Deck 12: Gene Structure Expression, and Mutation

Question 1

Proteins are assembled from the instructions found in which molecule?

A) mRNA
B) ribosome
C) tRNA
D) DNA

Answer 1

D

Question 2

Which codon/amino acid pairing represents the universal start codon in eukaryotes?

A) UUU-phenylalanine
B) UGA-proline
C) ACG-threonine
D) AUG-methionine

Answer 2

D

Question 3

How does the "Central Dogma" describe the flow of information of gene expression?

A) RNA
B) protein
C) DNA
D) protein

Answer 3

C

Question 4

Where in the sequence of a eukaryotic gene would one find the TATA box?

A) in the coding region
B) at the transcription start point
C) in the terminator
D) in the promoter

Question 5

How many proteins are specified in the genetic code?

A) 4
B) 5
C) 20
D) 64

Question 6

Genetic Code Table
In the genetic code table, the incorporation of which amino acid is directed by the start codon for translation?

A) methionine
B) phenylalanine
C) lysine
D) glycine

Question 7

Suppose that a mutant organism is unable to make the amino acid arginine. Knowing that the metabolic pathway to the production of arginine is ornithine citrulline argininosuccinate arginine, you test the ability of the mutant to grow in the presence of each one of these compounds, providing just one of the compounds in each of your tests. Also suppose that you find that the mutant can grow in the presence of argininosuccinate or arginine, but NOT in the presence of citrulline or ornithine. From this information, which step in the metabolic pathway do you think is blocked?

A) citrulline to argininosuccinate
B) argininosuccinate to arginine
C) ornithine to citrulline
D) ornithine to argininosuccinate

Question 8

Which enzyme performs the DNA unwinding function during transcription elongation?

A) DNA helicase
B) DNA ligase
C) topoisomerase
D) RNA polymerase

Question 9

What does the degeneracy of the genetic code refer to?

A) the fact that the code varies considerably between different organisms
B) the fact that the code is commaless
C) the fact that the code is universal
D) the fact that the code has multiple codons for some amino acids

Question 10

Which of the following best defines what occurs during transcription?

A) DNA is used to make a polypeptide.
B) A polypeptide is used to make RNA.
C) RNA is used to make a DNA strand.
D) DNA is used to make a complementary RNA copy.

Question 11

The alpha-amanitin toxin exerts its toxic effects by blocking which of the following?

A) DNA polymerase
B) RNA polymerase
C) ligase
D) topoisomerase

Question 12

Which of the following best defines what occurs during translation?

A) RNA is used to make a polypeptide.
B) RNA is used to make a DNA strand.
C) DNA is used to make a polypeptide.
D) A polypeptide is used to make RNA.

Question 13

Transcription Diagram
In the transcription diagram, what is the name of item B?

A) DNA double helix
B) RNA-DNA hybrid
C) complementary DNA strand
D) RNA copy

Question 14

Genetic Code Table
Suppose that an mRNA molecule is made complementary to the DNA sequence 3'-CTTACATGGCATCC-5'. In the genetic code table, the incorporation of which amino acid in the polypeptide is directed by the third codon (counting the start codon as the first codon)?

A) serine
B) histidine
C) threonine
D) cysteine

Question 15

Studies of arginine biosynthesis in mutant stains of Neurospora provided evidence of a direct relationship between genes and enzymes, including development of the one gene-one enzyme hypothesis. Who conducted these studies?

A) Archibald Garrod
B) Watson and Crick
C) Beadle and Tatum
D) Frederick Griffith

Question 16

Genetic Code Table
Suppose that an mRNA molecule is made complementary to the DNA sequence 3'-CTTACATGGCATCC-5'. In the genetic code table, the incorporation of which amino acid in the polypeptide is directed by the second codon (assuming the start codon is counted as the first codon)?

A) alanine
B) asparagine
C) proline
D) arginine

Question 17

Which molecule is involved in transcription?

A) tRNA
B) DNA, 5'-3' strand
C) DNA, 3'-5' strand
D) DNA polymerase

Question 18

How many letters are in the RNA "alphabet" of the genetic code?

