简答题Which enzyme is NOT present in a replisome? A、DNA primase B、DNA helicase C、DNA gyrase D、DNA polymerase III简答题The location on a bacterial chromosome where DNA replication begins is ______, and the binding of ______ opens up the double helix. A、oriG / DNA gyrase B、oriC / DNA gyrase C、oriG / DnaA D、oriC / DnaA简答题In bacteria, the origin of replication consists of a specific sequence of about 3000 bases. A、True B、False简答题The sigma subunit of RNA polymerase functions to A、form RNA polymerase–DNA complexes, and locate, recognize, and bind to promoter regions. B、form RNA polymerase–DNA complexes only C、locate, recognize, and bind to promoter regions only D、terminate mRNA synthesis of genes at their stop sites简答题DNA Major grooves are sites for interaction with proteins. A、True B、False简答题Topoisomerase I can break and reseal of double strands, while topoisomerase II can break single strand and remove supercoiling in DNA. A、True B、False简答题Which statement below provides an explanation of why a lagging strand (rather than two leading strands) exists during DNA replication? A、New nucleotides can only be added to a 3' (–OH) end B、Only one primer can exist at a time C、There is only one DNA polymerase per cell D、There is only one replisome per cell简答题The enzymes that catalyze addition of the nucleotides are called DNA polymerases.All DNA polymerases synthesize new DNA in the 3’ to 5’ directions. A、True B、False简答题DNA polymerases I, II, III can not start a new chain, they can only add a nucleotide onto a preexisting 3’-OH group. A、True B、False简答题Which enzyme is responsible for opening up the dsDNA in order for RNA polymerase to transcribe a gene? A、topoisomerase B、DNA helicase C、DNA gyrase D、RNA polymerase