Deck 25: Gene Expression and Protein Synthesis

Question 1

Where does translation occur in eukaryotes?

A) in the nucleus
B) in the cytoplasm
C) on the cell membrane
D) on the lysosomal membrane

Answer 1

B

Question 2

Which of the following statements is true of a promoter?

A) There is a common promoter for all genes.
B) It is the part of a structural gene that codes for mRNA.
C) It is the part of a structural gene that codes for tRNA.
D) The promoter for each gene is unique.

Answer 2

D

Question 3

Which of the following statements is true of transcription?

A) Both the strands of DNA serve as templates for mRNA synthesis.
B) The antisense strand of DNA alone serves as a template for mRNA synthesis.
C) The sense strand of DNA alone serves as a template for mRNA synthesis.
D) The 3' ends of both strands serve as templates for mRNA synthesis.

Answer 3

B

Question 4

Which of the following is the consensus base sequence of a TATA box?

A) TATA
B) TATATA
C) TATAAT
D) TTAATTAA

Question 5

How many polymerases catalyze transcription in eukaryotes?

A) one
B) two
C) three
D) four

Question 6

Which of the following is true of a TATA box?

A) It is a consensus sequence.
B) It is a response element.
C) It is a termination sequence.
D) It is a transcription factor.

Question 7

Which of the following statements is true of prokaryotes?

A) Transcription occurs in the nucleus.
B) Translation mostly occurs in the nucleus.
C) Transcription occurs along with translation in the cytoplasm.
D) Translation occurs before transcription in the cytoplasm.

Question 8

Which of the following is a characteristic of a functional mRNA molecule?

A) Its 5' end has an acetylated thymine.
B) It lacks exons.
C) Its 3' end has a poly-A tail.
D) It contains introns.

Question 9

Which of the following RNAs is formed by the catalytic action of RNA polymerase I (Pol I)?

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

Question 10

Which portion of a eukaryotic gene carries information that is transcribed to RNA?

A) the termination sequence
B) the consensus sequence
C) the initiator portion
D) the structural gene

Question 11

Which of the following statements is true of transcription in eukaryotes?

A) Transcription occurs in the nucleus.
B) Transcription occurs in the cytoplasm.
C) Transcription occurs along with translation in the cytoplasm.
D) Transcription occurs after translation in the nucleus.

Question 12

Which of the following occurs in retroviruses?

A) DNA is replicated in the 3' → 5' direction.
B) DNA is replicated in the 5' → 3' direction.
C) DNA is transcribed to RNA.
D) RNA is reverse-transcribed to DNA.

Question 13

Which of the following bases will be added to the growing mRNA if the base on the DNA template is adenine?

A) cytosine
B) guanine
C) thymine
D) uracil

Question 14

Which of the following statements is true of the structural sequence of a gene?

A) It is made of exons and introns.
B) It is made of promoters and enhancers.
C) It controls the function of regulatory genes.
D) It controls the expression of initiation factors.

Question 15

Which of the following statements is true of retroviruses?

A) They use reverse transcriptase to synthesize DNA.
B) They use RNA synthetase to replicate their own RNA.
C) They use reverse transcriptase to synthesize DNA and they use RNA synthetase to replicate their own RNA
D) None of these

Question 16

Where does transcription occur in eukaryotes?

A) in the nucleus
B) in the cytoplasm
C) on the cell membrane
D) on the lysosomal membrane

Question 17

Which of the following is a function of Pol III?

A) It catalyzes the formation of mRNA.
B) It catalyzes the formation of tRNA.
C) It catalyzes the acetylation of snRNA.
D) It catalyzes the methylation of rRNA.

Question 18

How many bases in a sequence code for an amino acid?

A) one
B) two
C) three
D) five

Question 19

Which of the following enzymes unwinds the double strand of a DNA molecule?

A) acetylase
B) helicase
C) DNA polymerase I
D) deacetylase

Question 20

Which of the following RNAs is formed by the catalytic action of RNA polymerase II (Pol II)?

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

Question 21

Which of the following amino acids are found at the C-terminal domain of Pol II?

A) alanine and serine
B) alanine and glycine
C) glycine and threonine
D) serine and threonine

Question 22

Which of the following scientists is most closely associated with deciphering the genetic code?

