Structure of DNA (Edexcel GCSE Biology & Combined Science)

This lesson describes the structure of DNA as a double-stranded polymer coiled into a double helix and focuses on nucleotides as the monomers. The PowerPoint and accompanying resources have been designed to cover the detail of point 3.4 of the Edexcel GCSE Biology & Combined Science specifications.

The lesson begins with a reveal of the acronym DNA and students will learn that this stands for deoxyribonucleic acid. There is a focus on the use and understanding of key terminology throughout the lesson so time is taken to look at the meanings of the prefixes poly and mono as well as the suffix -mer. This leads into the description of DNA as a polymer which is made up of many monomers known as nucleotides. Students will be introduced to the three components of a DNA nucleotide and will learn that four different bases can be attached to the sugar. An observational task is used to get them to recognise that DNA consists of two strands and that complementary bases are joined by hydrogen bonds. Understanding checks are interspersed throughout the lesson along with mark schemes so that students can assess their progress