Exam 3 Flashcards
How is the phylogenetic tree determined? (3.9)
- Relatedness based on comparing sequences of Small Subunit Ribosomal RNA (SSU rRNA)
- –Bacteria and Archaea: 16S rRNA
- –Eukarya: 18S rRNA
Phylum [definition] (3.9)
Group sharing a common ancestor
Genus [definition] (3.9)
Well defined group of one or more strains
By what system are microbes named? (3.9)
- A binomal system
- Genus and species
Thermus aquaticus [bacteria] (21.2)
- Grows at 70 - 75 C
- Source of Taq polymerase for PCR
- In phyla Thermus
Deinococcus radiodurans [bacteria] (21.2)
- Not thermophilic
- Extremely resistant to radiation and dessication
- In phyla Deinococcus
Cyanobacterium [phyla overview] (21.4)
- Primary producers in many ecosystems
- Undergo oxygenic photosynthesis
- –Water oxidized (electron donor), produces oxygen
- –Two photosystems
- –Calvin cycle to fix CO2 into carbohydrate
- Contain subcellular structures
- –Chlorophyll
- –Thylakoids
- –Carboxysomes
- —–Found in cytoplasm
- —–Where calvin cycle takes place with the use of the protein RubisCO
Anabena [bacteria] (21.4)
- Type of cyanobacteria
- Gram negative
- Aquatic
- Both oxygenic photosynthesis and nitrogen fixation take place
- –Problem with this: Enzyme nitrogenase for Nitrogen fixation is sensitive to the O2 produced by oxygenic photosynthesis
- –Solution: Differentiate vegeatative cells into hetercyst cells devoid of O2 that fix N2
- Fig. 21.12
Chlamydia [phyla] (21.6)
- Part of phylum Chlamydiae
- Gram negative
- Obligate intracellular bacteria
- –Require a host cell to reproduce, similar to a virus (but it is NOT a virus)
- Human and animal pathogens
Chlamydia trachomatis [bacteria] (21.6)
- Part of phylum Chlamydiae
- Causes #1 reported STI in the US
- Unique developmental cycle - Contains two distinct cell types (dimorphic)
Chlamydia Cell Types [two types] (21.6)
i) Elementary Body (EB)
- –Dormant, infectious
- –Attaces, enters, & develops into a reticulate body
ii) Reticulate Body (RB)
- –Reproductive, non-infectious, intracellular
- –Develops back into EB – leads to cell lysis
Spirochaetes [phyla overview] (21.7)
- Flexible, helical shape
- Flagella contained within the periplasm – underneath the outer membrane
- –Axial filament
- –Flagella rotation turns the whole cell
- Pathogens
Treponema pallidum [bacteria] (21.7)
- Cause of syphillus
- In phyla Spirochaetes
Borrelia burgdorferi [bacteria] (21.7)
- Cause of Lyme Disease
- Tick bite, causes bulls-eye rash
- In phyla Spirochaetes
Bacteroidetes [phyla overview] (21.8)
-Obligate anaerobes
Bacteroide [bacterial genus] (21.8)
- In phyla Bacteroidetes
- Anaerobic
- Gram negative
- Major component of intestinal microflora
- Degrade complex dietary polysaccharides
Proteobacteria [phyla overview] (22)
- Largest group
- Contains five major classes: Alpha, Beta, Gamma, Delta, and Epison
- Diverse cell forms & metabolism
- –Heterotrophs, phototrophs, and lithotrophs all contained in this phyla
Alpha Proteobacteria [class overview] (22.1)
- Some are photoheterotrophs
- –All that undergo photosynthesis do so anoxygenically (do not produce oxygen)
- Some are endosymbionts
Rhodospirillum [bacterial genus] (22.1)
- Part of class Alpha Proteobacteria
- A photoheterotroph
- Undergoes anoxygenic photosynthesis
Rhizobium [bacterial genus] (22.1)
- Part of class Alpha Proteobacteria
- An endosymbiont
- Produces root nodules on plants
- Symbiotic relationship with plants – It fixes N2 into ammonia for the plants to use, and in return, the plant gives it a place to live & food
- Essentially a fertilizer
Agrobacterium [bacterial genus] (22.1)
- Part of class Alpha Proteobacteria
- Causes plant tumors (galls)
- Not a symbiotic relationship with plants– it kills them
Rickettsia [bacteria genus] (22.1)
- Part of class Alpha Proteobacteria
- Occurs in animals
- Obligate intracellular bacteria (requires host to reproduce)
- Cause of Rocky Mountain Spotted Fever
- –From tick bites
Caulobacter [bacterial genus overview] (22.1)
- Gram negative
- Aquatic
- Dimorphic
- –Gives rise to two distinct cell types
Caulobacter Cell Types [two types; bacterial genus] (22.1)
i) Swarmer cell
ii) Stalked cell
Caulobacter Swarmer Cell (22.1)
- Motile ; Contains a flagella
- Cannot replicate its DNA – must transform into stalked cell to do so
- To transform into stalked cell, it ejects its flagellum, and a stalk will grow in its place
- Fig. 22.10
Caulobacter Stalked Cell (22.1)
- Non-motile
- Contains a stalk
- –Increases surface area of cell, attachment
- Has a Holdfast at the tip of the stalk
- Can replicate
- –Creates new swarmer cells, NOT new stalked cells
Caulobacter Stalk Holdfast (22.1)
- Made of polysaccharides
- Very sticky
- –Bonds more strongly than superglue
Beta Proteobacteria [class overview] (22.2)
- Some are lithotrophs
- –Oxidize nitrate, sulfur, and iron
- Some are important human pathogens
Nitrosomonas [bacterial genus] (22.2)
- Part of class Beta Proteobacteria
- A lithotroph
- Oxidizes ammonia to nitrite
- First step of nitrification
- –Important part of processing wastewater
Neisseria meningitidis and Neisseria gonorrhoeae [bacteria] (22.2)
- Part of class Beta Proteobacteria
- Cause of meningitis and gonorrhea
- Gram negative
- Diplococcus
Gamma Proteobacteria [class overview] (22.3)
- Includes a lot of enterics
- –Bacteria in human & animal intestinal tract
- Facultative anaerobes
- –Prefer oxygen but can live without it
- Includes some non-enterics as well
Escherichia coli [bacteria] (22.3)
- Part of class Gamma Proteobacteria
- Some strains are normal inhabitants of the intestinal tract (enteric)
- Some strains are pathogenic
- –O157:H7
Salmonella [bacterial genus] (22.3)
- Part of class Gamma Proteobacteria
- Enteric
- Cause of food poisoning
Proteus [bacterial genus] (22.3)
- Part of class Gamma Proteobacteria
- Cause of urinary tract infections (enteric)
- Has a ton of flagella covering its entire surface (peritrichous)
- –This helps it stay in the urinary tract even with the flow of urine
Psuedomonas aeruginosa [bacteria] (22.3)
- Part of class Gamma Proteobacteria
- Opportunistic pathogen
- –Will generally not hurt healthy people
- –Infects people with cystic fibrosis, burn patients, etc with compromised immune systems
Shewanella [bacterial genus] (22.3)
- Part of class Gamma Proteobacteria
- Non-pathogenic
- Found both aquatically and in soil
- Conducts extracellular electron transport