A) O. Avery
B) E. Chargaff
C) M. Nirenberg
D) J. Watson

Question 23

Which of the following statements is true of the structure of tRNA?

A) The 5' end of the tRNA is single-stranded, and it carries the amino acid.
B) The 3' end of the tRNA is single-stranded, and it carries the amino acid.
C) The 3' end of the tRNA molecule carries the anticodon recognition site.
D) The 5' end of the tRNA molecule carries the anticodon recognition site.

Question 24

During elongation, which type of bond is formed between complementary bases using RNA polymerase?

A) a hydrogen bond
B) a phosphate ester bond
C) a peptide bond
D) none of these bonds

Question 25

Which of the following statements is true of enhancers?

A) They are located next to the TATA box.
B) They are a part of the initiation sequence.
C) They increase the transcription of a gene above the basal level.
D) They contain bases that polymerases recognize as initial signals.

Question 26

Which of the following statements is true of the relationship between the bases of an mRNA codon and a tRNA anticodon?

A) They have complementary base sequences.
B) They have identical base sequences.
C) They have methylated base sequences.
D) They have acetylated base sequences.

Question 27

Which of the following is a function of an aminoacyl-tRNA synthetase?

A) It catalyzes the binding of the smaller ribosomal subunit to its specific tRNA.
B) It catalyzes the binding of the larger ribosomal subunit to its specific tRNA.
C) It catalyzes the binding of a specific amino acid to its specific tRNA.
D) It catalyzes the binding of a specific transcription factor to its specific tRNA.

Question 28

What are the sizes of the ribosomal subunits in prokaryotes?

A) 30S and 50S
B) 30S and 60S
C) 40S and 60S
D) 40S and 50S

Question 29

Which of the following post-transcriptional modifications results in functional mRNA?

A) the addition of introns at the 5' end
B) the addition of exons at the 3' end
C) the addition of a methylated guanine at the 5' end and a poly-A tail at the 3' end
D) the addition of introns at the 3' end and a poly-A tail at the 5' end

Question 30

Which of the following statements is true of mRNA synthesis?

A) mRNA is synthesized in the 3' → 5' direction and the polymerase moves along the DNA template in the 3' → 5' direction.
B) mRNA is synthesized in the 5' → 3' direction and the polymerase moves along the DNA template in the 5' → 3' direction.
C) mRNA is synthesized in the 3' → 5' direction, but the polymerase moves along the DNA template in the 5' → 3'direction.
D) mRNA is synthesized in the 5' → 3' direction, but the polymerase moves along the DNA template in the 3' → 5' direction.

Question 31

How is an amino acid transported by its tRNA?

A) It is bound to the 3' end of the tRNA.
B) It is bound to the 5' end of the tRNA.
C) It is bound to either the 3' or the 5' end.
D) It is enveloped by the tRNA.

Question 32

The size of ribosomal subunits is given in "S" units. What does "S" stand for?

A) sense strand
B) structural sequence
C) Svedberg unit
D) structural unit

Question 33

Where is the anticodon located on a tRNA molecule?

A) at the 3' end of the tRNA molecule
B) at the 5' end of the tRNA molecule
C) in a loop opposite to both the terminals of the tRNA molecule
D) in a loop near the 3' end of the tRNA molecule

Question 34

Which of the following are the components of the pre-initiation complex formed during protein synthesis?

A) GTP, a tRNA molecule, and a 30S ribosomal subunit
B) GTP, a tRNA molecule, and a 60S ribosomal subunit
C) ATP, a tRNA molecule, and a 30S ribosomal subunit
D) ATP, a tRNA molecule, and a 60S ribosomal subunit

Question 35

Which of the following statements is true of the enzyme Pol II?

A) The phosphorylated form of the enzyme is necessary for initiating transcription.
B) The unphosphorylated form of the enzyme is necessary for the elongation of mRNA.
C) The unphosphorylated form of the enzyme is necessary for the termination of transcription.
D) The phosphorylated form of the enzyme is necessary for the elongation of mRNA.

Question 36

How many different forms of the enzyme Pol II exist?

A) one
B) two
C) three
D) four

Question 37

Which of the following polymerases interact with their promoters via transcription factors?

