metabolism Biochemistry 31 enzymes 26 morphology 22 photosynthesis 20 Plant cell 14 carbohydrates 10 Microbiology 8 viruses 8 cell physiology 7 proteins 7 Physiology 4 Plant physiology 4 biochemistry 4 Photosynthesis 3 nutrition 3 protein synthesis 3 reproduction 3 Fungi 2 Molecular genetics 2 Plant cells 2 animal nutrition 2 bacteria 2 cell division 2 energetics 2 genes 2 genetics 2 irritability 2 Biochemical genetics 1 Biological chemistry 1