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528 Cards in this Set
- Front
- Back
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what does growth refer to in bacteria
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an increase in the number of cells present
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What are the 5 temperature requirements? explain
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psychrophiles-can grow at 0, optimum <15.
psychrotrophs-can grow at 0, optimum 20-30; import. in food spoilage mesophiles-optimum 25-40, range 10-50, most common, pathogenic usually thermophiles-opt. 50-60, range 40-70; in hot springs usually extreme thermophiles-optimum of 80; archae |
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what pH do most bacteria thrive around
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neutrality
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what can exist in extremely hypertonic environments like the dead sea?
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halophiles
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What are chemical requirements for bacterial growth
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Sulfur
Phosphorus Oxygen Nitrogen Carbon Hydrogen |
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what is carbon needed for & where do organisms get it from
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needed for energy and molecule building; heterotrophs:organic sources like carbs, proteins, and lipids. autotrophs:CO2
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what is nitrogen needed for and where do organisms get it from
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needed for proteins, DNA, RNA, ATP
heterotrophs:proteins,DNA,RNA autotrophs:ammonia/nitrite/nitrate nitrogen fixers:atmospheric nitrogen (N2) |
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what is phosphorus needed for and where do organisms get it from
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needed for DNA,RNA,ATP,phospholipids
heterotrophs:DNA,RNA,ATP,phospholipids autotrophs: inorganic phosphate |
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what is sulfur needed for and where do organisms get it from
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needed for certain amino acids (cysteine, methionine)
heterotrophs:proteins autotrophs: hydrogen sulfide, sulfate |
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what are the trace chemicals requires for bacterial growth? explain
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minerals (inorganic, elements from periodic table) & vitamins (organic)
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what are the different organisms according to oxygen
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-obligate aerobes=need O2 to live
-facultative anaerobes=will use O2 if present, but can exist without it -obligate anaerobes:cant tolerate O2 -aerotolerant anaerobes:don't use O2 but it wont kill them -microaerophiles: need only low O2 concentrations |
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what are the products of O2 respiration
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O2- and H2O2
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what are the 3 enzymes for eliminating O2 byproducts
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-superoxide dismutase:O2- to H2O2
-catalase: H2O2 to H20 and O2 -peroxidase: H2O2 to H20 |
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what is most culture media
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complex (Luria-broth)
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what is the streak plate method
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grow bacteria in liquid medium, plate onto agar plate using serial dilutions, obtain colony, pick colony, put back in liquid medium, keep plate in fridge
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how does bacteria divide
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binary fission->form two daughter cells
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what is the generation time
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the time it takes for one cell to become two
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what are the phases of growth
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lag phase, log phase, stationary phase, death phase
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what is the plate count method for determining the number of bacterial cells present
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serially dilute your sample and plate out the solution until you get a countable plate. count the colonies and mult. by dilution factor
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what is sterilization
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complete destruction of all microbes on an object
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disinfection
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the reduction or inhibition of microbial growth on a non-living surface
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antisepsis
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the reduction or inhibition of microbial growth on living tissue
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what is sanitization
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reduce/inhibit microbial growth
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how do various agents harm bacteria
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-damage to cell wall
-alteration of membrane permeability -damage to proteins and/or nucleic acids |
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physical agents that control bacteria growth
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-heat
-moist heat (boiling, autoclaving-lab instruments, pasteurization) -dry heat=oxidizing effects (incineration, dry ovens) -cold=inhibits growth -desiccation=removal of water -freeze drying/lyophilization= combo. of freezing and desiccation -filtration=passage of a liquid or gas through a filter with pores -osmotic pressure treatment (salts) -radiation:ionizing (gamma,Xrays)=mutations, non ionizing(UV,microwaves)=abnormal DNA base linkages |
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chemical agents that control bacteria growth
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-halogens (group 7):chlorine=oxidizing agent
-halogens II (iodine)=denature enzymes -alcohols=dissolve membrane lipids and denature proteins (ex:ethanol, isopropyl alcohol) -surfactants (detergents and soaps)=disrupt cell membranes, cleansing agents, emulsifiers -surfactants II=QUATS->cationic detergents that disrupt plasma membranes -phenols and phenolics=disrupt plasma membranes and denature proteins (toxic) -aldehydes (terminal CHO)=inactivate proteins and nucleic acids, very toxic -heavy metals=inactivate proteins by interacting with functional groups -food preservatives=weak organic acids |
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who's more susceptive to growth control
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gram-positive bacteria & enveloped viruses
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who's very resistant to growth control
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endospores
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what are genes
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units of information made of DNA-they carry info. about particular traits
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what is the form of DNA
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-a polymer of nucleotides, which come in 4 varieties (A,G,C,T)
-found as double helix, in which 2 parallel strands are joined by hydrogen bonds between the bases |
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central dogma of biology
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DNA->RNA->Proteins
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what is replication
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DNA copies itself before transcription
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what is transcription
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DNA makes an RNA copy (mRNA) of itself
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what is translation
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messenger RNA directs the synthesis of a protein during translation
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what is transformation
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a type of recombination; uptake of naked DNA by cell; discovered in an experiment that eventually led to the idea that DNA is the genetic material
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what is conjugation
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transfer of genetic material form one bacterial cell to another (F+)
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what is transduction
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transfer of bacterial genes from one cell to another mediated by a bacteriophage
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what are the two types of transduction
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generalized=any bacteriophage may be involved and any genes may be transferred
specialized=only temperate phages may be involved specialized |
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what is taxonomy, what's the purpose of it
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the science of classification of organisms; to show evolutionary relationships between groups, to provide a means of identifying organisms
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what are the 2 methods of classification
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phylogenetic=reflects the actual ancestry (evolutionary relationships)
phenetics=observable characteristics; identification and common language |
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what is the 5 kingdom system
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-monera: unicellular prokaryotes
-protista: unicellular eukaryotes -fungi: multicellular heterotrophs (external digestion) -plantae: multicellular autotrophs -animalia: multicellular heterotrophs (internal digestion) |
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what belongs in kingdom monera
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domain bacteria & domain archaea
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what belongs in domain eukarya
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kingdom protista, plants, fungi, animals
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what is the linnaean taxonomic hierarchy
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Domain, Kingdom, Phylum, Class, Order, Family, Genus, Species
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what is the correct way for naming organisms
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binomial designation: genus & species
*must be underlined or italicized & genus name must be capitalized |
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what is bergey's manual of determinative bacteriology
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classification based on observable characteristics or phenetics (sometimes reflects phylogeny)
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what are characteristics used to classify bacteria
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*anything by DNA sequences
-morphological characteristics -differential staining -nutritional pattern -relationship with oxygen -biochemical characteristics -serological analysis -phage typing |
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what is bergey's manual of systematic bacteriology
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reflects phylogeny, uses DNA, RNA, and protein analysis techniques
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what is a species
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a group of potentially interbreeding organisms that can produce viable offspring
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how is bacterial species identified
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population of cells with similar characteristics (more than 3% difference=different species)
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how are viral species identified
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a population of viruses that have similar characteristics
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What are the four divisions (phyla)
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-gracilicutes=gram negative
-firmicutes=gram positive -tenericutes=(mycoplasms-no cell wall) -mendosicutes (archaebacteria-no peptidoglycan) |
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what are the classes in gracilicutes, respiration mechanism, genus
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-oxyphotobacteria (cyanobacteria, aerobic photosynthesizers, Oscillatoria
-anoxyphotobacteria, anaerobic photosynthesizers: green and purple sulfer bacteria (use reduced sulfur compounds as electron donor) genus chlorobium & chromatrium;green and purple non-sulfur bacteria genus chloroflexus & rhodospirillum -scotobacteria: non-photosynthetic bacteria; family spirochaetaceae, family sprillaceae (microaerophillic), family vibrionaceae (facultatively anaerobic), family enterobacteria (facultatively anaerobic rods), chlamydias & rickettsias (obligate parasites), chemoautotrophs (oxidize reduced sulfur, iron, and nitrogen compounds), aerobic rods and cocci |
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what are viruses
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obligate intracellular parasites
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what do viruses contain
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nucleic acid (DNA or RNA)
and a protein coat (capsid) (sometimes lipid envelope) |
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what is the host range
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the certain types of cells in a particular species that viruses can infect
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what is used to see viruses
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electron microscope
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what is the average size and shape of viruses
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100 nm, and they VARY in shape so there is no average!
