Bacterial cell division 2 Flashcards
Bacterial chromosome segregation mechanisms
Bacterial partitioning system (ParAB/parS)
Bulk chromosome segregation
FtsK
True or false. Chromosomes separate as dna replication occurs
True
What is bacterial partitioning system
(ParAB/parS)
Bulk chromosome segregation
is how bacterial maintenance of chromosomes (SMC) complexes
FtsK
Septum-located DNA translocase
Motor that converts chemical energy (hydrolysis of ATP) into movement of DNA substrate
Peptidoglycan added without compromising cell wall during cell division
How?
new material is added to the inner face of the wall not at the poles
what gives the bacteria structural support
peptidoglycan cell wall
disaccharides and amino acids
what do antibiotics often target
bacterial cell wall
what builds new peptidoglycans at mid cell
spherical cells
spherical cells only form new peptidoglycans
for septum at mid cell
what does the septum lead to
one daughter cell having an old and a new cell wall hemisphere
what happens during growth but prior to cell division
a new cell wall is made along the sides
not at the pole of the old one.
see slide 12
what determines the placement of the new cell wall
position of MreB homologues
What happens as division begins
Ft polymerization forms a z ring
new cell wall is confined to mid cell
rod shaped daughters cells
are formed with a new pole and old pole
see slide 12
Where does peptidoglycan synthesis start
the cytoplasm
3 peptidoglycan synthesis
autolysins
bactoprenol
Transpeptidation
What is function of autolysins
in peptidoglycan synthesis
enzymes that create small openings
Function of bactoprenol in peptidoglycan synthesis
Lipid carrier transports peptidoglycan precursors
Function of transpeptidation in peptidoglycan synthesis
Formation of cross-links between peptides on N-acetylmuramic acid residues
Inhibited by penicillin
extremophiles
Bacteria and Archaea
Require “extreme” conditions to grow
pH temp or pressure
what is normal pH and temp for growth
pH 7, temp 20-40C,
hyperthermophile
high temp over 90C, archaea
hyperthermophile
very hot loving
high temp over 90C,
archaea, thermovents, Pyrofulus
psychrophile
cold loving Antarctica
low temp bacteria 0 C,
polaramaus
alkaliphile
high pH 8-12 , archaea
barophile
high pressure over 500 atm
barophile
pressure over 500 atm, bacteria, deep ocean
Halophile
salt (naCl) between 15-32% to grow
archaea, salterns, halobacterium
Which of the following strategies enable non-acidophilic bacteria to endure lower pH environments?
A) Presence of internal buffers
B) Proton pumps that pump H+ out of the cell
C) Synthesis of acid shock proteins that protect other cellular proteins
D) All of the choices are correct.
D) all choices are correct
Organisms that are not drastically affected by increased pressure are called \_\_\_\_\_\_\_\_. A) barotolerant B) osmotolerant C) barophilic D) osmophilic
A) barotolerant
do not need it to grow
Organisms that require increased pressure for optimum growth are called \_\_\_\_\_\_\_\_. A) barotolerant B) osmotolerant C) barophilic D) osmophilic
C) barophilic
need it to grow
Organisms that grow near deep-sea volcanic vents are likely to be \_\_\_\_\_\_\_\_. A) psychrophilic B) psychrotrophic C) mesophilic D) thermophilic
D) thermophilic
Organisms that grow near deep-sea volcanic vents are likely to be \_\_\_\_\_\_\_\_. A) alkylophilic B) acidophilic C) barophilic or barotolerant D) picrophilic
C) barophilic or tolerant due to pressure
if thermophilic answer too
Organisms that grow in mud under relatively nonturbulent bodies of water are likely to be \_\_\_\_\_\_\_\_. A) obligate aerobes B) thermophilic C) barophilic D) anaerobes
D) anaerobes
DNA of thermophiles is stabilized by binding of special nucleoid-associated proteins. T/F
True
Membranes of some thermophilic Archaea are stabilized by ether linked phospholipids. T/F
True
Organisms that can grow in habitats with low water activity by maintaining a high internal salt concentration are called ________ organisms.
osmotolerant
Organisms that require high levels of sodium chloride in order to grow are called ________ organisms.
halophillic
Membranes of thermophilic bacteria are stabilized by phospholipids with ________.
A) fatty acids that tend to be more saturated
B) fatty acids that have lower molecular weights
C) fatty acids that have more double bonds
D) All of the choices are correct.
A) fatty acids that tend to be more saturated
water activity (aw)
measure of water available for use (not bound)
no microbial growth, less than 0.6
Osmolarity
number of solute molecules in solution
how are osmolarity and water activity related
look at slide 17
inversely
if one high, other low
one low, other high
what is halotolerant
tolerant to growth in increased salt NaCl
xerophiles
require low water activity for growth
mesophile
moderate loving
15-45 degrees,
pathogens
thermophillic
hot loving
40-80C
compost piles, water lines
