anabolism

what does growth refer to

increase in cell numebr

how do bacteria increase their numbers

by binary fission, not mitosis

what refers to doubling of population

generation

explain the process of binary fission

1. dna replication

2. cell elongates

3. septum forms

4. septum is completed with formation of distinct walls

5. cells separate

what does Fts proteins stand for

filamentous temperature sensitive mutants

what do Fts proteins do

• they grow at low temps and divide sucessfully

• fail to divide at high temps and grow into long filaments instead

briefly explain immuno-electron microscopy

1. antibodies recognize FtsZ at antigen-biding domains are conjugated to gold in the Fc portion of the antigen.

2. antibodies probe a section of the bacterium and is viewed through TEM

3. black dots on micrograph appear black and are the location of FtsZ

explain DNA replication with FtsZ

DNA replication comes before FtsZ ring formation

What do proteins like FtsK do

help chromosomes segregate towards poles

• segregate genomes into 2 daughter cells

what do FtsZ rings do

depolymerize, constricting the membrane at the septum to help form a septum

how many chromosomes end up in a daughter cell

one copy of the chromosome in each daughter cell

what does MinC do

prevent cell division and formation of Z rings until the center has been located

what does MinE do

inhibit MinC, localize the center, and recruit FtsZ

what does MreB do

• Form polymers similar to actin filaments that make up a cytoskeleton of a eukaryotic cells

• Dictates cell shape; cocci have no MreB

what do FtZ polymers resemble

tubulin, another cytoskeleton protein in eukaryotes

how does FtsZ find the cell midpoint

with ninE and minC

what are autolysins

break glycosidic bonds in peptidoglycan in a controlled way at point of new synthesis

describe bactoprenol

• hydrophobic

• shuttles precursors across membrane

• interacts with assembly proteins to catalyze incorporation of new sugars

what is a transpeptidase

it trades one peptide bond for another

• catalyzes cross linking

• target of penicillin

what is generation time

time required for one generation to occur and is inversely related to growth rate

what does it mean to be inversely related to growth rate

fast growth = slow time

slow growth= fast time

what is exponential growth

pattern of growth which the population doubles per unit of time

What does N = in exponential growth

number of cells at a given time

What does N₀ = in exponential growth

starting number of cells

What does n = in exponential growth

number of generations

What does g = in exponential growth

generation time

What does t = in exponential growth

time

how is generation time determined

from slope of line

• g= log2 /slope

how is division rate (v) determined

it is reciprocal of generation time (1/g)

how do you calculate the number of generations

3.3(logN - LogN₀)

describe chemostats

• steady state growth

• allow for control of bacterial growth by varying nutrient supply

• allow for control of cell density by varying concentration in medium

• allow for extended exponential growth

explain the growth process in chemostats

it grows for a long period of time; speed is based on how quick you grow the nutrients

what are the stages (in order) for batch culture growth

1. lag

2. exponential

3. stationary

4. death

explain the lag stage in batch culture growth

early stage; interval before growth occurs

explain the exponential stage in batch culture growth

maximum/rapid growth; cells divide to make more cells, cell population increases, and is the healthiest state

explain the stationary stage in batch culture growth

growth plateaus;  no net increase or decrease in cell number, growth rate is zero, and is either caused by an essential nutrient of

the culture being used up or a waste product of the organism accumulates in the medium and inhibits growth

explain the death stage in batch culture growth

end of cell growth; cells die, some death accompanied by lysis, can be caused by lack of nutrients

explain the components of a chemostat growth on a graph

• dilution rate (sets the growth rate)

• washout (caused when adding medium too fast)

• doubling time

• bacterial concentration

• steady state (growing exponentially)

what are some experimental uses of chemostat

• constant supply of cells in a stable condition

• ecological studies to measure relationships in mixed populations

• enrichment and isolation of strains with specific growth characteristics

• measurement of genetic variation over extended generations

how do organisms in chemostat differ from batch

chemostat: metabolic status is the same, always growing

batch: lag, exponential, stationary, death

do pure cultures have to be used in a chemostat

no!