Chapter 4 (Book) Bacterial Growth Flashcards
essential nutrients
compounds a microbe cant make, but must gather from the environment to grow and divide
macronutrients
nutrients needed in large quantities
carbon, nitrogen, phosphorous, hydrogen, oxygen, sulfur
form carbohydrates, lipids, nucleic acids, proteins
cofactors
Mg
Fe
K
micronutrients (components of enzymes)
cobalt
copper
zinc
manganese
nickel
defined mineral medium
contains only the nutrients a microbe needs to grow
what percent of microbes are unculturable
99.9%
microbes build biomass through _______ or _______
autotrophy, heterotrophy
heterotrophy
rely on other organisms to form the organic compounds they use as carbon sources
autotrophy
fix CO2 into complex organic molecules
2 classifications of autotrophs
photoautotroph
chemoautotrophs
photoautotroph
use light for photosynthesis (energy)
chemoautotrophs
gain energy by oxidizing inorganic substances like iron/ ammonia or oxidizing organic compounds
chemolithotrophs
organotrophs
membrane potential
energy stores by an electrical potential across the membrane
generated when protons are pumped outside of the cell (inside negative)
electrochemical potential
ion gradient + charge difference
aka proton motive force
what can the proton motive force be used for
move nutrients into cell via transporters
drive motors that rotate flagella
drive synthesis of ATP by ATP synthase
the nitrogen cycle depends on _______ and _______
bacteria, archaea
N2 gas makes up how much of Earth’s atmosphere
79%
for nitrogen to be used for growth, it must be ______, or converted into ammonium ions
fixed
nitrogen fixing bacteria
free-living in soil or water
or form symbiotic associations with plants
symbiont
an organism that lives in intimate association with another organism
mixotrophic
able to use photosynthesis or heterotrophic respiration depending on environmental conditions
3 ways selective permeability is achieved
substrate-specific carrier proteins in the memb
nutrient-binding proteins in periplasmic space
membrane-spanning protein channels/pores
facilitated diffusion
from high concentration to low concentration
ex. aquaporin, GlpF glycerol transporter in E.coli
GlpF
2 conformations – one exposes glycerol binding site to environment, other releases glycerol into cytoplasm
facilitated diffusion, so passive and high [ ] to low [ ]
coupled transport
using the energy from moving an ion down its conc gradient to move a molecule against its conc gradient
symport - same direction
antiport - opposite directions
LacY symporter in E. coli
moves lactose inside cell
powered by proton also moving in the cell
Na/H antiporter
moves Na+ out and H+ in
ABC transporters are powered by ___
ATP
ATP-binding cassete transporters
ABC transport
substrate-binding protein snags a solute (periplasm of gram neg, outside of gram pos)
solute attaches to ABC transporter which hydrolyzes ATP –> ADP
conformational change allows solute to enter cell
siderophores
secreted molecules with an affinity for iron
attached iron sent into cell by ABC or a transporter
group translocation
alters substrate during transport by attaching a different group to it so it is moving down a [ ] gradient
ex. phosphotransferase system (PTS)
phosphotransferase system (PTS)
a group translocation system in bacteria
attach phosphate to sugars during transport
can an ABC transporter be used as a multidrug efflux pump?
yes
