Cell Biology Exam 2

What is the Central Dogma of Molecular Biology?

DNA is used as instructions to make RNA, and RNA is used as instructions to make proteins

What are the main steps of transcription?

Initiation, elongation, and termination

What is initiation?

The first step in transcription, in which proteins attach to DNA and open the two strands to prepare starting the process.

What is elongation?

The second step of transcription where the new RNA polymer is produced and extended (complimentary RNA molecule)

What is Termination?

The last step of transcription where RNA molecules get detached and the process is over

During intimation, a proteins called what bind gene at the promoter?

transcription factors

What are transcription factors?

proteins that bind gene at the promoter and attract an enzyme called RNA polymerase

What are promotor elements?

A promotor on a gene has a small nucleotide sequence that attracts specific transcription factors (this is a response to environmental factors)

T or F: Different genes have different promotor elements.

True, they are bound to different transcription factors

How do different transcription factors influence transcription?

Some factors want to increase it and some want to decrease it, they can exist together in combinations to determine actual transcription of a gene.

What enzyme is recruited by transcription factors?

RNA polymerase

What kind of polymerase is most relevant to this unit?

RNA pol II (mRNA, IncRNA, and miRNA)

RNA poly II is brought to…

promoters via a cascade of transcription factors

What is the mediator complex?

a complex including multiple proteins that hold them all together and helps release poly II to begin elongation

What is the pre-initation complex?

a full complex of factors necessary to start trasncription and mediates how much is transcribed

How is poly II released? slide 13

mediator enables poly II to be phosphorylated (which is a post-transitional modification) which causes it to be released