Unit 3: Chapter 14

Question 1

Global Regulatory Systems

Answer 1

Regulatory systems that affect many genes, operons, and pathways simultaneously
Important for bacteria to respond rapidly to wide variety of changing conditions

Question 2

Regulon

Answer 2

Genes or operons controlled by common global regulatory protein

Question 3

Mechanisms for global regulation

Answer 3

• two componet signal transduction systems
• phosphorelay systems
• sigma factors
• second messengers

Question 4

Two component Signal Transduction

Answer 4

Link events outside the cell to gene expression inside the cell

Question 5

Sensor kinase

Answer 5

• Spans plasma membrane so a part is exposed to extracellular environment, while other part is in cytoplasm
• phosphorylates itself and transfers phosphate group to response regulator (response regulator undergoes conformational change)

Question 6

Sensor kinase phosphorylates itself and transfers phosphate group to _________

Answer 6

Response regulator

Question 7

Phosphorelay Systems

Answer 7

When phosphoryl groups are transferred to many proteins through a complex system

Question 8

Why are phosphorelay systems important?

Answer 8

Important in quorum sensing and endospore formation

Question 9

Alternate sigma factors

Answer 9

immediately change expression of many genes as they direct RNA polymerase to specific subsets of bacterial promoters

Question 10

Second messengers

Answer 10

Produced in response to a signal (first messenger) that is outside the cell

Question 11

Examples of Second messengers include:

Answer 11

• Cyclic adenosine monophosphate (cAMP)
• Guanosine tetraphosphate (ppGpp)
• Guanidine pentaphosphate (pppGpp)
• Cyclic dinucleotides (c-Di-GMP/ c-di-AMP/ cGMP)

Question 12

Carbolite Repression

Answer 12

Regulation of transcription by both repressors and activators
Plays role in Diauxic growth

Question 13

Diauxic Growth

Answer 13

Biphasic growth pattern and lag occurs

Question 14

Carbolite activator protein (CAP)

Answer 14

Aka cyclic AMP receptor protein (CRP)
Brings about coordinate regulation of catabolite operons

Question 15

Carbolite Activator protein (CAP) exists in two states:

Answer 15

Active form when 3’, 5’- cyclic adenosine monophosphate (cAMP) is bound
Inactive form when free of cAMP

Question 16

CAP Regulation of lac operon

Answer 16

• catabolite operons CAP binding site
• CAP must be bound to site before RNA polymerase can bind to promoter and begin transcription
• CAP interacts with RNA polymerase to stabilize interaction with promoter to stimulate transcription

Question 17

Stringent response

Answer 17

Global mechanism to slow growth in response to nutritional stress
Ex. Amino acid starvation

Question 18

Amino acid starvation

Answer 18

• cell decreases production of tRNA and rRNA while increasing transcription of amino acid biosynthesis of genes
• Protein ReIA produces pppGpp when an uncharged tRNA enters ribosome

Question 19

Alarmones

Answer 19

molecules that respond to nutritional stress

Question 20

Signaling by Cyclic Dinucleotides

Answer 20

• Proteins with diguanylate cyclase activity syntesize c-di-GMP
• Phosphodiesterase (PDE) degrade c-di-GMP
  -C-di-GMP binds effector molecules in cytoplasm

Question 21

Chemotaxis in E. Coli

Answer 21

Methyl accepting chemotaxis proteins (MCPs) are chemoreceptors in membrane

Bind environmental chemicals
Initiates series of reactions why cytoplasmic proteins that affect flagellar rotation

Activates sensor kinase CheA which autophosphorylates
Phosphoryl group transferred to CheY
CheY governs rotation of flagella

Question 22

Quorum Sensing

Answer 22

Cell to cell communication mediated by small signaling
Coordinates gene expression
Plays an essential role in regulation of genes whose products are needed for virulence, symbiosis, biofilm production, and morphological differentiation in a wide range of bacteria