Lecture 3 and 4 Flashcards
How can microorganisms be classifed?
Nutritional pattern (source of energy and carbon)
What two groups can chemotrophs and phototrophs be divided into?
Autotroph
Heterotroph
What do autotrophs use as a carbon source?
CO2 (anabolic)
What do heterotrophs use as a carbon source?
Organic carbon (catabolic)
What do chemoautotrophs do?
Oxidise inorganic compounds to produce chemical energy,
use energy to reduce CO2
What inorganic compounds to chemoautotrophs oxidise?
Hydrogen sulfied
Elemental sulfur
Ferrous iron
H2
What organisms are chemoautotrophs?
Usually bacteria/archaea living in hostile environments
Name an organism that oxidises ferrous iron (Fe2+)
Acidithiobacillus ferroxidans
Give an example of an organism oxidises hydrogen sulfide
Beggiatoa
Give an example of an organism that oxidises sulphur
Acidithiobacillus thiooxidans
Give an organism that oxidses ammonia
Nitrosomonas
Give an organism that oxidises nitrite into nitrate
Nitrobacter
What groups do chemoheterotrophs include?
Fungi, most protozoa, most bacteria
What are the carbon and energy source that chemoheterotrophs use?
Organic molecules (e.g. glucose, glycogen, cellulose)
Name some photoautotroph micro-organisms.
Photosynthetic bacteria
Algae
Give examples of photosynthetic bacteria.
Green and purple sulphur bacteria
Cyanobacteria
How do cyanobacteria/algae photosynthesise?
Oxidise H2O to O2
oxygenic
How do green and purple sulphur bacteria photosynthesise?
Oxidise H2S to sulfur
No O2 produced
(anoxygenic)
What microorganisms are photoheterotrophs?
Green non-sulphur and purple non-sulphur bacteria
What are photoheterotrophs usually?
Anoxygenic (do not produce oxygen)
What is diversity the result of?
3.8 billion years of evolution
What is the size of a cocci in diameter?
0.2-2 microM
What is the length of a typical rod?
2-8 microM long
What is the typical size of a eukaryotic cell?
10-100 microM
What is the structure of the prokaryotic flagella?
Simple: 2 proteins
What is the structure of the eukaryotic flagella?
Complex: multiple microtubules
Do bacteria or archea have histones?
Bacteria don’t
Archaea do
What is the must abundant group of living organisms on Earth?
Bacteria
How do bacteria divide?
Binary fission
What type of growth does binary fission result in?
Exponential growth
What type of ribosome do bacteria have?
70S
What are bacterial cells enclosed in?
Cell membrane and rigid cell wall
Where is peptidoglycan found in bacteria?
The cell wall
What is peptidoglycan?
Sugar polymer
What is the bacterial cell membrane composed of?
Unbranched fatty acid chains attached to glycerol by ester linkages
Name 5 shapes of bacteria.
Coccus Rod Spirillum Spirochete Filamentous
What name is given to two cocci linked together in a pair? What about 4? What about a chain?
Diploccci, tetrad
Streptococci
What are the three main groups of archaea?
Methanogens
Extreme halophiles
Extreme thermophiles
What nutritional group do archaea predominantly belong to?
Chemoautotrophs
Who proposed that archaea are a distinct group?
Woese and fox (1977)
What ribosome do archaea have?
70S, but unique to archaea
What do archaea cell walls have?
Some have S-layer
Some have psuedopeptidoglycan
What is an S layer?
Proteins/glycoproteins
5-25nm thick
Poorly conserved
What are archaea membranes composed of?
Branched hydrocarbon chains attached to glycerol by ether linkages
What molecules do fungi degrade to produce energy?
Ligin, cellulose
What is chitin?
Polymer of N-acetylglucosamine
Give an example of unicellular fungi
Candida albicans
What are multicellular fungi (molds, mushrooms) composed of?
Mycelium made of vegetative hyphae
What is the type of big mushroom called?
Armillaria ostoyae
How big is the big boi?
8.9km^2 in Oregon (USA)
How do multicellular fungi reproduce asexually?
Hyphal fragmentation
Sporgangia
How do multicellular fungi reproduce sexually?
Gametangia
Some fungi can switch to grow as a mold or yeast. These are said to be ______.
Dimorphic
Name a dimorphic fungi
Blastomyces dermatitidis
Where does blastomyces dermatitidis normally live?
Soil that contains organic debris, lives as mycelium
What does the unicellular form of Blastomyces dermatitidis cause when it infects mammals?
Blastomycosis
What triggers the switch from mycelium to yeast in B. dermatitidis?
37 degree C switch
What nutritional group do protozoa belong to?
Chemoheterotrophs (hunters and grazers)
Name some free living protozoa.
Paramecium, Amoeba
Name some parasitic protozoa.
Plasmodim, Trypanosoma, Giardia
Protozoa are unicellular or multicellular?
Unicellular
Do protozoa have cell walls?
No
How do protozoa move?
Psuedopodia
Flagella
Cilia
What protozoa reproduce sexually by fusion of gametes?
Plasmodium
What protozoa can produce cysts?
Giardia, Entamoeba
What are 3 ways protozoa reproduce asexually?
Binary fission
Schizogony
Budding
What is schizogony?
The nucleus divides many times before the cell divides
What drives the photosynthetic machinery of algae?
Cyanobacteria
What do algae cell walls contain?
Cellulose
Why aren’t algae plants?
They lack organs found in plants (roots, leaves)
Who started the modern biological classification system?
Carl Linnaeus
What was Carl Linnaeus’ two major ideas?
- Scientific nomenclature
2. Natural classification
What was Linnaeus’ idea about natural classification?
Grouped species according to shared physical traits to reveal natural order of life
What were the 2 classifications Linnaeus came up with?
Vegetabilia
Animalia
Who came up with the most modern classification taxonomies before domains were elevated above kingdoms?
Whittaker (1969)
What bacteria causes whooping cough?
Bordetella pertussis (gram negative)
What bacteria causes cholera?
Vibrio cholerae
What bacteria causes boils on the skin?
Staphylococcus aureus
Why classify micro-organisms?
- Accurate diagnosis
- Appropriate treatment
- Analysis of transmission
What are 3 limitations to using physical traits to classify bacteria?
- Don’t necessarily reveal relatedness
- Don’t reveal biology
- Don’t reveal phylogeny
Who developed the use of rRNA gene sequences for uncovering bacteria phylogeny?
Carl Woese
What is the small rRNA contained in the ribosome of bacteria and eukaryotes?
16S in bacteria
18S in eukaryotes
Why were SSU rRNA genes used?
Present in all cellular organisms
Function essential for survival
Changes acquire slowly
What is SSU rRNA said to function as?
A molecular clock- because it measures evolutionary relatedness of sequneces
What did Woese et al do to the taxonomic classifications in the 1990’s?
He elevated domains (bacteria, archaea, eukarya) above kingdoms
What are the 8 taxonomic rankings?
Domain, kingdom, phylum, class, order, family, genus, species
