Question 1

Which of the following conditions does not lead to a change in gene expression patterns in bacterial cells?

Accepted Answer

All the conditions listed (sporulation, heat shock, nutrient availability, nitrogen deprivation) can lead to changes in gene expression patterns in bacterial cells. Therefore, none of the choices are correct and the answer is E.

Question 2

Which of the following is involved in maintaining lysogeny in $\lambda$ phage?

Accepted Answer

P_RM (Promoter for Repressor Maintenance) is involved in maintaining lysogeny by promoting the expression of the cI repressor, which keeps the prophage integrated into the host genome.

Question 3

Which of the following sigma specificity factors is involved in middle gene transcription during SPO1 phage infection of bacteria?

Accepted Answer

gp28 is the sigma factor involved in middle gene transcription during SPO1 phage infection of bacteria. Sigma factors are proteins that bind to RNA polymerase and direct it to specific classes of promoters, thus controlling the expression of genes. In the case of SPO1, a bacteriophage that infects Bacillus subtilis, gp28 is necessary for the transcription of middle genes during the phage infection cycle.

Question 4

When a $\lambda$ lysogen suffers DNA damage,it induces the ____________ response.

Accepted Answer

The answer of When a $\lambda$ lysogen suffers DNA damage,it...

Question 5

An experiment is planned to look at the transcription start site for the spoIID gene during sporulation.Which of the following techniques would yield the most information in this experiment?

Accepted Answer

S1 mapping is a technique used to map the precise location of transcription start sites. It involves hybridizing labeled DNA probes to RNA transcripts, and then using the S1 nuclease to digest the single-stranded regions of the RNA, leaving only protected fragments that can be visualized on a denaturing gel. This technique is widely used for mapping the start sites of transcription in prokaryotes and eukaryotes, making it the best choice for this experiment. Southern analysis is used to detect specific DNA fragments by hybridizing them to a labeled DNA probe that is complementary to a specific sequence. Northern analysis is used to detect specific RNA molecules by hybridizing them to a labeled DNA probe that is complementary to a specific sequence. Run-on assays involve labeling newly synthesized RNA in a cell, isolating the labeled RNA, and hybridizing it to a DNA probe to determine which genes are actively being transcribed. DNAse footprinting involves using DNAse to cleave the DNA at random points, and then hybridizing the resulting fragments to a labeled DNA probe to determine which regions of the DNA are protected by bound proteins. None of these techniques are designed specifically for mapping transcription start sites.

Question 6

Which of the following explains the events in late stage T4 infection in bacteria?

Accepted Answer

In late stage T4 infection, the host core enzyme participates in transcription conjunction with phage-encoded specificity factors, allowing for increased transcription of viral genes and shut down of host gene transcription.

Question 7

Which of the following statements is true about the cro gene?

Accepted Answer

Cro repression is crucial for lysogeny because it helps to inhibit the synthesis of proteins necessary for the lytic cycle, thus favoring the lysogenic cycle where the viral DNA integrates into the host genome.

Question 8

Which of the following operators is a target of cI gene production?

Accepted Answer

The cI gene product, the lambda repressor, targets operators in the lambda phage genome to regulate its own production and the switch between lysogenic and lytic cycles. The notation given for the options, although not standard, suggests variations of operator sites, which the cI protein could potentially bind to. Since the question does not provide specific details about the functionality of these operators, and given the broad nature of the question, it's reasonable to infer that all the choices could be correct in the context of a hypothetical scenario where each represents a valid operator site for cI binding.

Question 9

Which of the following is a possible mechanism for the action of NusA in termination?

Accepted Answer

NusA facilitates termination at intrinsic terminators by binding to the nascent RNA and promoting the formation of a stable hairpin loop, which signals for the release of the RNA polymerase from the DNA template.

Question 10

Which of the following proteins is not involved the lytic phase of $\lambda$ infection of bacteria?

Accepted Answer

CIII is not involved in the lytic phase of lambda phage infection; it is involved in the lysogenic cycle, helping to regulate the decision between the lytic and lysogenic pathways.

Question 11

Which of the following is true about the early phase of T7 infection of bacteria?

Accepted Answer

During the early phase of T7 infection of bacteria, the phage-encoded polymerase transcribes the class I genes first. These genes are involved in controlling the transcription of the later-expressed genes in the lytic cycle. Class II genes are transcribed later and encode enzymes needed for DNA replication, while class III genes are involved in the production of the structural proteins needed for virion assembly. Class II and III genes are transcribed by the phage-encoded RNA polymerase, while class I genes are transcribed by the host bacterial RNA polymerase.

Question 12

Which of the following is true about the interaction with the $\lambda$ repressor and RNA polymerase at P_RM?

Accepted Answer

Interaction between repressor and polymerase is essential for activation of transcription and interaction involves region 4 of F1F1F1S1F1F1F10-factor are correct.

Question 13

Predict the outcome of the removal of the N gene from the DNA sequence of the $\lambda$ phage:

Accepted Answer

The N gene of phage lambda is responsible for regulating antitermination during transcription, which allows RNA polymerase to continue transcription past terminators. Without the N gene, antitermination will be affected, which will result in termination of transcription at the first terminator encountered, interrupting transcription from the left promoter. Therefore, option E (antitermination will be affected and transcription from the left promoter will be interrupted) is the best choice.

Question 14

During an experiment to study the rate of infection of bacteria with T4,the bacterial cultures were accidentally exposed to a UV light source.Which of the following would be expected for this exposure?

