Lecture 6 Bacterial Genome Replicaiton, Expression, And Reguluation 2 Mecahnisms Of Geneitc Variation Flashcards

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1
Q

Methyl-accepting chemotaxis proteins (MCPs) are chemoreceptors in ______. That binds environmental chemicals and initiates a series of interactions with cytoplasmic proteins that affects _____

A

Membrane, flagella the rotation

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2
Q

Explain how methyl-accepting chemotaxis proteins (MCPs) can affect flagella the rotation

A
  • Activates sensory kinase CheA (wiht help of CheW) which autophosphorylates
  • CheA phosphorylase so the response regulator CheY
  • CheY governs rotation of flagella
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3
Q

When attractant concentration is high MCP is ______. Thus leading to

A

Methylated (CheR) Thus leading to CheA/CheW is active (phosphorylated) thus phony lasting CheY wich leads to a clockwise (CW) rotation and a thumbless

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4
Q

When the attractant concentration decreases MCP is _______ thus

A

Not methylated (CHeB) thus CheA is inactive (not phosorylated) this means CheY is inactive and the flagellar rotation is counter-clockwise (CCW) and a run occurs

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5
Q

What is Quorum sensing

A
  • Cell-to-cell communication mediated by small signaling a molecules such as N-acylhomoserine lactone (AHL)
  • couples cells density and intercellular communication to transcription regulation
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6
Q

Example of Quorum sensing in V. Fischeri

A
  • High concentrations of AHL produced by increased density of cells diffuse back into the cell, bind to the transcriptional regulator LuxR and active transcription
  • LuxR stimulates transcription of the genes for AHL synthase (luxl) and proteins needed for light production
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7
Q

Sporulation is another example of global regulatory system in which ______, _______ , ______ and ______

A
  • Phosphorelay, post translational modification of proteins, transcription initiation regulatory proteins and alternative sigma factors play a role.
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8
Q

Starvation signal induces production of _______ to lead to sporulation

A

Alternative sigma factors

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9
Q

Explain how starvation leads to alternative sigma factors

A

Kin A and Kin B phosphorylate Spo0F, which thus makes Spo0F-Phosphate, this phosphorylated Spo0B to make Spo0B-P this phosphorylated Spo0A to make Spo0A to make Spo0A-P which activate sigma f
- Sigma F leads to early sporulation of gene transcription and activates Active sigma G which leads to late sporulation gene transcription

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10
Q

Most prevalent form of a gene is called the

A

Wild type

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11
Q

What is a forward mutation

A

Wild type to mutant form

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12
Q

What is a reversion mutation

A

Mutant phenotype to wild type phenotype

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13
Q

What is a suppressor mutation

A
  • A type of reversion mutation ( mutant phenotype to wild type phenotype) that occurs when the second mutation is at a different site than the original mutation but the wild type phenotype is still the same
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14
Q

An example of of post translational regulation is control of chemotaxis. Regulatory enzymes control chemotaxis proteins by _____ and ____

A
  • Phosphorelay system

- Covalent modification

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