Question 1

A primer comprised of _______ is needed at the origin of nucleotide addition.

Accepted Answer

A)  polymerase III
B)  polymerase I
C)  helicase
D)  RNA
E)  DNAF) D) and E)
G) A) and D)

Question 2

Replication of DNA begins at a/an _______ rich area.

Accepted Answer

A)  guanine-cytosine
B)  uracil-adenine
C)  adenine-thymine
D)  adenine-cytosine
E)  guanine-adenineF) A) and B)
G) C) and D)

Question 3

The antiparallel arrangement within DNA molecules refers to

Accepted Answer

A)  each base bonding at the 1'position of the sugar.
B)  a purine always bonding to a pyrimidine.
C)  one helix strand that runs from the 5'to 3'direction and the other strand runs from the 3'to 5'direction.
D)  an original parent DNA strand and one newly synthesized DNA strand comprising a new DNA molecule.E) B) and C)
F) A) and B)

Question 4

A mutation has occurred during DNA replication while the cell was preparing to divide.As a result of this, the codon ACU of mRNA has now become ACC.Interestingly, there is no change to the protein being made.Why not?

Accepted Answer

A)  This is a silent mutation.
B)  The original amino acid isoleucine was changed to leucine, but they are the same variation of amino acid so no change to the protein.
C)  The mutation was fixed, and even though the codon is now ACC the correct amino acid is put into place for the normal protein.
D)  This is not a mutation that causes a big change, so there is no change to the protein being made.E) None of the above
F) A) and B)

Question 5

The mechanism of DNA synthesis differs between the two new daughter strands during replication.This is due to the fact that

Accepted Answer

A)  both RNA primers attach to the 3'end of the template strands, which are at opposite ends from each other.
B)  both daughter strands can't extend toward the replication fork because there would not be room for two DNA polymerase enzymes.
C)  one RNA primer attaches to the 5'end of the parent strand and the other primer to the 3'end.
D)  the DNA strands run antiparallel to each other and the DNA polymerase can only add nucleotides to the 3' end of the growing strand.E) B) and D)
F) All of the above

Question 6

The process in which mutations are removed and the correct bases added is called ________.

Accepted Answer

A)  transduction
B)  excision repair
C)  frameshift
D)  back-mutation
E)  transformationF) A) and B)
G) C) and E)

Question 7

DNA photolyase, in the presence of visible light, can repair DNA damage due to ultraviolet radiation.

Accepted Answer

A) True 
 B)False

Question 8

The antibiotic rifamycin is selectively toxic in blocking protein synthesis in Mycobacterium tuberculosis because

Accepted Answer

A)  the drug binds to the initiator tRNA, preventing the formation of the protein synthesis initiation complex in the bacterial cell.
B)  it binds preferentially to bacterial RNA polymerase rather than the eukaryotic protein, effectively halting transcription in the pathogen but not the host.
C)  the antibiotic binds to the mRNA once synthesized, preventing it from participating in the initiation complex with the ribosome.
D)  bacterial ribosomes are 70s whereas host ribosome are 80s, thus the antibiotic binds to the M.tuberculosis ribosome but does not bind to the eukaryotic machinery.E) B) and D)
F) A) and B)

Question 9

Synthesis of a repressible enzyme is inhibited by

Accepted Answer

A)  repressor alone bound to operator.
B)  substrate bound to repressor.
C)  substrate bound to promoter.
D)  corepressor and repressor binding to operator.E) A) and B)
F) None of the above

Question 10

The fundamental difference between an organism's genotype and its phenotype is that

Accepted Answer

A)  the phenotype refers to all of the genetic material in the organism, whereas the genotype represents only the genetic material that is expressed into proteins.
B)  the genotype refers to the organism's genes and the phenotype refers to the non-coding segments of DNA.
C)  the genotype refers to eukaryotic genes that contain both introns and exons, whereas phenotype refers to bacterial DNA that has only exons.
D)  the genotype refers to all of the genetic material in the organism, whereas the phenotype represents only the genetic material that is expressed into proteins.E) A) and D)
F) A) and C)

Question 11

The site where the old DNA strands separate and new DNA strands will be synthesized is called the ________.

Accepted Answer

A)  primer
B)  Okazaki fragment
C)  template
D)  rolling circle
E)  replication forkF) A) and E)
G) None of the above

Question 12

Which of the following is not a type of bacterial DNA recombination?

Accepted Answer

A)  Transformation
B)  Conjugation
C)  Mitosis
D)  TransductionE) A) and D)
F) B) and D)

Question 13

Which of the following is not true of an organism's genotype?

