Class I AMGs encode for metabolism pathways in the cell and are found in KEGG. In particular, these genes are found in photosynthesis and carbon metabolism. psbA is almost a ubiquitous photosynthetic AMG for the photosystem Il reaction center D1 found in Synechococcus and Prochlorococcus cyanophages. Photosynthetic machinery for other reaction centers and electron transport are also found in many viruses infecting phototrophs. Phages encode for nearly all genes involved in carbon metabolism. In particular, viruses redirect host metabolism to increase dNTP biosynthesis for viral genome replication. glgA can induce starvation by converting glucose-6-phosphate to glycogen, forcing the host to compensate by deriving ribulose-5-phosphate from glyceraldehyde-3-phosphate and fructose-6-phosphate.