Question

1. which of the following antimicrobials inhibits the activity of dna gyrase?

a. polymyxin b
b. clindamycin
c. nalidixic acid
d. rifampin

1. which of the following would be a sign of an infection?

a. muscle aches
b. headache
c. fever
d. nausea

1. which of the following is an example of a noncommunicable infectious disease?

a. infection with a respiratory virus
b. food poisoning due to a preformed bacterial toxin in food
c. skin infection acquired from a dog bite
d. infection acquired from the stick of a contaminated needle

Explanation:

• Question 5: Nalidixic acid is a quinolone antimicrobial that specifically inhibits DNA gyrase (a type of topoisomerase II), which is crucial for bacterial DNA replication. Polymyxin B acts on the cell membrane, clindamycin affects protein synthesis (binds to 50S ribosomal subunit), and rifampin inhibits RNA polymerase.
• Question 6: Fever is a classic sign of infection as the body's immune response (e.g., release of pyrogens) raises the body temperature. Muscle aches, headache, and nausea can be caused by many non - infectious factors (e.g., stress, dehydration, migraine for headache; over - exercise for muscle aches; digestive issues for nausea).
• Question 7: Non - communicable infectious diseases are not transmitted from person to person. Food poisoning due to preformed bacterial toxin in food (e.g., Staphylococcus aureus toxin in food) is non - communicable. Respiratory virus infections (A) are communicable (e.g., via droplets). A skin infection from a dog bite (C) could potentially be transmitted (if the causative agent is transmissible), and an infection from a contaminated needle (D) (e.g., HIV, hepatitis) is also a form of transmission (blood - borne).

Answer:

1. C. nalidixic acid
2. C. fever
3. B. food poisoning due to a preformed bacterial toxin in food