BIology chapter 14

in the trpl mrna __ stem loops are possible

3

Repressor

operator

catabolite activator protein

CAP

the intracellular concentration of the inducer__ remains high as long as lactose is available in the eniornment

allolactose

the small effector molecule __ prevents the lac repressor from binding to the operator site

allolactose

a regulatory site on a protein that is not the active site is called an __ site

allosteric

unregulated genes have

constant levels of expression

unregulated genes are also called

constitiutive

posttranslational regulation refers to

control of proteins already in the cell

in attenuation transcription

is stopped prematurley

the lacy gene encodes lactose __, a membrane protein

permease

the tpp riboswitch in E coli controls __ whereas the TPP riboswitch in b subtills controls __

translation, transcription

a benefit of gene regulatoion is the encoded proteins will not be produced when they are not needed

true

the transport of glucose into a bacterial cell causes the intercelular level of cyclic- amp to fall because the enzyme __ __ is inhibited

adenylyl cyclase

in post transitional regulation the final product of a metabolic pathway may binf to the __ site of an enzyme and inhibit its catalytic ability

allosteric

in postranslational regulation the final product of a metabolic pathway may bind to the __ site of an enzyme and inhibit its catalytic ability

allosteric

the RNA transcribed from the micF gene is complementary to the ompF mRNA and act as an __ strand

antisense

what do you call an RNA strand that is complementary to an mRNA molecule

antisense RNA

in the thi operon when levels of TPP are low the 5' end of the mRNA forms an __ stem loop structure that allows transcription to continue

antiterminator

the lac repressor protein binds to the operator and

blocks transctiption

when the product of a gene produced in a metabolic pathway inhibits an enzyme that acts early on in the pathway it is called

feedback inhibition

constitutuve genes encode proteins the cell needs

all the time

charles yonofsky discovered

attenuation

transctiption begins the terminates before the entire mRNA is made during

attenuation

what effect would either a loss of function mutation in the lact gene ot a mutation in operator that prevents reprssor binding have

both result in constitutive expression of the lac operon

a dna segment that must be adjacent to the gene it regulates is a __ __ element

cis acting

in the trp operon, the attenuator DNA

does not encode an enzyme

examples of an __ stress that might require a bacterium to produce a specific protein include osmotic shock or heat shock

enviornmental

effector molecules influence gene expression by binding to DNA

false

gene regulation is constant

false

the lacA gene encodes the enzyme

galactoside transacetylase

in catabolite repression, transcription is influenced by the presence of

glucose

when four molecules of allolatose are bound to lac repressor and repressor can no longer bind to operator and rna polumemrase is free to transcribe the operon, the operon has been __

induced

in feedback inhibition the final product in a metabolic pathway

inhibits an enzyme that acts eatly in the pathway

in the 1950s_,_,and _ studied mutations in the lac operon of e coli

jacob pardee monod

when only __ is present allolactose and cAMP levels are high

lactose

a transitional repressir protein binds to

mRNA near the start codon

A protein such as repressor that inhibits transcription is exerting __ control of transcription

negaitve

certain proteins help a bacterium survuve enviornmental stress such as heat shock. these proteins required

only when confronted with the stress

when the lac repressor binds to the lac __ site, RNA polymerase cannot transcribe the lac Z lac Y or lac A genes

operator

types of __ covalent modification includes disuldife bond formation and attchment of prosthetic groups

posttranslational

RNA Polumerase

promoter

anabolic enzymes are usually encoded by __ operons and __ operons usually encode catabolic enzymes

repressible, inducible

a regulatory protein that binds to DNA and inhibits transription is an

repressor

An rna molecule that can exist in two different secondary conformations and therby affect gene regulation is known as

riboswitch

regulatory rna sequences known as __ are widespread in nature and may be found in bacteria, archaea, fungi, and plants

riboswithes

why does transcription of the trp operon continue when tryptophan levels are low

the ribosome pauses in region 1 preventing the 3-4 stem loop from forming