What is the half-life of nitric oxide in the presence of oxygen?

The half-life of nitric oxide (NO) in the presence of oxygen is indeed very short, typically measured to be less than 1 second. This rapid degradation is primarily due to the reaction of nitric oxide with oxygen to form nitrogen dioxide (NO2). In physiological conditions, NO acts as a signaling molecule with various functions, including vasodilation and neurotransmission. However, its effectiveness is limited by its brief half-life, which means that it must be continuously produced in the body to maintain its biological effects.

A half-life of less than 0.1 seconds would suggest an extremely rapid reaction unlikely for NO in typical biological contexts. A duration of less than 10 seconds is too long, as it does not accurately reflect the swift reactive nature of nitric oxide in an oxygenated environment. Similarly, a half-life of less than 100 seconds far exceeds the actual duration observed in vivo. Hence, the choice indicating a half-life of less than 1 second best encapsulates the rapid degradation of nitric oxide due to its interactions with other biological molecules, especially in the presence of oxygen.