exam 2 microbio
What statement is true? a. YACs are more likely than BACs to undergo recombination and rearrangement b. BACs are more likely than YACs to undergo recombination and rearrangement c. YACs and BACs undergo recombination and rearrangement at about the same rate d. it is impossible to state with any certainty whether YACs or BACs are more likely to undergo recombination and rearrangement, because environmental factors play a major role in the probability of one or the other occurring.
A
The lac operon is an example of ________ control in which the presence of an ________ is required for transcription to occur. a. negative/activator b. negative/inducer c. positive/activator d. positive/inducer
B
what makes eukaryotic transcripts easier to isolate than bacterial transcripts? a. eukaryotic transcripts are not methylated but their genes are often methylated. b. larger transcript size in eukaryotes enables easy size-selection methods c. mRNA is polyadenylated in eukaryotes d. transcripts are the most abundant RNAs in eukaryotes
C
which of the following sequences is a palindrome, characteristic of many recognition sequences for restriction endonuclease? a. TTGCCGA AACGGCT b. GGGGGGG CCCCCCCC c. GTAATG CATTAC d. GAATTC CTTAAG
D
If a foreign gene is cloned into an expression host, it is important that the host itself a. genetic is stable b. produce the protein in larger amounts than the vector c. repress the genetic expression being studied d. produce signal proteins to tag the host protein
a
viral replication is a. independent of the host cell's DNA but dependent on the host cell's enzymes and metabolism b. independent of both the host cell's DNA and the host cell's enzymes and metabolism c. dependent on the host cell's DNA and RNA d. dependent on the host cell's DNA, RNA, enzymes, and metabolism
a
which of the following statement is true? a. the toxin component of TA modules helps ensure survival during stressful growth conditions b. persistence is a heritable trait c. when Mycobacterium tuberculosis is in the dormant state it is still susceptible to antibiotics, but the rate of death is slower d. antibiotic-sensitive bacteria never produce cells that are tran resistant to multiple antibiotics
a
In contrast to positive ssRNA viruses such as coronaviruses and polioviruses, the genome of retroviruses a. lacks genes encoding for tRNA primers b. must first integrate into the host's genome before transcription c. is negative ssRNA d. lacks ribonuclease activity
b
When arginine is added to a culture growing exponentially in a medium without arginine, what occurs? a. all cellular growth ceases b. growth continues, but the production of enzymes required for the synthesis of arginine ceases c. growth continues, but the production of enzymes required for the synthesis of arginine increases. d. the cell returns to the lag stage of growth to synthesize the proteins necessary for the metabolism of arginine.
b
the CRISPER system a. facilitates homologous recombination through a complex system of proteins and clustered repeats b. recognizes foreign DNA sequences that have previously entered the cell and directs the Cas proteins to destroy them c. repairs DNA and increases DNA damage tolerance during times of stress d. synthesizes gene transfer agents during stationary phase
b
which statement is TRUE? a. all viruses contain their own nucleic acid polymerases b. RNA viruses contain their own nucleic acid polymerases c. viruses do not contain their own nucleic acid polymerases d. the origin of the nucleic acid polymerases used by viruses are eukaryotic
b
you are attempting to mutate lambda to affect whether lysis and lysogen occurs after infection. Which mutation would strongly INCREASE the chances of LYSOGENY over lysis? a. deletion or inactivation of the cl gene b. deletion or inactivation of the cro gene c. over expression of the cro gene d. deletion of both the cro and cl genes
b
which of the following statement related to riboswitches is FALSE? a. most riboswitches control translation b. the activity of a riboswitch controlled metabolite c. sigma factor binding alters its structure d. none of the above
c
Chemotaxis in bacteria occurs through the use of a. adaptation b. quorum sensing c. autoinduction d. a modified two-component system
d
attenuation is a type of regulation that can control a. allosteric enzyme activity b. transcriptional activity exclusively c. translational activity exclusively d. both transcriptional and translational activity
d
the evolutionary origin of mitochondria is demonstrated by which of the following key genomic characteristics? a. variable numbers of protein-encoding genes b. large stretches of AT-rich DNA c. linear and circular genome structure in different organisms d. rRNA genes most closely related to bacteria
d
what of the following statement is FALSE? a. to investigate expression of a target protein, the promoter of the target gene is ligated to the coding sequence of the reporter gene b. a new gene is most likely to arise as a results of a(n) duplication event c. transduction require homologous recombination for incorporation of hertiable new genes into the genome, meaning successful horizontal gene transfer. d. none of the above
d
which of the following is NOT an obstacle for expressing cloned eukaryotic genes in Bacteria? a. introns must be removed b. sequences may need editing due to codon usage c. the host may not be able to perform post-translational modifications d. a strong promoter
d
