Question 1

Which of the lettered arrows in the following diagram of translation indicates a codon?

Accepted Answer

A)  A 
B)  B 
C)  C 
D)  D 
A)  A 
B)  B 
C)  C 
D)  D

Question 2

If both strands of the DNA of a gene underwent transcription and translation,they would produce the same mRNA and protein.

Accepted Answer

A) True 
 B)False

Question 3

An insertion or deletion mutation can cause a change in the reading of the mRNA codons; in essence,it scrambles the codons.Such a mutation results in a genetic ________.

Accepted Answer

The answer of An insertion or deletion mutation can cause...

Question 4

A chemical that causes the formation of covalent bonds between adenines and thymines on opposite DNA strands is added to a cell in such a way that the bonds between the nucleotides cannot be broken.How does this drug affect gene expression in the cell?

Accepted Answer

A)  The chemical increases the efficiency of protein production by making it easier for tRNA to interact with the correct mRNA codons. 
B)  The chemical prevents transcription from occurring so that proteins cannot be made. 
C)  The chemical prevents protein production because once made, the RNA cannot separate from its DNA template. 
D)  The chemical has no effect on protein production because mRNA contains uracil rather than thymine. 
A)  The chemical increases the efficiency of protein production by making it easier for tRNA to interact with the correct mRNA codons. 
B)  The chemical prevents transcription from occurring so that proteins cannot be made. 
C)  The chemical prevents protein production because once made, the RNA cannot separate from its DNA template. 
D)  The chemical has no effect on protein production because mRNA contains uracil rather than thymine.

Question 5

Each set of three bases in an mRNA molecule codes for one of 20 specific

Accepted Answer

A)  rRNA molecules. 
B)  nucleotides. 
C)  amino acids. 
D)  proteins. 
A)  rRNA molecules. 
B)  nucleotides. 
C)  amino acids. 
D)  proteins.

Question 6

A mutation occurs in the promoter of a protein-encoding gene.How might this mutation affect the production of the protein encoded by the gene?

Accepted Answer

A)  The mRNA made from this gene would exhibit the same mutation and therefore would not fold or function properly. 
B)  The protein made from the promoter would have a different amino acid sequence and therefore would not function properly. 
C)  The promoter might not be recognized by RNA polymerase, so the enzyme would be unable to attach to the promoter and start transcription. 
D)  The start codon would be missing from the mRNA made from this gene, so the mRNA could not be translated. 
A)  The mRNA made from this gene would exhibit the same mutation and therefore would not fold or function properly. 
B)  The protein made from the promoter would have a different amino acid sequence and therefore would not function properly. 
C)  The promoter might not be recognized by RNA polymerase, so the enzyme would be unable to attach to the promoter and start transcription. 
D)  The start codon would be missing from the mRNA made from this gene, so the mRNA could not be translated.

Question 7

Most molecules of RNA are ________-stranded.

Accepted Answer

The answer of Most molecules of RNA are ________-stranded....

Question 8

The sequence of nucleotides in an mRNA molecule

Accepted Answer

A)  is complementary to the DNA template strand. 
B)  matches the sequence of the ribosome that will translate the mRNA. 
C)  exactly matches the template strand (except where U is substituted for T). 
D)  is identical to that of the promoter. 
A)  is complementary to the DNA template strand. 
B)  matches the sequence of the ribosome that will translate the mRNA. 
C)  exactly matches the template strand (except where U is substituted for T). 
D)  is identical to that of the promoter.

Question 9

A tRNA molecule produced in a laboratory has the anticodon for the amino acid serine,but carries the amino acid leucine.When it reaches the serine codon on a molecule of mRNA where translation is under way,what is the most likely outcome?

Accepted Answer

A)  It will not bind with the codon on the mRNA molecule. 
B)  A potentially dysfunctional protein will result. 
C)  A proofreading enzyme will change leucine to serine. 
D)  Translation will stop. 
A)  It will not bind with the codon on the mRNA molecule. 
B)  A potentially dysfunctional protein will result. 
C)  A proofreading enzyme will change leucine to serine. 
D)  Translation will stop.

Question 10

A codon can specify up to three different amino acids.

Accepted Answer

A) True 
 B)False

Question 11

If a strand of DNA has the sequence CGTAA,the mRNA made from this molecule will have the sequence

Accepted Answer

A)  CGTAA. 
B)  GCUTT. 
C)  TAGCC. 
D)  GCAUU. 
A)  CGTAA. 
B)  GCUTT. 
C)  TAGCC. 
D)  GCAUU.

