Many enzymes consist of a protein and a non-protein (called the cofactor). The proteins in enzymes are usually globular. The intra- and intermolecular bonds that hold proteins in their secondary and tertiary structures are disrupted by changes in temperature and pH. This affects shapes and so the catalytic activity of an enzyme is pH and temperature sensitive.
Everyday in the U.S. millions of cars and trucks idle needlessly, sometimes for hours. You may not be able to avoid keeping your engine running when youâre stopped at a traffic signal or stuck in slow-moving traffic. But other times idling is unnecessary. An idling car can release as much pollution as a moving car.
There are plenty of occasions where you might find your car idling. In a long drive through, picking someone up from work, or just sitting in your driveway. If you're idling longer than 10 seconds, though, you're better off turning off the engine. Obviously, it's a bad idea to shut your car off at an intersection. However, a common myth is that you waste more gasoline starting your car than you would by idling. This is technically true, but only for about 5-10 seconds.