prokaryotic gene regulation - content video - intro quiz - Q1

Post Reply
mcatacct1
Posts: 65
Joined: Sat Oct 26, 2019 4:35 pm

prokaryotic gene regulation - content video - intro quiz - Q1

Post by mcatacct1 » Mon Feb 10, 2020 10:46 pm

What enzyme is unwinding the strands in transcription? Is it RNA Polmerase? I thought helicase unwound the strands. Then RNA Pol would read. My answer was incorrect though. So what, if any, role does helicase play in transcription?
NS_Tutor_Mathias
Posts: 616
Joined: Sat Mar 30, 2019 8:39 pm

Re: prokaryotic gene regulation - content video - intro quiz - Q1

Post by NS_Tutor_Mathias » Tue Feb 11, 2020 5:56 pm

Helicase still unwinds strands in prokaryotic transcription. The question is simply very picky about the order of events (since it is an ordering question) and wants you to realize that RNA Polymerase will bind to a promoter before any unwinding happens.
mcatacct1
Posts: 65
Joined: Sat Oct 26, 2019 4:35 pm

Re: prokaryotic gene regulation - content video - intro quiz - Q1

Post by mcatacct1 » Wed Feb 12, 2020 6:41 pm

Thank you! My mistake, for some reason I thought helicase unwound the strand before RNA Pol landed. This cleared that up. Thanks again!
mcatacct1
Posts: 65
Joined: Sat Oct 26, 2019 4:35 pm

Re: prokaryotic gene regulation - content video - intro quiz - Q1

Post by mcatacct1 » Sun Feb 23, 2020 5:01 pm

Is this applicable to replication as well? Specifically, does DNA Polymerase bind before helicase unwinds the dsDNA? Or does primase bind before helicase unwinds the dsDNA, and then DNA Polymerase comes in when there is ssDNA?
NS_Tutor_Mathias
Posts: 616
Joined: Sat Mar 30, 2019 8:39 pm

Re: prokaryotic gene regulation - content video - intro quiz - Q1

Post by NS_Tutor_Mathias » Thu Feb 27, 2020 5:20 pm

That is a good (and very tricky) question. The exact, step-by-step action of DNA Polymerase holoenzymes and when exactly helicase (of which there are also many variants) binds is way beyond the scope of the MCAT. Maybe in your future research, this will be a very relevant thing to think about ;)
mcatacct1
Posts: 65
Joined: Sat Oct 26, 2019 4:35 pm

Re: prokaryotic gene regulation - content video - intro quiz - Q1

Post by mcatacct1 » Sat Feb 29, 2020 7:28 am

Understood! Thank you! :D
Post Reply