This is a revision resource for GCSE Biology. It is a PPT, but could be printed and used as individual worksheets or in a booklet format. It contains a visual image and some questions on the following topics. However, the answers to the questions are not in the PPT. Topics in the PPT How enzymes work Denature of enzymes Photosynthesis Environmental conditions Surveying plants in a location: a transect Diffusion Osmosis Active transport Respiration: aerobic Respiration: anaerobic Uses of anaerobic respiration to make biogas, bread and alcohol Cells tissues and organs Structure of plant cells, organelles and their functions Structure of animal cells, organelles and their functions Stem cells: embryonic and adult The structure of DNA: base pairing How DNA is replicated How proteins are made (genes switching on and off) Mitosis Meiosis Phototropism and auxins in the tips