Why is oxygen consumption inhibited by malonate

Q1. Malonate is a competitive inhibitor of succinate dehydrogenase. If malonate is aIDed to mitochondria that are actively respiring, then oxygen consumption stops and a metabolic intermediate accumulate. (a) What intermediate accumulates, and why give reason? (b) Why is oxygen consumption inhibited by malonate? (c) Besides simply removing malonate, can you propose a treatment that would reverse the inhibition caused by malonate?

Q2. You get a soil sample and run an enrichment culture on it. You give the organisms in the culture with all of the ingredients required for growth except for nitrogen. What result do you expect to have at the end of the experiment?