mcb3020 4a 2

The lac operon is composed of ___ (number) structural genes that encode enzymes that act to catabolize lactose.

3

Riboswitches contain effector-binding elements at the ____ of the mRNA. Multiple choice question. 5' end AT-rich middle G-rich middle 3' end GC-rich middle

5' end

The adenyl cyclase enzyme converts _____ to cAMP and PPi. Multiple choice question. ATP ADP GTP AMP

ATP

Which two of the following are characteristics of transcriptional regulatory proteins? Multiple select question. Bind to RNA Bind to palindromic DNA sequences Are transmembrane proteins Bind to DNA

Bind to palindromic DNA sequences Bind to DNA

The catabolite activator protein binds to a specific DNA sequence called the ___ recognition site.

CAP or catabolite activator protein

Catabolite operons cannot be transcribed unless the catabolite activator protein is bound to the ____. Multiple choice question. operator sequence CAP recognition site leader activation sequence Shine-Dalgarno sequence

CAP recognition site

Which two of the following are characteristics of the lac repressor protein? Multiple select question. Composed of four identical subunits Composed of two identical subunits Each monomer has a helix-turn-helix domain Has an arabinose binding site

Composed of four identical subunits Each monomer has a helix-turn-helix domain

Which two of the following are characteristics of the lac repressor protein? Multiple select question. Composed of four identical subunits Has an arabinose binding site Each monomer has a helix-turn-helix domain Composed of two identical subunits

Composed of four identical subunits Each monomer has a helix-turn-helix domain

Which of the following is NOT a characteristic of regulatory proteins? Multiple choice question. Responsible for processes such as induction and repression Individual subunits associate to form dimers Controls which molecules can be transported across a biological membrane Binds to palindromic sequences on DNA

Controls which molecules can be transported across a biological membrane

True or false: The lac operon is an example of a positive control system, implying that it is turned "on" until turned "off" by its regulatory protein. True false question. True False

False

True or false: The trp operon is an example of a positive control system. True false question. True False

False

What is the name given to genes whose protein products must be present all the time? Multiple choice question. Housekeeping genes Structural genes Developmental genes Regulatory genes

Housekeeping genes

The first processes that regulate gene expression to be understood in detail were Multiple select question. Phosphorylation Methylation Induction Degradation Repression

Induction Repression

Which two of the following conditions must exist to fully induce the lac operon? Multiple select question. Shortage of tryptophan Lack of preferred carbon and energy source Lactose present in the medium Glucose present in the medium Excess of preferred carbon and energy source Excess of tryptophan

Lack of preferred carbon and energy source Lactose present in the medium

Under which condition is adenyl cyclase active? Multiple choice question. Lactose is present at levels high enough to support the cell's carbon and energy needs Little or no glucose is available Little or no lactose is present Glucose is present at levels high enough to support the cell's carbon and energy needs

Little or no glucose is available

Which of the following terms indicates that the binding of a repressor protein to DNA inhibits transcription initiation? Multiple choice question. Negative transcriptional control Feedback inhibition Competitive inhibition Positive transcriptional control

Negative transcriptional control

Which statement best describes the lac operon in E. coli? Multiple choice question. Positive transcriptional control of repressible genes (i.e.,"on" until turned "off") Negative transcriptional control of inducible genes (i.e., turned "off" until turned "on") Constitutively expressed genes (i.e., always "on")

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

When transcription initiation is promoted by an activator protein binding to DNA, it is termed ___ transcriptional control.

