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
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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
Which of the following statements about telomere is correct?()
A. Telomeres are special structure composing of nucleosomes in the end of eukaryotic chromosomes
B. Telomeres can stable DNA secondary structure
C. Telomerases act as template as well as reverse transcriptase
D. Cell aging is related to the abnormal extend of telomere
E. Telomere refers to the DNA sequences in the end of linear chromosome which are rich in guanine nucleotide
Telomerase is a()
A. DNA-dependent DNA polymerase
B. DNA-dependent RNA polymerase
C. RNA-dependent DNA polymerase
D. RNA-dependent RNA polymerase
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