Question 1

To begin transcription,RNA polymerase must bind to a segment of DNA called the ________.

Accepted Answer

A)  initiation site
B)  primer
C)  inducer
D)  promoter
E)  transcription bubbleF) B) and E)
G) A) and C)

Question 2

The genetic code uses ________ nucleotide(s) to specify one amino acid.

Accepted Answer

A)  one
B)  two
C)  three
D)  four
E)  64F) B) and E)
G) D) and E)

Question 3

A scientist makes three artificial mRNA strands: 
(x) 5' AAAUUUAAAUUUAAAUUUAAAUUUAAA 3'
(y) 5' UUUCCCUUUCCCUUUCCCUUUCCCUUU 3'
(z) 5' AUAUAUAUAUAUAUAUAUAUAUAUAU 3'
When he analyzes the polypeptides produced,he finds that:
X produces a polypeptide that is 50% phenylalanine and 50%lysine.
Y produces a polypeptide that is 50% phenylalanine and 50% proline.
Z produces a polypeptide that is 50% isoleucine and 50% tyrosine.
Based on these results only,the best conclusion to make is that

Accepted Answer

A)  AUA codes for isoleucine
B)  AAA codes for phenylalanine
C)  AAA codes for lysine
D)  AAA codes for lysine and AUA codes for isoleucine
E)  AAA codes for phenylalanine and AUA codes for isoleucineF) B) and E)
G) A) and B)

Question 4

During translation,uncharged tRNA molecules leave the ribosome from the ________ site.

Accepted Answer

A)  E
B)  P
C)  A
D)  termination
E)  releaseF) A) and C)
G) None of the above

Question 5

During protein synthesis in eukaryotes,what happens during RNA splicing?

Accepted Answer

A)  The product of translation,called the primary transcript,is cut and some pieces are joined back together to form the mature mRNA.
B)  The product of transcription,called the primary transcript,is cut and some pieces are joined back together to form the mature tRNA.
C)  The product of transcription,called the secondary transcript,is cut and some pieces are joined back together to form the mature mRNA.
D)  The product of transcription,called the primary transcript,is cut and some pieces are joined back together to form the mature mRNA.
E)  The product of transcription,called the primary transcript,is cut and all pieces are joined back together to form the mature mRNA.F) C) and D)
G) B) and E)

Question 6

The A,P,and E sites are progressively occupied by amino acids being assembled into a polypeptide.These sites are part of

Accepted Answer

A)  DNA.
B)  the large ribosomal subunit.
C)  mRNA.
D)  tRNA.
E)  the spliceosome.F) C) and D)
G) D) and E)

Question 7

You are working to characterize a novel protein in mice.Analysis shows that high levels of the primary transcript that codes for this protein are found in tissue from the brain,muscle,liver,and pancreas.However,an antibody that recognizes the C-terminal portion of the protein indicates that the protein is present in brain,muscle,and liver,but not in the pancreas.What is the most likely explanation for this result?

Accepted Answer

A)  The gene that codes for this protein is not transcribed in the pancreas.
B)  The transcript is immediately degraded in the pancreas.
C)  The transcript receives a 5' cap in the pancreas.
D)  Alternative splicing in the pancreas creates a protein missing the domain that the antibody recognizes.
E)  The transcript receives a 3' poly-A tail in the pancreas.F) C) and E)
G) A) and E)

Question 8

How many unique mRNA codons can be constructed from the four different RNA nucleotides?

Accepted Answer

A)  four
B)  12
C)  16
D)  61
E)  64F) B) and E)
G) None of the above

Question 9

Specific amino acids are attached to tRNA molecules by

Accepted Answer

A)  aminoacyl-tRNA synthetases.
B)  hydrogen bonds.
C)  anticodons.
D)  deactivating enzymes.
E)  initiation factors.F) All of the above
G) A) and B)

Question 10

During ________,nucleotide sequence information is changed into amino acid sequence information.

Accepted Answer

A)  replication
B)  sequencing
C)  transcription
D)  translocation
E)  translationF) D) and E)
G) A) and B)

Question 11

DNA affects the traits of an organism by providing the instructions for synthesizing _______.