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what is a virion
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a mature, infective particle consisting of a nucleic acid and protein coat (sometimes lipid envelope)
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what types of nucleic acids can a virus have
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single or double stranded, linear or circular
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what is the capsid and what is it made of
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protein coat, made of subunits called capsomeres
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what must a virus have if it has an envelope
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SPIKES
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what is the general morphology of viruses
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helical viruses
polyhedral enveloped complex |
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describe helical viruses
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resemble long rods, their capsids are hollow cylinders surrounding the nucleic acid
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describe polyhedral viruses
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many-sided, usually the capsid is an icosahedron (20 triangular faces)
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describe enveloped viruses
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may be helical or polyhedral, acquire their envelope by taking part of the plasma membrane of the host cell as they "bud" from the cell
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what is a "naked" virus
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a virus that lacks an envelope (usually animal viruses)
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describe complex viruses
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have a polyhedral head with a complex tail attached (ex: bacteriophage)
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what is the structure of a complex virus
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capsid (head), sheath, tail fiber, pin, baseplate
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what is the taxonomy of viruses based on
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type of nucleic acid, life-cycle strategy, and morphology
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what are the species/families of RNA viruses
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HIV (retroviridae), Poliovirus (picornaviridae) , Rabies Virus (rhabdoviridae)
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what the species/families of DNA viruses
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HPV/human papillomavirus (papovaviridae), HSV/herpes simplex virus (herpesviridae)
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why is it difficult to grow viruses in culture
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cuz their host cells must be present
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how are bacteriophages grown
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phages are incubated on a lawn of bacteria and plaques (hole in bacteria) develop where they are multiplying
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how do viruses reproduce?
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by turning the host cell into a factory for producing more viruses
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what do most bacteriophages carry their genomes as?
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double-stranded DNA
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what are the most studied viruses
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E.Coli (T-even and phage lambda)
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what is the lytic cycle
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a phage causes the lysis (breaking) and death of its host bacterium as it replicates
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What are T-even phages and what cycle do they use
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T2 and T4, use the lytic cycle
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what are virulent phages
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they lead to the death of the host
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what happens in the lysogenic cycle
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the phage incorporates its nucleic acid into the host cell chromosome and remains dormant for a period of time
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what cycle do phage lambda use? and what type of phage does that make it
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phage lambda, its a temperate phage
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what are the stages of the lytic cycle
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-attachment
-penetration -biosynthesis -maturation -release |
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what are the stages of the lysogenic cycle
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-attachment/penetration
-viral DNA recombines with bacterial chromosome to form a PROPHAGE -prophage replicates with bacterial DNA until sometime triggers it to excise itself, then it goes into lytic cycle |
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what is kingdom protista
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seaweed algae (plantlike, unicellular, primary producers in aquatic environment)
planktonic (floating) algae |
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what divisions are seaweed algae
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phaeophytha->sargassum
rodophyta->gelidium chlorophyta->ulva, spyrogyra |
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what divisions are planktonic algae
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chrysophyta (glass)
dinophyta/pyrrophyta (red tides) ->fossil fuels are largely the remains of these two groups |
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characteristics of protozoa
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-animal-like protists (chemoheterotrophs)
-unicellular -symbiotic relationships with animals -some are pathogens |
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phyla of protozoa
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sarcodina (entamoeba)
mastigophora (giardia) ciliophora (paramecium) apicomplexa (plasmodium) |
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what are the phylum in kingdom animalia
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phylum platyhelminthes (trematodes, cestodes)
phylum nematoda phylum rotifera phylum arthropoda (class insecta & arachnida) |
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pathogen
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any agent capable of causing disease
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infection
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successful invasion and growth of pathogens in the body
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disease
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abnormal state in which the body or one of its parts is incapable of performing its functions properly
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when is an organism said to have a disease
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when a pathogen overcomes the body's defenses
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host
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organism that shelters and/or supports the growth of pathogens
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infectious disease
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disease caused by infective pathogens
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pathology
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study of disease
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normal microbiota
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microbiota that are "supposed" to be there
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what is more numerous in the body normal microbiota or human cells
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normal microbiota
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members of normal microbiota
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bacteria, fungi, protozoa
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examples of normal microbiota
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E.coli, streptococcus, staphylococcus, lactobacillus, candida (yeast)
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examples of symbiotic relationships
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E. Coli- gets warm environment with free food, we get Vitamin K and protection from pathogens
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types of symbiosis
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commensalism=one benefits, the other is unaffected
parasitism=when pathogen is involved |
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opportunistic pathogens
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cause disease under certain circumstances when they normally wouldnt
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symptoms
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subjective reports by a patients (stomach ache)
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signs
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objectively measurable changes in body function (fever)
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diagnosis
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identification of a disease
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syndrome
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if a certain group of signs and symptoms always accompany a certain disease
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acute disease
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develops rapidly, relatively severe symptoms, lasts a short time (flu)
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chronic disease
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develops slowly, less severe symptoms, lasts longer (tuberculosis)
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latent disease
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causative agent is dormant for some time, then causes disease
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local disease
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remains confines to a small part of the body
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systemic disease
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spread throughout the body (usually by the circulatory system)
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degrees of infection
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primary:its the initial cause
secondary:occurs after host is weakened subclinical: doesnt cause signs or symptoms |
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nosocomial infection
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acquired in the hospital or other health care facility
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pathogenesis
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the development of a disease in an individual
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pattern of pathogenesis
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incubation-betw. initial infection & 1st appearance of signs
prodromal:pd. of mild signs pd. of illness:height of disease;all signs apparant pd. of decline:signs decline pd. of convalescence:return to normal |
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portals of entry
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specific routes by which pathogens enter the body
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integumentary system
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protects u & surrounds your body entirely, the site of entrance of the pathogen
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examples of portal of entry
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respiratory tract (inhalation)
urogenital tract (sex) gastrointestinal (food, etc) |
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parenteral route
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if a pathogen is introduced through the skin via injection, insect bite, or presence of a wound
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adherence
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when pathogens need to attach to the host tissue
