(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.
Members of the deer family are unique because they shed their antlers every year. Horns, in contrast, remain permanently affixed to the skull. (The American pronghorn antelope sheds its horn sheaths each year, but the bony horn cores remain in place) In the wild in Maine, only deer and moose grow antlers. Antlers have a covering of living skin called velvet.