Explain the dideoxy sequencing method
What will be an ideal response?
Sanger's method, which is also referred to as chain termination, is based on the use of
dideoxynucleotides (ddNTP's) in addition to the normal nucleotides (NTP's) found in DNA.
Dideoxynucleotides are essentially the same as nucleotides except they contain a hydrogen group
on the 3' carbon instead of a hydroxyl group (OH). These modified nucleotides, when integrated
into a sequence, prevent the addition of further nucleotides. This occurs because a
phosphodiester bond cannot form between the dideoxynucleotide and the next incoming
nucleotide, and thus the DNA chain is terminated. A nested set of products can then be used to
determine the actual nucleotide sequence.
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Which of the following would inhibit binary fission in protists, but not in bacteria?
A. Blocking ribosome function B. Blocking DNA replication C. Blocking RNA synthesis D. Blocking spindle function
The first known hominin species to leave Africa was ____
a. Homo sapiens b. Homo erectus c. Homo habilis d. Australopithecus afarensis e. Homo neanderthalensis
Which of the following species interactions is(are) considered symbiotic?
A. competition B. predator/prey C. parasite/host D. mutualism E. Both C and D are correct.
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.