A glass capillary tube containing a chemical was placed inside a turbid pure culture of cells. Most cells moved away from the tube, but some cells were found inside the capillary tube. The chemical is likely
a. an attractant to all cells, but only a few had time to go into the tube.
b. an attractant to most cells and a repellent to those within the tube.
c. a repellent to all cells, and some cells by chance were within the tube.
d. a repellent to most cells and an attractant to those within the tube.
Answer: C
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Energy yields are high enough for Fe2+ oxidation that the bacteria that perform this reaction require only small quantities of Fe2+ to be available
Indicate whether the statement is true or false.
When DNA probes are used to identify bacterial DNA similarities by hybridization, the probe DNA is heated and the template DNA is treated to separate the two strands.Why would the probe DNA be heated?
A. This is the only way to properly label the probe DNA. B. The probe may contain portions that are double-stranded. Heating it up breaks any possible hydrogen bonds that may have formed allowing the single-stranded sequences to hybridize with their complementary targets. C. Heating it up activates the tag on the probe DNA before it hybridizes to the bacterial template DNA. D. DNA hybridization can only take place at high temperatures, so all the DNA must be heated up prior to hybridization.
A construction company has cleared all the trees from an area near a river in order to build luxury homes with unobstructed views of the river. What do you predict will be the effects of this action? Check all that apply.
_____ An increase in the volume of water running off into the river. _____ A decrease in the amount of nutrients leached from the soil. _____ An increase in the concentration of nutrients in the run off entering the river. _____ A build up of inorganic nutrients in the soil of the deforested area. _____ Increased weathering of rocks in the deforested area.
You lose track of your friend in a store and start looking for her. Which strategy represents the use of a search image?
A) You ask a woman if she has seen anyone around this part of the store. B) You think about what color clothing your friend is wearing and look for that color. C) You go to the department in the store where your friend most likes to shop. D) You return to the last place you saw your friend.