This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Glycogen, Subject name: Biochemistry
Enzyme involved in both glycogenesis and glycogenolysis is: 
Select and explain. 
A. Glycogen synthase, B. Phosphoglucomutase(PGM), C. Phosphorylase, D. Phoshoglycero mutase
B: Phosphoglucomutase(PGM)
Answer: B: Phosphoglucomutase(PGM) 
Explanation: Enzyme common between glycogenesis and glycogenolysis is phosphoglucomutase for interconversion between glucose-1-P and glucose-6-P. (see treasure) Phosphoglyceromutase- for isomerization of 3-phosphoglycerate to 2-phosphoglycerate in glycolysis Enzyme common between glycogenesis and glycolysis Hexokinase/ Glucokinase glycogenesis and glycogenolysis Phosphoglucomutase. gluconeogenesis and glycogenolysis Glucose-6- phosphatase