Sex determination REVISION

This short revision lesson (@15-20 minutes) reminds students how to use a Punnett cross to show the inheritance of biological sex. The lesson has been primarily designed for use with those students taking the AQA Combined Science FT in the lead up to mock and GCSE examinations, but is also suitable for students taking the HT, or separate biology. Due to the nature of the DO NOW task, there is also some revision of homeostasis, enzymes, and the menstrual cycle hormones.

The lesson begins by challenging the students to predict why the numbers 37, 28, and 23 are important in biology. This reminds students that body temperature is maintained around 37 degrees celsius, the average length of the human menstrual cycle is 28 days, and that there are 23 pairs of chromosomes in human body cells. This leads into a few multiple-choice, or short answer questions about homeostasis and the cycle. However, the focus of the lesson is the determination of biological sex, so students are then challenged to remember the sex chromosomes of each sex. The answer to a question involving a Punnett cross about the inheritance of a genetic disorder is modelled on the board to remind students how to use this genetic diagram, before they are challenged to show how sex is determined. All answers to the understanding checks are embedded into the PowerPoint to allow students to assess their understanding and progress. The key points associated with the topic have also been displayed on a resource which can be kept with the understanding checks for use in the final days and hours before the exam.

More short revision lessons in this format are uploaded, and topics including relative formula mass, half-life graphs, and mitosis vs meiosis have been covered.