Exam

• Gene Regulation


  A process where genes are turned on and off in different patterns during development to make a specific body cell look and act different from a different body cell
• Repressor


  Proteins that suppress transcription of a gene in response to an external stimulus
• Activator


  Proteins that increase transcription of a gene in response to an external stimulus
• Inducer


  Proteins that increase transcription of a gene depending on the needs of the cell and the availability of substrate
• Operon


  Units where proteins that share a metabolic pathway or are required for a certain function are encoded together
• If tryptophan is present in the environment, then E. coli does not need to synthesize it and the switch controlling the activation of the genes in the trp operon is switched on
• When tryptophan availability is low, the switch controlling the operon is turned off, transcription is initiated, the genes are expressed, and tryptophan is synthesized
• Catabolite Activator Protein (CAP)


  A protein that complexes with cAMP to bind to the promoter sequences of operons that control sugar processing when glucose is not available
• When glucose levels drop, cAMP begins to accumulate in the cell
• CAP Binding Sites (CBS) is located upstream of the RNA polymerase binding site in the promoter
• When cAMP is absent, transcription occurs at a low rate
• CAP is a signaling molecule involved in glucose metabolism
• The binding of cAMP to CAP occurs when glucose levels are low
• Lac Operon


  Will be turned on in high transcription when lactose is present and glucose is absent or limited
• The lac repressor indirectly senses or detects allolactose
• There are 3 structural genes present in a lac operon
• The lac operon utilizes lactose as an alternative fuel source for prokaryotes
• Gene regulation in prokaryotes occurs during transcription, not translation
• Regulators in the lac operon

  • Lac repressor
  • Operator
• The process of "turning off" a gene in order to produce mRNA and proteins is called gene expression
• The addition of methyl groups to cytosine causes genes to be turned off and transcription to be suppressed
• Metamorphosis


  The process of transformation from an immature form to an adult form that involves two or more distinct stages
• Control of gene expression in eukaryotes is more complex than in prokaryotes
• Nucleosomes


  Control the access of proteins to the DNA regions
• Acetylation of histones


  Causes conformational changes to histones, turning on genes
• miRNAs


  Binding of miRNAs will decrease the stability of the RNA molecule
• Enhancers


  Binding of transcription factors to enhancers will increase transcription of a distant gene
• Post-transcriptional control mechanisms


  • Control of RNA splicing
  • Control of RNA stability
  • Control of RNA interference
• Mediator proteins


  Bring an enhancer into contact with transcription factors and other proteins to increase transcription
• Alternative splicing


  Allows different products to be produced from one gene
• Cleavage and polyadenylation specificity factor

  Responsible for the recognition of AAUAAA sequence as a signal for addition of adenines in 3' polyadenylation
• miRNAs were discovered in 1993 by Lee and colleagues in Caenorhabditis elegans
• Translational control


  Governs whether mRNA molecules in the cytoplasm are translated into proteins
• Post-translational control


  Controls protein activity after the protein is synthesized
• Proteolytic cleavage


  The process of breaking down proteins into smaller pieces which allows the polypeptide chain to fold and conform in the right ways that are required for activation
• COL E1 type plasmid replication is not unique to the bacteriophage family m13
• The Rolling Circle is a two-way process of plasmid replication
• 1. negative plasmid


  A plasmid that is devoid of a copy of the F- plasmid
• The fertility F factor or the F-factor codes for the production of the sex pili during conjugation-based recombination
• Kissing Complex


  The binding of the RNA I and the ROM protein to the RNA II