microbiology Flashcards
1
Q
Characteristics of gram-negative bacteria cells?
A
less sturdy - thinner layer of peptidoglycan
complex outer membrane
do not retain stain
2
Q
Characteristics of gram-positive bacteria cells?
A
simple structure
several layers of peptidoglycan - crosslinks
retain stain
teichoic acid
3
Q
what is the lag phase?
A
number of cells do not change
cells grow larger
4
Q
what happens in log phase?
A
bacteria actively dividing
number increases exponentially
medium has continuous change
5
Q
what happens in stationary phase?
A
nutrients used and waste builds up
depletion of o2 limits growth
new cells = cells dying - equilibrium
6
Q
what happens in death phase?
A
dying exceeds dividing cells
toxic products build
nutrients exhausted
7
Q
how can death phase be reversed?
A
replenishing the growth medium
