This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Replication, Subject name: Biochemistry
Enzyme which prevents aging/senescence is: 
Select and explain. 
A. DNA Polymerase, B. Catalase, C. Telomerase, D. Peroxidase
C: Telomerase
Answer: C: Telomerase 
Explanation: Teloemrase prevents ageing. Telomerase RNA dependent DNA polymerase/ Reverse transcriptase Absent in somatic cells Not a ribozyme It is a ribonucleoprotein (RNA + protein)(act as enzyme). Increases longevity of cells Prevents telomere shoening (prevents ageing or senescence) Activity of enzyme decreased in ageing increased in cancer Premature ageing (Progeria) occurs if telomerase decreases