Question 1

A consensus sequence of any genetic element is
A) sequences that are rarely found in nature.
B) the sequence with the most likely base (or bases) at each position.
C) hairpins in RNA to slow down or stop transcription.
D) sequences to which ribosomes bind.
E) primer sequences used to initiate transcription.

Accepted Answer

A consensus sequence is the sequence that is most frequently observed at each position. It is used to represent the typical or "average" sequence for a given genetic element, such as a promoter or a protein-coding region. This allows for easy comparison between different sequences and can aid in identifying important functional elements.

Question 2

Which of the following is normally read as a stop codon but encodes tryptophan in vertebrate mitochondria?
A) AUG
B) UCA
C) UAC
D) UGA
E) UAG

Accepted Answer

UGA is normally read as a stop codon in the standard genetic code, but in vertebrate mitochondria it can encode for tryptophan.

Question 3

In the figure below, which label represents the promoter? 
A) A
B) B
C) C
D) D
E) -35

Accepted Answer

A

Question 4

DNA-dependent ________ polymerase makes a copy of DNA that is then used for translation. The process carried out by this enzyme is called ________.
A) RNA; transformation
B) protein; transcription
C) DNA; transcription
D) RNA; transcription
E) protein; transposition

Accepted Answer

DNA-dependent RNA polymerase makes a copy of DNA into RNA, a process known as transcription, which is then used for translation into proteins.

Question 5

The average half-life for mRNA in a typical bacterium such as E. coli is
A) 1-3 seconds.
B) 10-30 seconds.
C) 1-3 minutes.
D) 1-3 hours.
E) 1-3 days.

Accepted Answer

The average half-life for mRNA in a typical bacterium such as E. coli is 1-3 minutes. This is relatively short compared to eukaryotic cells where the half-life can range from minutes to days.

Question 6

During transcription of the ________ genes, normal, unmodified bases are incorporated, but specific enzymes modify some of these later.
A) tRNA
B) tmRNA
C) mRNA
D) sRNA
E) catalytic RNA

Accepted Answer

The answer of During transcription of the ________ genes, normal,...

Question 7

The process of taking a DNA template and making a complementary RNA molecule is called
A) transposition.
B) transertion.
C) replication.
D) translation.
E) transcription.

Accepted Answer

The process of taking a DNA template and making a complementary RNA molecule is called transcription.

Question 8

Which of the following is NOT part of initiation of transcription?
A) -10 and -35 sequences
B) binding of RNA polymerase to the beginning of the gene
C) melting of the helix
D) binding of sigma factor to promoter followed by binding of core RNA polymerase
E) base pairing of the first nucleotide of the RNA

Accepted Answer

The answer of Which of the following is NOT part...

Question 9

The unusual bases found in tRNA are poor substrates for
A) proteases.
B) polymerases.
C) ribosomes.
D) ribozymes.
E) RNases.

Accepted Answer

The unusual bases found in tRNA are poor substrates for RNases, which are enzymes that degrade RNA. These modifications can protect tRNA from degradation, ensuring its stability and functionality in protein synthesis.

Question 10

The RpoD sigma-70 factor of E. coli recognizes promoters for
A) stress-response genes.
B) motility and chemotaxis genes.
C) "housekeeping" genes.
D) heat shock-induced genes.
E) genes for nitrogen metabolism.

Accepted Answer

The RpoD sigma-70 factor of E. coli recognizes promoters for "housekeeping" genes, which are genes that are needed for basic cellular functions and are expressed under normal growth conditions. These include genes involved in metabolism, DNA replication, and translation.

Question 11

Molecules of sRNA do not encode proteins but are used to ________ the stability or translation of specific mRNAs into proteins.
A) start
B) regulate
C) stop
D) speed up
E) slow down

Accepted Answer

Molecules of sRNA are used to regulate the stability or translation of specific mRNAs into proteins. They do not encode proteins themselves, and they can either increase or decrease the translation of mRNA into a protein. Therefore, the best choice is B, regulate.

Question 12

Which drug intercalates into DNA and inhibits transcription in both prokaryotes and eukaryotes?
A) streptomycin
B) actinomycin D
C) chloramphenicol
D) rifampin
E) tetracycline

Accepted Answer

Actinomycin D is a drug that intercalates into DNA and inhibits transcription in both prokaryotes and eukaryotes. Streptomycin inhibits protein synthesis by binding to the 30S subunit of bacterial ribosomes. Chloramphenicol inhibits protein synthesis at the peptidyltransferase center of the bacterial ribosome. Rifampin inhibits bacterial RNA polymerase by binding to the β-subunit. Tetracycline inhibits protein synthesis by binding to the 30S subunit of bacterial ribosomes.

Question 13

Using the genetic code shown below, find the correct start and stop codons. Which of the following peptides might this message code for? 
5'-GAGUUAUGCACGGGUUCUAUGUGUAG-3'
A) GLU-LEU-CYS-MET-GLY-SER-MET-CYS
B) MET-GLY-SER-MET-CYS
C) MET-HIS-GLY-PHE-TYR-VAL
D) MET-CYS-ILE-LEU-GLY-THR-TYR
E) ASP-VAL-TYR-LEU-GLY-TYR-VAL-LEU

Accepted Answer

The answer of Using the genetic code shown below, find...