Accepted Answer

A)  proteins
B)  nucleotides
C)  codons
D)  amino acidsE) C) and D)
F) B) and C)

Question 12

During the splicing reaction,the intron-exon junctions are recognized by

Accepted Answer

A)  snRNPs.
B)  miRNAs.
C)  SRP RNAs.
D)  the lariat.
E)  the branch point.F) D) and E)
G) A) and E)

Question 13

Two 6-base sequences are present in bacterial promoters: TATAAT (located 10 nt upstream from the start site) and TTGACA (located 35 nt upstream from the start site) .What is the significance of the fact that these two base sequences are different?

Accepted Answer

A)  Binding sites for both the holoenzyme and ATP are provided.
B)  Both the location of the start site and the direction of transcription can be established.
C)  Binding sites for both the core polymerase and holoenzyme are provided.
D)  The transcription bubble can be properly formed.
E)  It allows RNA polymerase to distinguish between the template strand and the coding strand of the DNA molecule.F) A) and B)
G) B) and D)

Question 14

If the sequence of bases in the template strand of a DNA molecule is 3' ATCGCTCC 5',what is the sequence of bases in the RNA that is transcribed from this molecule?

Accepted Answer

A)  3' UAGCGAGG 5'
B)  3' TAGCGAGG 5'
C)  5' UAGCGAGG 3'
D)  5' TAGCGAGG 3'
E)  5' AUCGCUCC 3'F) None of the above
G) All of the above

Question 15

What is the likely consequence of a mutation that alters the branch point within an intron?

Accepted Answer

A)  no effect,since introns are not expressed
B)  failure to form a lariat
C)  failure of snRNPs to recognize the 5' end of intron
D)  no exon shuffling
E)  failure of snRNAs to combine with protein and form snRNPsF) None of the above
G) All of the above

Question 16

Why are there fewer tRNA anticodons than the 61 needed to match each mRNA codon that codes for an amino acid?

Accepted Answer

A)  There is some flexibility in pairing between the 5' base of the codon and the 3' base of the anticodon.
B)  There is some flexibility in pairing between the middle base of the codon and the middle base of the anticodon.
C)  There is some flexibility in pairing between the 3' base of the codon and the 5' base of the anticodon.
D)  There is some flexibility in pairing between all 3 bases of the codon and all 3 bases of the anticodon.E) A) and B)
F) C) and D)

Question 17

Although 61 different codons code for amino acids,cells contain fewer than 61 different tRNAs.Why?

Accepted Answer

A)  Because the 5' base on the tRNA anticodon has some flexibility (wobble) ; thus,some tRNA anticodons can pair with more than one mRNA codon.
B)  Although 61 different codons code for amino acids,any given cell contains fewer than 61.
C)  Because the 5' base on the mRNA codon has some flexibility (wobble) ; thus,some mRNA codons can pair with more than one tRNA anticodon.
D)  Because each amino acid is coded for by just one codon.E) A) and B)
F) C) and D)

Question 18

Which statement about the genetic code is false?

Accepted Answer

A)  There is no punctuation or spacing between codons.
B)  Nucleotides are always read in groups of three.
C)  Every codon codes for one amino acid.
D)  Some amino acids are specified by more than one codon.
E)  The genetic code is almost universal,but not quite.F) A) and B)
G) None of the above

Question 19

In eukaryotic cells,transcription occurs

Accepted Answer

A)  on the surface of the nuclear membrane.
B)  on ribosomes.
C)  on spliceosomes.
D)  inside the nucleus.
E)  on the surface of the plasma membrane.F) None of the above
G) A) and C)

Question 20

Within the transcription bubble,the 9 most recently added nucleotides in the newly synthesized RNA strand temporarily form a helix with the template DNA strand.How might transcription be affected if helix formation did not occur?

Accepted Answer

A)  Rewinding the DNA molecule would be inhibited.
B)  Unwinding the DNA molecule would be inhibited.
C)  The position of the 5' end of the RNA would be unstable,inhibiting elongation.
D)  The position of the 3' end of the RNA would be unstable,inhibiting elongation.
E)  The position of the 5' end of the RNA would be unstable,stimulating elongation.F) B) and C)
G) B) and D)

Exam 15: Genes and How They Work

To begin transcription,RNA polymerase must bind to a segment of DNA called the ________.

Correct Answer
verified

The genetic code uses ________ nucleotide(s) to specify one amino acid.