Accepted Answer

A)  It contains structural genes that code for proteins.
B)  It has regulatory genes that control gene expression.
C)  It contains genes that code for RNA.
D)  It is inherited.
E)  It has expressed traits governed by the genes.F) C) and D)
G) A) and E)

Question 14

Which of the following is not true of conjugation?

Accepted Answer

A)  Involves direct contact between cells
B)  Transfers genes for drug resistance
C)  Transfers genes for enzymes and adherence molecules
D)  Involves the action of bacteriophage
E)  The donor retains a copy of the transferred genesF) D) and E)
G) B) and E)

Question 15

The lactose repressor

Accepted Answer

A)  is transcribed with the structural lac genes.
B)  is activated by binding lactose.
C)  is inactivated by binding lactose.
D)  requires lactose for its transcription.E) None of the above
F) A) and C)

Question 16

Okazaki fragments are attached to the growing end of the lagging strand by _______.

Accepted Answer

A)  DNA ligase
B)  DNA polymerase
C)  DNA helicase
D)  DNA gyrase
E)  primaseF) B) and C)
G) A) and E)

Question 17

All mutations are not beneficial to the cell.

Accepted Answer

A) True 
 B)False

Question 18

Streptomycin, an aminoglycoside, inhibits protein synthesis

Accepted Answer

A)  by preventing the formation of the initiation complex.
B)  by binding to the tRNA preventing peptide bond formation between amino acids.
C)  by binding to the ribosome, preventing translocation due to interference with the attachment of mRNA.
D)  by interfering with both the initiation and elongation stages of translation.E) B) and C)
F) A) and D)

Question 19

Bacterial conjugation involves

Accepted Answer

A)  a bacteriophage carrying donor DNA to the recipient cell.
B)  a donor cell with a plasmid that synthesizes a pilus.
C)  naked DNA fragments from a lysed donor cell taken up by a recipient cell.
D)  new progeny cells with genes from two parent bacterial cells.E) A) and C)
F) C) and D)

Question 20

Synthesis of an inducible enzyme requires

Accepted Answer

A)  repressor alone bound to operator.
B)  substrate bound to repressor.
C)  substrate bound to promoter.
D)  corepressor and repressor binding to operator.E) A) and B)
F) A) and C)

Exam 9: Microbial Genetics

The antibiotic rifamycin is selectively toxic in blocking protein synthesis in Mycobacterium tuberculosis because

Correct AnswerverifiedShow Answer

Bacterial conjugation involves

Correct AnswerverifiedShow Answer

Replication of DNA begins at a/an _______ rich area.

Correct AnswerverifiedShow Answer

The process in which mutations are removed and the correct bases added is called ________.

Correct AnswerverifiedShow Answer

Streptomycin, an aminoglycoside, inhibits protein synthesis

Correct AnswerverifiedShow Answer

DNA photolyase, in the presence of visible light, can repair DNA damage due to ultraviolet radiation.

Correct AnswerverifiedShow Answer

A mutation has occurred during DNA replication while the cell was preparing to divide.As a result of this, the codon ACU of mRNA has now become ACC.Interestingly, there is no change to the protein being made.Why not?

Correct AnswerverifiedShow Answer

Synthesis of an inducible enzyme requires

Correct AnswerverifiedShow Answer

Okazaki fragments are attached to the growing end of the lagging strand by _______.

Correct AnswerverifiedShow Answer

Which of the following is not true of an organism's genotype?

Correct AnswerverifiedShow Answer

Synthesis of a repressible enzyme is inhibited by

Correct AnswerverifiedShow Answer

The antiparallel arrangement within DNA molecules refers to

Correct AnswerverifiedShow Answer

The mechanism of DNA synthesis differs between the two new daughter strands during replication.This is due to the fact that

Correct AnswerverifiedShow Answer

The lactose repressor

Correct AnswerverifiedShow Answer

Which of the following is not a type of bacterial DNA recombination?

Correct AnswerverifiedShow Answer

The fundamental difference between an organism's genotype and its phenotype is that

Correct AnswerverifiedShow Answer

All mutations are not beneficial to the cell.

Correct AnswerverifiedShow Answer

Which of the following is not true of conjugation?

Correct AnswerverifiedShow Answer

The site where the old DNA strands separate and new DNA strands will be synthesized is called the ________.

Correct AnswerverifiedShow Answer

A primer comprised of _______ is needed at the origin of nucleotide addition.

Correct AnswerverifiedShow Answer

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