Midterm 1 Flashcards
True or false: Human cells outnumber the amount of bacterial cells in the body
False: BACTERIAL cells outnumber human cells
What are bacteriophages?
They are viruses that kill bacteria
- attach to the surface of the cell and inject their DNA
What are some other uses for bacteriophages?
Can be used to treat infections (specific for certain bacteria)
- less threat of antibiotic resistance (but, phage resistance can occur)
- kills infections without killing all of the healthy microbiomes in the body
What are two difference medicinal applications of intact bacteria?
Probiotics and Fecal microbiota transplants
Describe probiotics
- live microbes
- manage inflammation, prevent infections, etc
- not all claims valid…
Describe fecal microbiota transplants (FMTs)
- fecal bacteria from healthy donor used as therapeutic
- helps with gastrointestinal disorders, infections
What is the role of microbes in food production? Provide some examples.
Can ferment carbohydrates, make acids, alcohols
In baking:
- S. cerevisiae (yeast) makes CO2, causes bread to rise
- sourdough: lactobacili make lactic acid
Pickling:
- lactic acid bacteria make lactic acid
- low pH limits microbial growth
Brewing/winemaking:
- yeasts make ethanol from sugars in grape juice (wine), steeped grain (beer)
Discuss how microbes affect dairy products?
Removing microbes:
- raw milk can contain pathogens so it is pasteurized (killed by mild heat)
Inserting microbes:
- to coagulate milk proteins (yoghurt, cheese)
What are the three domains of life?
Bacteria, archaea, and eukarya
What are bacteria and archaea considered and why?
prokaryotes, has to do with the structure of the cell and components of the cytoplasm
Describe the difference between prokaryotes (bacteria and archaea) and eukaryotes (eukarya)
Prokaryotes (are **usually):
- DNA in cytoplasm
- lack membrane-enclosed organelles (like golgi-apparatus or ER)
- single-celled
Eukaryotes:
- DNA surrounded by nuclear membrane
- Membrane-bound organelles
- single celled (e.g. algae) or multicellular (e.g. animals)
What is a key thing about bacteria that have capsules?
They are much more difficult to be controlled by the immune system (which allows it to cause infections easier)
What are major differences between bacteria and archaea?
- Cell wall components (bacteria contains peptidoglycan which is very important for their survival)
- types of lipids in membranes
- transcriptional, translational components
Why are archaea are more similar to eukaryotes than bacteria?
The DNA sequences are much more similar to eukaryotic cells than bacterial cells
How would use taxonomic ranks to name an organism?
in italics we write
genus + species
we capitalize the first letter of the genus
What is a strain?
Descendants of a single pure microbial culture
What is a bacterial species?
Groups of strains with similar properties
True or false: Bacteria replicate through sexual reproduction
FALSE
True or false: Strains have genetic differences
TRUE
How can we identify prokaryotes? (3 ways)
- morphology and composition
- metabolism
- ecology (where were they isolated, what kind of environment?)
What can we visualize through simple staining?
Size, shape, arrangements of cells
What can we visualize through differential staining?
Differentiate between different types of bacteria based on type of cell wall (e.g. Gram staining) or look at cellular components of the bacterial cell (e.g. capsules or flagella)
Describe gram staining and how it shows us cell wall structure
It differentiates between gram-positives and gram-negatives
these diff cell wall structures impact:
- antibiotic susceptibility
- interactions with immune system
Which ones are de-stained by the alcohol, and which ones retain the crystal violet dye?
- Gram negative
- Gram positive
Gram-negative is DESTAINED by the alcohol
Gram-positive retains the crystal violet dye