Lecture 3 Flashcards
Significance of Smallness
greater surface to volume ratio
greater growth rates
faster evolution
coccus
sphere
bacillus
cylindrical
spirillum
spiral
spirochete
cork-screw
filamentous
clusters
last main shape for cell morphology
appendaged
diplo cluster types
pairs (2 cells)
strepto cluster types
chains (3+)
staphylo cluster types
group
structure and function of cytoplasmic membrane
phospholipid bilayer
separate cytoplasm (inside) from environment (outside) and selective permeability
membrane proteins are like
buoys! they float around
membraned proteins are…
anchored in cytoplasmic membrane
hydrophobic and hydrophilic regions
types of membrane proteins
integral (whole way through) and peripheral (inside or outside of cell)
archaea vs. bacteria linkage of glycerol head and fatty acids tail
bacteria- ester linkage
archaea- ether linkage
archaea vs. bacteria fatty acid composition
archaea–isoprene
what kind of membranes are only in archaea? what is advantage?
monolayer membranes
increase strength (found in extreme environments)
archaea vs. bacteria similarities
functionality of the cytoplasmic membrane
what are the functions of cytoplasmic membrane?
permeability barrier (selective)– nutrient and waste exchange
protein anchor– hold transport proteins and move substances across membranes
energy conservation– proton motive force
simple transport proteins
drive by the energy in the proton motive force
ex. lac permease (in e. coli)
group translocation
chemical modification of the transported substance driven by phosphoenolpyruvate
ex. phosphotransferase system
periplasmic (ABC)
periplasmic binding proteins are involved and energy comes from ATP
what is the importance of transport proteins?
enhances the uptake of necessary substances (much faster than simple diffusion)
what are the 3 transport events?
uniport (1), antiport (2; 1 in and 1 out), and symport (2 in or out)
Lac permease (e. coli)
transports lactose into cells
symporter
energy driven (against the gradient)–more lactose in the cell takes energy to get in
uses proton motive force
passive; least efficient
phosphotransferase system
transports sugars into cells, requires 5 proteins
energy-driven using phosphoenolpyruvate (PE-P)
medium efficiency with the cascade
still passive
periplasmic (ABC system)
“ABC” = ATP-Binding Cassette System
occurs in the periplasm (between the cytoplasmic and outer membranes)
requires multiple proteins (periplasmic binding proteins, membrane transporter, and ATP-hydrolyzing proteins)
active
most efficient
Translocases
export and insert proteins into the membrane
ex. SEC system (secretion)
functions: exoenzymes, periplasmic enzymes, and toxins
Teichoic acids
embedded in cell wall and negative electrical charge of the cell surface
transport cations (Mg2+, Ca2+)
Gram negative bacteria has an ____
the outer membrane which is a second lipid bilayer (lipopolysaccharide–LPS)
lipoproteins
anchor the outer membrane to the peptidoglycan layer
periplasm
between the cytoplasmic and outer membranes
contains different classes of proteins
hydrolytic enzymes
trapped into the periplasm by outermembrane
initial breakdown of food molecules (so then they can be brought into cell)
Binding proteins
ABC systems example
begin translocation process
chemoreceptors
detect chemical gradients (chemotaxis)
porins
Technically transport protein but considered to be different because of the location
channels for small molecule transport
specificity by size (upregulated by genetics to change size and amount)
Capsules and slime layers
sticky material on the cell surface
polysaccharides or proteins
Functions: attachment to surfaces, avoid phagocytosis, and dessication
Pili
hollow protein filaments
Functions: attachment ot surfaces, exchanging genes (conjugation), and colonization factors (colonizing on human body)
Types of cell inclusions
carbon storage polymers; polyphosphate, sulfur, and carbonate minerals; and magentosomes
Carbon storage polymers
storage of carbon and energy
ex. PHB and glycogen
Polyphosphate, sulfur, and carbonate minerals
storage of inorganic compounds
Magnetosomes
mangetic sotrage inclusions
gas vesicles
structure: protein, spindle-shaped (in bacter and archaea only)
function: buoyancy and flotation (important for planktonic microorganism)
Endospores
highly resistnat bacterial “seeds”
used for bacterial dispersion across unfavorable habits
vegetative cell = active cell
spore= inactive cell
how are endospores so resistant?
Physical protection: exosporium (protein), spore coat (protein), and cortex (peptidoglycan)
chemical protection: dipicolinic acid and small acid-soluble proteins (SASPs)
Dipicolinic acid
dehydrates the cell
stabilizes DNA against heat
SASPs
energy source during germination
stabilizes DNA againdt UV radiation
Flagella
types: polar (one 1 side) and peritrichous (around the cell)
Structure: flagellin (protein) and uses proton motive force
Gliding motility
movement without a flagella is slowers and must be in contact with a solid surface
types: slime extrusion, twitching (w/ pili), and cell surface proteins
reasons for motility
chemotaxis (chemical gradients) and phototaxis (light gradients)
