Microbiology test 3 week 2
Microbiology test 3 week 2 Biol 2041
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This 5 page Class Notes was uploaded by UNT_Scientist on Sunday April 3, 2016. The Class Notes belongs to Biol 2041 at University of North Texas taught by Daniel Kunz in Winter 2016. Since its upload, it has received 26 views. For similar materials see Microbiology in Biology at University of North Texas.
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Date Created: 04/03/16
o Mutation Occurrences 8 spontaneously 1X10 Chemical mutagens point Uses a single base Segments of DNA 1< Physical changes Xrays,radiation Point mutation Segments Aflatoxin Benzpyrene Normal only transcribed DNA strand, it is fully active (Missense)Transition Point mutation Substitute purine for purine, or pyrimidine for prymaidine Altered polypeptide chain, one wrong, may still be active, likely to have partial activity or no activity (leaky) Example Sickle cell anemia (Nonsense) Transversion Point mutation Substitute purine for a pyrimidine Mutation to stop codon no further polypeptide synthesized. Results in an inactive truncated polypeptide chain (frameshift) insertion Point mutation Addition of a new amino acid causing the reading frame to be moved down (Frameshift) deletion Point mutation Taking out of an amino acid causing the reading frame to shift upward result in the wrong polypeptide and no activity (Frameshift) Insertion deletion Results from adding an amino acid and taking out of another, there is a temporary reading frame shift partly wrong China may still be active Replica plating Aka mutant detection Selection Will this organism grow in minimal media Negative selection Wild type normal Phototroph Auxotroph is his Gene expression and regulation o Genetic capacity Average Molecular weight of polypeptide = 30,000 Dal Average molecular weight of amino acid = 100 Dal 30,000/100= 300 amino acid average per polypeptide 300 amino acids per polypeptide X 3 base pair per codon = 900 base pairs per gene When going from a # of base pairs to a # of genes # base pairs/ 900 =# of genes in an organism When going from a # of genes to a # of base pairs # of genes in an organism X 900= # of base pairs in an organism o Gene organization Operons Read the book Intervening sequences Global control Multiple operons Figure 8.14 The dual action of repressor and the catabolite activation protein in LAC expression When glucose is high the cyclicAMP level will be low When the glucose is low the cyclic AMP is high Glucose level lactose level operon event + + off CAP not bound + off no CAP bond no lac off no lac + on lac are not bond CAP bond microRNA’s miRNAs can control gene expression post transcriptionaly Fig 8.16 Viruses chapter 13 o History Latin name Virus poison Originally definite do and an infectious agent that passes through the filter First virus discovered tobacco mosaic TMV by ivanowski in Russia (1892) and beijerinck in holland (1899) First one to infect plants Second virus discovered foot in mouth disease hoeffler and Frosch 1898 First one to infect animals Third virus discovered yellow fever discovered by Walter Reed (1900) Infects humans o General properties Filterable <.2um Obligate intracellular parasites Metabolism is absent Composed of DNA or RNA plus a protein coat (usually) Propagation totally dependent on host cell machinery o How classified Type of nucleic acid Structureenveloped vs nonenveloped Enveloped Noneveloped Geometry helical vs polyhedral Helical Polyhedral Size Human red blood cell 10000 no Ebola 97 nm Host/tissue symptoms log Immunological “serotyping” o Groups of infecting vertebrates Non Enveloped,polyhedral do DNA Adenovirus Upper respiratory infections Papovavirus Shope’s papilloma “human warts” Enveloped, polyhedral as DNA Herpesviruses Herpes simplex Cold sores and fever blisters type 1 Genital herpes type 2 Herpes zoster (shingles in middle age) Infectious mononucleosis Enveloped, complex, do DNA Poxviruses Variola (smallpox) very large size Naked,polyhedral, Ss RNA Picornaviruses Smallest RNA viruses known Poliovirus Rhinovirus (common cold) Hepatitis o Vocabulary Conventional virion Nucleic acid + protein Unconventional prion Protein (infected) Sheep scrapie Viroid Nuclei can acid Potato spindle tuber virus 300400 base pairs o How to tell if there is a virus present or that it is infected Bacteria Mix the virus with the bacteria The cells are lysed and create and area of clearing known as plaques We then count the number of plaques (each plaque representing one virus) This is know as the viral titer to determine the viral count Animals Propagate in living animals or in embryo acted eggs o Growth period Onestep growth curve 1030 min for bacteriophage 68 hrs for picot a virus (common cold) 40 hrs for herpes