Positive

Which of the following terms indicates that the binding of an activator protein to DNA promotes transcription initiation? Multiple choice question. Reverse transcription Feedback activation Negative transcriptional control Positive transcriptional control

Positive transcriptional control

Which two of the following conditions are required for full activation of the lac operon? Multiple select question. Presence of lactose Low levels or absence of lactose Low levels or absence of glucose High levels of glucose

Presence of lactose Low levels or absence of glucose

The transcription of all catabolite operons are regulated by which two of the following? Multiple select question. Riboswitches Attenuation sequences in the mRNA leader Regulatory protein specific to the operon Catabolite activator protein Antisense RNA sequences

Regulatory protein specific to the operon Catabolite activator protein

Which two of the following describe the catabolite activator protein? Multiple select question. Activates specific operons when glucose is available Represses specific operons when glucose is not available Represses specific operons when glucose is available Activates specific operons when glucose is not available

Represses specific operons when glucose is available Activates specific operons when glucose is not available

Transcription of the trp operon is controlled by which two of the following mechanisms? Multiple select question. Activator protein enables initiation Repression of termination by the ribosome Repressor protein inhibits initiation Premature termination through attenuation

Repressor protein inhibits initiation Premature termination through attenuation

Which term is used to describe genes that encode the non-regulatory proteins (enzymes) in an operon? Multiple choice question. Developmental genes Structural genes Repressible genes Inducible genes

Structural genes

Which term is used to describe genes that encode the non-regulatory proteins (enzymes) in an operon? Multiple choice question. Repressible genes Developmental genes Structural genes Inducible genes

Structural genes

Which statement best describes ara operon regulation? Multiple choice question. The ara operon is regulated by both negative and positive transcriptional control. The ara operon is regulated by negative transcriptional control only. The ara operon is regulated by positive transcriptional control only.

The ara operon is regulated by both negative and positive transcriptional control.

A DNA-binding protein that promotes transcription initiation is termed a(n) ___ protein

activator

Proteins that promote transcription initiation by binding to DNA are called Blank______. Multiple choice question. activator proteins binding proteins repressor proteins repair proteins

activator proteins

ATP is converted to cAMP by the enzyme

adenyl cyclase

ATP is converted to cAMP by the enzyme ___ ___

adenyl cyclase

The stringent response is induced when bacterial cells are starved for ______. Multiple choice question. carbohydrates nitrogen amino acids glucose

amino acids

A regulatory process that results in transcription termination within a leader sequence that precedes the structural genes is termed __

attenuation

Termination of transcription elongation before RNA polymerase enters the first structural gene of an operon is called ___. Multiple choice question. attenuation repression reverse transcription activation

attenuation

Transcription of the trp operon is regulated at the level of initiation by the trp repressor, and at the level of elongation by a process called

attenuation

Transcription of the trp operon is regulated at the level of initiation by the trp repressor, and at the level of elongation by a process called ___

attenuation

DNA-bound repressor proteins inhibit the initiation of transcription by either ___ or ___. [Choose two.] Multiple select question. degrading RNA polymerase blocking the binding of RNA polymerase preventing the movement of RNA polymerase removing RNA polymerase from promoter

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

This image shows the molecules involved in transcriptional regulation of the lac operon. Considering the lac repressor (inactive) and CAP (inactive) proteins illustrated here, which carbon sources are available? Multiple choice question. both lactose and glucose glucose but not lactose neither glucose nor lactose lactose but no glucose

both lactose and glucose

Which cyclic nucleotide activates CAP? Multiple choice question. cAMP cTMP ppGpp cGMP

cAMP

Which cyclic nucleotide activates CAP? Multiple choice question. cTMP cGMP ppGpp cAMP

cAMP

The binding of __ to the catabolite activator protein causes it to change to the active form.

cAMP, cyclic adenosine monophosphate, cyclic AMP, or cyclic-AMP

The binding of to ___ the catabolite activator protein causes it to change to the active form.

cAMP, cyclic adenosine monophosphate, cyclic AMP, or cyclic-AMP

In E. coli, the proteins necessary to utilize lactose as an energy and carbon source will not be expressed, even when lactose is present, unless the ___ ____ protein is activated by the absence of glucose in the cell.

catabolite activator

The positive regulatory system called ___ ___ prevents the expression of genes encoding proteins necessary for the utilization of sugars other than glucose when adequate supplies of glucose are present.