A) 4
B) 5
C) 20
D) 64

Question 19

What is implied by the concept that the genetic code is universal?

A) It is a recent evolutionary development.
B) It is different in every type of organism.
C) It frequently changes.
D) It was established early in evolution.

Question 20

The studies of alkaptonuria provided the first evidence of a connection between genes and metabolism. Who conducted these studies?

A) Archibald Garrod
B) Watson and Crick
C) Frederick Griffith
D) Beadle and Tatum

Question 21

Transcription Diagram
In the transcription diagram, what is the name of item E?

A) DNA double helix
B) template DNA strand
C) RNA-DNA hybrid
D) complementary DNA strand

Question 22

Where does precursor-mRNA (pre-mRNA) typically exist?

A) in both prokaryotes and eukaryotes
B) only in prokaryotes
C) only in the nucleus of eukaryotes
D) only in the cytoplasm of eukaryotes

Question 23

How are protein-encoding genes in eukaryotes transcribed?

A) by RNA polymerase III
B) by RNA polymerase I
C) by RNA polymerase II
D) by DNA polymerase

Question 24

Which process occurs in the cytoplasm of a eukaryotic cell?

A) DNA replication
B) translation
C) transcription
D) translocation

Question 25

What is the function of the 3' poly-A sequence in eukaryotic mRNA?

A) It provides an intron splicing signal.
B) It provides protection from cytosolic enzymes.
C) It helps with translation termination.
D) It is the initial attachment site for ribosomes.

Question 26

Transcription Diagram
In the transcription diagram, what is the name of item A?

A) reverse transcriptase
B) spliceosome
C) RNA polymerase
D) primase

Question 27

What is the function of the 5' cap in eukaryotic mRNA?

A) It provides an intron splicing signal.
B) It helps with nuclear export.
C) It provides attachment site for ribosomes.
D) It stabilizes pre-mRNA.

Question 28

After processing of pre-mRNAs is complete, some regions are retained in finished mRNAs. What are these regions called?

A) exons
B) snRNPs
C) UTRs
D) domains

Question 29

In a messenger RNA, what region of the mRNA does the 3' UTR refer to?

A) the coding region
B) the region after the stop codon
C) the region before the start codon
D) the region before the site for initiation of transcription

Question 30

Which region of the DNA does RNA polymerase interact with during transcription initiation?

A) the promoter
B) the initiator
C) the intron
D) the start codon

Question 31

What triggers the termination of transcription in prokaryotes?

A) a stop codon
B) an enzyme
C) an RNA hairpin loop
D) a poly-A sequence

Question 32

In which complex does the process of removing introns from mRNA and putting the remaining exons together occur?

A) in the anticodon
B) in the polysome
C) in the spliceosome
D) in the ribosome

Question 33

Transcription Diagram
In the transcription diagram, what is the name of item D?

A) RNA-DNA hybrid
B) template DNA strand
C) DNA double helix
D) complementary DNA strand

Question 34

Suppose that during transcription of a eukaryotic gene, the RNA polymerase does NOT encounter a polyadenylation signal. What aspect of the transcription of this gene would be affected?

A) The pre-mRNA would be truncated.
B) The pre-mRNA would be elongated.
C) There would be no effect; the gene is transcribed normally.
D) The pre-mRNA would be exported prematurely.

Question 35

Which of the following is included in the lariat structure?

A) the intron
B) the exon
C) the snRNP
D) the mRNA

Question 36

Why do smooth muscle and skeletal muscle have distinct mRNA forms?

A) due to aminoacylation
B) due to degeneracy
C) due to alternative splicing
D) due to polyadenylation

Question 37

Which of the following processes best explains the diversity of human á-tropomyosin proteins?

A) the wobble hypothesis
B) exon shuffling
C) alternative splicing
D) degeneracy

Question 38

Which process involves small ribonucleoprotein particles (snRNPs)?

A) initiation of translation
B) mRNA splicing
C) initiation of transcription
D) aminoacylation of tRNA

Question 39

Which type of transcription are the proteins called transcription factors involved in?