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adhesins
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molecules on the pathogen's glycocalyx or fimbriae that react with cellular receptors on host cells
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how do capsules contribute to virulence
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they protect against phagocytosis
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direct damage by bacteria
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host cells can be harmed or destroyed if bacteria are growing and metabolizing in or around them
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what is most bacterial damage due to
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production of toxins (poisonous substances)
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two groups of toxins
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exotoxins:byproducts of bacterial metabolism and are released into the host
endotoxins:part of the cell wall, liberated wen the bacteria dies |
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examples of exotoxins
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cytotoxins:kill host cells or inactivate them
neurotoxins:interfere with transmission of nerve impulses enterotoxins: adversely affect cells lining the GI tract |
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antitoxins
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antibodies produced against exotoxins
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what are endotoxins usually
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lipopolysaccharides (in gram neg. bacteria)
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what is the result of endotoxins
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fever & chills, sometimes shock (systemic inflammation)
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effects of viruses
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cytopathic (cell+disease) effects, which may cause cell death or damage
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interferons
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chemicals produced by host cells to protect against viral infection
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epidemiology
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study of disease in populations
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incidence of a disease
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the rate of occurrence of new cases
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prevalence
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total number of cases of disease in a population
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virulence
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degree of pathogenicity for a given pathogen
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how is virulence measured
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LD50 (lethal dose for 50% of inoculate hosts) or ID50 (infectious dose for 50% of inoculated hosts)
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communicable disease
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can be transmitted from one host to another
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contagious disease
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very easily communicable
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non-communicable
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cant be transmitted from one host to another (acquired from the environment)
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sporadic
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occurs occasionally in a population
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endemic
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constantly present in a population
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epidemic
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acquired by many people in a given area over a short time
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pandemic
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epidemic worldwide
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reservoir
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continual source of infective pathogens
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examples of reservoir
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human, animal, non-living like soil or water
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contact transmission
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direct contact:direct contact
indirect contact:from living reservoir to a host via intermediate object called fomite droplet transmission: via droplets of mucus |
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vehicle transmission
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transmission of a pathogen by physical contact betw non-living reservoir and host
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non-living reservoirs
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foodborne
waterborne airborne |
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arthropod vectors as biological transmission
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special form of direct contact in which an arthropod harbors a pathogen and transmits it from host to host
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koch's postulates
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set of rules to determine which microorganism caused which disease
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what is necessary to use koch's postulates
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same pathogen must be present in every case of the disease, cultured pathogen must be capable of causing the disease in healthy lab animals
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exceptions to koch's postulates
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viruses & certain bacteria, diseases caused by various pathogens
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resistance to disease
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ability to ward off disease
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immunity
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specific resistance
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susceptible
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when u're not resistant to a particular disease
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three lines of defense
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first:blocks invasion at portals of entry
second:internalized, non-specific reactions including inflammation and phagocytosis third:specific immune reactions |
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physical barriers
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intact skin
mucous membrane |
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keratin
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"sealant" protein in epithelial cells
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examples of mucous membranes
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-lacrimal apparatus of conjuctiva:lubricates and protects the eye from pathogens
-saliva:washes pathogens from teeth and gums -urine flow:cleanses urethra and vaginal secretions -ciliary escalator: moves mucus upwards |
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sebum
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oily substance produced by sebaceous glands on the skin inhabits the growth of most pathogenic bacteria
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chemical defense from pathogens
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sebum, perspiration, lysozyme, high acidity of stomach, acidic pH in skin
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how is perspiration a chemical defense
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it causes osmotically unfavorable conditions due to its salt/urea content
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lysozyme
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enzyme that damages bacterial cell walls
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biological defense
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presence of E. Coli and other normal microbiota prevents the growth of many pathogens
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what is the mandate of the 2nd and 3rd lines of defense
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search for invaders, recognize and/or react with them, and destroy them
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what do white blood cells do
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they're on patrol and have access to virtually areas of the body, movie freely betw bloodstream & lymphatic circulation via tissue fluid, patrol reticuloendothelium
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blood
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connective tissue made of various cells suspended in a liquid matrix, the plasma
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types of cells in blood
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red blood cells (erythrocytes), platelets (thrombocytes), white blood cells (leukocytes)
->granulocytes & agranulocytes |
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types of granulocytes
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neutrophils:most numerous white blood cells
eosinophils:play a role in combating eukaryotic parasites basophils: act in inflammation |
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type of agranulocytes
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monocytes (macrophages)
lymphocytes (B cells or T cells) |
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B cells
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anti-body mediated immunity
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T cells
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cell-mediated immunity
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lymphatic system
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a system of one-way vessels that returns excess tissue fluid back to cardiovascular circulation
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lymph nodes
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small organs positioned, often in clusters, along lymphatic pathways. They're packed with lymphocytes, and many of the reactions of the specific immune response
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lymphoid organs
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spleen:like giant lymph node;filters blood, destroys red blood cells
thymus gland: site of maturation of T cells tonsils, adenoids: exposed to sites of heavy microbial populations bone marrow: site of production of all blood cells |
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inflammation
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coordinated response to injury
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inflammatory response
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generalized nonspecific response to body tissue damage, whether caused by a pathogen or cut in the skin
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what is inflammation characterized by
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redness and heat, swelling, pain
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why is inflammation beneficial
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stops intruders from progressing any further and to promote tissue repair
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what chemical initiates inflammation
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histamine
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what happens at the start of inflammation
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vasodilation, increased permeability of blood vessels, increased blood flow, edema (fluid buildup)
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pus
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dead cells and tissue fluid
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margination
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phagocytes stick to the walls of the blood vessels lining the abcess
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emigration or diapedesis
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phagocytes squeeze through the blood vessel walls and enter the abscess
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how does the tissue repair itself after the pathogens are destroyed
