Simple<br/>set of rules for primer sequence design include( ) A: PCR<br/>primers should be 15-30 nucleotides in length. B: optimal GC content of the primer is 40%-60%. C: prefer one or two G or C at the 3’-end of primer. D: avoid primer self complementarities.

In the following descriptions of DNA polymerase and RNA polymerase, the error is: ( ) A: RNA polymerase requires primers B: DNA polymerase can synthesize DNA using RNA as a template C: The extension direction of the new chain catalyzed by both enzymes is 5'-3'. D: RNA polymerase uses NDP as raw material.

The correct statement about RNA polymerase and DNA polymerase is (1 point) A: Synthesis of polynucleotide chain using nucleoside diphosphate B: RNA polymerase requires primers and bases are added at the 5′-end of the extended polynucleotide chain C: DNA polymerase can only synthesize DNA using RNA as a template D: DNA polymerase can add nucleotides on both ends of a chain at the same time E: , DNA polymerase and RNA polymerase can catalyze the formation of 3',5'-phosphodiester bond

What's the disadvantage of currently used BLAST in comparison with Smith-Waterman algorithm? BLAST相比Smith-Waterman算法，缺点是？ A: It cannot handle cases where there are gaps. 无法处理有空位的情况 B: It cannot guarantee to find the globally optimal solution. 不能保证找到全局最优解 C: It is always slightly slower. 速度总是稍慢 D: It cannot handle short query sequences such as primers 无法处理短查询序列如引物