Question 12

The base sequence of mRNA specifies the sequence of amino acids in a ________.

Accepted Answer

The answer of The base sequence of mRNA specifies the...

Question 13

The lac repressor has been mutated so that its binding site for the operator has been altered to the extent that it is unable to bind to the operator.What is the likely effect of this mutation on the lac operon?

Accepted Answer

A)  The repressor will be unable to bind to the operator; the operon will bind RNA polymerase and it will thus be turned on. 
B)  The repressor will bind to the operator despite the mutation, and will suppress transcription of the operon in the presence and absence of lactose. 
C)  The lac operon will be protected by the altered repressor. 
D)  The repressor will be unable to bind to the operator; therefore, the ability of RNA polymerase to bind there will be severely hampered. 
A)  The repressor will be unable to bind to the operator; the operon will bind RNA polymerase and it will thus be turned on. 
B)  The repressor will bind to the operator despite the mutation, and will suppress transcription of the operon in the presence and absence of lactose. 
C)  The lac operon will be protected by the altered repressor. 
D)  The repressor will be unable to bind to the operator; therefore, the ability of RNA polymerase to bind there will be severely hampered.

Question 14

The stop codon is the sequence of bases at which transcription ends.

Accepted Answer

A) True 
 B)False

Question 15

The position of the start codon is important because every molecule of mRNA can be read by a ribosome in three different ways.

Accepted Answer

A) True 
 B)False

Question 16

A gene affects an organism's phenotype by controlling

Accepted Answer

A)  protein production. 
B)  the mutation rate. 
C)  the organism's environment. 
D)  the organism's ribosomes. 
A)  protein production. 
B)  the mutation rate. 
C)  the organism's environment. 
D)  the organism's ribosomes.

Question 17

Proteins are produced directly from DNA,with no intermediate steps.

Accepted Answer

A) True 
 B)False

Question 18

The sugar molecule present in RNA is

Accepted Answer

A)  uracil. 
B)  deoxyribose. 
C)  ribose. 
D)  sucrose. 
A)  uracil. 
B)  deoxyribose. 
C)  ribose. 
D)  sucrose.

Question 19

Molecule B in the following image is RNA.

Accepted Answer

A) True 
 B)False

Question 20

The importance of tRNA is that it

Accepted Answer

A)  carries a specific amino acid to the mRNA and the ribosome. 
B)  reads the DNA molecule. 
C)  contains codons that specify amino acids. 
D)  is important in the construction of ribosomes. 
A)  carries a specific amino acid to the mRNA and the ribosome. 
B)  reads the DNA molecule. 
C)  contains codons that specify amino acids. 
D)  is important in the construction of ribosomes.

Exam 12: From Gene to Protein

Which of the lettered arrows in the following diagram of translation indicates a codon?

If both strands of the DNA of a gene underwent transcription and translation,they would produce the same mRNA and protein.

An insertion or deletion mutation can cause a change in the reading of the mRNA codons; in essence,it scrambles the codons.Such a mutation results in a genetic ________.

A chemical that causes the formation of covalent bonds between adenines and thymines on opposite DNA strands is added to a cell in such a way that the bonds between the nucleotides cannot be broken.How does this drug affect gene expression in the cell?

Each set of three bases in an mRNA molecule codes for one of 20 specific

A mutation occurs in the promoter of a protein-encoding gene.How might this mutation affect the production of the protein encoded by the gene?

Most molecules of RNA are ________-stranded.

The sequence of nucleotides in an mRNA molecule

A tRNA molecule produced in a laboratory has the anticodon for the amino acid serine,but carries the amino acid leucine.When it reaches the serine codon on a molecule of mRNA where translation is under way,what is the most likely outcome?

A codon can specify up to three different amino acids.

If a strand of DNA has the sequence CGTAA,the mRNA made from this molecule will have the sequence

The base sequence of mRNA specifies the sequence of amino acids in a ________.

The lac repressor has been mutated so that its binding site for the operator has been altered to the extent that it is unable to bind to the operator.What is the likely effect of this mutation on the lac operon?

The stop codon is the sequence of bases at which transcription ends.

The position of the start codon is important because every molecule of mRNA can be read by a ribosome in three different ways.

A gene affects an organism's phenotype by controlling

Proteins are produced directly from DNA,with no intermediate steps.

The sugar molecule present in RNA is

Molecule B in the following image is RNA.

The importance of tRNA is that it

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