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mitosis
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fever
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abnormally high body temperature produced in response to an infection
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what do chills indicate about body temperature
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it is rising
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what does sweating indicate about body temperature
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it is falling
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benefits of fever
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-inhibiting replication of some pathogens sensitive to temperature effects
-increased rate of metabolism, which speeds up phagocytosis and all specific immune reactions |
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phagocytosis
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2nd line of defense, ingestion & digestion of pathogens by phagocytes (white blood cells)
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purpose of phagocytosis
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-to search for foreign invaders and destroy them
-to gather immunological "intelligence" in the form of antigens from the invaders that are discovered |
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most important and prevalent granulocyte phagocyte
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neutrophil
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most important agranulocyte phagocyte
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macrophage
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when do neutrophils predominate
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early in infection
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when do macrophages predominate
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towards the end
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process of phagocytosis
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-chemotaxis:phagocytes are attracted chemically to the site of pathogen infiltration
-adherence:attachment of the phagocyte's plasma membrane to the pathogen -ingestion:pseudopods engulf the pathogen, creating a phagocytotic vesicle or phagosome -digestion: phagosome fuses with a lysosome to form a phagolysosome, where pathogens are degraded -after lysosomal enzymes have done their job, vesicle is termed residual body, and its contents are discharged from the cell |
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complement
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system of plasma proteins that cause foreign cells to lyse by attacking their plasma membrane
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what is the complement cascade triggered by
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variety of chemicals like Lipid A (nonspecific) and antigen-antibody complexes (specific)
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what do interferons stimulate
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nearby cells to produce antiviral proteins, thereby protecting themselves from infection
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where do interferons play roles
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cancer suppression and in immune system regulation
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immunity
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the ability of the body to counteract SPECIFIC foreign organisms or agents that possess ANTIGENS
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what is responsible for immunity
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white blood cells called lymphocytes
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two types of lymphocytes
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B cells and T cells
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acquired immunity
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specific resistance to infection developed during the life of an individual
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2 types of naturally acquired immunity
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active:results from infection by a pathogen, and is long lasting
passive:results from antibodies transferred from mother to fetus, short in duration |
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2 types of artificially acquired immunity
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active:results from vaccination, long lasting
passive: results from antibodies transferred by direct injection, short in duration |
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What are B cells responsible for
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antibody-mediated humoral immunity, defense against bacteria, viruses, and toxins
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What are T cells responsible for
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cell-mediated immunity, defense against intracellular bacteria and viruses, and eukaryotic invaders
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antigens
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"markers" on cells, usually glycoproteins, protruding from the plasma membrane
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MHC/HLA proteins
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major histocompatibility complex/human leukocytic antigen system- allows a particular human organism to tell "self" cells from those that lack the "right" MHC proteins (nonself)
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what does an antigen have the ability for
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to provoke an immune response
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antibody
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immunoglobulin, and a polymeric protein produced by a B-cell in response to stimulation by an antigen and capable of specifically binding to that antigen
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IgG
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typical antibody, contains 4 polypeptide chains, 2 heavy and 2 light
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2 regions on antibody chains
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constant region responsible for its structure & unique variable region, responsible for antigen binding
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How can millions of different antibodies be produced in the body if there are only 30,000 protein-coding genes in the genome
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Ig genes are somatically rearranged in B-cells
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clonal deletion
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a process before birth, where all the lymphocytes that could react with self molecules are destroyed
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where are B cells produced
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bone marrow
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antigen receptor
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unique antibody on the cell surface of B cells
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where do most B cells go
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lymphatic system, lymph nodes, circulate freely in the blood
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when does a B cell become activated
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when it reacts with a free antigen via its antigen receptor
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what happens when the B cell becomes activated
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it divides into plasma cells and memory cells
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what do plasma cells do
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manufacture and secrete huge quantities of antibodies that go out and bind to antigen
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memory cells
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do nothing until the pathogen is encountered again in the future, at which time they stand ready to mount a quick reaction; responsible for naturally acquired active immunity
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neutralization
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when antibodies bind to antigens and can inactivate toxins or viruses directly
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complement fixation
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if antibodies bind to antigens on a bacterial cell, they tag the bacterium to be targeted by the complement system, which lyses and kills the foreign cells
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agglutination
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clumping of cells
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opsonization
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process by which antibodies coat foreign cells, which identifies them to phagocytes
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where are T cells produced
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bone marrow
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where do T cells mature
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thymus gland
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where do most T cells go
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lymphatic system, lymph nodes, may circulate in the blood
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types of T cells
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-cytotoxic T cells/CD8 cells:neutralize cells containing antigens
-Helper T cells/CD4 cells:generally stimulatory to the entire immune system -Suppressor T cells: limit activities of the immune response -Delayed Hypersensitivity: delayed allergic reactions |
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Antigen presenting cell (APC)
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usually a macrophage that had digested the pathogen and is now displaying pathogenic antigens on its cells surface
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what must the displayed antigen be complexed with for the T cell to recognize it and be stimulated
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with the major histocompatibility complex (MHC)
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cytotoxic response
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cells divide and release the protein perforin into the attached cell, directly causing it to lyse
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what happens when the helper T cells are activated by an antigen
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they stimulate the APC to release interleukin 1, which activates the helper cell further, then produces interleukin 2 and other cytokines, which communicate with other cells in the immune system
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what does the helper T cell instruct
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B cells and other T cells to become activated
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who makes "first contact" with the antigen
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helper T cell
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vaccine
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suspension/portion of pathogens that is used to induce artificially acquired immunity
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types of vaccinations
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-inactivated whole-agent:killed bacteria/inactivated viruses
-attenuated whole-agent:weakened pathogens -toxoids:inactivate toxins |
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subunit vaccines
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consist of antigenic fragments of a pathogen; recombinant vaccines & acellular vaccines
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recombinant vaccines
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subunit vaccines; genetic engineering is used to artificially produce a protein antigen
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acellular vaccines
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subunit vaccines; fractionate the bacteria and isolate only a portion of them
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DNA vaccines
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introduce the gene for an antigenic protein into an organism, causing it to express the protein
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why vaccine?
