Exam 3 Quiz 3 Flashcards
thermophiles
-soils in direct sunlight
-seen around hotsprings
hyperthermophiles
-hot springs and steam vents
-more extreme hot ranges
proteins/enzymes in thermophiles
-highly hydrophobic interior
-stabilizing solutes
stabilizing solutes used in enzyme
- di-inositol phosphate
-diglyceride phosphate
membrane of thermophiles
-saturated, long chain fatty acid
-more hydrophobic environment
-higher melting point
Archaea membrane in hyperthermophile environment have
biphatanol that gives a monolayer instead of bilayer
internal pH
has to be between 5-9
typical pH of neutrophiles on outside
7
what is used to keep the pH at 7?
a buffer, typically sodium bicarbonate or potassium phosphate
acidophiles
-more archaea seen here than bacteria
-seen when pH below 5.5
-[ ] of protons greater outside the cell
how do acidophiles survive
-transport cations into cell to balance out (typically K+)
-proton transporters that protons in and back out
-highly impermeable membrane to deter protons from crossing
Alkaliphiles
- [ ] of protons lower outside the cell
-uses sodium mode of force, not proton mode of force
-pH around 8 and higher
what do most bacteria prefer?
isotonic (E. coli) or slightly hypotonic environments
how do bacteria survive hypotonic conditions
mechanosensitive channels
mechanosensitive channels
detect increased tension/pressure on membrane and will open channels to release excess solutes
how do bacteria survive hypertonic environments
compatible solutes
compatible solutes main idea*****
-draw in a solute or synthesize solute that allows you to even out
-make sure it doesn’t downplay a necessary enzymatic pathway
-CAN NOT inhibit cellular metabolism
how are compatible solutes controlled?
genetically controlled
genetically controlled
categorized by how much compatible solutes present
haplophiles
grow optimally in the presence of NaCl
mild haplophile
1-6% NaCl
moderate haplophile
7-15% NaCl
extreme haplophile
15-30% NaCl
Halotolerant organisms
grow best in the absence of NaCl but can withstand a small concentration in the environment
bacteria and archaea use what for their compatible solute
inorganic substance, typically KCl
aerobe
-requires gaseous oxygen for metabolism
-e- acceptor
-21% oxygen concentration
microaerophile
-cannot withstand atmospheric oxygen levels but requires a low level of oxygen
-found in deeper ocean and deep soil
-2-10% oxygen
anaerobes
do not use gaseous oxygen in metabolism
aerotolerant
does not use oxygen inmetabolism but can be in the presence of oxygen
obligate/strict anaerobe
cannot be in the presence of oxygen or will die
facultative anaerobes
-can use oxygen in respiration but can also live in its absence
-only will convert to a different source if there is no oxygen available
-can use anerobic respiration or fermentation as other option
thioglycollate broth ingredients
-sodium thioglycollate that reduces O2 (not perfect system bc vented cap)
-redox indicator that tells you where O2 is in tube by turning pink
-small amount of agar to add viscosity
aerobes in T broth
grow at top in the pink layer
facultative anaerobes in T broth
prefer O at the top near pink but can grow throughout
aerotolerant in T broth
all throughout broth without any bias
anaerobes in T broth
only found at the bottom of the tube where O not present
Microaerophile in T broth
not used/ not good because you will not form a good gradient bc of the 2-10% O requirement
oxygen in cellular respiration
can be converted into toxic oxygen byproducts or reactive oxygen species
reactive oxygen species
not good, highly reactive with proteins or anything thats around
examples of toxic byproduct
-singlet oxygen
-superoxide anion
-hydrogen peroxide
-hydroxyl radical
first byproducts made
superoxide anion and hydrogen peroxide , they need enzymes to prevent these from sticking in their cells
enzymes that combat hydrogen peroxide
catalase and peroxidase
enzyme that combats superoxide anion
superoxide dismutase
how do superoxide anion and hydrogen peroxide form
in electron transport chain, flavoproteins, quinones, and Fe-S proteins allow for side reactions where they form
aerotolerant prevention methods
use protein-free manganese complexes
strict anaerobes
-see only superoxide reductase which is odd because anaerobes don’t need oxygen
-also no oxygen byproduct formed
