Ultrastructure of plant cells (Pearson Edexcel A-level Biology A)

This fully-resourced lesson describes the ultrastructure of plant cells and includes the cell walls, chloroplasts, amyloplasts, vacuole, tonoplast, plasmodesmata, pits and middle lamella. The detailed PowerPoint and accompanying resources have been designed to cover point 4.7 of the Pearson Edexcel A-level Biology specification and also compares this structure against animal cells that was covered at the beginning of topic 3.

The lesson begins with a task called REVERSE GUESS WHO which will challenge the students to recognise a particular organelle from a description of its function. This will remind students that plant cells are eukaryotic and therefore contain a cell-surface membrane, a nucleus (+ nucleolus), a mitochondria, a Golgi apparatus, ribosomes and rough and smooth endoplasmic reticulum like the animal cells. Moving forwards, the next part of the lesson focuses on the relationship between the structure and function of the vacuole, chloroplast, plasmodesmata and cellulose cell wall. When considering the vacuole, key structures such as the tonoplast are described as well as critical functions including the maintenance of turgor pressure. A detailed knowledge of the structure of the chloroplast at this early stage of their A-level studies will increase the likelihood of a clear understanding of photosynthesis when covered in topic 5. For this reason, time is taken to consider the light-dependent and light-independent reactions and to explain how these stages are linked. Students will learn that chloroplasts and amyloplasts can contain stores of starch so an opportunity is taken to challenge them on their knowledge of this polysaccharide as it was covered in topic 1. The final task challenges them to recognise descriptions of the cell wall, chloroplast, amyloplasts, vacuole, tonoplast and plasmodesmata which will leave 2 remaining which describe the pits and middle lamella.