(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.
Frozen Planet Woolly Bear Caterpillars A Frozen Planet researcher discusses the life cycle of the Canadian Arctic's woolly bear caterpillar, which freezes solid every year for 14 years until it has enough energy to transform into a moth.rozen Planet Woolly Bear Caterpillars A Frozen Planet researcher discusses the life cycle of the Canadian Arctic's woolly bear caterpillar, which freezes solid every year for 14 years until it has enough energy to transform into a moth.