Which factor does NOT consume energy by breaking phosphoanhydride bonds?
A) the action of DnaB
B) the action of DnaG
C) DNA gyrase
D) TUS/Ter binding
E) DNA ligase D) TUS/Ter binding
the ans. is D
To determine which factor does not consume energy by breaking phosphoanhydride bonds, we need to identify the factors listed and understand how they relate to the consumption of energy.
A) The action of DnaB: DnaB is a helicase enzyme involved in DNA replication. It uses energy from ATP hydrolysis to separate (unwind) the DNA strands and initiate replication. Therefore, this action consumes energy by breaking phosphoanhydride bonds.
B) The action of DnaG: DnaG is a primase enzyme involved in DNA replication. It synthesizes short RNA primers that are required for DNA polymerase to initiate replication. The action of DnaG also consumes energy by breaking phosphoanhydride bonds.
C) DNA gyrase: DNA gyrase is a type of topoisomerase enzyme that helps relieve the torsional strain created during DNA replication or transcription. It introduces negative supercoiling into DNA and requires energy in the form of ATP hydrolysis to break phosphoanhydride bonds. Therefore, DNA gyrase also consumes energy.
D) TUS/Ter binding: Transcription termination utilization sequence (TUS) and terminator (Ter) binding are involved in regulating the termination of DNA transcription. While TUS/Ter binding is an essential step in transcription termination, it does not directly consume energy by breaking phosphoanhydride bonds. Therefore, the correct answer is D.
E) DNA ligase: DNA ligase is an enzyme that catalyzes the formation of phosphodiester bonds between adjacent DNA fragments during DNA replication and repair. DNA ligase requires energy in the form of ATP hydrolysis to join the DNA fragments together. Therefore, DNA ligase also consumes energy by breaking phosphoanhydride bonds.