A) elongation
B) initiation
C) termination
D) stabilization

Question 40

Transcription Diagram
In the transcription diagram, what is the name of item C?

A) newly synthesized RNA
B) template DNA strand
C) complementary DNA strand
D) RNA-DNA hybrid

Question 41

Where does the process of translation of nuclear protein-coding genes in eukaryotic cells occur?

A) in the nucleolus
B) in the nucleus
C) in the Golgi apparatus
D) in the cytoplasm

Question 42

Figure 12-1
What does the structure in Figure 12-1 represent?

A) a molecule of tRNA
B) a molecule of snRNA
C) a molecule of mRNA
D) a molecule of pre-mRNA

Question 43

Relative to the mRNA, what move(s) during translocation?

A) attached tRNAs and the polypeptide chain
B) attached tRNAs and the ribosome
C) the ribosome and the polypeptide chain
D) the ribosome only

Question 44

What is the most likely fate of a molecule of eukaryotic mRNA that contains no 5' cap?

A) It would be translated at a reduced level.
B) It would be translated as usual.
C) It would not be translated.
D) It would be degraded.

Question 45

During translation, where does the energy for translocation come from?

A) from the breaking of bonds between tRNA and mRNA
B) from hydrolysis of GTP
C) from the breaking of bonds between mRNA and the ribosome
D) from the removal of a tRNA from the E site

Question 46

How is the reading frame established during translation?

A) by pairing initiator tRNA with the start codon
B) by the first base in the mRNA molecule
C) by the first tRNA to bind a codon at the A site
D) by removal of the cap from mRNA

Question 47

Which enzyme catalyzes the joining of amino acids during translation?

A) peptidyl transferase
B) reverse transcriptase
C) polyadenylase
D) RNA polymerase

Question 48

How is the process of adding the correct amino acid onto a tRNA molecule catalyzed?

A) by RNA polymerase
B) by the tRNA itself
C) by an aminoacyl-tRNA synthetase
D) by an mRNA

Question 49

At the start of translation, where is the initiator tRNA base paired with the start codon?

A) at the A site in the ribosome
B) first at the A site in the ribosome, and then the E site in the ribosome
C) first at the A site in the ribosome, and then the P site in the ribosome
D) at the P site in the ribosome

Question 50

Which molecule provides the energy that the cell requires for protein translation?

A) GTP
B) TTP
C) ATP
D) ADP

Question 51

Which of the following regions of the ribosome accept(s) charged tRNA molecules during the elongation phase of translation?

A) the P site
B) the A site
C) either the A site or the E site
D) either the P site or the E site

Question 52

What is a ribosome made of?

A) tRNA and rRNA
B) tRNA, rRNA, and mRNA
C) rRNA and proteins
D) rRNA and mRNA

Question 53

In which part of the ribosome is the growing polypeptide chain positioned during translation?

A) in the P site
B) in the small subunit
C) in the A site
D) in the E site

Question 54

Which region of the ribosome accepts charged tRNA molecules during the elongation phase of translation?

A) first the A site in the ribosome, and then the E site in the ribosome
B) the P site in the ribosome
C) first the A site in the ribosome, and then the P site in the ribosome
D) the A site in the ribosome

Question 55

Which region in a tRNA bonds with mRNA during translation?

A) the aminoacylation site
B) the anticodon
C) the cloverleaf
D) the TATA box

Question 56

Which of the following types of RNA is typically found as a strand that is about 75 to 90 bases long and folds into a structure with four double-helical segments?

A) tRNA
B) snRNA
C) pre-mRNA
D) rRNA

Question 57

Which molecule becomes "charged" with an amino acid on its 3' end?

A) snRNA
B) tRNA
C) mRNA
D) pre-mRNA

Question 58

Some tRNAs have the ability to pair with different codons due to imprecise base pairing with the third base in the codon. How is this ability described?

A) by degeneracy
B) by exon shuffling
C) by the wobble hypothesis
D) by alternative splicing

Question 59

How is the formation of the peptide bond catalyzed during translation?

A) by aminoacyl-tRNA synthetases
B) by snRNP
C) by peptidyl transferase
D) by RNA polymerase

Question 60

Which molecule consists entirely of protein?

