lecture 9 Flashcards
(42 cards)
eukaryotic cell “walls” can be made of _____ or _____
cellulose or chitin
archaea cell walls are made of:
polysaccharides and proteins
bacteria cell walls are made of :
peptidoglycan, a network of sugar polymers cross-linked by polypeptides
the gram + cell wall of bacteria is what type of toxin?
exotoxin
the gram - cell wall of bacteria is what type of toxin?
endotoxin
capsules often present:
sticky coating of polysaccharides or proteins
fimbrae often present:
sticky hair-like projections
what are pili?
allow prokaryotes to exchange DNA
what do fimbrae and capsules have in common?
allow bacteria to adhere to eachother or other surfaces
what is exaptation?
existing structures take on a new function through descent with modification. such as flagella likely evolving from existing proteins.
how do prokarytoes reproduce?
binary fission, in short generation times like 1-3 hours
what 3 factors contribute to prokaryotic genetic diversity?
rapid reproduction
mutation
genetic recombination
what is genetic recombination
when DNA from different individuals can be brought together by transformation, transduction, and conjugation
what is horizontal gene transfer
movement of genes among individuals from different species
what are the 2 categories of obtaining energy
phototrophs and chemotrophs
chemotrophs obtain energy from:
chemicals
what is a phototroph
an organism that obtains ENERGY by LIGHT
what are autotrophs
use CO2 as a carbon source
what are heterotrophs
require an organic nutrient to make organic compounds
what is a photoautotroph?
organism that gets energy from light and carbon from CO2
if an organism requires chemicals and organic nutrients for nutrition, its called a:
chemoheterotroph
what is nitrogen fixation in prokaryotes?
when they convert atmospheric nitrogen (N2) to ammonia (NH3)
which vitamins do bacteria in our microbiome produce?
B vitamins such as vitamin B12, thiamine and riboflavin, and vitamin k (used for blood coagulation)
besides produce vitamins, what do bacteria in our microbiomes help us do?
digest food, regulate immune system, protect against bad bacteria