Prokaryotic and Eukaryotic cells
The understanding of cell structure and sub-cellular structures in relation to function is a fundamental concept in biology. GCSE students need to understand the similarities and differences between Prokaryotic and Eukaryotic cell structure and sub-cellular structures and how this relates to function. Sub-cellular structures include: the nucleus/genetic material, plasmids, mitochondria, chloroplasts and cell membranes. GCSE Biology students need to be able to effectively use a light microscope and explain how electron microscopy has increased understanding of sub-cellular structures. They also need to be familiar with the culturing of micro-organisms using aseptic technique.
A common difficulty with this topic area is the understanding of the concept of a cell as a 3D structure. Teaching strategies to address this include using modelling activities, where students make a cell and sub-cellular structures using a variety of substances such as plastic bags, wallpaper paste, golf balls, peas etc.. There are also a number of websites that provide 3D images of the cell which will help to overcome this misconception.
Developing the required microscopy skills often proves difficult for many students, and labelled diagrams produced as a result are poor with labels not carefully added. A range of practical activities should be incorporated into the teaching strategy for this topic to help develop the fine motor skills required in effective microscopy.
Links and Resources
This is an extensive resource package, which includes the Wellcome Trust Big Picture magazine. In addition to the magazine there are several presentations which include some great images that will help students to develop their using of the cell as a 3D structure.
These images would work well as class presentations; one of the presentations is an activity where students have to identify the presented images (answers are provided). There is also a useful video on working with cells.
This is an article from the Catalyst magazine. The article includes detailed electron micrographs of two Acinar cells from a pancreas, which would work well on a white board or on hand held devices.
Students could be asked to identify as many organelles as possible (with a description of their function) and then compare this with the detailed key provided on the final page of the article.
There are many ways to make effective use of Catalyst articles, a booklet has been produced which provides ideas on how Catalyst articles can be used with students and includes six exemplar activities. This booklet can be accessed at: https://www.stem.org.uk/elibrary/resource/27308
This is quite a basic and relatively short interactive resource looking at the workings of light and electron microscopes. Through illustrations and quizzes, students investigate the structure and function of animal, plant and bacterial cells.
It would work well as a plenary activity or a short homework activity to recap some important knowledge and understanding on cell structure, function and the use of different microscopes.
This Catalyst article shows how various types of microscope allow scientists to see what is going on inside living plant cells. Students could be given this article as pre-reading for a lesson, they could be asked to make use of the web link in the article to view images from a range of different microscopes.
This manual from the Society of General Microbiology provides a basic introduction to microbiology, aseptic technique and safety. It is a useful guide for teachers and many of the photographs within the booklet could be used to demonstrate to students the techniques in culturing microorganisms
In this short video, wallpaper paste in a plastic bag is used to model a bacterial cell. This video could be watched as a class activity with students asked how effective a model is this, what's good/not so good about it? Students could then work in teams, tasked with producing a better model of a cell. The results could then be "judged".
There are numerous examples of models on Youtube, students could view this before starting their project. For example: https://www.youtube.com/watch?v=5b5ziuSBUiw