Many types of mammalian cancer cells are notable for
their（）Many types of mammalian cancer cells are notable for
their（）
A. telomerase activity
B. lack
C. of telomerase activity
D. C．lack
E. of telomeres
F. D．increased
G. number of telomeres
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During synthesis, all DNA polymerases add
nucleotides in which direction（）During synthesis, all DNA polymerases add
nucleotides in which direction（）
A. from
B. left to right
C. B．from3’to5’
D. C．from5’to3’
E. D．in
F. more than one direction at a time
1941年，（）提出了一个基因一个酶假说
A. George Beadle and
B. Edward Tatum
C. B．Johansen W
D. C．Jacob
E. D．Monod
In the Hershey-Chase blender experiments, their
major conclusion was that（）In the Hershey-Chase blender experiments, their
major conclusion was that（）
A. a
B. single gene directed the synthesis of a single polypeptide
C. B．DNA
D. was the genetic material
E. C．DNA
F. was a double helix
G. D．the
H. genetic material was located in the nucleus of cells
Viral genomes may be composed of（）
A. RNA
B. only
C. B．DNA
D. only
E. C．either
F. RNA or DNA
G. D．both
H. RNA and DNA
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