(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.
Although baby squirrels have been recorded in almost every month of the year, these two litters, early spring and late summer, are the norm. Typically the early spring babies have the highest survival rate, especially in areas where it snows, since a small squirrel has to expend more energy than a large one to stay warm and find food.