pptx, 3.5 MB
pptx, 3.5 MB
docx, 17.49 KB
docx, 17.49 KB
docx, 13.1 KB
docx, 13.1 KB
docx, 12.35 KB
docx, 12.35 KB
docx, 16.15 KB
docx, 16.15 KB
docx, 13.86 KB
docx, 13.86 KB

This lesson describes how Fick’s law of diffusion is governed by the three main properties of gas exchange surfaces in living organisms. The PowerPoint and accompanying worksheets have been designed to cover points 2.1 (i & ii) of the Edexcel International A-level Biology specification and there is a particular focus on the relationship between the size of an organism or structure and its surface to volume ratio.

Adolf Fick is briefly introduced at the start of the lesson and the students will learn that his law of diffusion governs the diffusion of a gas across a membrane and is dependent on three properties. The students are likely to know that surface area is one of these properties but although they may have been introduced to the surface area to volume ratio at iGCSE, their 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 the 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 to walk 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 an organism and this leads into the next part of the lesson, where the adaptations of a human to increase the ratio at the gas exchange surface is 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. The remainder of the lesson introduces concentration difference and thickness of membrane as the other two properties in Fick’s law of diffusion and students are reminded that the maintenance of a steep concentration gradient and a reduction in the diffusion distance are critical for this transport mechanism.

This lesson has been specifically planned to prepare students for the next lesson which describes how the structure of the mammalian lung is adapted for rapid gas exchange (specification point 2.1 [iii])

Get this resource as part of a bundle and save up to 30%

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

Bundle

Edexcel Int. A-level Biology Topic 2: Membranes, Proteins, DNA and Gene expression

Hours and hours of planning have gone into each and every lesson that's included in this bundle to ensure that the students are engaged and motivated whilst the detailed content of topic 2 of the Edexcel International A-level Biology specification is covered. Membranes, proteins, DNA and gene expression represent some of the most important structures, molecules and processes involved in this subject and a deep understanding of their role in living organisms is important for a student's success. The 20 lesson PowerPoints and accompanying resources contain a wide range of activities which cover the following topic 2 specification points: * Know the properties of gas exchange surfaces in living organisms * Understand how the rate of diffusion can be calculated using Fick's Law of Diffusion * Understand how the structure of the mammalian lung is adapted for rapid gas exchange * The structure and properties of cell membranes * The movement of free water molecules by osmosis * The movement across membranes by passive and active transport * The role of channel and carrier proteins in membrane transport * The basic structure of an amino acid * The formation of polypeptides and proteins * The structure of proteins * The mechanism of action and specificity of enzymes * Enzymes are biological catalysts * Intracellular and extracellular enzymes * The basic structure of mononucleotides * The structure of DNA and RNA * The process of DNA replication * The nature of the genetic code * A gene as a sequence of bases on DNA that codes for a sequence of amino acids * The process of transcription and translation * Errors in DNA replication give rise to mutations * Mutations give rise to disorders but many mutations have no observable effect * The meaning of key genetic terms * Understanding the pattern of monohybrid inheritance * Sex linkage on the X chromosome * Understand how the expression of a gene mutation in people with cystic fibrosis impairs the functioning of the gaseous exchange, digestive and reproductive systems * The uses and implications of genetic screening and prenatal testing Due to the detail included in all of these lessons, it is estimated that it will take in excess of 2 months of allocated A-level teaching time to complete the teaching of the bundle If you would like to sample the quality of these lessons, then download the rapid gas exchange, osmosis, DNA & RNA, genetic code, genetic terms and cystic fibrosis lessons as these have been uploaded for free.

£28.00

Reviews

Something went wrong, please try again later.

This resource hasn't been reviewed yet

To ensure quality for our reviews, only customers who have purchased this resource can review it

Report this resourceto let us know if it violates our terms and conditions.
Our customer service team will review your report and will be in touch.