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-protect oneself from disease
-protect public's health |
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herd immunity
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when more people get vaccinated and there'll be less carriers, less reservoir for the pathogen
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antimicrobial drugs
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substances meant to be taken internally to kill or retard the growth of pathogens in individuals with infections
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what do the most effective drugs have
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high toxicity to pathogen & low toxicity and occurrence of adverse side effects in human host
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antibiotics
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ALL naturally occurring chemicals produced by ascomycete fungi or bacteria
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synthetic drugs
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produced in the lab
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semisynthetics
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lab-modified versions of antibiotics
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categories of antimicrobial drugs
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-inhibition of cell wall synthesis/destruction of cell walls
-inhibition of nucleic acid function or nucleic acid synthesis -protein synthesis inhibition -interference with the function of the plasma membrane |
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antibiotics that affect bacterial cell wall
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peniCILLIN
cephalosporin bacitracin vancoMYCIN |
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penicillin
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narrow spectrum (effective against gram-pos. cocci & spirochetes) and work by inhibiting peptidoglycan cross-linking
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penicillinases
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enzymes that many bacteria have evolved that make them resistant to penicillin
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what has resistance to penicillinases
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semi-synthetic penicillins like amoxycillin, methicillin, carbenicillin, oxacillin
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cephalosporin
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produced by fungal genus penicillium, similar to penicillin
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bacitracin
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damages cell walls by interfering with NAG/NAM polymerization, effective against gram pos. bacteria & is limited to topical use
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vancomycin
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produced by streptomyces, used to treat infections by staphylococci resistant to penicillin and other drugs
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antibiotics that interfere with protein synthesis
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aminoglycosides
tetracyclines macrolides |
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aminoglycosides
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amino sugars linked by glycosidic bonds, made by streptomyces species. broad spectrum, all antibiotics that inhibit protein synthesis
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tetracyclines
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complex ring structures produced by various species of streptomyces. often adversely affect the normal microbiota, can cause upset stomach & yeast infection
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erythromycin
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type of macrolide-inhibits protein synthesis
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antibiotics that damage plasma membrane
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polymyxin B- effective against gram neg. bacteria & is often used topically (will affect cell in mitochondria)
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antibiotics that inhibit nucleic acid synthesis
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rifamycins (rifampin)-inhibits mRNA synthesis (transcription) and is often used against mycobacterium species that causes tuberculosis and leprosy
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skin
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the cutaneous membrane of the integumentary system
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what does the skin consist of
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-epidermis: epithelial tisses filled and sealed with keratin
-dermis: contains sweat & sebaceous glands & hair follicles -subcataneous layer: mostly fat |
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what is the purpose of the skin producing sweat and sebum
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inhibits the growth of microorganisms
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what is the most common normal skin microbiota
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gram-possitve cocci, staphylococcus sp.
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skin lesions terms
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vesicles>bullae>macules>papules>pustules
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staph infections
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S. epidermidis, S. aureus
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how does S. aureus usually infect skin
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by entering hair follicle
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manifestaation of staph infection
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folliculitis (pimple), sties (eyelash), boils
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what the danger in staph infections
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underlying tissue may become infected or infection will enter the bloodstream (septicemia)
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what is toxemia caused by
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circulation of toxins
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what are examples of staph toxemia
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-scaled skin syndrome:skin peels off when touched
-toxic shock syndrom: fever, vomiting, rash, shock |
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what are species of streptococcus classified according to
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hemolytic enzymes and cell wall antigens
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what is the most medically important streptococci
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group A beta-hemolytic streptococci-> S. pyogenes
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erysipelas disease
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skin erupts into reddish particles with enlarged margins and high fever
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what is effective against S. pyogenes
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penicillin
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necrotizing fascitis
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flesh eating bacteria, agressive strain of S. pyogenes that produced a toxin that destroyed skin, muscle, and connective tissue.
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cellulitis & myositis
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infection of the deep tissue without necrosis, caused by S. pyogenes
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purpose of nervous system
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electrical communications
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structure of nervous system
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CNS-brain & spinal cord
PNS-all other nerves |
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meninges
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membranes filled with cebrebrospinal fluid, they surroung the CNS
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meningitis
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inflammation of the meninges that can be caused by various bacteria and other pathogens
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when can meningitis occur
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-after an infection of respiratory tract (when bacteria reach the CNS via blood)
-injury which exposes CNS |
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symptoms of bacterial meningitis
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sudden fever, severe headache, rigidity of neck, nausea, vomiting, convulsions, coma, death
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how is bacterial meningitis treated
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broad spectrum antibiotics
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how is meningitis diagnosed
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spinal tap
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types of bacterial meningitis
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Haemophilus influenzae
neisseria meningitidis (meningococcus) streptococcus pneumoniae(pneumococcus) |
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haemophilus influenzae
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gram negative, common member of throat microbiota, generally begins as an upper respiratory infection (pharyngitis) that enters blood & carries it to the CNS
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meningococcus
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gram negative, commonly present in nasopharynx
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Hib vaccine
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controls haemophilus influenza
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pneumococcus
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member of normal pharyngeal microbiota, gram POSITIVE, majority of bacterial meningitis cases, presence of CAPSULE is important
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pathogen for tetanus
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clostridium tetani-obligate anaerobe, endospore-forming, gram positive rod
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what is tetanospasmin
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potent neurotoxin produced by the tetanus pathogen which inhibits muscle relaxation
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physical characteristics of tetanus
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lockjaw, difficulty swallowing, spasms of diaphragm->respiratory arrest
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what is the transmission for tetanus
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when spores are introduced via a puncture wound
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what is treatment for tetanus
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toxoid vaccine DTP & antitoxin
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botulism pathogen
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clostridium botulinum (obligate anaerobe, endospore-forming, gram positive rod)
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botulinum toxin
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potent neurotoxin from botulism pathogen that inhibits nerve transmission, blocking acetylcholine release from neurons
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early symptoms of botulism
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blurred vision and trouble swallowing
->death by respiratory & cardiac arrest |
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how does botulism transmission occur
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when the toxin is ingested (grows in improperly canned foods)
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how does nitrite affect endospores
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nitrite inhibits endospore germination
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treatment for botulism
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antitoxin mixture, NO ANTIBIOTICS
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cardiovascular system purpose
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transport of various substances throughout the body
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structures of cardiovascular system
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blood, heart, blood vessels
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heart
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pumps blood
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blood vessels
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tubes through which blood flows
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blood
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connective tissue
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anthrax pathogen
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bacillus anthracis (aerobic, endospore forming, gram pos. rod)
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term for anthrax affecting grazing animals
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zoonosis
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2 major forms of getting anthrax
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cutaneous
inhalation |
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what does anthrax cause when inhaled
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pneumonia
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what does anthrax cause when contracted by contact
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skin lesions
