Which statement about UV light sterilization is right?
A. It breaks the disulfide bonds in peptide chain to inactivate proteins function.
B. It induces formation of dimmers of adjacent thymine-thymine in DNA ;
C. It inhibits gyrase activity so that the DNA chain can not be uncoiled .
D. It has much stronger penetration power.
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Which pore size of filter membrane is smaller enough to trap most bacterial cells and largest viruses more efficiently?
A. 0.025um
B. 1um;
C. 0.45um ;
D. 0.22um;
Which type of alcohol is more effective to kill bacteria?
A. 80%;
B. 95%
C. 70% ;
D. 100%;
Which one of the following chemicals was used by Dr. Joseph Lister to reduceinfection during surgery in 1867 ?
A. surfactants,
B. heavy metals,
C. phenol ,
D. alcohol
Which type of the halogens is used in toothpaste to prevent dental caries?
A. iodine,
B. chlorine,
C. bromine,
D. fluorine.