micro ch 14 LS module

two common motifs of the DNA binding domain of regulatory proteins are _____ fingers and _____ - _____ - helix

- zinc fingers - helix - turn - helix

the ara operon is under the regulatory control of the ____protein and the ____activator protein

-AraC -catabolite

which of the following are common motifs of the DNA-binding domains of regulatory proteins?

-Zinc fingers -helix-turn-helix

which conditions must be met for AraC to act as an activaor of the ara operon?

-arabinose must be present -two AraC proteins must bind to aral

which of the following statements about the inhibition of transcription by the lac repressor protein are true?

-binds to O1 and one additional lac operator site -bends to DNA in the promoter region

DNA-bound repressor proteins inhibit the initiation of transcription by ____?

-blocking the binding of RNA polymerase -preventing the movement of RNA polymerase

which of the following are characteristics of the AraC protein?

-can interact with three different regulatory sequences -can act as an activator -can bind arabinose -can act as a repressor

characteristics of the lac repressor protein

-each subunit contains a helix-turn-helix domain -composed of four identical subunits -forms a dimer

which of the following is not a component of bacterial operons? -structural genes -promoter -operator -regulatory genes -enhancer

-enhancer

which choices are steps where gene expression is commonly regulated in bacteria?

-feedback inhibition -transcription elongation -initiation of transcription -initiation of translation

which of the following statements about the interactions between the lac repressor and inducer are true?

-inducer binding causes repressor to lose ability to bind to the operator sites -inducer binding changes the repressor shape

which of the following are encoded by the lac operon?

-lacl -three structural genes

which of the following are possible components of a bacterial operon?

-operator -structural genes -promoter -activator binding genes

DNA bound repressors proteins inhibit the initiation of transcription by ____

-preventing the movement of RNA polymerase -blocking the binding of RNA polymerase

which of the following conditions must exist to fully induce the lac operon?

-shortage of preferred carbon and energy source -lactose present in the medium

which of the following are characteristics of the trp repressor protein

-synthesized in an inactive form -active form binds to operator -tryptophan acts as a corepressor

which conditions must be met for AraC to act as a repressor of the ara operon?

-two AraC proteins on different regulatory sequences must interact -Arabinose must be absent

the term used to describe the metabolic pathway that uses DNA as a template for the manufacture mRNA is called ____, and the pathway that uses mRNA as the template for the manufacture of protein is called _____.

1) transcription 2) translation

A repressor protein that is synthesized in its inactive form is referred to as a(n) ____

Aporepressor

what protein is responsible for binding the ara operon DNA in such a way to prevent RNA poly. from binding to the ara promoter

AraC

A(n) _____protein is a DNA-binding protein that promotes the initiation of transcription

activator

A(n) ____protein is a DNA binding protein that promotes the initiation of transcription

activator

AraC acts a(n)____of transcription initiation when two AraC-arabinose complexes bind to the aral regulatory sequences

activator

when ____proteins bind to their regulatory sites they facilitate the binding of RNA polymerase

activator

positively controlled inducible genes

activator protein is inactive; activated by an inducer

the sugar ____is the inducer of the lac operator

allolactose

the lac repressor protein inhibits transcription by ____?

bending DNA in the promoter region

which of the following is most likely to contain repressible enzymes?

biosynthetic pathways

which statement best describes the ara operon?

both negative and positive transcriptional control

which of the following is most likely to contain inducible enzymes?

catabolic pathways

the lac operon is under the regulatory control of the lac repressor protein, and the ____ ____ protein or CAP

catabolite activator

Aporepressors are activated by the binding of a(n) ___?

corepressor

the zinc finger DNA-binding domain are most commonly observed in the regulatory proteins of the domain ___?

eukaryotes

DNA-bound activator proteins promote the initiation of transcription by ____?

facilitating RNA polymerase binding

which of the following are encoded by the trp operon?

five structural genes

the term "regulation of ___expression" refers to the process of controlling transcription and/or translation

gene

constitutive genes:

genes that are expressed continuously

regulatory:

genes that are only expressed when needed

the catabolite activator protein functions in a regulatory network that allows E.coli to preferentially use _____over all other carbon and energy sources

glucose

enzymes that catalyze reactions that are in constant demand in a cell are encoded by genes referred to as?

housekeeping genes

what is the name given to the collection of genes that encode protein products that must that must be all the time?

housekeeping genes

the level of some enzymes, such as B-galactosidase, increase significantly in the presence of a small effector molecule called a(n):

inducer

small effector molecules whose presence increases the level of specific enzymes are called ____

inducers

enzymes whose level increases in the presence of small effector molecules are encoded by?

inducible genes

which proteins are regulators of the lac operon?

lac repressor catabolite activator protein

the arrangement of functionally related genes in bacteria is

lined up together on the same chromosome

___ ____ control occurs when the initiation of transcription is inhibited by the binding of a protein to DNA

negative transcriptional

which of the following terms indicates that the binding of a protein to DNA inhibits the initiation of transcription?

negative transcriptional control

which statement best describes the lac operon?

negative transcriptional control of inducible genes(i.e turned "off" until turned "on")

the trp operon is best described as a example of the?

negative transcriptional control of repressible genes

which of the following statements about bacterial genes expression is NOT true?

no partial or low levels of gene expression

the activity of regulatory proteins is typically influenced by what type of interaction with small effector molecules?

non-covalent binding

in bacteria, repressor proteins bind to a specific DNA sequence called the ___?

operator

Which statement about th trp operon is true

operon is functional when tryptophan is absent

which statemenet about the trp operon is true?

operon is functional when tryptophan is absent

Many regulatory proteins are DNA-binding proteins that form dimers and bind to short, inverted sequences of bases in DNA that are called

palindromes

short, inverted sequences of bases in DNA are called ____

palindromes

which of the following terms indicates that the binding of a protein DNA promotes the initiation of transcription?

positive transcriptional control

proteins that are responsible for the induction or repression of enzyme encoding genes are referred to as _____ proteins

regulatory

A(n) ____protein is a DNA binding protein that inhibits the initiation of transcription

reppressor

the genes that encode enzymes that have their expression levels decrease in the presence of the pathway end-products are best describes as?

repressible genes

A(n) _____protein is a DNA-binding protein that inhibits the initiation of transcription

repressor

negatively controlled inducible genes

repressor protein is active; inactivated by an inducer

proteins that inhibit the initiation of transcription by binding the DNA are called____

repressor proteins

genes that do not code for regulatory proteins are referred to as ____genes

structural

What term is used to describe non-regulatory genes?

structural genes

one of the ways the trp operon is regulated is that it is _____

synthesized in an inactive form

which of the following statements about functionally related structural genes in bacteria are true?

they are located next to each other on the chromosome they often produce a polycistronic mRNA

repressible genes

those genes that are "turned off" by the product of repressible genes

the trp operon is only active when ____ is not present in the cell

tryptophan