Compare and contrast the streak-plate method of isolation with the pour-plate method of isolation.
What will be an ideal response?
The streak-plate and the pour-plate methods of bacterial isolation are both used to produce pure cultures of bacteria from specimens. Both techniques involve the use of agar-based growth media contained in Petri plates. Additionally, both techniques involve the use of dilutions as a means of isolating single cells or groups of cells that then grow into isolated colonies. However, there are several significant differences between the two techniques. The main difference is the way in which the specimen is diluted. In the streak-plate method, the specimen is diluted by use of an inoculating loop that spreads organisms over the surface of the agar. Thus, colonies appear only on the agar surface. In the pour-plate method, however, dilutions of the specimen are made in tubes of broth and then each dilution is added to melted agar, which is then poured into Petri dishes. Thus, microbes are mixed throughout the agar, and colonies will appear both in and on the medium.
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a. glomerulus b. loops of Henle c. proximal tubules d. distal tubules e. peritubular capillaries
The enzyme nitrogenase is rather unique, as it specifically functions:a
in the absence of oxygen. b. in the absence of nitrogen. c. in the absence of carbon dioxide. d. in the presence of oxygen. e. in the presence of carbon dioxide.
Which of the following is a member of the domain bacteria?
a. euglena b. methanogens c. halophiles d. cyanobacteria e. giardia
What is meant by the clonal expansion of a B cell?
a. An activated B cell will engulf and digest anything foreign. b. An activated B cell divides into cells that give rise to memory B cells and plasma cells. c. An activated B cell will immediately begin to produce antibodies. d. An activated B cell will kill infected host cells.