Question 14

Which of the following is NOT true of initiation of transcription?
A) The RNA polymerase holoenzyme binds.
B) GTP hydrolysis catalyzes bubble formation.
C) The promoter unwinds.
D) The first rNTP is usually a purine.
E) Position +1 marks the start of the gene.

Accepted Answer

The initiation of transcription involves several steps, including the binding of the RNA polymerase holoenzyme to the promoter and the unwinding of the DNA to form a "transcription bubble." However, GTP hydrolysis does not play a direct role in this process. Instead, the first rNTP is usually paired with a complementary base on the template strand, and its addition marks the start of transcription. The +1 position refers to the first nucleotide of the transcribed RNA, which may be located downstream of the initiation site.

Question 15

Most tRNA molecules begin with a 5' ________ and all end with a 3' ________, to which the amino acids attach.
A) phosphate; hydroxyl
B) C; GGA
C) G; CCA
D) A; TTA
E) C; AAT

Accepted Answer

Most tRNA molecules start with a 5' guanine (G) and all end with a 3' cytosine-cytosine-adenine (CCA) sequence, where the amino acids attach.

Question 16

In the figure below, which label represents the Shine Delgarno site? 
A) A
B) B
C) C
D) D
E) -35

Accepted Answer

The answer of In the figure below, which label represents...

Question 17

The figure below shows subunits of a structure in a bacterial cell. This structure is 
A) a type I secretion system.
B) RNA polymerase.
C) a ribosome.
D) aminoacyl-tRNA synthetase.
E) sigma factor and RNA polymerase.

Accepted Answer

The subunits shown in the figure represent a ribosome, which is responsible for protein synthesis in bacterial cells. The other options do not have the same subunit structure as a ribosome.

Question 18

In the absence of Rho, what can bring about transcription termination?
A) stem and loop and stretches of uridines
B) stem and loop only
C) GC-rich region near the 3¢ terminus
D) GC-rich region near the 3¢ terminus followed by four to eight uridines
E) stem and loop followed by a GC-rich region

Accepted Answer

In the absence of Rho, transcription termination can still occur through the presence of a GC-rich region followed by four to eight uridines. This sequence can allow for the formation of a stem and loop structure, leading to RNA polymerase dissociation and termination of transcription.

Question 19

A researcher is studying transcription and has added a chemical to a transcription experiment using both E. coli and mammalian cells. This chemical inhibits both systems. The chemical is most likely
A) streptomycin.
B) rifamycin.
C) erythromycin.
D) rifampin.
E) actinomycin D.

Accepted Answer

Actinomycin D is known to inhibit both prokaryotic and eukaryotic transcription by binding to DNA and preventing RNA polymerase from elongating the RNA strand. Streptomycin only affects prokaryotic translation, rifamycin and rifampin both target bacterial RNA polymerase, and erythromycin mainly inhibits bacterial protein synthesis.

Question 20

________ RNA polymerase plus sigma factor together are called ________.
A) Transcription; translation
B) Holoenzyme; core
C) Translation; transcription
D) Core; holoenzyme
E) Ribosome; rRNA

Accepted Answer

RNA polymerase alone is called the core enzyme, but when it binds to a sigma factor (which helps it recognize and bind to specific DNA sequences), it becomes the holoenzyme.

Quiz 8: Transcription, Translation, and Bioinformatics

A consensus sequence of any genetic element is

Which of the following is normally read as a stop codon but encodes tryptophan in vertebrate mitochondria?

In the figure below, which label represents the promoter?

DNA-dependent polymerase makes a copy of DNA that is then used for translation. The process carried out by this enzyme is called .

The average half-life for mRNA in a typical bacterium such as E. coli is

During transcription of the ________ genes, normal, unmodified bases are incorporated, but specific enzymes modify some of these later.

The process of taking a DNA template and making a complementary RNA molecule is called

Which of the following is NOT part of initiation of transcription?

The unusual bases found in tRNA are poor substrates for

The RpoD sigma-70 factor of E. coli recognizes promoters for

Molecules of sRNA do not encode proteins but are used to ________ the stability or translation of specific mRNAs into proteins.

Which drug intercalates into DNA and inhibits transcription in both prokaryotes and eukaryotes?

Using the genetic code shown below, find the correct start and stop codons. Which of the following peptides might this message code for? 5'-GAGUUAUGCACGGGUUCUAUGUGUAG-3'

Which of the following is NOT true of initiation of transcription?

Most tRNA molecules begin with a 5' and all end with a 3' , to which the amino acids attach.

In the figure below, which label represents the Shine Delgarno site?

The figure below shows subunits of a structure in a bacterial cell. This structure is

In the absence of Rho, what can bring about transcription termination?

A researcher is studying transcription and has added a chemical to a transcription experiment using both E. coli and mammalian cells. This chemical inhibits both systems. The chemical is most likely

RNA polymerase plus sigma factor together are called .