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Mizzou MICROB 2800 - Exam 1 Study Guide

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Microb 2800 1st Edition Exam # 1 Study Guide Lectures: 1 - 5Lecture 1 (January 22)Microbial Structure and FunctionDescribe external and internal structures of a bacterial cell. Then describe a virus and the ways itcan replicate. What's different? What's the same?External Structures- Flagellao Long, flexible, whip-likeo Endoflagella- integrated into membrane (wrapped around)o Can vary in number, arrangement, and locationo Help with movement and rotation- Fimbriaeo Small, bristle like fibers, mostly proteino Solido Stick to each other and other surfaces- Pilio Elongate, rigid, tubular protein structureso Hollowo Used in conjugation- transfer of genetic material between bacterial cells- Bacterial membraneo Lipid bilayer with embedded proteins- Bacterial cell wallo Made of unique lipids, protein, and sugar molecules Peptidoglycan (PPG)- polymer of sugars and amino acids Mesh layer that provides support Made of NAG and NAM Gram Positive-one lipid membrane surrounded by a large, thick wall of PPG Teichoic acids- interwoven in PPG to make cell wall stronger Gram negative- two lipid membranes with a periplasmic space (PPS) in between) No teichoic acids Easily flexible  Gram not applicable Those that use unique molecules or lack a cell wallInternal structures- Cytoplasmo Messy gelatinous structure, 70-80% watero Site for biochemical and synthetic activities- Inclusions and granuleso Storage structures during periods of nutrient absence/depletiono Allows for survival under varying conditionso Want to survive in any situation- Bacterial genomeo DNA aggregate in a clump in the cell (nucleoid)- Plasmidso Nonessential, sharable, extra DNA stored hereo Often carry protective genes such as drug resistance genes or virulence factor genes- Ribosomeso Translates RNA into a proteino 2 units Small subunit=30S Large subunit=50S Whole package=70So Different than Eukaryotic ribosome= antibiotic target- Endosporeso Dormant and inactive structureso “Safe” for a copy of the bacterium’s chromosomeo Bacterium may be killed but endospores will surviveo Has a hard structural coat to resist heat, drying, freezing, chemicals, and radiationo Spores will germinate- Break from dormancy- and convert back into a growing bacteriumViruses- An infectious agent composed of a nucleic acid, a protein shell (capsid) and an optional lipid envelope- Propertieso Acute infectionso Cannot exist independently of host cellso Antibiotics are ineffective o Smaller than any known organismo Have tropism- like to be in one certain cell type Only multiply if they have a specific cell type- Building a viruso Main component= nucleic acido Genome is DNA or RNA Can be single(ss) or double(ds) stranded DNA-- dsDNA or ssDNA RNA--ssRNA or dsRNAo Capsid protein shell (fragile) covers and protects the viral genomic material may allow for attachment to host cell two shapes Icosahedral Top (circular) Helical  Bottom (straw)o Envelope (optional) Outermost coating of protection for a virus, surrounds the capsid Stolen from host Composed of a lipid bilayer from host and integrated viral proteins Acquired during budding release Looks like body cells so gets ignored by the immune system All helical capsids=envelopedViral Replication- Viral synthesis: key virus replication enzymeso RDRP= RNA-dependent RNA polymerase Takes RNA and makes more RNA Essential to all RNA viruses Bad at proofreading mistakes Antigenic drift- mutations in viral RNAo RDDP- RNA-dependent DNA polymerase Reverse transcriptase Used by retrovirus Takes RNA and makes DNA and then RNA and then protein- Viral synthesis: DNA viruseso Viral DNA enters the cello Cell happily duplicates viral DNA→ (part of normal cell replication)o Our cells quickly produce new viral capsid proteins and viral DNA genomes- Viral synthesis: RNA viruseso Viral genome enters ribosomeo vRNA made directly into proteinso RDRP made right away It copies new vRNA genomes- Viral Synthesis: Retroviruseso vRNA genome enters ribosomes without complication o vRNA made directly into RDDP protein reverse transcriptase turns vRNA into DNAo use viral integrase protein to become part of the host genome- Viral synthesis: assembly and releaseo assembly all proteins and genome built back together bring together all the newly formed vDNA/vRNA and capsid proteins to form new virus typically self-assembling units enveloped viruses built near membranes chance for “grab bag” variation (Antigen shift)o Release budding- push through membrane into extracellular space takes pieces of host membrane along, become enveloped lysis- fill cell to bursting, release naked viruses by lysis of cell large burst size cytopathic effects- tissue destabilize and falls apart cell explodes and releases all viruses integration/non-replicationLecture 2 (January 27) Microbial Virulence factors and basics of disease pathogenesisDescribe the normal flora and why it is important. Then, describe the different types of virulence factors and how they affect the host cell. Then describe how viruses cause harm to thehost cell.“Normal” Flora (NF)- essential- The bacteria in and on youo changes according to diet, antibiotics, stresso Transient Flora- breathing in bacteria (internal and external)- essential for nutrition, metabolism, survival- possible source of carcinogens- immune stimulation- common source of infectionso endogenous(already inside you and cause infection)o exogenous(comes inside and causes infection)- Straino based on genotype and mutations“bad” microorganisms- pathogenic/pathogenicity- ability to produce disease/harmo opportunistic pathogen- change (in location) produces chance to infecto dedicated/obligate pathogen- not found in harmonious relationship with host if it gets inside it is going to cause disease- virulence- degree of pathogenicity (chance of it causing disease)Causing disease- virulence factors- Virulence factorso molecules used to help the pathogen cause diseaseo increase severity of diseaseo determine the degree of damage doneo produce recognizable symptoms inflammation, fever, pain Leukocytosis(white blood cell count raised) Leukopenia(white blood cell count downo types: physical cell structures Functional microbial proteins (toxins, enzymes-things that chew up cells)BEAT ICE (acronym for virulence factors)- B-biofilms- E-enzymes-


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