Ch 8 micro

A gene is best defined as
A) A segment of DNA.
B) A sequence of nucleotides in DNA that codes for a functional product.
C) Three nucleotides that code for an amino acid.
D) A transcribed unit of DNA.
E) A sequence of nucleotides in RNA that codes for a functional product.

Which of the following pairs is mismatched?
A) DNA ligase – joins segments of DNA
B) Transposase – insertion of DNA segments into DNA
C) DNA polymerase – makes a molecule of DNA from a DNA template
D) DNA gyrase – coils and twists DNA
E) RNA polymerase – makes a molecule of RNA from an RNA template

Which of the following statements is false?
A) The leading strand of DNA is made continuously.
B) DNA replication proceeds in one direction around the bacterial chromosome.
C) DNA polymerase joins nucleotides in one direction only.
D) Multiple replication forks are possible on a bacterial chromosome.
E) The lagging strand of DNA is started by an RNA primer.

DNA is constructed of
A) A single strand of nucleotides with internal hydrogen bonding.
B) Nucleotides bonded A–C and G–T.
C) Two strands of nucleotides running antiparallel.
D) Two strands of identical nucleotides with hydrogen bonds between them.
E) None of the above.

Which of the following is NOT a product of transcription?
A) A new strand of DNA 
B) rRNA 
C) tRNA 
D) mRNA 
E) None of the above

Which of the following statements about bacteriocins is false?

A) They cause food-poisoning symptoms.
B) Nisin is a bacteriocin used as a food preservative.
C) The genes coding for them are on plasmids.
D) They can be used to identify certain bacteria.
E) Bacteriocins kill bacteria.

An enzyme produced in response to the presence of a substrate is called
A) An operator.
B) A repressible enzyme.
C) A restriction enzyme.
D) A promoter.
E) An inducible enzyme.

When glucose is high, cAMP is ________ : CAP ________ bind the lac operator, and RNA polymerase ________ bind the lac promoter.
A)    high, doesn’t, does
B)    low, doesn’t, doesn’t
C)    high, does, does
D)    low, doesn’t, doesn’t
E)    low, does, does

Transformation is the transfer of DNA from a donor to a recipient cell
A) By sexual reproduction.
B) By cell-to-cell contact.
C) By a bacteriophage.
D) As naked DNA in solution.
E) By crossing over.

Genetic change in bacteria can be brought about by
A) Mutation.
B) Conjugation.
C) Transduction.
D) Transformation.
E) All of the above.

Which of the following statements is false regarding a bacterium that is R+?
A) It is resistant to certain drugs and heavy metals.
B) R+ can be transferred to a cell of the same species.
C) It is F+.
D) It possesses a plasmid.
E) R+ can be transferred to a different species.

The initial effect of ionizing radiation on a cell is that it causes
A) Base substitutions.
B) Bonding between adjacent thymines.
C) The cells to get hot.
D) DNA to break.
E) The formation of highly reactive ions.

According to the operon model, for the synthesis of an inducible enzyme to occur, the
A) Substrate must bind to the enzyme.
B) Repressor must bind to the operator.
C) Substrate must bind to the repressor.
D) Repressor must not be synthesized.
E) End-product must not be in excess.

Synthesis of a repressible enzyme is stopped by
A) The allosteric transition.
B) The corepressor-repressor binding to the operator.
C) The corepressor binding to the operator.
D) The substrate binding to the repressor.
E) The end-product binding to the promoter.

The damage caused by ultraviolet radiation is
A) Repaired during transcription.
B) Repaired during translation.
C) Never repaired.
D) Cut out and replaced.
E) Repaired by DNA replication.

Conjugation differs from reproduction because conjugation
A) Copies RNA to make DNA.
B) Replicates DNA.
C) Transcribes DNA to RNA.
D) Transfers DNA horizontally, to cells in the same generation.
E) Transfers DNA vertically, to new cells.

The necessary ingredients for DNA synthesis can be mixed together in a test tube. The DNA polymerase is from Thermus aquaticus, and the template is from a human cell. The DNA synthesized would be most similar to
A) T. aquaticus DNA.
B) T. aquaticus RNA.
C) Human DNA.
D) Human RNA.
E) A mixture of human and T. aquaticus DNA.

The mechanism by which the presence of glucose inhibits the arabinose operon is
A) Induction.
B) Repression.
C) Translation.
D) Catabolite repression.
E) DNA polymerase.

