Lecture 1 - Introduction Flashcards Preview

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Flashcards in Lecture 1 - Introduction Deck (12):

What are two common bacterial shapes?

Cocci (spheres), bacilli (rods)


What is unique about gram-positive bacterial cell walls? What color do they stain?

The cell wall has a thick peptidoglycan layer. They stain purple.


How does penicillin work?

It mimics the D-ala-D-ala portion of the proteoglycan in the cell wall, so cross links are unable to be formed in new bacteria cells. This weakens the cell walls, and the bacteria lyse due to naturally high osmotic pressure.


Do bacteria grow quickly?



What do bacteria do during the stationary phase?

They are looking for nutrients, secreting degradative enzymes, activating catabolic pathways, secreting toxin, and can form spores.


Why do bacteria enter stationary phase?

Nutritional limitation.


What is the difference between anaerobic respiration and fermentation?

Anaerobic respiration is generation of ATP using the electron transport chain but with a molecule other than O2 as the final e- acceptor. Fermentation is just doing glycolysis.


What are spores? What are some attributes?

Spores are hardy, non-growing structures that some Gram positive bacteria produce. Spore formation is triggered by nutritional limitation. Spores can survive harsh conditions.


Name three spore-producing bacteria.

C. dificile, C. botulinum, C. tetani.


Compare exotoxin vs. endotoxin.

Endotoxin is the toxic effects of the LPSs on the Gram-neg cell wall. Exotoxins are proteins produced by bacteria that have toxic effects.


What is a prototroph? Auxotroph?

Prototrophs require only a simple carbon source (like a sugar).
Auxotrophs have more complex nutritional requirements.


What do porin proteins do?

Found on the outer membrane of gram negative bacteria, they transport small hydrophilic molecules.