BCH 5413 EXAM 2 STUDY GUIDE QUESTIONS
AND CORRECT ANSWERS (VERIFIED
ANSWERS) | ALREADY GRADED A+ | LATEST
UPDATE 2025-2026
Transcription and gene regulation
- prokaryote v eukaryote - ANSWER Prokaryote
- no nucleosome
- regulatory sequences immediately available for transcription without having to
regulate accessibility and chromatin structure
- no nucleus
- transcription tightly coupled with translation
RNA synthesis
- direction
- type of bond (between what two things)
- incoming nucleotide determined by... - ANSWER 5' -> 3' synthesis
- formation of phosphodiester bond btwn/ incoming ribonucleotide and 3'
hydroxyl of nascent RNA
- incoming ribonucleotide determined by DNA sequence of template strand
What happens after phosphodiester bond formation? - ANSWER Release of
PPi
- synthesis 5' -> 3'
,Does RNA synthesis require a primer? - ANSWER RNA synthesis and
transcription does not require primer
- can initiate de novo
RNA transcription
- carried out by..
- what does it do
- separation of two DNA strands? - ANSWER transcription carried out by RNA
Pol
- Pol catalyzes synthesis of nascent RNA
- separation of two DNA strands creates transcription bubble
Rate of transcription - ANSWER eukaryotes: 15-30 nt/sec
Bacteria: 50-100 nt/sec
Mechanisms of bacterial transcription initiation: RNA Pol
- synthesizes what from what
- in E. coli how many Pol synthesize most of the DNA - ANSWER - synthesizes
RNA from one strand of dsDNA template
- in E. coli a single RNA Pol synthesizes most mRNA, tRNA, rRNA
Holoenzyme subunits - ANSWER 4 subunits: alpha, beta, beta', sigma
- Core enzyme: alpha, beta, beta' (synthesizes RNA randomly on dsDNA templates)
- sigma factor: confers promoter binding and specificty
,Sigma factor(s) with Pol
- most E. coli promoters bound by...
- allows for...
- sigma is released upon.... what continues transcription elongation?
- alternative sigma factors recognize... - ANSWER - most E. coli promoters
bound by sigma 70 associated RNA Pol
- allows correct binding and transcription initiation at specific promoters
- sigma is released upon transcription initiation; core enzyme continues
transcription elongation
- alternative sigma factors recognize different promoters
Corresponding gene to holoenzyme subunit
- subunit functions - ANSWER rpoA: 2 alpha subunits (enzyme assembly,
promoter recognition, binds some activators)
rpoB: beta subunit (catalytic center)
rpoC: Beta' subunit (catalytic center)
rpoD: sigma subunit (promoter specificity)
What is the use of the following factors:
- sigma70
- sigma 32
, - sigmaE
- sigma54
- sigmaF - ANSWER - sigma70: general
- sigma 32: heat shock
- sigmaE: heat shock
- sigma54: nitrogen
- sigmaF: flagellar
Prokaryotic transcription: overall steps
- transcription unit is..
- during transcription..
- transcription takes place in... - ANSWER - transcription unit is a sequence of
DNA transcribed into a single RNA, starting at the promoter and ending at the
terminator
- during transcription, the bubble is maintained within bacterial RNA Pol, which
unwinds and rewinds DNA, maintains the conditions of the partner and template
DNA strands, and synthesizes RNA
- transcription takes place in a "bubble" in which RNA is synthesized by phase
pairing with one strand of DNA in the transiently unwound region. As the bubble
progresses, the DNA duplex reforms behind it, displacing the RNA in the form of a
single polynucleotide chain
Prokaryotic RNA Pol Structure - ANSWER - ribonucleotide triphosphate tunnel
(enter for elongation)
- active site
- RNA exit channel
AND CORRECT ANSWERS (VERIFIED
ANSWERS) | ALREADY GRADED A+ | LATEST
UPDATE 2025-2026
Transcription and gene regulation
- prokaryote v eukaryote - ANSWER Prokaryote
- no nucleosome
- regulatory sequences immediately available for transcription without having to
regulate accessibility and chromatin structure
- no nucleus
- transcription tightly coupled with translation
RNA synthesis
- direction
- type of bond (between what two things)
- incoming nucleotide determined by... - ANSWER 5' -> 3' synthesis
- formation of phosphodiester bond btwn/ incoming ribonucleotide and 3'
hydroxyl of nascent RNA
- incoming ribonucleotide determined by DNA sequence of template strand
What happens after phosphodiester bond formation? - ANSWER Release of
PPi
- synthesis 5' -> 3'
,Does RNA synthesis require a primer? - ANSWER RNA synthesis and
transcription does not require primer
- can initiate de novo
RNA transcription
- carried out by..
- what does it do
- separation of two DNA strands? - ANSWER transcription carried out by RNA
Pol
- Pol catalyzes synthesis of nascent RNA
- separation of two DNA strands creates transcription bubble
Rate of transcription - ANSWER eukaryotes: 15-30 nt/sec
Bacteria: 50-100 nt/sec
Mechanisms of bacterial transcription initiation: RNA Pol
- synthesizes what from what
- in E. coli how many Pol synthesize most of the DNA - ANSWER - synthesizes
RNA from one strand of dsDNA template
- in E. coli a single RNA Pol synthesizes most mRNA, tRNA, rRNA
Holoenzyme subunits - ANSWER 4 subunits: alpha, beta, beta', sigma
- Core enzyme: alpha, beta, beta' (synthesizes RNA randomly on dsDNA templates)
- sigma factor: confers promoter binding and specificty
,Sigma factor(s) with Pol
- most E. coli promoters bound by...
- allows for...
- sigma is released upon.... what continues transcription elongation?
- alternative sigma factors recognize... - ANSWER - most E. coli promoters
bound by sigma 70 associated RNA Pol
- allows correct binding and transcription initiation at specific promoters
- sigma is released upon transcription initiation; core enzyme continues
transcription elongation
- alternative sigma factors recognize different promoters
Corresponding gene to holoenzyme subunit
- subunit functions - ANSWER rpoA: 2 alpha subunits (enzyme assembly,
promoter recognition, binds some activators)
rpoB: beta subunit (catalytic center)
rpoC: Beta' subunit (catalytic center)
rpoD: sigma subunit (promoter specificity)
What is the use of the following factors:
- sigma70
- sigma 32
, - sigmaE
- sigma54
- sigmaF - ANSWER - sigma70: general
- sigma 32: heat shock
- sigmaE: heat shock
- sigma54: nitrogen
- sigmaF: flagellar
Prokaryotic transcription: overall steps
- transcription unit is..
- during transcription..
- transcription takes place in... - ANSWER - transcription unit is a sequence of
DNA transcribed into a single RNA, starting at the promoter and ending at the
terminator
- during transcription, the bubble is maintained within bacterial RNA Pol, which
unwinds and rewinds DNA, maintains the conditions of the partner and template
DNA strands, and synthesizes RNA
- transcription takes place in a "bubble" in which RNA is synthesized by phase
pairing with one strand of DNA in the transiently unwound region. As the bubble
progresses, the DNA duplex reforms behind it, displacing the RNA in the form of a
single polynucleotide chain
Prokaryotic RNA Pol Structure - ANSWER - ribonucleotide triphosphate tunnel
(enter for elongation)
- active site
- RNA exit channel