A) Pol I
B) Pol II
C) Pol III
D) All of these

Question 38

Which of the following terms refers to a sequence of three nucleotide bases on an mRNA molecule?

A) anticodon
B) codon
C) enhancer
D) chaperone

Question 39

Which pair of ribosomal subunits is found in eukaryotes?

A) 30S and 50S
B) 30S and 60S
C) 40S and 60S
D) 40S and 50S

Question 40

Which of these is a function of RNA Pol II?

A) It catalyzes the formation of mRNAs.
B) It catalyzes the formation of snRNAs.
C) It catalyzes the methylation of its amino acid residues.
D) It catalyzes the methylation of 30S ribosomal subunits.

Question 41

Which of the following statements is true of methionine?

A) It is the last amino acid at the C-terminus of an active protein in the body.
B) It is the last amino acid at the N-terminus of an active protein in the body.
C) It is the first amino acid that is added to the C-terminus of a new protein during protein synthesis
D) It is the first amino acid that is added to the N-terminus of a new protein during protein synthesis.

Question 42

Which of the following codons terminates protein synthesis?

A) UUA
B) AUG
C) CUA
D) UAA

Question 43

How many codons, including redundant codons, will there be if proteins involved 100 different amino acids rather than 20?

A) 4
B) 128
C) 256
D) 512

Question 44

Where does an amino acid bind on a tRNA molecule?

A) at the 3' end
B) at the 5' end
C) at the anticodon loop
D) at the methionine residue

Question 45

How many initiation codons are there?

A) 1
B) 3
C) 4
D) 20

Question 46

One of the codons for threonine is 5' ACG 3'. Which of the following is the anticodon for this codon?

A) 5' GCA 3'
B) 5' ACG 3'
C) 5' CGT 3'
D) 5' CGU 3'

Question 47

Which of the following amino acids is coded by only one codon?

A) glycine
B) phenylalanine
C) proline
D) tryptophan

Question 48

Which of the following molecular components are required for the binding of tRNA to the A site?

A) elongation factors and GTP
B) initiation factors and ATP
C) transcription factors and ATP
D) termination factors and GTP

Question 49

Which of the following processes involves the enzyme aminoacyl-tRNA synthetase?

A) DNA replication
B) translation
C) transcription
D) all of these

Question 50

Which of the following is referred to as the "second genetic code"?

A) the ability of the codon and anticodon to recognize each other
B) the ability of aminoacyl-tRNA synthetase to pair an amino acid with its corresponding tRNA
C) the ability of an enhancer molecule to recognize its specific substrate
D) the ability of RNA polymerase I to recognize its binding site in mRNA

Question 51

Which of the following codons codes for methionine?

A) UAA
B) AUG
C) UUG
D) UGA

Question 52

Which of the following statements is true of aminoacyl-tRNA synthetase?

A) There is a single aminoacyl-tRNA synthetase for all the amino acids.
B) There are four different aminoacyl-tRNA synthetases, one for each different type of amino acid side chain
C) There are different aminoacyl-tRNA synthetase for each amino acid.
D) None of these are correct.

Question 53

How many stop codons are there?

A) 1
B) 3
C) 4
D) 20

Question 54

Which of the following codons initiates protein synthesis?

A) UGA
B) AUG
C) UAG
D) UAA

Question 55

One of the codons for leucine is 5' UUA 3'. Which of the following is the anticodon for this codon?

A) 5' GCA 3'
B) 5' UAA 3'
C) 5' UGU 3'
D) 5' CGU 3'

Question 56

Which of the following is a function of the fMet residue of tRNA during protein synthesis?

A) It activates an amino acid for its binding to tRNA.
B) It activates aminoacyl-tRNA synthetase.
C) It initiates protein synthesis.
D) It elongates the polypeptide chain during protein synthesis.

Question 57

One of the codons for histidine is 5' CAU 3'. Which of the following is the anticodon for this codon?

A) 5 'UAC 3'
B) 5' AUG 3'
C) 5' AUA 3'
D) 5' CAU 3'

Question 58

Which of the following is the first step of protein synthesis?

A) the activation of an amino acid by its reaction with ATP
B) the binding of an mRNA to a 30S ribosomal subunit
C) the formation of a peptide bond between an amino acid and a tRNA molecule
D) the binding of GTP to an mRNA molecule

Question 59

One of the codons for glycine is 5' GGU 3'. Which of the following is the anticodon for this codon?

