Microbio (Exam 3): Ch 10: Prokaryotic Gene Regulation

Methylation is gene expression control expressed at the _________ level.

DNA.

Control of gene expression at the transcriptional level affects _________ _________ function.

RNA polymerase.

Control of gene regulation at the translational level affects _________ function.

ribosome.

Post-translational gene regulation affects _________.

protein (modifies or degrades).

Constitutive genes are _________ expressed.

always.

Regulatory proteins include _________ and _________.

repressors and activators.

Permease (_________) transports lactose into the cell.

LacY.

Low levels of B-galactosidase (_________) convert lactose into allolactose.

LacZ.

Regulatory gene (_________) codes for respressor.

LacI.

A low level of _________ transcription always occurs.

LacZYA.

Lactose detector

LacY

In the absence of lactose, the lacI repressor is _________.

active.

In the presence of allolactose, the lacI repressor is _________.

inactive.

cAMP-CRP complex binds lac _________, increasing transcription.

promoter.

When glucose and lactose are both present, the lactose operon is _________.

repressed.

Lactose operon is repressed when glucose and lactose are present due to _________ repression.

catabolite.

Glucose and lactose media yields _________ growth.

diauxic.

Glucose turns off lac operon via _________ _________.

inducer exclusion.

Glucose blocks the transport of _________.

lactose.

For maximal expression of lac operon, _________ must be absent.

glucose.

Tryptophan operon has genes of a _________ pathway to synthesize tryptophan.

biosynthetic.

Repressor in trp operon.

TrpR.

Co-repressor in trp operon.

tryptophan.

Low or no tryptophan present results in _________.

derepression (transcription proceeds).

Tryptophan present acts as a _________.

corepressor.

When tryptophan is present, an active _________ forms.

holorepressor.

The _________ blocks transcription of Trp operon.

holorepresor.

The ribosome is a sensor of amino acid levels via transcription translation of a leader sequence prior to trpE, called _________.

trpL.

Attenuation relies on formation of competing stem loop structure in the _________ mRNA.

leader.

The leader mRNA forming stem loops between _________ terminates transcription.

3:4.

When tryptophan levels are high, the _________ loop forms.

attenuator (3:4).

When tryptophan levels are low, the _________ loop forms.

2:3.

When the 2:3 loop forms, the ribosome stalls at _________ codons, and the anti-attenuator loop forms.

trp.

A reduction in energy sources requires a slow down in ribosome formation due to the reduced cellular _________ rate.

growth.

The _________ response results in a decrease in ribosomal RNA transcripts.

stringent.

Starvation induced response:

stringent response.

_________ interacts with RNA polymerase to decrease expression of different genes.

ppGpp.

ppGpp interaction with RNA polymerase reduces expression of _________ RNA genes and _________ RNA genes.

ribosomal; transfer.

Protein-coding DNA rearrangements of bacteria cell surface proteins.

phase variation.

Phase variation results in _________ _________, where pathogens bypass host immune systems.

immune avoidance.

An example of phase variation is the Salmonella _________ protein that can switch between H2 (fljB) and H1 (fljC).

flagellin

A _________ event flips the orientation of DNA segment in phase variation, causing a gene inversion.

recombination.

A _________ _________ results in inactivation of one gene and activation of the other.

gene inversion.

Bacteria can coordinate gene expression of several genes at once by regulating _________ _________.

sigma factors.

Heat shock sigma factor is produced very _________ due to hidden ribosome-binding site, unless the temp is hot.

little.

_________ are untranslated, regulatory RNA between genes.

sRNA (small regulatory RNA).

sRNA are efficient because they do not require:

protein synthesis.

_________ hybridizes with mRNA and prevents ribosome binding or induces RNase III activity.

RNA III.

_________ RNA arise from transcription of sense DNA strands from protein-coding genes.

antisense (asRNA).

asRNA originate in the _________-coding gene and affect only that gene.

protein.

asRNA binds to mRNA compliment to prevent _________ and trigger RNA degradation.

translation.