 The mechanism by which the presence of arabinose controls the arabinose operon is
A) Translation.
B) Catabolite repression.
C) DNA polymerase.
D) Repression.
E) Induction.

If you knew the sequence of nucleotides within a gene, which one of the following could you determine with the most accuracy?
A) The secondary structure of the protein
B) The quaternary structure of the protein
C) The primary structure of the protein
D) Can't tell
E) The tertiary structure of the protein

An enzyme that makes covalent bonds between nucleotide sequences in DNA is

A) DNA polymerase.
B) DNA ligase.
C) Transposase.
D) Restriction enzyme.
E) RNA polymerase.

An enzyme that copies DNA to make a molecule of RNA is
A) DNA ligase.
B) RNA polymerase.
C) Restriction enzyme.
D) DNA polymerase.
E) Transposase.

An enzyme that cuts double-stranded DNA at specific nucleotide sequences.
A) DNA ligase
B) DNA polymerase
C) Transposase
D) Restriction enzyme
E) RNA polymerase

Repair of damaged DNA might be viewed as a race between an endonuclease and
A) Helicase.
B) Methylase.
C) DNA ligase.
D) DNA polymerase.
E) Primase.

The cancer gene ras produces mRNA containing an extra exon that includes a number of UAA codons. Cancer cells produce ras mRNA missing this exon. This mistake most likely is due to a mistake by
A) snRNPs.
B) DNA polymerase.
C) A chemical mutagen.
D) Photolyases.
E) UV radiation

In transcription,
A) DNA is copied to RNA.
B) DNA is changed to RNA.
C) Proteins are made.
D) RNA is copied to DNA.
E) DNA is replicated.

Assume the two E.coli strains shown below are allowed to conjugate.Hfr:  pro+, arg+, his+, lys+, met+, ampicillin-sensitive
F:  pro-, arg-, his-, lys-, met-, ampicillin-resistantWhat supplements would you add to glucose minimal salts agar to select for a recombinant cell that is lys+, arg+, amp-resistant?
A) Ampicillin, lysine, arginine
B) Proline, histidine, methionine
C) Ampicillin, proline, histidine, methionine
D) Lysine arginine
E) Ampicillin, prolein, histidine, lysine

Protein synthesis in eukaryotes is similar to the process in prokaryotes in that both eukaryotes and prokaryotes
A) Have introns.
B) Have exons.
C) Use methionine as the “start” amino acid.
D) Require snRNPS.
E) Use codons to arrange amino acids.

Transfer of DNA from a donor to a recipient cell by a bacteriophage
A) transduction 
B) conjugation 
C) transcription 
D) transformation 
E) translation

Transfer of DNA from a donor to a recipient as naked DNA in solution. 

A) transcription 
B) conjugation 
C) translation
D) transduction 
E) transformation

Feedback inhibition differs from repression because feedback inhibition
A) is less precise
B) is slower acting
C) stops the action of preexisting enzymes
D) stops the synthesis of new enzymes
E) all of the above

Bacteria can acquire antibiotic resistance by all of the following except
A) conjugation
B) trasnformation
C) mutation
D) snRNPs
E) insertion of transposons

Suppose you inoculate three flasks of minimal salts broth with E coli.  Flask A contains glucose.  Flask B contains glucose and lactose.  Flask C contains lactose.  After a few hours of incubation, you test the flasks for the presence of B-galactosidase.  Which flask(s) do you predict will have this enzyme? 

A)  A and B 
B)   B and C
C) B 
D)  C 
E) A 

Plasmids differ from transposons in that plasmids
A) become inserted into chromosomes
B) are self-replicated outside the chromosome
C) move from chromosome to chromosome
D) carry genes for antibiotic resistance
E) none of the above

Mechanism by which the presence of glucose inhibits the lac-operon
A) repression 
B) induction 
C) DNA polymerase 
D) catabolite repression 
E) translation

Mechanism by which the presence of glucose controls the lac-operon 
A) induction 
B) repression 
C) DNA polymerase 
D) translation
E) catabolite repression 

Two offspring cells are most likely to inherit which one of the following from the parent cell? 
A) a change in a nucleotide in mRNA
B) a change in a protein
C) a change in a nucleotide in DNA
D) a change in a nucleotide in rRNA
E) a change in a nucleotide in tRNA

Which of the following is not a method of horizontal gene transfer?
A) binary fission
B) transformation
C) conjugation
D) integration of a transposon
E) transduction