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