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what does B. anthracis produce
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exotoxins
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what do exotoxins from anthrax result in
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fatal septicemia
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how is anthrax treated
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penicillin
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(Gas) Gangrene pathogen
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clostridium perfringens (obligate anaerobe, endospore forming, gram pos. rod)
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ischemia
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if a wound causes blockage of blood supply
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necrosis
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tissue death
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gangrene
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tissue death resulting from blockage of blood supply (ischemia) and wound becoming anaerobic
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when does gas gangrene occur
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if the disease is allowed to progress, as fermentation by the bacteria produces CO2 and diatomic hydrogen
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what does gangrene bacteria produce
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toxins that destroy muscle tissue, and eventually become systemic
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plague pathogen
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yersenia pestis (gram neg. rod)
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what is the plague normally a disease of
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rat, which contract it from bites of the rat flea
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how can the plague be contracted
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droplet transmission
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forms of plague
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bubonic plague
pneumonic plague |
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bubonic plague
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pathogens become localized in lymph nodes, causing enlargement (buboes)
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bubonic plague symptoms
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fever, pain, tissue necrosis, subcutaneous hemorrhages which manifest as blackened skin
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how is pneumonic plague usually contracted
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droplet transmission
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pneumonic plague symptoms
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respiratory difficulty
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pneumonic plague treatment
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antibiotics like streptomycin and tetracycline
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lyme disease pathogen
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borellia burgdorferi (spirochete)
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how is lyme disease transmitted
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via the deer tick
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symptoms/signs of lyme disease
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target-shaped rash, flu-like symptoms, arrythmias, arthritis
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lyme disease treatment
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antibiotics, penicillin
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pharyngitis
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sore throat; inflammation of the mucous membranes of the pharynx
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laryngitis
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inflammation of the mucous membranes of the larynx, affects ability to speak
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sinusitis
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inflammation of the mucous membranes of the nasal sinuses, usually leads to mucus production
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strep throat pathogen
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streptococcus pyogenes
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symptoms of strep throat
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local inflammation (redness and pain), fever
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strep throat treatment
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penicillin
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strep throat complications
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some strains produce an erythrogenic toxin which enters the circulation and causes scarlet fever
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scarlet fever symptoms
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high fever, red skin rash
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how is scarlet fever transmitted
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droplet transmission
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tuberculosis pathogen
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mycobacterium tuberculosis (gram pos., acid fast rod)
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tuberculosis transmission
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droplet transmission, if not phagocytized many white blood cells accumulate at the infection site forming a "tubercle" causing lung inflammation
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tuberculosis symptoms
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weight loss, coughing, lack of vigor (consumption)
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tuberculosis treatment
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used to be streptomycin, now need prolonged treatment with multiple antibiotics
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pneumonia pathogens
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streptococcus pneumoniae, mycoplasma pneumoniae
klebsiella pneumoniae |
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pneumonia symptoms
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inflammation, swelling, coughing, inhibition of gas exchange
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most common pneumonia pathogen, symptoms
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streptococcus pneumoniae, high fever, difficulty breathing, chest pain
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pneumococcal pneumonia treatment
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penicillin
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who is mycoplasma pneumoniae common in
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children
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who does klebsiella pneumoniae and haemophilus influenza usually effect
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older people, or debilitated people
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what else can pneumonia be caused by
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variety of viruses
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microorganisms (microbes)
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organisms too small to be seen with the naked eye
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significance of microorganisms in ecology
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-primary photosynthesizes in aquatic environments
-primary decomposers -dominant organisms on earth |
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significance of microorganisms in symbiosis
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-E.Coli in our large intestines
-bacteria & protozoans in termite & cow guts |
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significance of microorganisms: commercial
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-yeasts are involved in making alcoholic beverages and bread
-some bacteria are involved in making cheeses and yogurt -bacteria are genetically engineered to produce useful chemicals |
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significance of microorganisms in disease
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viruses-HIV, flu
bacteria-strep throat, tuberculosis fungi-ringworm, yeast infections protozoa-malaria |
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Robert Hooke
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observed cells in 1665
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Antoni van Leeuwenhoek
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observed microorganisms under the microscope in 1673
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Edward Jenner
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performed first vaccination by exposing a person to cowpox virus, person was then protected from small pox infection- 1796
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Rudolph Virchow
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introduced the cell theory (cells can only come from other cells)- 1858
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Louis Pasteur
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-disproved spontaneous generation in 1861
-discovered fermentation -developed pasteurization to make liquid foods safer |
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Joseph Lister
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introduced disinfectant to clean human wounds and prevent surgical infections-1860s
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Robert Koch
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introduced Koch's Postulates- a set of procedures to determine the causative agent of a particular disease- 1876
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Alexander Fleming
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discovered the first antibiotic, penicillin- 1928
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Classification of organisms
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bacteria- Kingdom Monera
protozoa & algae- Kingdom Protista yeasts & fungi- Kingom Fungi Worms- Kingdom Animalia Viruses- NO KINGDOM cuz theyre not alive |
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Kingdom Monera
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-unicellular prokaryotes (no nucleus)
-bacteria, archaea -usually have cell wall of peptidoglycan |
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Kingdom Protista
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-unicellular eukaryotes
-protozoa=animal like protists (amoeba, paramecia, no cell walls) -algae=plantlike protists (can photosynthesize, usually have cell wall of cellulose) |
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Kingdom Fungi
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-multicellular eukaryotic heterotrophs with external digestion
-usually have cell wall of chitin |
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yeasts
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unicellular fungi
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Kingdom Animalia
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-multicellular eukaryotic heterotrophs with internal digestion
-most organisms and microscopic worms and rotifers -no cell walls |
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Viruses
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-obligate acellular parasites
-consist of nucleic acid and protein -infect all known types of cells |
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virus structure
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-capsid/head
-sheath -tail fiber |
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virus size
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about 100 nanometers
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bacteria size
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about 1 micrometer
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eukaryotic cell size
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10 micrometers
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magnification
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ability to make objects appear larger
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resolution
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ability of an optical system to distinguish between two adjacent points
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what does resolving power have to do with
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the wavelength of the light employed for viewing
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Compound Light Microscope (brightfield microscopy)
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-ocular lens & objective lens
-uses visible light -max resolving power: 200 nanometers -maximum magnification: 2000X -specimens are usually stained since most microorganisms are clear |
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immersion oil
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used under high magnification to reduce loss of light; has refractive index similar to the microscopic slide
-much better resolution |
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dark field microscopy
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specimen appears light against a dark background (no staining)
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fluorescence microscopy
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specimens are stained with "fluorochromes" which absorb and reradiate UV light
-sample appears bright against a dark background |
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electron microscopy