A) ribosomal large subunit
B) peptidyl transferase
C) aminoacyl-tRNA synthetase
D) ribosomal small subunit

Question 61

Describe the process of transcription in prokaryotes.

Question 62

Suppose that two bases are inserted into the coding region of a gene just after the start codon of a gene. What type of mutation has occurred?

A) a missense mutation
B) a chromosomal mutation
C) a silent mutation
D) a frameshift mutation

Question 63

Suppose that a DNA change results in the substitution of one codon for another, but the codon specifies the same amino acid as it did originally. What type of mutation has occurred?

A) a chromosomal mutation
B) a frameshift mutation
C) a silent mutation
D) a missense mutation

Question 64

Which of the following are unique to prokaryotes?

A) aminoacyl-tRNA synthetases
B) UTRs in mRNA
C) introns
D) polysomes connected to DNA

Question 65

Which of the following describes a polysome?

A) the combination of a large and a small ribosome subunit
B) an mRNA with multiple ribosomes attached
C) the assembly at a promoter at the start of transcription
D) the complex where mRNA splicing occurs

Question 66

Describe the process of mRNA splicing.

Question 67

During translation, which molecule is used to bind tRNA to the codon in the A site?

A) GTP
B) ATP
C) ADP
D) GDP

Question 68

Suppose that a DNA change results in the substitution of one codon for another, and the new codon specifies a different amino acid from the original. What type of mutation has occurred?

A) a chromosomal mutation
B) a missense mutation
C) a frameshift mutation
D) a silent mutation

Question 69

Which gene sequence elements are present in prokaryotes?

A) codons
B) capping signals
C) poly(A) signals
D) sorting signals on proteins

Question 70

Suppose that the first part of a new polypeptide chain being produced in a eukaryotic cell has a signal peptide. Where would this polypeptide be located within the cell as it is maturing?

A) first in the rough ER, and then in the Golgi apparatus
B) first in the cytoplasm, and then in the rough ER
C) in the cytoplasm only
D) in the Golgi apparatus only

Question 71

Briefly describe the places where tRNA would be found in a ribosome and what its function is at each place.

Question 72

Suppose that the first part of a new polypeptide chain being produced in a eukaryotic cell does NOT have a signal peptide. Where would this polypeptide be located within the cell as it is maturing?

A) in the Golgi apparatus only
B) in the cytoplasm only
C) first in the rough ER, and then in the Golgi apparatus
D) first in the cytoplasm, and then in the rough ER

Question 73

Which sentence best describes the role of the signal recognition particle (SRP)?

A) It activates gene expression.
B) It assists in polyadenylation of mRNA.
C) It assists in mRNA splicing.
D) It temporarily blocks translation.

Question 74

Which sentence describes the routing of proteins to their final destinations in eukaryotic cells?

A) It is essentially random.
B) It is based on transcription factors.
C) It is directed by signals that are part of the proteins.
D) It is controlled by the type of ribosome used.

Question 75

Which site on a ribosome does the release factor bind to?

A) site A
B) site E
C) site P
D) site R

Question 76

Suppose that a DNA change results in the substitution of one codon for another, and the new codon specifies a stop codon where it did NOT previously. What type of mutation has occurred?

A) a nonsense mutation
B) a missense mutation
C) a chromosomal mutation
D) a silent mutation

Question 77

In the expression of the gene for insulin, which is secreted outside certain mammalian cells, which of the following steps will occur last?

A) binding of signal recognition particle (SRP)
B) removal of introns
C) binding of transcription factors
D) binding of a release factor

Question 78

Which type of molecule is a translation elongation factor?

A) mRNA
B) amino acid
C) tRNA
D) protein

Question 79

Individuals with the genetic condition sickle cell anemia have hemoglobin coded with the gene that codes for valine instead of glutamic acid. What kind of mutation does this condition result from?

A) a frameshift mutation
B) a missense mutation
C) a chromosomal mutation
D) a silent mutation

Question 80

Describe how exon shuffling could lead to the formation of novel proteins.