Question 1

Helicase ______.

Accepted Answer

A)   unwinds DNA
B)   supercoils DNA
C)   unwinds RNA
D)   winds RNAE) A) and B)
F) A) and C)

Question 2

RNA molecules differ from DNA molecules because only RNA _______.

Accepted Answer

A)   has ribose
B)   has uracil
C)   is typically one strand of nucleotides
D)   does not have thymine
E)   All of the choices are correct.F) C) and D)
G) A) and B)

Question 3

In bacteria, initiator tRNA carries formyl methionine.

Accepted Answer

A) True 
 B)False

Question 4

Lactose is a corepressor in the lac operon.

Accepted Answer

A) True 
 B)False

Question 5

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 cellsE) A) and B)
F) A) and C)

Question 6

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 proteinF) A) and B)
G) All of the above

Question 7

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 nextF) C) and D)
G) D) and E)

Question 8

DNA gyrase _______.

Accepted Answer

A)   copies DNA bases
B)   synthesizes RNA primers
C)   closes gaps between DNA bases
D)   removes supercoiling ahead of originE) B) and D)
F) C) and D)

Question 9

You have taken E. coli strain A which has its own plasmids, and mixed it with E. coli B strain without plasmids. E. coli B cells now have plasmids but, in addition, they also carry some genes from E. coli A strain. What has happened is _______.

Accepted Answer

A)   the E. coli B cells have become mutants of the original culture
B)   vertical transmission of DNA has occurred
C)   an example of transformation F
D)   the cells of E. coli A were Hfr cellsE) B) and D)
F) A) and B)

Question 10

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 operatorE) A) and B)
F) A) and C)

Question 11

Gene regulation can involve a protein repressor that blocks ______ from initiating transcription.

Accepted Answer

A)   DNA polymerase I
B)   DNA polymerase III
C)   RNA polymerase
D)   mRNA
E)   rRNAF) A) and D)
G) C) and D)

Question 12

DNA polymerase can only add new nucleotides to the 3' DNA end of the template.

Accepted Answer

A) True 
 B)False

Question 13

DNA replication proceeds in one direction around the bacterial chromosome.

Accepted Answer

A) True 
 B)False

Question 14

A ______ is a speci?c segment of DNA that codes for the production of one functional product.

Accepted Answer

A)   intron
B)   exon
C)   gene
D)   operator
E)   tripletF) B) and C)
G) A) and E)

Question 15

In Gri?th's experiments with Streptococcus pneumoniae, rough nonencapsulated streptococci were converted into smooth encapsulated streptococci in the presence of the heat-killed smooth encapsulated streptococci. Which microbial process had Gri?th identi?ed?

Accepted Answer

A)   Transduction
B)   Conjugation
C)   Transformation
D)   CloningE) A) and D)
F) All of the above

Question 16

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

Accepted Answer

A)   the antibiotic binds to the mRNA once synthesized, preventing it from participating in the initiation complex with the ribosome
B)   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
C)   it binds preferentially to bacterial RNA polymerase rather than the eukaryotic protein, effectively halting transcription in the pathogen but not the host
D)   the drug binds to the initiator tRNA, preventing the formation of the protein synthesis initiation complex in the bacterial cellE) A) and D)
F) B) and C)

Question 17

Structural genes code for _______.

Accepted Answer

A)   ribosomal RNA molecules
B)   transfer RNA molecules
C)   cellular proteins
D)   gene expression elementsE) A) and B)
F) C) and D)

Question 18

Proteomics is the study of all proteins that are expressed by an organism, whereas genomics refersto the study of the organism's entire genome, not simply the protein-coding regions.

Accepted Answer

A) True 
 B)False

Question 19

A mutation that changes a normal codon to a stop codon is called a ______ mutation.

Accepted Answer

A)   point
B)   silent
C)   back
D)   missense
E)   nonsenseF) C) and D)
G) A) and E)

Question 20

The DNA of an organism is made up of subunits called _______.

Accepted Answer

A)   histones
B)   amino acids
C)   nucleotides
D)   mRNA
E)   polymerasesF) None of the above
G) A) and C)

Exam 9: Microbial Genetics

RNA molecules differ from DNA molecules because only RNA _______.

Correct AnswerverifiedShow Answer

Lactose is a corepressor in the lac operon.

Correct AnswerverifiedShow Answer

You have taken E. coli strain A which has its own plasmids, and mixed it with E. coli B strain without plasmids. E. coli B cells now have plasmids but, in addition, they also carry some genes from E. coli A strain. What has happened is _______.

Correct AnswerverifiedShow Answer

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

Correct AnswerverifiedShow Answer

Bacterial conjugation involves _______.

Correct AnswerverifiedShow Answer

Proteomics is the study of all proteins that are expressed by an organism, whereas genomics refersto the study of the organism's entire genome, not simply the protein-coding regions.

Correct AnswerverifiedShow Answer

DNA gyrase _______.

Correct AnswerverifiedShow Answer

Gene regulation can involve a protein repressor that blocks ______ from initiating transcription.

Correct AnswerverifiedShow Answer

The following pertain to ribosomes during protein synthesis except _______.

Correct AnswerverifiedShow Answer

Structural genes code for _______.

Correct AnswerverifiedShow Answer

All of the following pertain to transcription except _______.

Correct AnswerverifiedShow Answer

In bacteria, initiator tRNA carries formyl methionine.

Correct AnswerverifiedShow Answer

Synthesis of a repressible enzyme is inhibited by _______.

Correct AnswerverifiedShow Answer

The DNA of an organism is made up of subunits called _______.

Correct AnswerverifiedShow Answer

In Gri?th's experiments with Streptococcus pneumoniae, rough nonencapsulated streptococci were converted into smooth encapsulated streptococci in the presence of the heat-killed smooth encapsulated streptococci. Which microbial process had Gri?th identi?ed?

Correct AnswerverifiedShow Answer

DNA polymerase can only add new nucleotides to the 3' DNA end of the template.

Correct AnswerverifiedShow Answer

Helicase ______.

Correct AnswerverifiedShow Answer

A mutation that changes a normal codon to a stop codon is called a ______ mutation.

Correct AnswerverifiedShow Answer

A ______ is a speci?c segment of DNA that codes for the production of one functional product.

Correct AnswerverifiedShow Answer

DNA replication proceeds in one direction around the bacterial chromosome.

Correct AnswerverifiedShow Answer

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