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-a beam of electrons is used instead of visible light
-much greater resolution and magnification -electromagnets act as lenses to focus the beam |
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two types of electron microscopy
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transmission electron microscopy
scanning electron microscopy |
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transmission electron microscopy
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-beam penetrates the sample like in light microscopy
-samples must be very thin -highest magnification and resolution (1,000,000X, 1nM) similar in idea to brightfield microscopy |
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scanning electron microscopy
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-electrons bounce of the surface of the specimen, revealing a 3D image
-best pictures- magnification typically 10,000X, res. 10nM) -similar in idea to darkfield microscopy |
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staining
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coloring a microbe with a dye that binds to and emphasizes certain structures
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stain preparation: fixing
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a smear of bacteria (thin film containing cells) is spread over the slide and the cells are killed and fixed in place by exposure to dry heat
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dyes
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salts composed of positive and negative ion, one of which is colorful, called a chromophore
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what is the chromophore in basic dye
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positive ion
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what is the chromophore in acidic dye
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negative ion
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which dyes bind to bacterial structures
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basic dyes like crystal violet and methylene blue
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what do acidic dyes cause
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negative staining because they may bind to the background and avoid binding to the bacteria (charge repulsion)
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simple stain
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solution of a single basic dye that generally highlights the entire microorganism
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mordant purpose
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improves binding of dye to sample
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differential staining
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divides bacteria into groups according to their reaction to the staining procedure (like Gram stain)
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gram stain
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divides bacteria into gram positive and gram negative
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gram stain procedure
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-apply a basic dye (primary dye that stains all of the cells purple or blue)
-wash off dye and apply mordant, iodine: after its washed off, all the cells appear purple -wash preparation with alcohol, a decolorizing agent which removes the stain from SOME bacteria -apply another basic dye, safranin (counterstain) which colors the unstained bacteria pink or red -at the end, gram pos. cells look purple/blue and gram negative cells look pink/red |
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Acid-fast stain
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distinguishes bacteria of the genus Mycobacterium which cause tuberculosis
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acid-fast stain procedure
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-apply basic dye like carbolfuchsin (primary dye) which stains all cells red
-wash preparation with acid-alcohol, a decolorizing agent which removes the stain from SOME bacteria (those without the waxy substance) -apply another basic stain, methylene blue (counterstain) which colors the unstained bacteria blue -at the end, acid-fast cells look red and non acid-fast cells look blue |
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what do special stains exist for
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-visualizing microbial capsules (negative capsule staining)->use acid dye that colors background then safranin (colors entire bacterium except capsule) and capsule appears as a halo
-highlight endospores -highlight flagella |
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monomers
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subunits that when polymerized, make up a larger polymer
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four types of biological molecules
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-carbohydrates: monomers+polymers
-lipids: have one physical property in common -proteins: polymers of amino acids with versatile functions -nucleic acids: polymers of nucleotides, may be DNA or RNA |
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basic building blocks of carbohydrates
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monosaccharides like glucose, fructose, or galactose
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how does a dissarcharide form
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when 2 monosaccharides are joined by a glycosidic bond (dehydration synthesis)
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examples of disaccharides
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sucrose, lactose, maltose
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starch
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plant storage polysaccharide
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cellulose
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plant structural polysaccharide
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glycogen
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animal storage polysaccharide
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chitin
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makes up fungal cell walls and arthropod exoskeleton- polymer of NAG
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peptidoglycan
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polymer of alternating NAG and NAM subunits, most bacterial cell walls contain it
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functions of carbs
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-energy
-structural components of cell walls -may be attached to proteins and function as antigens |
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simple carbohydrates or sugars
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mono and disaccharides
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complex carbs
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polysaccharides
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lipids
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biological molecules that are insoluble in water
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types of lipids
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triglycerides (fats & oils)
phospholipids sterols |
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triglyceride formation
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2 fatty acids joined to a molecule of glycerol by dehydration synthesis
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FATS
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solid at room temp, C-C saturated fatty acids
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OILS
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liquid at room temp, C=C unsaturated fatty acids
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phospholipids
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a glycerol, 2 fatty acids, 1 phosphate group->amphipathic
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popular sterol/steroid
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cholesterol
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triglyceride function
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long term energy storage, cushioning and insulation in multicellular organisms
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phospholipid function
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structural basis of cell membranes and lipid-transporting lipoproteins
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steroids
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cholesterol function in the structure of cell membrane, others are hormones, etc
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proteins
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long chains of subunits called amino acids joined by peptide bonds (dehydration synthesis)
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levels of protein structure
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primary: sequential order of amino acids in chains
secondary: alpha helix & beta pleated sheet tertiary: molecule folded up in 3D space quaternary: folded polypeptides associate with eachother to form a functional protein |
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interactions that cause tertiary protein structure
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hydrogen bonds, ionic/electrostatic, and hydrophobic interactions between R groups
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functions of proteins
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enzymes
hormones antibodies structural membrane associated transporters |
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famous proteins
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hemoglobin, insulin, collagen, keratin
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nucleic acids
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long chains of nucleotides joined together by phosphodiester bonds
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two classes of nucleic acids
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DNA and RNA
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what does the nucleotide contain
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nitrogenous base
phosphate group 5 carbon sugar |
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DNA bases
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adenine, guanine, cytosine, thymine
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what does DNA exist as
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double helix with 2 nucleotide strands running antiparallel and joined by hydrogen bonding between the bases
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functions of nucleic acids
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-DNA makes up the genes, which contain genetic information
-RNA functions in various capacities in the process of protein synthesis |
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ATP
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triphosphate form of an RNA nucleotide that functions as the major energy carrying molecule of the cell
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bacterial shapes
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coccus-sphere
bacillus-rod spiral-corkscrew shape pleiomorphic-no fixed shape |
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bacterial arrangements
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diplo: in pairs
staphylo: in clusters strepto: in chains |
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glycocalyx
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outermost layer of the cell
capsule: if firmly attached slime layer: if loosely attached |
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flagella
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filamentous appendage used for movement
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axial filament
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flagellum that coils around a spiral shaped bacterium
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fimbriae and pili
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appendages for attachment
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capsule
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important in determining virulence of pathogens and formation of biofilms
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flagellum structure
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basal body- attaches to the cell wall and membrane
hook- rotates due to basal body movement filament- projection that acts as a propeller |
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axial filament (periplasmic flagellum)
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-structurally like flagellum, only occurs in spiral shaped bacteria
-between cell wall and cell membrane |
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fimbriae
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-short and numerous
-allow adherence of a bacterium to a substratum. -play roles in biofilm formation -contribute to pathogenicity |
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pili
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-long and sparse
-involved in bacterial conjugation: transfer of genetic material (DNA) from one bacterial cell to another -generally found on gram negative bacteria |
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functions of bacterial cell wall
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-protection from osmotic changes
-determination and maintenance of cell shape |
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what is bacterial cell wall made of
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peptidoglycan made of NAG and NAM
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gram-positive cell wall
