Knocking out the kinase A of mouse can lead to its death in embryonic period, then which of the following mutation of the sequence encoding kinase A most likely lead to the death of mouse:()
A. adenine replaces cytosine
B. cytosine replaces guanine
C. methylcystein replaces cytosine
D. loss of three nucleotides
E. insertion of one nucleotide
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Sickle cell anemia is the homozygote genotype of abnormal hemoglobin. β-strand aberrance is caused by which of the following mutations:()
A. chromosome arm exchange
B. mononucleotide insertion
C. mononucleotide loss
D. chromosome nondisjunction
E. base substitution
The Dam methylase in E. coli can methylate the A of GATC sequence in DNA. Which of the following is unrelated to this modification:()
A. Protein SeqA can inhibit the methylation of GATC by Dam
B. The marker of DNA parental strand after replication
C. The full-methylated sequence GATC is the binding site of initiator protein DnaA
D. The methylation site is recognition site of MutH in mismatch repair system
The protein MutH in E. coli can recognize:()
A. Twisty double-strands of DNA
B. Hemi-methylated GATC
C. The insertion site of the intercalator
D. The gap between Okazaki fragments
A man suffers from fragile X syndromen. The cause is that n turns to 300 from 60. Then which the following is the cause of this disease:()
A. synonymous mutation
B. missense mutation
C. nonsense mutation
D. frameshift mutation
E. dynamic mutation
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