1.6: Microbial Growth

reproduction

making a copy of bacteria

microbial eating

nutrients enter the cells by passing through the cell membrane

Diffusion

movement in a gradient from high to low density/concentration

osmosis

diffusion of water through a cell membrane/permeable membrane

active transport

movement of particles/nutrients against the concentration gradient using protein pumps and ATP

endocytosis

the cell encloses the substance in its membrane forming a vacuole

environmental factors that impact growth

• temperature

• gases

• pH

• pressure

• symbiosis

optimum temperature

a small range that promotes the fastest growth and metabolism

aerobes

microbes that use oxygen in their metabolism

obligate aerobes

microbes that can not grow without oxygen

anaerobes

microbes that can not use oxygen in respiration

obligate anaerobes

can not grow in oxygen environment because they cant process oxygen

facultative anaerobes

use oxygen when present but don’t require it

aerotolerant anaerobes

don’t use oxygen but have ways to process it

isotonic solution

equal solute concentration and pressure inside and outside of cell

hypotonic solution

more solute in the cell than outside, so water moves into cell and cell may burst

hypertonic solution

more solute outside of the cell, water moves out of the cell and cell shrinks

symbiosis

situation where two organisms live together in a close partnership (not always positive)

mutualism

benefits both organisms

commensalism

one organism benefits while the other isn’t harmed or benefitted

parasitism

a host organism suffers a the parasite receives nutrients and a habitat

antagonism

the association between free-living species that arise when members of community compete (only so much nutrients available)

synergism

interrelationship between 2 or more free living organisms that benefit them but isn’t necessary for their survival

binary fission

two daughter cells created from 1 parent

lag phase

population doesn’t appear to be growing, cells need to adjust

exponential growth phase

cells reach maximum rate of cell division and will continue as long as nutrients and environment are favorable

stationary phase

rates of new cells and dying cells reach equilibrium

death phase

cells die at an exponential rate but slower than growth