Which of the following predictions is the most accurate about a person who has normal external barriers and specific internal defenses but lacks nonspecific internal defenses?
A) He will have many more infections than normal.
B) He won't get sick because the external barriers will keep out pathogens.
C) He won't get sick because the specific defenses will kill invading pathogens.
D) Invading microbes will be able to enter through the respiratory tract.
A
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Which of the following is not true of mycoplasmas?
a. They are the smallest truly living organisms. b. They are members of the domain Bacteria. c. They only inhabit multicelled organisms. d. Although classified as gram-positive, they lack cell wall. e. They can be pathogenic, causing pneumonia and urinary tract infections.
When a farmer grows cotton containing the gene for Bt toxin, they often leave a strip of non-Bt cotton around the outside of the field for what reason? Select one:
a. to allow some rr bollworm caterpillars to survive b. to allow the non-Bt and Bt cotton plants to cross pollinate c. because the non-Bt cotton does not drive the moths and caterpillars to extinction d. because the non-Bt cotton grows better e. to allow some RR bollworm caterpillars to survive and limit selection pressure for resistance
Moving genes from one organism to another is often referred to as ________.
Fill in the blank(s) with the appropriate word(s).
The polymerase chain reaction (PCR) is used as a tool for
A. rearranging the gene sequences in isolated fragments of DNA. B. amplifying the amount of DNA to provide a large sample. C. extracting DNA from nuclei. D. fragmenting DNA into smaller pieces. E. breaking down DNA for analysis.