A) 5' ACC 3'
B) 5' UAA 3'
C) 5' CCU 3'
D) 5' CCA 3'

Question 60

How many different codons are there?

A) 3
B) 20
C) 64
D) 256

Question 61

Which of the following is considered the 21st amino acid because it can bond to tRNA^sec during protein synthesis?

A) citrulline
B) ornithine
C) selenocysteine
D) xanadine

Question 62

Which statement is true of the translocation phase of elongation during protein synthesis?

A) The empty tRNA moves to the A site of the ribosomal complex.
B) The empty tRNA moves to the T site of the ribosomal complex.
C) The dipeptide moves from the A site to the P site of the ribosomal complex.
D) The dipeptide moves from the P site to the A site of the ribosomal complex.

Question 63

Which of the following is the mechanism of peptide bond formation during protein synthesis?

A) Nucleophilic attack on the carbon of a carbonyl group by an amino group
B) Nucleophilic attack on the nitrogen of an amino group by the carbon of a carbonyl group
C) Nucleophilic attack on the nitrogen of an amino group by the oxygen of a carbonyl group
D) Nucleophilic attack on the oxygen of a carbonyl group by an amino group

Question 64

Which of the following occurs after the formation of the full initiation complex?

A) the dissociation of initiation factors and the hydrolysis of GTP
B) the release of initiation factors and the hydrolysis of ATP
C) the release of elongation factors and the hydrolysis of GTP
D) the dissociation of elongation factors and the hydrolysis of ATP

Question 65

How many fundamental types of transcription factors are there?

A) one
B) two
C) four
D) six

Question 66

Which of the following is not involved in the regulation of transcription in eukaryotes?

A) enhancers
B) promoters
C) response elements
D) tRNAs

Question 67

How many sites are present within the full ribosomal complex?

A) five
B) two
C) three
D) four

Question 68

What is the size of the full prokaryotic ribosomal complex?

A) 30S
B) 50S
C) 70S
D) 80S

Question 69

A tRNA carries the anticodon 5' UAA 3'. What is its complementary codon?

A) 5' UUA 3'
B) 5' GAA 3'
C) 5' UAU 3'
D) 5' AUU 3'

Question 70

How many general transcription factors are there?

A) one
B) two
C) four
D) six

Question 71

Which of the following residues is carried by tRNA during the formation of the pre-initiation complex?

A) formylarginine
B) formylalanine
C) formylmethionine
D) formylvaline

Question 72

Which of the following biochemical compounds is involved in the formation of the pre-initiation complex?

A) ATP
B) CTP
C) GTP
D) UTP

Question 73

Which of the following enzymes adds a new amino acid to the growing chain of a protein during protein synthesis?

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

Question 74

Which of the following must occur so that the pre-initiation complex can be converted to the open complex?

A) The C terminal end of the RNA polymerase must be dephosphorylated.
B) The C terminal end of the RNA polymerase must be phosphorylated.
C) The N terminal end of the RNA polymerase must be dephosphorylated.
D) The N terminal end of the RNA polymerase must be phosphorylated.

Question 75

Which of the following ensures proper alignment of the small ribosomal unit on the mRNA during protein synthesis?

A) the anticodon
B) the codon
C) the Shine-Dalgarno sequence
D) the initiation sequence

Question 76

What happens to tRNA^fMet after its fMet residue forms a peptide bond with an amino acid?

A) It moves to the A site of the ribosomal complex.
B) It moves to the E site of the ribosomal complex.
C) It remains at the P site of the ribosomal complex.
D) It remains at the T site of the ribosomal complex.

Question 77

During protein synthesis, which ribosomal site accepts an aminoacyl-tRNA molecule bound to an amino acid?

A) the A site of the ribosomal complex
B) the E site of the ribosomal complex
C) the P site of the ribosomal complex
D) the S site of the ribosomal complex

Question 78

How many general transcription factors are released during elongation?

A) zero
B) two
C) three
D) six

Question 79

How many transcription factors are required for the initiation of transcription?

A) one
B) two
C) four
D) six

Question 80

Which of the following biochemical compounds is involved in the termination of protein synthesis?

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