Answer:
The suitable answer to the given blank is
Two reactions or pathways that share the substrate or products and result in no net gain of ATP.
Explanation:
A futile cycle can be defined as those cycles which are involved in metabolism at cellular level to control or regulate biochemical pathways.
It is also known as substrate cycle and is when two metabolic pathways follow directions opposite to each other so that the overall effect is zero other than to dissipate energy.
Therefore, the result is zero net gain.
