Video clip – Chloroplasts and starch

This video clip from the BBC  (from the TV series Botany: A Blooming History) introduces chloroplasts and the accumulation of starch grains, putting them in the context of their discovery by pioneering scientist Julius von Sachs in the 19th century.

You can find the video clip here: BBC Four Botany: A Blooming History.

Sachs worked to find out where in a plant the starch is made. New microscope technology enabled him to see inside plant cells, where he found chloroplasts. The products from the chloroplasts enable a plant to grow. Modern microscopes can be used to look at chloroplasts in living cells, showing them moving around inside the cells in order to trap the optimum amount of light. Electron microscopy can also be used to show the accumulation of starch grains inside cells.

This can be used as an introduction to the importance and then the structure of the chloroplast. Older students can then discuss the internal structure of the chloroplast and relate it to the different stages in photosynthesis. The clip is also relevant when looking at the development of microscopy techniques and the types of images generated from light microscopy compared to electron microscopy.