【单选题】Which of the following statements about carbon monoxide (CO) poisoning is wrong?
A.
CO, a colorless, odorless gas, is responsible for more than half of yearly deaths due to poisoning worldwide. In the United States alone, nearly 4,000 people succumb to CO poisoning each year, both accidentally and intentionally.
B.
CO has an approximately 2,500-fold greater affinity for hemoglobin than does oxygen. Consequently, relatively low levels of CO can have substantial and tragic effects.
C.
When CO combines with hemoglobin, the complex is referred to as carboxyhemoglobin, or COHb.
D.
In the United States, the government-mandated (Occupational Safety and Health Administration, OSHA) limit for CO at worksites is 50 ppm for people working an eight-hour shift.
【单选题】Staphylococcus aureus is a pathogenic bacterium that can infect a wide range of host species, including humans. S. aureus has a particular protein that binds with hemoglobin from the host organism. He...
A.
Each host transcribes and translates this gene differently.
B.
S. aureus develops a mutualistic relationship with each host species.
C.
Changes in amino acid sequence are unrelated to protein function.
D.
Each strain is best adapted to a specific host species.