(4) The attachment of the pyrimidine base to the ribose phosphate ring is catalyzed by orotate phosphoribosyl transferase (OPRT) and PRPP provides the ribose-5-phosphate moeity. Hydrolysis of the PP i that is split off of the PRPP makes this reaction irreversible.
Red Squirrels shed their coats twice a year, switching between a thinner coat in summer and a darker, thicker winter coat. 6. Males may live in an area of up to 17 hectares of woodland... thatâs about the same size as 34 football pitches! 7.
White squirrels are almost always a white version of the eastern grey squirrel. There are a few types of genetic aberrations that cause the white coats. The first is albinism, caused by a mutation on a gene that codes for pigmentation. Albinos have red eyes. The other is a white morph, caused by a different gene.