Question 1

A screening system called the _______ test is used for detecting chemicals with carcinogenic potential.

Accepted Answer

A)   Koch
B)   Ames
C)   mutation
D)   cancer
E)   IowaF) A) and D)
G) None of the above

Question 2

Base pairs in DNA are held together by ______ bonds.

Accepted Answer

A)   peptide
B)   nonpolar covalent
C)   polar covalent
D)   hydrogen
E)   sulfhydrylF) B) and C)
G) C) and E)

Question 3

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) C) and D)
F) A) and B)

Question 4

An unidentified cell was found to contain introns and exons.It also expresses DNA polymerase and RNA polymerase.Although it exhibits a promoter region,it has no operons.You conclude that this cell

Accepted Answer

A)   is eukaryotic.
B)   is prokaryotic.
C)   is either a prokaryotic or eukaryotic cell.
D)   is actually a virus.E) None of the above
F) B) and D)

Question 5

All of the following pertain to transcription except

Accepted Answer

A)   it occurs on a ribosome in the cytoplasm.
B)   it occurs before translation.
C)   it requires RNA polymerase.
D)   it requires a template DNA strand.
E)   it is a process that contributes to the synthesis of protein.F) A) and D)
G) A) and E)

Question 6

Semiconservative replication 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 that 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) All of the above
F) A) and D)

Question 7

Which of the following is not associated with a bacterial ribosome?

Accepted Answer

A)   It is a 70s holoenzyme.
B)   It has a peptide (P)  site.
C)   It has an exit site.
D)   Its small subunit provides the enzymes for making peptide bonds.
E)   It has an amino acid (
A)   site.F) C) and D)
G) B) and C)

Question 8

A sequence of bases within a gene that does not code for protein is called a/n _______.

Accepted Answer

A)   promoter
B)   operator
C)   operon
D)   exon
E)   intronF) B) and D)
G) B) and C)

Question 9

Which of the following additions have been made to principles of the central dogma of biology?

Accepted Answer

A)   DNA information cannot be converted into RNA information.
B)   Protein information can be converted into DNA information.
C)   RNA can be used to regulate gene function.
D)   DNA codes for proteins.E) None of the above
F) B) and C)

Question 10

A frameshift is caused by ______ mutations.

Accepted Answer

A)   missense and insertion
B)   missense and nonsense
C)   nonsense and deletion
D)   deletion and insertion
E)   insertion and nonsenseF) C) and E)
G) B) and E)

Question 11

The following pertain to ribosomes during protein synthesis except

Accepted Answer

A)   they contain codons within their rRNA molecules.
B)   they participate only in translation.
C)   they bind to the 5'end of mRNA by their small subunit.
D)   they use their large subunit to supply enzymes for peptide bonding.
E)   they shift towards the 3'direction along the mRNA strand from one codon to the next.F) None of the above
G) A) and C)

Question 12

The three-base sequence on DNA that codes for an amino acid is called a/an ________.

Accepted Answer

A)   codon
B)   exon
C)   anticodon
D)   intron
E)   tripletF) D) and E)
G) A) and B)

Question 13

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) C) and D)
F) A) and D)

Question 14

Which cell can transfer the most DNA?

Accepted Answer

A)   F+ cell
B)   F-cell
C)   Hfr cell
D)   R cell
E)   B cellF) A) and B)
G) D) and E)

Question 15

The nontranscribed region of DNA to which RNA polymerase binds to initiate transcription is called the ________.

Accepted Answer

A)   promoter
B)   operator
C)   operon
D)   exon
E)   intronF) A) and B)
G) A) and C)

Question 16

Which of the following is not true of transposons?

Accepted Answer

A)   They can change pigmentation.
B)   They can replace damaged DNA.
C)   They can transfer drug resistance.
D)   They can change the genome.
E)   They are always part of plasmids.F) A) and E)
G) C) and E)

Question 17

Groups of three consecutive bases along the DNA of a gene have the code for one _______.

Accepted Answer

A)   protein
B)   nucleotide
C)   amino acid
D)   purineE) A) and B)
F) B) and C)

Question 18

All of the following pertain to nitrogenous bases except

Accepted Answer

A)   they form pairs by hydrogen bonding.
B)   guanine pairs with uracil.
C)   adenine pairs with thymine.
D)   cytosine and thymine are pyrimidines.
E)   they allow variation from one nucleotide to another which creates the encoded information.F) B) and C)
G) None of the above

Question 19

The duplication of a cell's DNA is called _______.

Accepted Answer

A)   mitosis
B)   replication
C)   transcription
D)   translation
E)   mutationF) A) and B)
G) A) and C)

Question 20

If the wild type DNA sequence reads THE CAT ATE THE BIG RAT,what type of mutation would change the sequence to THE CAT ATE THE BAG RAT?

Accepted Answer

A)   Point
B)   Nonsense
C)   Insertion
D)   Deletion
E)   SilentF) All of the above
G) C) and D)

Exam 9: Microbial Genetics

The three-base sequence on DNA that codes for an amino acid is called a/an ________.

Correct AnswerverifiedShow Answer

Which of the following additions have been made to principles of the central dogma of biology?

Correct AnswerverifiedShow Answer

Groups of three consecutive bases along the DNA of a gene have the code for one _______.

Correct AnswerverifiedShow Answer

All of the following pertain to nitrogenous bases except

Correct AnswerverifiedShow Answer

The duplication of a cell's DNA is called _______.

Correct AnswerverifiedShow Answer

Semiconservative replication refers to

Correct AnswerverifiedShow Answer

Which of the following is not associated with a bacterial ribosome?

Correct AnswerverifiedShow Answer

All of the following pertain to transcription except

Correct AnswerverifiedShow Answer

The following pertain to ribosomes during protein synthesis except

Correct AnswerverifiedShow Answer

A sequence of bases within a gene that does not code for protein is called a/n _______.

Correct AnswerverifiedShow Answer

A frameshift is caused by ______ mutations.

Correct AnswerverifiedShow Answer

If the wild type DNA sequence reads THE CAT ATE THE BIG RAT,what type of mutation would change the sequence to THE CAT ATE THE BAG RAT?

Correct AnswerverifiedShow Answer

Which cell can transfer the most DNA?

Correct AnswerverifiedShow Answer

Base pairs in DNA are held together by ______ bonds.

Correct AnswerverifiedShow Answer

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

Correct AnswerverifiedShow Answer

The nontranscribed region of DNA to which RNA polymerase binds to initiate transcription is called the ________.

Correct AnswerverifiedShow Answer

A screening system called the _______ test is used for detecting chemicals with carcinogenic potential.

Correct AnswerverifiedShow Answer

An unidentified cell was found to contain introns and exons.It also expresses DNA polymerase and RNA polymerase.Although it exhibits a promoter region,it has no operons.You conclude that this cell

Correct AnswerverifiedShow Answer

Which of the following is not true of transposons?

Correct AnswerverifiedShow Answer

Synthesis of a repressible enzyme is inhibited by

Correct AnswerverifiedShow Answer

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