the Pearson Edexcel A-level Biology A specification and focuses on the essential features of the alveolar epithelium as well as the mechanism of ventilation to maintain a steep concentration gradient for the simple diffusion of oxygen and carbon dioxide.

Gas exchange at the alveoli is a topic that was covered at GCSE and considered during the previous lessons in topic 2.1 so this lesson has been written to challenge the recall of that knowledge and then to build on it. The main focus of the first half of the lesson is the type of epithelium found lining the alveoli and students will discover that a single layer of flattened cells known as simple, squamous epithelium acts to reduce the diffusion distance.

The following features of the alveolar epithelium are also covered:

Surface area
Moist lining
Production of surfactant

The maintenance of a steep concentration gradient is the role of the respiratory system and the next part of the lesson focuses on the diaphragm and intercostal muscles. As the mechanism of inhalation is a cascade of events, the details of this process are covered in a step by step format using bullet points. At each step, time is taken to discuss the key details which includes an introduction to Boyle’s law that reveals the inverse relationship between volume and pressure. It is crucial that students are able to describe how the actions of the diaphragm, external intercostal muscles and ribcage result in an increased volume of the thoracic cavity and a subsequent decrease in the pressure, which is below the pressure outside of the body. At this point, their recall of the structures of the mammalian gas exchange system is tested, to ensure that they can describe the pathway taken by air when moving into the lungs.

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A bundle is a package of resources grouped together to teach a particular topic, or a series of lessons, in one place.

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Topic 2: Genes and Health (Pearson Edexcel SNAB)

Some of the key biological topics are covered in topic 2 of the Pearson Edexcel A-level Biology A (Salters Nuffield) course and include the transport of materials across cell membranes, DNA structure and replication, protein synthesis and monohybrid inheritance. In line with this, many hours of intricate planning have gone into the design of all of the 19 lessons that are included in this bundle to ensure that the content is covered in detail, understanding is constantly checked to immediately address misconceptions and that engagement is high. This is achieved through the wide variety of tasks in the PowerPoints and accompanying worksheets which include exam-style questions with clear answers, discussion points, differentiated tasks and quick quiz competitions. The following specification points are covered by the lessons within this bundle: * The properties of gas exchange surfaces in living organisms * Understand how the rate of diffusion is dependent on these properties and can be used in the calculation of the rate of diffusion by Fick's law * Adaptations of the mammalian lung for rapid gaseous exchange * Structure and properties of cell membranes * Simple and facilitated diffusion as methods of passive transport * The involvement of ATP and carrier proteins in active transport, endocytosis and exocytosis * The basic structure of mononucleotides * The structures of DNA and RNA * The process of protein synthesis * The roles of the template strand, mRNA and tRNA * The nature of the genetic code * A gene is a sequence of bases on DNA that codes for the amino acid sequence of a polypeptide * The basic structure of an amino acid * The formation of polypeptides and proteins * The primary, secondary, tertiary and quaternary structure of proteins * Globular and fibrous proteins using haemoglobin and collagen as examples * The mechanism of action and the specificity of enzymes * Enzymes are biological catalysts that reduce activation energy * The process of DNA replication * Errors in DNA replication can give rise to mutations * The meaning of key genetic terms * Patterns of inheritance, in the context of monohybrid inheritance * Understand how the expression of a gene mutation in people with cystic fibrosis impairs the functioning of the gaseous exchange, digestive and reproductive systems * Understand the uses and implications of genetic screening and prenatal testing Due to the detail included in each of these lessons, it is estimated that it will take in excess of 2 months of allocated teaching time to cover the content. If you would like to see the quality of the lessons, download the gas exchange surfaces, cell membranes, transcription, globular and fibrous proteins, monohybrid inheritance and cystic fibrosis lessons as these have been shared for free

£23.00

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