This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Biochemistry
Which of the following is true for phosphofructokinase? 
Select and explain. 
A. It uses Fructose 1,6 bisphosphate as substrate., B. It generates ATP, C. It catalyses an irreversible reaction in glycolysis, D. It is activated by increased levels of ATP and citrate.
C: It catalyses an irreversible reaction in glycolysis
Answer: C: It catalyses an irreversible reaction in glycolysis 
Explanation: Phosphofructokinase catalyses the first committed step of glycolysis. It is the rate limiting enzyme of glycolysis. The reaction is irreversible.