catabolite repression

The global control of operons encoding enzymes for the catabolism of carbohydrates that must be modified prior to entering glycolysis is referred to as ____. Multiple choice question. competitive inhibition catabolite repression feedback inhibition carbohydrate repression

catabolite repression

In E. coli, rotation of the flagella in a ________ direction result in a cellular motion called a run. Multiple choice question. clockwise counterclockwise

counterclockwise

When E. coli is grown on medium containing glucose and lactose, a two exponential phase pattern called ___ growth is seen as the glucose is preferentially metabolized.

diauxic

A pattern of bacterial growth with two exponential phases caused by the presence of two sugars in the medium is called ___. Multiple choice question. binary fission diauxic growth phase variation diazotrophic growth

diauxic growth

Riboswitches are regulatory mRNAs that can fold into different patterns based upon ____. Multiple choice question. allosteric regulation of RNA polymerase alternative splicing patterns of the mRNA position of the ribosome on the mRNA direct binding of an effector molecule to mRNA

direct binding of an effector molecule to mRNA

This image shows the molecules involved in transcriptional regulation of the lac operon. Which carbon sources are available when considering the lac repressor (attached) and CAP (attached) proteins illustrated here? Multiple choice question. both lactose and glucose neither glucose nor lactose lactose but no glucose glucose but not lactose

either glucose nor lactose

Two-component signal transduction systems link changes in _________ to gene expression. Multiple choice question. amino acid levels energy levels nucleotide levels environmental conditions

environmental conditions

The term "regulation of ____ expression" refers to the process of controlling transcription and/or translation.

gene

Regulatory systems that simultaneously control the expression of multiple operons or pathways are referred to as ________. Multiple choice question. global regulatory systems secretion systems DNA binding proteins response regulators

global regulatory systems

Adenyl cyclase activity is inversely proportional to the level of ___ in the cell.

glucose

lac operon

glucose absent/lactose present: inactive lac repressor and CAP active glucose/lactose absent: CAP binds, repressor binds

Enzymes that catalyze reactions that are in constant demand in a cell are encoded by genes referred to as ___ genes.

housekeeping

Which two of the following are components or regulatory sequences for the lac operon? Multiple select question. lacI Five structural genes trpR Four structural genes Three structural genes

lacI Three structural genes

The lac operon is expressed at high levels when the sugar __ is available and a preferred source of carbon and energy is lacking.

lactose

Full transcriptional activation of the lac operon requires high levels of the sugar ___ and low levels or the absence of the sugar ___

lactose glucose

This image shows the molecules involved in transcriptional regulation of the lac operon. With the lac repressor (inactive) and CAP proteins (bound) illustrated here, which carbon sources are available? Multiple choice question. glucose but not lactose both lactose and glucose lactose but no glucose neither glucose nor lactose

lactose but no glucose

The trpL operon encodes the ___ peptide and attenuator sequences.

leader

When transcription initiation is inhibited by a repressor protein binding to DNA, it is termed ___ transcriptional control.

negative

The trp operon is best described as an example of the ______. Multiple choice question. negative transcriptional control of inducible genes negative transcriptional control of repressible genes positive transcriptional control of inducible genes positive transcriptional control of repressible genes

negative transcriptional control of repressible genes

Bacterial repressor proteins bind to a DNA sequence called the ___

operator

Bacterial repressor proteins bind to a DNA sequence called the ___.

operator

In bacteria, repressor proteins bind to a specific DNA sequence called the ____. Multiple choice question. operator promoter enhancer terminator

operator

In bacteria, repressor proteins bind to a specific DNA sequence called the ____. Multiple choice question. promoter terminator enhancer operator

operator

Many transcriptional regulatory proteins bind to short, inverted sequences in DNA called __.

