genetics chapter 15

regulation of gene expression in bacteria

constitutive

____ enzymes are ones that are always constantly being produced (rRNA)

adaptive

_____ enzymes are ones that are only made when needed

inducible

_____ transcription: production is ‘on’ when a inducer is present

repressive

_____ transcription: production is ‘off’ when a product is present

operon

single transcriptional unit, one promoter, series of multiple genes (multiple shine-delgarno’s)

transcriptional

________ control: can be negative or positive

negative

_____ means there is a repressor used (may be initially on or have to be added)

positive

_____ means there is an activator used (may be initially and removed or have to be added)

inducible, repressor

With a negative ______ operon, the _______ initially blocks the RNA polymerase from binding

repressible, repressor

With a negative _______ operon, the ____ comes in later to block the RNA polymerase from binding

repressible, activator

With a positive _______ operon, the ______ is initially there to keep the process going.

inducible, activator

With a negative _____ operon, the ________ comes in later to start the process.

Jacob, monod

Discovered the operon model, found lactose metabolism and the *lac* operon

negative inducible

The lac operon is _____ _____ (normally off, repressor)

alloactose

For the *lac* operon, what binds with the repressor so that it can complete transcription?

catabolite

______ repression: when bacteria metabolize glucose they repress genes required to metabolize other sugars if glc is present.

cap

catabolite activator protein, enhances RNA pol binding to promoter (with cAMP)

regulate

glucose levels _____ cAMP levels.

no

when glucose is present in the lac operon, does translation or transcription usually happen? (bc cAMP will not bind w cap)

sigma

cap and camp help ___ find the promoter which helps increase translation and transcription

merozygotes

How did Jacob and Monod find out about the operon? (what did they use)

no

Does transcription happen if the sequence or operater is altered?

cannot

When the operator is mutated the activator or repressor _____ bind!

repressor

a super _____ means that even tho lactose binds, the repressor doesn’t come off

repressible

the *trp* operon is _______

UTR

One nesscary component of attunation is the 5’ ___ (upstream from genes)

off

the tryptophan can cut itself ___ by an excess of product

attenuation

only in proks, the premature termination of transcription!

2/3

in attenuation, if the trp is low, the ribosome is slow to get the trp tRNA and so the ___ region interact because transcription occurs so fast while the ribosome is lagging.

3/4

in attenuation, if the trp is high, the ribosome is fast to reach region 2 and so the regions __ interact.

operator

Both attenuation and repression are occurring at the ____ and they have a 600 time reduction together.

riboswitches

alternative secondary structure in the 5’ UTR of mRNA that impact gene expression

noncoding

some prokaryotes have small _____ RNA which interact to either help or prevent translation

processing

____ of a protein can affect it’s ability to function and its transportation to parts of cell.