Correct Answer
verified

Two 6-base sequences are present in bacterial promoters: TATAAT (located 10 nt upstream from the start site) and TTGACA (located 35 nt upstream from the start site) .What is the significance of the fact that these two base sequences are different?

Correct Answer
verified

DNA affects the traits of an organism by providing the instructions for synthesizing _______.

Correct Answer
verified

During the splicing reaction,the intron-exon junctions are recognized by

Correct Answer
verified

What is the likely consequence of a mutation that alters the branch point within an intron?

Correct Answer
verified

Although 61 different codons code for amino acids,cells contain fewer than 61 different tRNAs.Why?

Correct Answer
verified

Why are there fewer tRNA anticodons than the 61 needed to match each mRNA codon that codes for an amino acid?

Correct Answer
verified

During translation,uncharged tRNA molecules leave the ribosome from the ________ site.

Correct Answer
verified

Correct Answer
verified

During ________,nucleotide sequence information is changed into amino acid sequence information.

Correct Answer
verified

Which statement about the genetic code is false?

Correct Answer
verified

During protein synthesis in eukaryotes,what happens during RNA splicing?

Correct Answer
verified

How many unique mRNA codons can be constructed from the four different RNA nucleotides?

Correct Answer
verified

In eukaryotic cells,transcription occurs

Correct Answer
verified

Within the transcription bubble,the 9 most recently added nucleotides in the newly synthesized RNA strand temporarily form a helix with the template DNA strand.How might transcription be affected if helix formation did not occur?

Correct Answer
verified

The A,P,and E sites are progressively occupied by amino acids being assembled into a polypeptide.These sites are part of

Correct Answer
verified

Correct Answer
verified

If the sequence of bases in the template strand of a DNA molecule is 3' ATCGCTCC 5',what is the sequence of bases in the RNA that is transcribed from this molecule?

Correct Answer
verified

Specific amino acids are attached to tRNA molecules by

Correct Answer
verified

Exam 15: Genes and How They Work

To begin transcription,RNA polymerase must bind to a segment of DNA called the ________.

Correct AnswerverifiedShow Answer

The genetic code uses ________ nucleotide(s) to specify one amino acid.

Correct AnswerverifiedShow Answer

Two 6-base sequences are present in bacterial promoters: TATAAT (located 10 nt upstream from the start site) and TTGACA (located 35 nt upstream from the start site) .What is the significance of the fact that these two base sequences are different?

Correct AnswerverifiedShow Answer

DNA affects the traits of an organism by providing the instructions for synthesizing _______.

Correct AnswerverifiedShow Answer

During the splicing reaction,the intron-exon junctions are recognized by

Correct AnswerverifiedShow Answer

What is the likely consequence of a mutation that alters the branch point within an intron?

Correct AnswerverifiedShow Answer

Although 61 different codons code for amino acids,cells contain fewer than 61 different tRNAs.Why?

Correct AnswerverifiedShow Answer

Why are there fewer tRNA anticodons than the 61 needed to match each mRNA codon that codes for an amino acid?

Correct AnswerverifiedShow Answer

During translation,uncharged tRNA molecules leave the ribosome from the ________ site.

Correct AnswerverifiedShow Answer

Correct AnswerverifiedShow Answer

During ________,nucleotide sequence information is changed into amino acid sequence information.

Correct AnswerverifiedShow Answer

Which statement about the genetic code is false?

Correct AnswerverifiedShow Answer

During protein synthesis in eukaryotes,what happens during RNA splicing?

Correct AnswerverifiedShow Answer

How many unique mRNA codons can be constructed from the four different RNA nucleotides?

Correct AnswerverifiedShow Answer

In eukaryotic cells,transcription occurs

Correct AnswerverifiedShow Answer

Within the transcription bubble,the 9 most recently added nucleotides in the newly synthesized RNA strand temporarily form a helix with the template DNA strand.How might transcription be affected if helix formation did not occur?

Correct AnswerverifiedShow Answer

The A,P,and E sites are progressively occupied by amino acids being assembled into a polypeptide.These sites are part of

Correct AnswerverifiedShow Answer

Correct AnswerverifiedShow Answer

If the sequence of bases in the template strand of a DNA molecule is 3' ATCGCTCC 5',what is the sequence of bases in the RNA that is transcribed from this molecule?

Correct AnswerverifiedShow Answer

Specific amino acids are attached to tRNA molecules by

Correct AnswerverifiedShow Answer

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