This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Carbohydrates, Subject name: Biochemistry
Glycogenin primer is glucosylated by: 
Select and explain. 
A. UDP Glucose, B. Glucose 1 PO4, C. UDP Glucose 1 PO4, D. UDP Glucose 6 PO4
A: UDP Glucose
Answer: A: UDP Glucose 
Explanation: Ans. A. UDP Glucose(Ref: Harper 31/e page 164)Glycogenin, a 37 kDa protein is glucosylated on specific tyrosine residue by UDP glucose.Glycogenenin catalyses transfer of 7 glucose residue from UDP-Glc, in l-4 linkage to form Glycogen primer.Further Glucose on glycogen primer are added by Glycogen Synthase to nonreducing end till growing chain is at least 11 glucose residue long.