The necessary conditions for PCR to amplify DNA is ①target gene ②primer③four deoxynucleotide ④DNA polymerase ⑤mRNA⑥ribosome()
A. ①②③④
B. ②③④⑤
C. ①③④⑤
D. ①②③⑥
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After sheep Dolly was born, it is doubtable that Dolly was not from somatic cell of an adult sheep, but from polluted embryonic cell in the experiment. The evidence that supports Dolly is from somatic cell rather than embryonic cell is:()
A. DNA fingerprint of Dolly
B. DNA melting temperature of Dolly
C. Telomere length of Dolly
D. Biological clock of Dolly
A special structure () is the “clock” that controls the frequency of cell division, which will become shorter with cell division. There are some enzymes extending telomere both in cancer cells and normal germ cells. According the information, the reason why somatic cells can not divide indefinitely is:()
A. Lack of amino acid required to synthesize telomere
B. Lack of genes to control synthesis of telomerase
C. The mutagenesis of genes that control synthesis of telomerase
D. The expression level and activity of telomerase are strictly controlled
Which of the following will not happen when telomerase loses its function in cells?()
A. Telomere was gradually shortened with every cell division
B. Cells exhibit aging or even death after 30 to 50 times of cell division
C. Immune system loses some defense ability gradually
D. Numerous somatic cells start to proliferate indefinitely
The correct description about the telomerases is()
A. They are abound in eukaryotes
B. C, H, O, N, P are included in the telomerases
C. They belong to ribozyme, catalyzing the reaction which RNA is involved
D. They can carry genetic information
E. The RNA sequences as extension template are the same in telomerase from different species
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