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51 Cards in this Set
- Front
- Back
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Viruses
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-tiny infectious agents
-need host cell -consist of a protein coat called capsid -contain one to several hundred DNA or RNA -mature virus outside host cell is called virion -not living organisms -cant effect cell if specific receptor is not available |
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Virus is not a living organism because..
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-require host cell's reproductive machinery in order to transfer genetic information
-do not metabolize organic nutrients, use ATP from host cell -possess DNA or RNA not both like all other living organisms -no cell wall or membrane |
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bacteriophage
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-virus that infects bacteria
-nucleic acid is injected through the tail after viral enzymes digest a hole through cell wall (some virus have enzymes in capsid) |
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lytic infection
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virus commandeers cells reproductive machinery to make new viruses
-attaches, makes hole, injects nucleic acids, replicates,breaks cells apart, forms virion |
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latent period
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-time from infection to lysis in a lytic infection
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virulent virus
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-virus following lytic cycle
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lysogenic infection
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-viral DNA is incorporated into the host genome or if virus is an RNA virus it possess reverse transcriptase and DNA is reverse transcribed from RNA and incorporated into host
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temperate virus
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-virus in a lysogenic cycle
-may show no symptoms of infection and virus is dormant or latent, but it may be activated by stress ultraviolet light or carcinogens |
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provirus
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name for temperate virus aka virus on lysogenic tract whose host cell is bacteria
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plus-strand RNA
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-proteins can be directly translated from RNA in a virus
-enveloped Plus strand RNA viruses include retroviruses that carries reverse transcriptase |
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vaccine
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-an injection of antibodies or an injection of a nonpathogenic virus with the same capsid or envelope
-allows host to create antibodies |
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structure of virus
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capsid, nucleic acid, lipid rich protein envelope for some viruses,
tail base plate, and tail fibers for most bacteriophages -bacterium size of mitochondrion and hundreds of viruses fit into one bacterium |
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Prokaryotes
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-no membrane bound nucleus or organelles!
-split into bacteria and archaea (archaea have some in common with eukaryotes) |
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autotrophs
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-capable of using CO2 as sole source of carbon
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heterotrophs
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-use preformed organic molecules as source of carbon
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phototrophs
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-organisms that use light as energy
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chemotrophs
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-use oxidation of organic or inorganic matter
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structure of prokaryotes
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-dont have nucleus!
-have single circular double strand of DNA |
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Cocci
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round shape of bacteria
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bacilli
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rod shaped baceria
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spirilla
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helical shaped bacteria that are rigid
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spirochetes
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helical shaped bacteria that are not rigid
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nucleoid
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structure of circular DNA in prokaryotes
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prokaryotes and protein
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-since protein is translated, they have ribsomes.. (remember viruses dont have ribosomes)
-smaller then eukaryotic ribosomes, made from 50 and 30S sub units to form 70s ribosome |
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membranes
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-made up of phospholipid bilayer
-found surrounding cytosol of nearly all prokaryotes -composed of phosphate group, two fatty acid chains and glycerol 0amphipathic- both polar and nonpolar |
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micelle
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-when polar ends and non polar ends of an amphipathic membrane line up same way to form spherical structure
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integral or intrinsic proteins
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ampiphatic proteins that traverse the membrane from the inside of the cell to the outside
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peripheral or extrinsic proteins
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situated entirely on surface of membrane,and ionically bonded to integral proteins
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fluid mosaic model
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-model of membrane describing how it is entirely held together by intermolecular force and it is fluid, it can move but cannot separate
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facilitated diffusion vs. passive diffusion
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facilitated-method of transporting proteins across membrane
passive: if your nonpolar you can pass through membrane without help |
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bacterial envelope
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-surrounds bacterial plasma membrane
-component adjacent to plasma membrane is cell wall |
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cell wall of bacteria
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-prevents protoplase aka plasmamembrane enclosures from birsting
-made of peptidoglycan -series of dissacharide polymre chains with amino acids connected by amino acids, these connections usually are disrupted causing cell wall failure and lyses of bacteria |
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hypertonic
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-characterizes most bacteria
-means that aqueous solution of their cytosol has more particles than of environment |
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isotonic
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cytosol contains same number of particles as environment
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hypotonic
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cytosol contains less particles than environment
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hydrostatic pressure
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-builds when water fills a cell,
-eventually stops building when it equals osmotic pressure and equilibrium is reached |
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gram-positive bacteria
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thick peptidoglycan cell wall prevents gram stain from leaking out and cells show up PURPLE
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Gram-negative bacteria
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-appear pink when gram stained
-do not hold gram stain -have a phosolipid bilayer outside cell wall (this is not in gram positive bacteria!) |
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bacteria flagella
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long hollow rigid helical cylinders made from globular protein falgellin
-propelled from energy from proton gradeint not ATP |
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reproduction in bacteria
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-cannot sexually reproduce
-alternative forms of genetic recombination include: -conjugation, transformation, and transduction asexual reproduction: binary fission |
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binary fission
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-circular DNA is replicated in process similar to replication in eukaryotes
-two DNA polymerases begin at same point on circle (origin of replication) and move in opposite directions making complementary single strands that cmobine with template strands to form two complete DNA double stranded circles -cell divides giving two genetically identical daughter cells |
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conjugation
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-method of genetic recombination in bacteria
-requires bacteria to have plasmid that codes for sex pilus or bridge to other bacteria (occurs between two bacteria) and DNA is passed from cell with conjugative plasmid to cell without it |
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MCAT plasmids
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-F plasmid or fertility factor
-bacteria with it F+ without it F- -tranfer occurs from F+ to F- -R plasmid donates resistance to certain antibiotics -associate with sex pilus in conjugation for genetic recombination in bacteria |
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transformation
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process by which bacteria may incorporate DNA from the external environment
-may occur to lyses of other bacteria -typically experiment is when heat killed virulent bacteria are mixed with harmless living bacteria and living bacteria become virulent |
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transduction
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DNA transfer through viruses
-virus that mediates transduction is called vector |
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fimbriae
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-allow bacteria to hold solid objects
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lipopolysaccharide layer outside peptidoglycan cell wall of gram negative bacteria purpose:
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to protect bacterium against certain antibiotics
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Fungi
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-have both plant and animal like characteristics
-separated into divisions -most are considered saprophytic -that is they live off of dead organic matter -possess cell walls called septa made of chitin (most resistant to microbile attack) -lack centrioles mitosis occurs in nucleus -in growth state consist of tangled mass called mycelium of multiple branched hyphae -are eukaryotic heterotrophs |
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Fungal Reproduction and life cycle
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-alternate between haploid and diploid stages in cycle but haploid predominates
-haploid is their growth stage, hyphae are haploid -hypae release spores in asexual reproduction |
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yeasts
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-only unicellular fungi
-reproduce asexually by budding where small cell pinches off large cell |
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conditions determining type of reproduction in fungi
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-if conditions are good, fungi reproduce asexually (conditions will be good for offspring too)
-if conditions are tough fungi reproduce sexually because they may not be as bad for sexually reproduced offspring |
