Most strains of Escherichia coli can be presumptively identified on the basis of which characte-ristic?
a. Spot indole–positive
b. Citrate-positive
c. Methyl red–negative
d. Urease-positive
A
In the interests of cost containment, many clinical laboratories use an abbreviated identification scheme for identifying commonly isolated enteric organisms (Clinical Laboratory Standards In-stitute [CLSI], 35A). E. coli, the most commonly isolated enteric organism, can be identified us-ing a positive spot indole test.
You might also like to view...
Which is TRUE of succulent plants such as cacti or pineapple?
A. They are C3 plants. B. They are highly efficient at photosynthesis in cooler and wet environments. C. They tend to undergo substantial rates of photorespiration. D. They produce 4-carbon malate in the first step of carbon fixation. E. They continually produce sugar, both day and night under hot arid conditions.
A house plant seems to be growing slowly and lacks its normal bright green color. You call a botanist for advice. She suggests that the plant may be deficient in magnesium (Mg2+). Why are these symptoms associated with Mg2+ deficiency?
A) Mg2+ is important in the structure of many amino acids. B) Lack of Mg2+ in the soil allows pathogenic bacteria to grow. C) Mg2+ is required before NADPH can function. D) Mg2+ is an important component in chlorophyll. E) Cytochromes require Mg2+ to function properly.
Why is there a need to produce Okazaki fragments on the lagging strand, but not on the leading strand of DNA?
A. The two parental strands of DNA are antiparallel and DNA polymerase makes DNA in the 5? to 3? direction only. B. It is substantially more efficient to make several shorter strands rather than one longer strand of DNA. C. There is not enough cellular DNA ligase for bonding Okazaki fragments together if they were produced from both parental strands. D. By having one leading strand and one lagging strand the cell can limit the amount of DNA polymerase used for chromosomal replication. E. The leading strand opens first, and so Okazaki fragments are not needed. The lagging strand unwinds second resulting in the need to produce Okazaki fragments.
What structures are found within prokaryotic cells?
What will be an ideal response?