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-many layers of peptidoglycan surrounding the plasma membrane
-techoic acids and lipotechoic acids |
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gram-negative cell wall
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-single layer of peptidoglycan surrounding plasma membrane
-another membrane (outer membrane) |
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outer membrane components
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-lipoproteins
-lipopolysaccharides (lipid A and O polysaccharide) -porin proteins -NO techoic acids |
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outer membrane functions
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-protect the cell by excluding large toxic molecules like penicillin
-creates a periplasmic space (betw, the 2 membranes) in which there are enzymes and transport proteins |
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which cell walls are most susceptible to mechanical breakage, why
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gram negative, cuz theyre thin
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which cell walls are most successful in avoiding poor osmotic conditions, why
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gram negative, cuz of outer membrane
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what can cell walls be damaged by
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-lysozyme:enzyme that breaks the glycosidic bonds betw. NAG and NAM
-penicillin: antibiotic that interferes with cell wall synthesis by inhibiting peptide bridge formation |
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structures internal to the cell wall
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plasma membrane
chromosome ribosomes inclusions endospores |
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what does the plasma membrane consist of
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phospholipid bilayer associated with various proteins (fluid mosaic model)
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major functions of plasma membrane
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-delineate cell boundary, and hold in the contents
-control transportation of substances into and out of the cell |
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chromosome/nucleoid
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circular piece of DNA
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ribosome's job
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making proteins
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ribosomal components
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2 subunits made of RNA and proteins
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inclusions
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localized storehouses of needed substances such as nutrients
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granular inclusions
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concentrated areas of inorganic crystals
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endospores
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dormant structures that can survive essentially forever and are very difficult to destroy (like bacillus and clostridium)
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who can form endospores
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certain gram-positive cells
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when do endospores form
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when the environment is unfriendly (and the cell will otherwise die) , usually due to lack of oxygen and nitrogen source
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where does the spore form
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INTERNAL to the plasma membrane and then released to the environment
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what makes the eukaryotic cell different than in prokaryotes
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-membrane bounded nucleus and organelles
-extensive compartmentalization and internal organization -diploid complement of linear chromosomes complexed with histone proteins |
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eukaryotic flagella
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made of 9+2 arrangement of microtubules , also for locomotion
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cilia
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same structure as flagella, but shorter and more numerous
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what are algae cells walls made of
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cellulose, a single glucose polymers
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do animal cells and protozoa have cell walls
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NO!
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what are fungal cell walls made of
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chitin, a repeating NAG polymer
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what do animal cells and protozoans have associated with their plasma membrane and what for
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glycocalyx (outermost layer), for adhesion and protection of the cell
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major functions of eukaryotic plasma membrane
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-delineate cell boundary
-control transportation of substances into and out of the cell |
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transport processes
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-simple diffusion:CO2, O2
-osmosis:water -facilitated (passive) diffusion: glucose=requires carrier protein -active transport: ions= requires carrier protein & energy |
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simple diffusion
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things move along their concentration gradient from higher to lower concentration
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osmosis
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movement of water across a semi-permeable membrane along its concentration gradient
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isotonic
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concentration of water the same inside/outside
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hypotonic
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concentration of water is greater outside
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hypertonic
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concentration of water is greater inside
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facilitated diffusion
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transported substance if following its concentration gradient but its too large/polar so it requires a transmembrane transport protein
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active transport
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molecules are pumped from areas of lower concentration to higher concentration, requires transport protein & energy
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nucleus
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contains the genetic material (DNA) in the form of long, linear chromosomes
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what does nuclear envelope consist of
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2 membranes dotted with nuclear pores
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nucleolus
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site of production of ribosomal subunits
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endoplasmic reticulum
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part of the cytomembrane system, the ER is a continuous network of tubes surrounded by a single membrane
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rough ER
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has associated ribosomes and functions mainly in transporting proteins to the plasma membrane for secretion or insertion
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smooth ER
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has no associated ribosomes, and is involved in lipid biosynthesis
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golgi complex
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series of flattened sacs, the golgi apparatus receives proteins and lipids from the ER, then sorts, packages, and delivers them to their final destinations via secretory vesicles.
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lysosomes
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intracellular recycling centers, a sac surrounded by one membrane containing various hydrolytic enzymes
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disease involving lysosomes
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Tay-Sachs disease: materials build up in lysosomes
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ribosomes
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protein synthesis
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mitochondria components
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-consists of double membrane; inner one is highly folded and the folds are called cristae
-soluble portion of called the matrix -has its own ribosomes and a single, circular DNA molecule |
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mitchondria functions
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aerobic cellular respiration (generation of ATP)
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chloroplast components
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-2 membranes and a series of internal membranous sacs called thylakoids
-soluble inner portion: stroma -contain their own ribosomes and a single circular DNA |
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grana
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stacks of thylakoids; contains the chlorophyll
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endosymbiont theory
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both mitochondria and chloroplasts are evolutionary derived from bacteria (have size & shape of bacteria, has its own circular chromosome)
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metabolism
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the net sum of all chemical reactions taking place in a cell
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catabolism
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breakdown/hydrolysis reactions
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examples of catabolism
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glycolysis & fermentation
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anabolism
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synthesis/condensation reactions
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examples of anabolism
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protein synthesis, DNA replication
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carbohydrate catabolism reactants
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glucose is the most popular reactant, though other sugars work.
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beginning set of reactions of catabolism
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glycolysis
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glycolysis
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-redox reaction where glucose is split into two molecules of pyruvic acid (oxidation)
-net gain of 2 ATPs produced by substrate-level phosphorylation -2 molecules of the coenzyme NAD+ are reduced to NADH (reduction event) |
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what can occur after glycolysis
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pyruvic acid may enter fermentation pathway of a respiration pathway (aerobic or anaerobic)
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fermentation
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-pyruvic acid is converted into lactic acid or ethanol+CO2
-NADH is oxidized back into NAD+ so that glycolysis can continue -NO ATP is produced -popular in microorganisms like yeast (beer, alcohol, bread) |
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what does respiration involve
|
-Krebs Cycle (also citric acid cycle or TCA)
-electron transport chain with an inorganic terminal electron acceptor |
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TEA in aerobic respiration
|
oxygen
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TEA in anaerobic respiration
|
not oxygen; nitrate or sulfate
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heterotrophs
|
obtain carbon in an organic form
|
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autotrophs
|
obtain carbon in inorganic form (CO2)
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phototrophs
|
obtain energy from light; capable of photosynthesis
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chemotrophs
|
obtain energy from the oxidation of chemical compounds
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chemoheterotrophs
|
use reduced organic compounds for both carbon and energy (ex: E.Coli and humans)
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chemoautotrophs
|
oxidize reduced inorganic compounds for energy, use CO2 as carbon source (ex:deep sea vent bacteria, lithoautotrophs)
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photoautotrophs
|
use light as an energy source and CO2 as carbon source (most common ecological producers, like cyanobacteria)
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photoheterotrophs
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use light as energy source and organic compounds for carbon (ex:green and purple nonsulfur bacteria)
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