Accepted Answer

UV light exposure can cause DNA damage, leading to the activation of the SOS response in bacteria. The RecA protein plays a crucial role in this process; when activated by DNA damage, it gains coprotease activity, which helps in the initiation of the SOS response. Therefore, both the activation of coprotease activity in RecA and the induction of the SOS response are expected outcomes of UV light exposure.

Question 15

___________ ____________ bind to unfolded proteins and help them to fold properly.

Accepted Answer

The answer of ___________ ____________ bind to unfolded proteins and...

Question 16

P_RE is the promoter used to establish _____________ in $\lambda$ page.

Accepted Answer

The answer of P_RE is the promoter used to establish...

Question 17

Which of the following is an incorrect statement regarding antitermination?

Accepted Answer

The answer of Which of the following is an incorrect...

Question 18

O,P,S,and R genes are part of the lambda phage genome.A new clone of lambda was constructed that lacked the O and P region.Which of the following would be observed if this new clone were used to infect bacteria?

Accepted Answer

The O and P genes of the lambda phage are essential for the initiation of replication of the phage DNA in the lytic cycle. Without these genes, the phage DNA cannot replicate efficiently, leading to impaired replication in the lytic phase.

Question 19

Which of the following is a target of the Cro protein?

Accepted Answer

The answer of Which of the following is a target...

Question 20

_________________ suppression occurs when a mutation in one gene suppresses the mutation in another gene.

Accepted Answer

The answer of _________________ suppression occurs when a mutation in...

Quiz 8: Major Shifts in Bacterial Transcription

Which of the following conditions does not lead to a change in gene expression patterns in bacterial cells?

Which of the following is involved in maintaining lysogeny in $\lambda$ phage?

Which of the following sigma specificity factors is involved in middle gene transcription during SPO1 phage infection of bacteria?

When a $\lambda$ lysogen suffers DNA damage,it induces the ____________ response.

An experiment is planned to look at the transcription start site for the spoIID gene during sporulation.Which of the following techniques would yield the most information in this experiment?

Which of the following explains the events in late stage T4 infection in bacteria?

Which of the following statements is true about the cro gene?

Which of the following operators is a target of cI gene production?

Which of the following is a possible mechanism for the action of NusA in termination?

Which of the following proteins is not involved the lytic phase of $\lambda$ infection of bacteria?

Which of the following is true about the early phase of T7 infection of bacteria?

Which of the following is true about the interaction with the $\lambda$ repressor and RNA polymerase at P_RM?

Predict the outcome of the removal of the N gene from the DNA sequence of the $\lambda$ phage:

During an experiment to study the rate of infection of bacteria with T4,the bacterial cultures were accidentally exposed to a UV light source.Which of the following would be expected for this exposure?

_ __ bind to unfolded proteins and help them to fold properly.

P_RE is the promoter used to establish _____________ in $\lambda$ page.

Which of the following is an incorrect statement regarding antitermination?

O,P,S,and R genes are part of the lambda phage genome.A new clone of lambda was constructed that lacked the O and P region.Which of the following would be observed if this new clone were used to infect bacteria?

Which of the following is a target of the Cro protein?

_________________ suppression occurs when a mutation in one gene suppresses the mutation in another gene.

Quiz 8: Major Shifts in Bacterial Transcription

Which of the following conditions does not lead to a change in gene expression patterns in bacterial cells?

Which of the following is involved in maintaining lysogeny in λ\lambdaλ phage?

Which of the following sigma specificity factors is involved in middle gene transcription during SPO1 phage infection of bacteria?

When a λ\lambdaλ lysogen suffers DNA damage,it induces the ____________ response.

An experiment is planned to look at the transcription start site for the spoIID gene during sporulation.Which of the following techniques would yield the most information in this experiment?

Which of the following explains the events in late stage T4 infection in bacteria?

Which of the following statements is true about the cro gene?

Which of the following operators is a target of cI gene production?

Which of the following is a possible mechanism for the action of NusA in termination?

Which of the following proteins is not involved the lytic phase of λ\lambdaλ infection of bacteria?

Which of the following is true about the early phase of T7 infection of bacteria?

Which of the following is true about the interaction with the λ\lambdaλ repressor and RNA polymerase at PRM?

Predict the outcome of the removal of the N gene from the DNA sequence of the λ\lambdaλ phage:

During an experiment to study the rate of infection of bacteria with T4,the bacterial cultures were accidentally exposed to a UV light source.Which of the following would be expected for this exposure?

___________ ____________ bind to unfolded proteins and help them to fold properly.

PRE is the promoter used to establish _____________ in λ\lambdaλ page.

Which of the following is an incorrect statement regarding antitermination?

O,P,S,and R genes are part of the lambda phage genome.A new clone of lambda was constructed that lacked the O and P region.Which of the following would be observed if this new clone were used to infect bacteria?

Which of the following is a target of the Cro protein?

_________________ suppression occurs when a mutation in one gene suppresses the mutation in another gene.

Which of the following is involved in maintaining lysogeny in $\lambda$ phage?

When a $\lambda$ lysogen suffers DNA damage,it induces the ____________ response.

Which of the following proteins is not involved the lytic phase of $\lambda$ infection of bacteria?

Which of the following is true about the interaction with the $\lambda$ repressor and RNA polymerase at P_RM?

Predict the outcome of the removal of the N gene from the DNA sequence of the $\lambda$ phage:

_ __ bind to unfolded proteins and help them to fold properly.

P_RE is the promoter used to establish _____________ in $\lambda$ page.