Cell wall for higher growth rates in diatoms. In brown algae, phlorotannins may be a constituent of the cell walls. The group Oomycetes, also known as water molds, are saprotrophic plant pathogens like fungi. Until recently they were widely believed to be fungi, but structural and molecular evidence has led to their reclassification as heterokonts, related to autotrophic brown algae and diatoms. Unlike fungi, oomycetes typically possess cell walls of cellulose and glucans rather than chitin, although some genera (such as "Achlya" and "Saprolegnia") do have chitin in their walls. The fraction of cellulose in the walls is no more than 4
UTP—glucose-1-phosphate uridylyltransferase including the liver and the muscles. An exception is the brain, which has high levels of glycogen but low specific activity of UTP—glucose-1-phosphate uridylyltransferase. In animal cells, UTP—glucose-1-phosphate uridylyltransferase is found predominantly in the cytoplasm. UTP—glucose-1-phosphate uridylyltransferase is also required for galactose metabolism in animals and microorganisms. In galactose metabolism, the enzyme galactose 1-phosphate uridylyltransferase transfers a phosphate from UDP-glucose to galactose 1-phosphate to produce UDP-galactose, which is then converted to UDP-glucose. Bacteria with defective UTP—glucose-1-phosphate uridylyltransferase are unable to incorporate galactose into their cell walls. In this enzyme’s primary reaction, the phosphate group on glucose-1-phosphate replaces the phosphoanhydride bond