Question

A rat that has been running in a wheel for one hour continuously is taken out of its wheel and allowed to rest for one hour. The rat is then injected with ¹⁴C-labeled glucose and allowed to continue resting. After 2 hours, a muscle biopsy is taken. Which of the following molecules from the muscle tissue would you expect to contain most of the ¹⁴C radioactivity: Ribose, glycogen, fatty acid, or acetyl CoA? Explain your answer.

Answer 1

Ans - Glycogen.

During rigrous running, rat have used most of its energy and requires more glucose that is present in blood. So during rest all of the glucose have been utilized.  After that more glucose is injected in rat's body. And after taht rat is allowed to take rest. during this period glycogenesis (formation of glycogen) occurs. At rest there is no need of glucose,so glucose in blood is converted in glycogen.

So 14C must be present in glycogen.