Cells with a short life span that circulate in blood and tissues and are usually the first cells on the scene of a bacterial invasion are called:
a. monocytes.
b. polymorphonuclear neutrophils.
c. lymphocytes.
d. macrophages.
Cells that ingest and destroy bacteria and other foreign particles are called:
a. phagocytes.
b. lymphocytes.
c. goblet cells.
d. ciliated cells.
The persistent survival of microorganisms on a surface of the human body is called a(n):
a. infection.
b. colonization.
c. nosocomial infection.
d. reservoir.
A patient is infected with a bacteria that is resistant to erythromycin (the antibiotic is not effective) and sensitive to clindamycin (the antibiotic is effective). However, the patient is not improving and the organism now appears to be resistant to both antibiotics. The reason for this alteration in gene expression in the bacterium is likely due to:
a. genetic regulation that encodes the resis-tance mechanism is constitutive.
b. the genetic regulation encoding the en-hanced resistance is inducible.
c. the genetic regulation for the enhanced resistance is normally suppressed.
d. the organism was always resistant to both antibiotics and should not have been treated with the combination therapy.
In the following genetic sequence, identify the correct complementary strand of DNA for the sequence 3' CAGTACCGTAAGCT 5'
a. 3' GTCATGGCATTCGA 5'
b. 5' GTCATGGCATTCGA 3'
c. 5' AGCTTACGGTACTG 3'
d. 5' GTCATGGCTTCGA 3'