Microbes Pt2: Lec 5-8 Flashcards
(32 cards)
What si a prokaryote?
bacteria and archaea (defined by their lack of a membrane bound nucleus for chromosomes.
Explain the plasma membrane
a membranous semi-permeable barrier that contains cytoplasm, organelles, and is incharge of letting things pass into the cell, and is the sight of vital cell processes like respiration.
Define the cell wall:
provides structure, osmotic balance, and helps divide into gram negative or positive.
can either be gram negative or gram positive
Compare Gram negative and gram positive cell walls:
Gram negative - the cell wall property of a prokaryote that has only a small thin layer of peptidoglycan between two lipid bilayers.
Stains pink, has an outer membrane, and crystal violet is washed by alcohol
E.g: E. coli and Salmonella enteria
Gram positive - cell wall property of prokaryote that has only a thick multi-layer peptidoglycan on the outer side of the cell.
Stains vibrant violet, has no outer membrane, and crystal violet is unable to be alcohol washed.
E.g. Streptococcus pneumoniae, staphylococcus aureus
Explain a biofilm and waht it provides?
collection of organised microbial community encase in extracellular polymeric substance on different surfaces (is typically slimy)
Provides Protection - from (a)biotic factors
Nutrients - metabolic interdependency
Adaptive Environment - HGT and increased diversity
Multicellularity - communication
Explain Vibrio Fischeri and their relationship with the bobtail squid:
a certain bacteria that works mutually with the Bobtail squid.
Cilia on the squid hatch and draw in Vibrio Fischeri bacteria, which the squid’s mucus layer responds to the amount of bacteria accumulated (typically to very high levels)
The squid’s mucus layer responds to the change through chemical signals to produce a bioluminescent effect
A symbiotic abundance cycle
Uses Quorum Sense
Explain quorum sense and how it might be stopped:
Bacterial community signalling system using autoinducers to coordinate behaviours to population density; thus allowing them to express genes collectively when a high enough population is reached.
Signaling analogies - similarly shaped to binding inhibitors that involve QS-inhibition. Is able to mess up cell communication in a biofilm’s Quorum sense
What is a rarefaction curve?
Helps to sequence clarification - shows if we’ve sampled enough through “number of species (ASVs)” and “number of sequences”
What are the eukaryotic microorganisms?
Fungi and Protists/Protozoa
what are the main charactersitics of fungi and protists?
- Membrane bound organelles that perform specific functions
- Membrane bound nucleus that holds the genetic material (defining trait)
- More Structurally complex - larger than other bacteria (bound nucleus = large step more complex and intelligent organisms)
Mitochondria and chloroplasts
Kleptoplasty - when animals utilize chloroplasts they eat from plants (long term function of these chloroplasts suggest bidirectional communication) - Eukaryotic Cell Envelope (cell wall):
*Fungi cell walls contain: chitin (polysaccharides), and cellulose
Algae cell walls contain: cellulose, silica, and pectin
What are the three main fungal groups?
Chytridiomycota (chytrids)
Basidiomycota
Ascomycota
Explain Chytrids and give an example
Characteristics:
*Simplest fungi: free-living, saprotrophic, produces zoospores with single whip flagellum (very primitive)
*(A)sexual reproduction, degrade cellulose and keratin
Example: Batrachochytrium dendrobatidis (Bd)
*Aquatic pathogen disease dispersal through zoospores.
*Only some natural skin microbiota are resistant to Bd growth.
Explain Basidiomycota and give an example
Characteristics:
Produce spores, some are toxic, (a)sexually through basidiospores, important decomposers of wood and plants
Example: Myrtle Rust (Austropuccinia psidii)
Fungus undergoes two different life cycles (asexual then sexual)
Early stages show small purple spots. Later stages show lesions typically targeting new shoots and young leaves.
Explain Ascomycota nad give an example(s)
Characteristics
(a)sexual reproduction, found in all habitats, the red/green/blue molds on foods, some are human pathogens
Example: Claviceps purpurea (LSD wheat plants infected grain, ergotism) & Stachybotrys (black mold causing “sick building syndrome”)
what is the type of fungus taht makes wine and how does it do this?
Saccharomyces Cerevisiae:
Used in wine making with fungal species (either old or new world making)
Is a fungus that uses niche construction in order to out compete other fungus due to its high heat, osmotic pressure, and pH tolerance.
Method:
Yeast ferments to make energy → grape juice sugars broken from sugar-splitting reaction → pyruvate converted to acetaldehyde → ethanol = alcohol!
What si a protist?
a generalised term for different lineages of microbial eukaryotes, unicellular and multicellular species.
Made of: phototrophs, heterotrophs, and mixotrophs.
(a)sexually reproduce
What is macroalgae?
seaweeds, or other multicellular algae (typically brown, red, or green), primary producers
Explain the types of microalgae
- Dinoflagellates: flagella (spin), responsible for “red tides” (toxic), global warming helps increase dinoflagellates, produce neurotoxins for shellfish poisoning.
Important symbiotes; zooxanthellae (major nutrition for coral: “coral bleaching”) - Diatoms: made of silicon-dioxide that make signature glass-like walls, highly diverse, major part of phytoplankton
- Phytoplankton (chlorophytes): primary producers for sea (50% global photosynthesis), cyanobacteria and eukaryotes, help fix carbons
“6CO2 + 6H2O → C6H12O6 + 6O2”
Provide proxy measurement of potential Carbon fixation
Give an exmpale of macronutrients and why they’re necessary?
Nitrogen, Phosphorus, Silicon, - algae need these to grow, but they are short in supply.
Explain SOIREE (name, hypothesis, and results)
“Southern Ocean Iron Release Experiment”
Hypothesis - if we increase phytoplankton then more carbon will be fixed. Iron is a lacking macronutrient for microalgae, so let’s dump a bunch of iron into the sea.
Biological pump - dead organic matter (“marine snow”), fall to deep, dead phytoplankton having fixed Carbon will fall.
Iron↑ Phytoplankton↑ C settling↑ Co2 atmosphere↓
Results: Iron was absorbed, chlorophyll and phytoplankton increased, but excess iron depleted other macronutrients.
Increased phytoplankton, but didn’t settle (just floated)
Iron↑ Phytoplankton↑ C settling?? Co2 atmosphere↓
Explain SERIES (name and results)
“Subarctic Ecosystem Response to Iron-Enrichment”
(same thing, just to track where particulate organic carbon (POC) is going)
Results: Iron absorbed, Biomass and Diatoms↑ , Chlorophyll↑, Macronutrients↓
Only a small fraction of atmospheric CO2 fell as snow (about 258 POC were lost): 22% caught in traps, consumed by heterotrophs, remineralised as CO2 again through zooplankton.
What are viruses? what are they important for?
acellular, infectious, agent made of proteins and nucleic acids (DNA or RNA), can live in or out of host cells, can only reproduce intracellularly, and mostly infect eukaryotic cells.
Important to: aquatic life, evolution (HGT), and Human Virome
What is a viron?
a complete virus particle; consists of a capsid (at least 1 DNA or RNA protective protein coat) and envelopes (additional layers around capsid)
how do we classify virus families?
Genome structure (sRNA, ssRNA, dsDNA, or ssDNA)
Morphology
Genetic relatedness
Life cycle
