(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.
Some wild animals adapt, like Oklahoma farm animals that stay outdoors in winter. To keep warm, they may grow new, thicker fur. On weasels and snowshoe rabbits, the new fur is white to help them hide in the snow. Food is hard to find in the winter. Some animals, like squirrels, mice and beavers, gather extra food in the fall and store it to eat later. Some, like rabbits and deer, spend winter looking for moss, twigs, bark and leaves to eat. Other animals eat different kinds of food as the seasons change. The red fox eats fruit and insects in the spring, summer and fall. In the winter, it cannot find these things, so instead it eats small rodents.