Advanced Biochemistry Exam 3
Questions and Answers 100% Solved
All RNAs are synthesized from DNA templates by __? - ✔✔DNA-
dependent RNA polymerases
__ direct the synthesis of proteins. - ✔✔mRNAs
RNA polymerases link __ in the order specified by base pairing with a DNA
template. - ✔✔NTPs
RNA polymerase moves along the template strand in the __ direction, and
the RNA chain grows in the __ direction. - ✔✔3' --> 5'; 5' --> 3'
__ of Ppi to inorganic phosphate by __ makes the polymerase reaction
thermodynamically favorable. - ✔✔hydrolysis; pyrophosphatases
Transcription is initiated in prokaryotes by __. - ✔✔RNA polymerase
holoenzyme
Subunits of RNA polymerase holoenzyme. - ✔✔alpha x 2, beta, beta-
prime, sigma
Function of alpha subunit of RNA polymerase holoenzyme in prokaryotes. -
✔✔scaffold and regulation; dimerize
1
©JOSHCLAY 2024/2025. YEAR PUBLISHED 2024.
,Function of beta subunit of RNA polymearse holoenzyme in prokaryotes. -
✔✔Part of polymerase active site
Function of beta prime subunit of RNA polymerase holoenzyme in
prokaryotes. - ✔✔binds to and unwinds DNA
Function of sigma subunit of RNA polymerase holoenzyme in prokaryotes -
✔✔
Core polymerase structure - ✔✔alpha x 2, beta, beta-prime
Core polymerase can transcribe DNA into RNA, but cannot __. -
✔✔recognize promoters and initiate transcription
Binding of __ subunit allows polymerase to recognize __. - ✔✔sigma;
different DNA sequences that act as promoters
Promoters - ✔✔nucleotide sequences that identify the location of
transcription start sites
RNA polymerases (do/do not) require a primer. - ✔✔do not
Four stages of transcription - ✔✔1. Binding of RNA pol holoenzyme to
template DNA at promoter sites; 2. initiation of polymerization; 3. chain
elongation; 4. chain termination
RNA pol holoenzyme binds __ to DNA with __ affinity and migrates __
looking for a sigma promoter region. - ✔✔nonspecifically; low; downstream
2
©JOSHCLAY 2024/2025. YEAR PUBLISHED 2024.
, Holoenzyme + promoter - ✔✔closed promoter complex
open promoter complex - ✔✔polymerase unwinds 12 base pairs in the -9 to
+3 region
Operon: Promoter - ✔✔DNA sequence which identifies and binds to the
primary transcription site where transcription begins
Prokaryotic Promoters - ✔✔TATA box at -10 region; -35 region TTGACA
Operon: Operators - ✔✔sequence near the promoter which regulates the
transcription start
Operon: Structural Genes - ✔✔a gene that codes for any RNA or protein
product other than a regulatory factor
Lac Operon - ✔✔consists of 3 structural genes (LacZ, LacY, LacA),
promoter, terminator, regulator, and operator
Lac Operon Structural Genes - ✔✔LacZ - encodes beta-galactosidase
LacY
LacA
Beta-galactosidase - ✔✔intracellular enzyme that cleaves the disaccharide
lactose into glucose and galactose
3
©JOSHCLAY 2024/2025. YEAR PUBLISHED 2024.
Questions and Answers 100% Solved
All RNAs are synthesized from DNA templates by __? - ✔✔DNA-
dependent RNA polymerases
__ direct the synthesis of proteins. - ✔✔mRNAs
RNA polymerases link __ in the order specified by base pairing with a DNA
template. - ✔✔NTPs
RNA polymerase moves along the template strand in the __ direction, and
the RNA chain grows in the __ direction. - ✔✔3' --> 5'; 5' --> 3'
__ of Ppi to inorganic phosphate by __ makes the polymerase reaction
thermodynamically favorable. - ✔✔hydrolysis; pyrophosphatases
Transcription is initiated in prokaryotes by __. - ✔✔RNA polymerase
holoenzyme
Subunits of RNA polymerase holoenzyme. - ✔✔alpha x 2, beta, beta-
prime, sigma
Function of alpha subunit of RNA polymerase holoenzyme in prokaryotes. -
✔✔scaffold and regulation; dimerize
1
©JOSHCLAY 2024/2025. YEAR PUBLISHED 2024.
,Function of beta subunit of RNA polymearse holoenzyme in prokaryotes. -
✔✔Part of polymerase active site
Function of beta prime subunit of RNA polymerase holoenzyme in
prokaryotes. - ✔✔binds to and unwinds DNA
Function of sigma subunit of RNA polymerase holoenzyme in prokaryotes -
✔✔
Core polymerase structure - ✔✔alpha x 2, beta, beta-prime
Core polymerase can transcribe DNA into RNA, but cannot __. -
✔✔recognize promoters and initiate transcription
Binding of __ subunit allows polymerase to recognize __. - ✔✔sigma;
different DNA sequences that act as promoters
Promoters - ✔✔nucleotide sequences that identify the location of
transcription start sites
RNA polymerases (do/do not) require a primer. - ✔✔do not
Four stages of transcription - ✔✔1. Binding of RNA pol holoenzyme to
template DNA at promoter sites; 2. initiation of polymerization; 3. chain
elongation; 4. chain termination
RNA pol holoenzyme binds __ to DNA with __ affinity and migrates __
looking for a sigma promoter region. - ✔✔nonspecifically; low; downstream
2
©JOSHCLAY 2024/2025. YEAR PUBLISHED 2024.
, Holoenzyme + promoter - ✔✔closed promoter complex
open promoter complex - ✔✔polymerase unwinds 12 base pairs in the -9 to
+3 region
Operon: Promoter - ✔✔DNA sequence which identifies and binds to the
primary transcription site where transcription begins
Prokaryotic Promoters - ✔✔TATA box at -10 region; -35 region TTGACA
Operon: Operators - ✔✔sequence near the promoter which regulates the
transcription start
Operon: Structural Genes - ✔✔a gene that codes for any RNA or protein
product other than a regulatory factor
Lac Operon - ✔✔consists of 3 structural genes (LacZ, LacY, LacA),
promoter, terminator, regulator, and operator
Lac Operon Structural Genes - ✔✔LacZ - encodes beta-galactosidase
LacY
LacA
Beta-galactosidase - ✔✔intracellular enzyme that cleaves the disaccharide
lactose into glucose and galactose
3
©JOSHCLAY 2024/2025. YEAR PUBLISHED 2024.
