BIOL 2604 Final Exam Questions With
Complete Answers
What constitutes a prokaryotic operon? - ANSWER A promoter unit with 35 T-A-
G-C sequences, Pribnow Box, and a startpoint. A transcription unit and gene A
and B, and a terminating end. Starts with a 5-3' and ends with 3-5'.
What is the difference between how sugar operons and amino acid operons are
named? - ANSWER Sugar: gene expression is turned on in the presence of
sugar, named for metabolic pathways in breaking down & using
Amino Acid: gene expression turned on in the absence of amino acid, named for
enzymes used to synthesize amino acid
What is "messenger RNA (mRNA)"? - ANSWER an RNA molecule that contains
the genetic information to encode one of more polypeptides
What is a "polycistronic mRNA"? - ANSWER mRNA encoding such a group of
contranscribed genes (a group of related genes that are transcribed together to
give a single polycistronic mRNA is an operon)
Which direction (5-3' or 3-5') along the template strand does transcription
occur? - ANSWER 3'-5'
What is a promoter? - ANSWER initiation site on transcription operons
What is an intrinsic terminator? - ANSWER mechanism in prokaryotes that
causes RNA transcription to be stopped
What is a stem-loop structure? - ANSWER Immediately upstream from a run of
uracils leads to transcription termination
What is a consensus sequence? - ANSWER the calculated order of most
frequent residues, either nucleotide or amino acid, found at each position in a
sequence alignment
In a eukaryote, which type of RNA polymerase transcribes genes that encode
proteins? - ANSWER RNA Polymerase II (contains sigma)
, What two specific sequences are recognized by the RNA polymerase within the
promoter? - ANSWER -35 region and TATAAT (Pribnow) box
List some differences between prokaryotes and eukaryotes in reference to
transcription. - ANSWER *Prokaryotes:* single RNA polymerase, polycistronic
messages, little RNA processing, few transcription initiation factors, transcribed
in cytoplasm
*Eukaryotes:* multiple RNA polymerase, monocistronic messages, extensive
RNA processing, multiple transcription initiation factors, transcribed in nucleus
What are the five major subunits of the RNA polymerase? Which subunit is
responsible for recognizing the promoter? - ANSWER alpha, beta, beta prime,
omega, and sigma
*Sigma*
At what three levels can you control bacterial gene expression? - ANSWER
transcription
translation
enzyme
Why is it necessary to regulate certain genes at certain control levels? (When
might you want to control something at each of the levels?) - ANSWER Control
products (amount, type)
DNA proteins tend to bind DNA in the major groove at what type of sequences? -
ANSWER Molecular palindromes (Dyad symmetry)
Repressors bind to operator/promoters (circle one). - ANSWER operator
A molecule that binds to a repressor to turn on expression of a gene is called a
___________________________. - ANSWER inducer
Activators bind to operators/activator binding site (circle one). - ANSWER
activator binding site
A molecule that binds to an activator to turn on gene expression is termed a
___________________________. - ANSWER Inducer
Does RNA polymerase move faster through A-T or G-C regions of DNA? -
ANSWER A-T
When glucose is present, cAMP levels are (high/low). - ANSWER low
High levels of cAMP lead to the ____________ expression of the lac operon. -
ANSWER maximum
Complete Answers
What constitutes a prokaryotic operon? - ANSWER A promoter unit with 35 T-A-
G-C sequences, Pribnow Box, and a startpoint. A transcription unit and gene A
and B, and a terminating end. Starts with a 5-3' and ends with 3-5'.
What is the difference between how sugar operons and amino acid operons are
named? - ANSWER Sugar: gene expression is turned on in the presence of
sugar, named for metabolic pathways in breaking down & using
Amino Acid: gene expression turned on in the absence of amino acid, named for
enzymes used to synthesize amino acid
What is "messenger RNA (mRNA)"? - ANSWER an RNA molecule that contains
the genetic information to encode one of more polypeptides
What is a "polycistronic mRNA"? - ANSWER mRNA encoding such a group of
contranscribed genes (a group of related genes that are transcribed together to
give a single polycistronic mRNA is an operon)
Which direction (5-3' or 3-5') along the template strand does transcription
occur? - ANSWER 3'-5'
What is a promoter? - ANSWER initiation site on transcription operons
What is an intrinsic terminator? - ANSWER mechanism in prokaryotes that
causes RNA transcription to be stopped
What is a stem-loop structure? - ANSWER Immediately upstream from a run of
uracils leads to transcription termination
What is a consensus sequence? - ANSWER the calculated order of most
frequent residues, either nucleotide or amino acid, found at each position in a
sequence alignment
In a eukaryote, which type of RNA polymerase transcribes genes that encode
proteins? - ANSWER RNA Polymerase II (contains sigma)
, What two specific sequences are recognized by the RNA polymerase within the
promoter? - ANSWER -35 region and TATAAT (Pribnow) box
List some differences between prokaryotes and eukaryotes in reference to
transcription. - ANSWER *Prokaryotes:* single RNA polymerase, polycistronic
messages, little RNA processing, few transcription initiation factors, transcribed
in cytoplasm
*Eukaryotes:* multiple RNA polymerase, monocistronic messages, extensive
RNA processing, multiple transcription initiation factors, transcribed in nucleus
What are the five major subunits of the RNA polymerase? Which subunit is
responsible for recognizing the promoter? - ANSWER alpha, beta, beta prime,
omega, and sigma
*Sigma*
At what three levels can you control bacterial gene expression? - ANSWER
transcription
translation
enzyme
Why is it necessary to regulate certain genes at certain control levels? (When
might you want to control something at each of the levels?) - ANSWER Control
products (amount, type)
DNA proteins tend to bind DNA in the major groove at what type of sequences? -
ANSWER Molecular palindromes (Dyad symmetry)
Repressors bind to operator/promoters (circle one). - ANSWER operator
A molecule that binds to a repressor to turn on expression of a gene is called a
___________________________. - ANSWER inducer
Activators bind to operators/activator binding site (circle one). - ANSWER
activator binding site
A molecule that binds to an activator to turn on gene expression is termed a
___________________________. - ANSWER Inducer
Does RNA polymerase move faster through A-T or G-C regions of DNA? -
ANSWER A-T
When glucose is present, cAMP levels are (high/low). - ANSWER low
High levels of cAMP lead to the ____________ expression of the lac operon. -
ANSWER maximum