palindromes

Short, inverted sequences of bases in DNA are called ____. Multiple choice question. palindromes spliceosomes nucleosomes promoters

palindromes

The mechanism to synthesize cAMP when glucose is absent involves the system for _____. Multiple choice question. induction of a response regulator alternate sigma factor synthesis phosphorylating glucose as it enters the cell the initial steps of the glycolytic pathway

phosphorylating glucose as it enters the cell

Which two of the following are examples of second messengers? Multiple select question. ppGpp dGTP ATP cAMP

ppGpp cAMP

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

regulatory

Proteins involved in the control of gene expression in processes such as induction and repression are referred to as ____. Multiple choice question. developmental proteins transport proteins structural proteins regulatory proteins

regulatory proteins

A DNA-binding protein that inhibits transcription initiation by binding to an operator is termed a(n) __.

repressor

When ___ proteins bind to the operator they either block the binding of RNA polymerase or inhibit its movement.

repressor

Proteins that inhibit transcription initiation by binding to operator DNA are called ___. Multiple choice question. repressor proteins binding proteins activator proteins termination proteins

repressor proteins

In translational riboswitches, the binding of an effector molecule alters the shape of the mRNA leader sequence and inhibits ___ binding at the Shine-Dalgarno sequence.

ribosome

Genetic regulatory features termed ___can fold into different patterns based upon the binding of an effector molecule to the mRNA.

riboswitches

Flagellar movement in E. coli involves a combination of smooth swimming motions called __, and nonspecific rotations called ___.

runs tumbles

RNA molecules that do not function as mRNA, tRNA, or rRNA are referred to as ___ or noncoding RNAs.

sRNA

__ __ are small molecules produced inside of cells in response to an external signaling event.

second messengers

cAMP, ppGpp, and cyclic dimeric GMP are all examples of ___. Multiple choice question. second messengers riboswitches sRNAs deoxyribonucleotides

second messengers

Producing alternate versions of ________ factors can immediately change the expression of many bacterial genes. Multiple choice question. AHL phosphodiesterase virulence sigma

sigma

The bacterial RNA polymerase core enzyme needs the assistance of a(n) ___ factor to bind to the promoter and initiate transcription. By producing alternate versions of this factor, the expression of gene sets can be rapidly switched.

sigma

Changes in environmental conditions are linked to changes in gene expression by regulatory proteins of two-component ____ ___ systems.

signal transduction

Global regulatory systems are not likely to involve the regulation of _____. Multiple choice question. multiple genes single operons multiple pathways multiple operons

single operons

RNA molecules that do not function as mRNA, tRNA, or rRNA are referred to as or ___ noncoding RNAs.

small

sRNAs are _____. Multiple choice question. standard RNAs S box RNAs synthetic RNAs small RNAs

small RNAs

second messengers are _____ in response to an external signal. Multiple choice question. small molecules produced changes in gene expression proteins that are activated

small molecules produced

The __ response is observed in many bacteria like E. coli when they are starved for amino acids.

stringent

Genes that encode the non-regulatory proteins in an operon are referred to as ___ genes.

structural

The lac repressor is composed of four identical subunits, called a(n) _____. Multiple choice question. quatramer isomer tetramer

tetramer

The term "regulation of gene expression" refers to the processes that controls ____. Multiple choice question. translation and replication replication and transcription transcription and translation

transcription and translation

As a general rule, Gram-negative bacteria use riboswitches to regulate the ___ of mRNA, and Gram-positive bacteria use riboswitches to regulate ___ termination.

translation, transcription

In translational riboswitches, the binding of an effector molecule alters the shape of the mRNA leader sequence and inhibits binding at the Shine-Dalgarno sequence.

trpL

True or false: All catabolite operons are regulated by CAP and a regulatory protein that is specific to each operon. True false question. True False

true

True or false: The ara operon is an example of both a positive and negative control system. True false question. True False

true

True or false: The intracellular level of cAMP depends on the state of a protein that functions in the phosphoenolpyruvate:sugar phosphotransferase system (PTS). True false question. True False

true