Plays a central role as a glucosyl donor in cellular metabolic pathways. During development the lack of the enzyme activity leads to cell death and lysis. Strains which lack UDPG pyrophosphorylase accomplish early developmental events but are unable to culminate. The enzyme affects the growth rate of the cells but is not essential for growth. alpha-D-glucose 1-phosphate + H(+) + UTP = diphosphate + UDP-alpha-D-glucose Carbohydrate metabolism; galactose metabolism. Homooctamer. Expressed in both prestalk and prespore cells. Expression becomes strong after 12 hours of development and peaks at 16 hours. By cAMP through transmembrane signal transduction. Belongs to the UDPGP type 1 family.