ECU Biology 1100 CH.17 Review
Questions and Correct Answers
The first step in converting genetic information into proteins is ✅transcription
Transcription ✅Synthesis of an mrna version of the instructions stored in DNA
Template strand ✅RNA polymerase performs this synthesis by transcribing only one
strand of DNA
The other DNA strand is called ✅non-template, or coding strand
-Matches the sequence of the mrna
- expect u are where the T's are
RNA polymerase do not require a ✅primer
Phosphodietser linage is formed by ✅RNA polymerase after case pairing occurs
Initiation ✅1st phase of transcription
RNA polymerase cannot initiate ✅transcription on
its own
Prokaryotic RNA polymerase ✅holoenzyme
Sigma ✅protein subunit
- must first bind to the polymerase
- guiding RNA polymerase to specific promoter sequneces
- on the DNA template strand.
Holoenzyme ✅- made up of the core enzyme and a sigma subunit
- has ability to synthesize RNA
Sigma acts as a ✅regulatory factor
Bacterial promoters ✅Are comprised of 4050 base pairs
Bacterial promoters have 2 key regions ✅-10 box and -35 box
-10 box ✅- Is found 10 bases upstream from the transcription start site (the 1 site)
- Consists of the sequence TATAAT
, -35 box ✅Is 35 bases upstream from the 1 site
Consists of the sequence TTGACA
Sigma factors bind to the ✅-35 and -10 boxes
- in the promoter
Transcription begins ✅- When sigma, as part of the holoenzyme complex
- Binds to the -35 and -10 boxes
Sigma, and not RNA polymerase, makes ✅- The initial contact with DNA that starts
transcription
- Supporting the hypothesis that sigma is a regulatory protein
Most bacteria have several types of sigma proteins ✅Each type allows RNA
polymerase to bind to a different type of promoter therefore a different kind of gene
Sigma opens the DNA double helix ✅The template strand is threaded through the
RNA polymerase active site
Sigma dissociates from the core enzyme ✅Once the initiation phase of transcription is
completed
Elongation phase of transcription ✅- RNA polymerase moves along the DNA template
- Synthesizes RNA in the 5 3 direction
Termination phase ✅- RNA polymerase transcribes a transcription
termination signal
- In the DNA template into RNA
In bacteria the transcription termination signal ✅- Codes for RNA that forms a hairpin
structure
- Causes the RNA polymerase to separate from the RNA transcript and thus to end
transcription
Eukaryotes have A much more diverse and complex series of promoters than
✅prokaryotes
Eukaryotic promoters ✅A unique sequence called the TATA box
Centered about 30 base pairs upstream of the 1
As with bacteria, the RNA polymerase does not bind directly to the ✅promoter
Basal transcription factors ✅Bind to the DNA promoter
Initiate transcription
Questions and Correct Answers
The first step in converting genetic information into proteins is ✅transcription
Transcription ✅Synthesis of an mrna version of the instructions stored in DNA
Template strand ✅RNA polymerase performs this synthesis by transcribing only one
strand of DNA
The other DNA strand is called ✅non-template, or coding strand
-Matches the sequence of the mrna
- expect u are where the T's are
RNA polymerase do not require a ✅primer
Phosphodietser linage is formed by ✅RNA polymerase after case pairing occurs
Initiation ✅1st phase of transcription
RNA polymerase cannot initiate ✅transcription on
its own
Prokaryotic RNA polymerase ✅holoenzyme
Sigma ✅protein subunit
- must first bind to the polymerase
- guiding RNA polymerase to specific promoter sequneces
- on the DNA template strand.
Holoenzyme ✅- made up of the core enzyme and a sigma subunit
- has ability to synthesize RNA
Sigma acts as a ✅regulatory factor
Bacterial promoters ✅Are comprised of 4050 base pairs
Bacterial promoters have 2 key regions ✅-10 box and -35 box
-10 box ✅- Is found 10 bases upstream from the transcription start site (the 1 site)
- Consists of the sequence TATAAT
, -35 box ✅Is 35 bases upstream from the 1 site
Consists of the sequence TTGACA
Sigma factors bind to the ✅-35 and -10 boxes
- in the promoter
Transcription begins ✅- When sigma, as part of the holoenzyme complex
- Binds to the -35 and -10 boxes
Sigma, and not RNA polymerase, makes ✅- The initial contact with DNA that starts
transcription
- Supporting the hypothesis that sigma is a regulatory protein
Most bacteria have several types of sigma proteins ✅Each type allows RNA
polymerase to bind to a different type of promoter therefore a different kind of gene
Sigma opens the DNA double helix ✅The template strand is threaded through the
RNA polymerase active site
Sigma dissociates from the core enzyme ✅Once the initiation phase of transcription is
completed
Elongation phase of transcription ✅- RNA polymerase moves along the DNA template
- Synthesizes RNA in the 5 3 direction
Termination phase ✅- RNA polymerase transcribes a transcription
termination signal
- In the DNA template into RNA
In bacteria the transcription termination signal ✅- Codes for RNA that forms a hairpin
structure
- Causes the RNA polymerase to separate from the RNA transcript and thus to end
transcription
Eukaryotes have A much more diverse and complex series of promoters than
✅prokaryotes
Eukaryotic promoters ✅A unique sequence called the TATA box
Centered about 30 base pairs upstream of the 1
As with bacteria, the RNA polymerase does not bind directly to the ✅promoter
Basal transcription factors ✅Bind to the DNA promoter
Initiate transcription
