Cell cycle: mitosis and meiosis
For A level Biology, students are required to have a considerably greater knowledge and understanding of the cell cycle and cell division than at Key Stage 4. There is a substantial increase in the level of detail that students are expected to know and there is a much greater requirement on technical vocabulary.
Students need to be able to explain in detail the events taking place at the various stages of both mitosis and meiosis. The control mechanisms of the cell cycle needs to be understood.
Students often forget that interphase is a period of considerable activity, and that this is when the replication of DNA takes place, before the nucleus and cell divide.
Students need to be able to recognise the stages of mitosis and meiosis diagrammatically and in images/photographs from microscopes. They need to be able to draw and label the stages as seen under the microscope
The significance of both mitosis and meiosis needs to be understood by A level biologists.
Practical microscopy skills need to be developed for this topic so that students are able to prepare stained slides that will allow them to view and identify the various stages of the cell cycle in tissues.
Whilst this list provides a source of information and ideas for experimental work, it is important to note that recommendations can date very quickly. Do NOT follow suggestions which conflict with current advice from CLEAPSS, SSERC or other recent safety guides. eLibrary users are responsible for ensuring that any activity, including practical work, which they carry out is consistent with current regulations related to Health and Safety and that they carry an appropriate risk assessment. Further information is provided in our Health and Safety guidance.
Links and Resources
This extensive set of resources is centred around a "Big Picture" issue from the Wellcome Trust focusing on the cell. The magazine itself has a number of interesting articles which could be separated and given out for students to read and review. Articles of particular interest to this topic are Dividing we stand, No limits? and Under development.
As well as the magazine itself, this set of resources includes an excellent PowerPoint presentation on cell division.
This Association of British Pharmaceutical industry website contains a range of animations which could be used within lessons to consolidate learning.
Pages 3 and 4 of this resource are particularly relevant to the topic of cell cycle. Additional details will need to be added by the teacher (or nominated students!) to ensure that the stages of cell division can be identified and there is correct use of the required technical vocabulary.
See also Cell division: animation 1 in this list which is an alternative version of this resource.
Teachers should consider a range of strategies for using animations and videos with students (see animation 2 below). With an animation such as this one students could be asked to give "voice over’s" to animations to confirm understanding.
This resource was written as a year 11 module, but provides a useful short activity for A level students.
Section 2 of the resource entitled "the gene machine" is the section which has the most relevance for this topic. In particular, teachers should read page 35 and use the student sheet 2.1 on pages 40 and 41.
Most questions on the student sheet should be straightforward for A level students. However, questions 3 and 4 may identify previous misconceptions in relation to the separation on chromosomes as a random process.
Students could work in groups or pairs to complete this activity and then be prepared to present their answers with explanations to the rest of the class who can comment on the answers/explanations given.
Although this is a relatively dated publication, the level of detail contained within it is exceptional. The format and content make it suitable as a teacher only resource for those wishing to consolidate their understanding of this topic before delivering it to their A level students
In this practical activity from science and plants for school (SAPS) students stain root tips and examine them for signs of cells dividing by mitosis. Students can either compare two different sources of root tip or two different stains.
Some pre-preparation is required for this practical as students will need to mark root tips 2 days before the actual practical in order to be able to calculate the mitotic index.
It would also be useful to have some bought slides available for students to compare against whist undertaking this practical investigation.