Functional Anatomy of Prokaryotic Cells Flashcards
prokaryotic cells that play an important role on human disease and health
bacteria
has no nuclear membrane and membrane bound organelles (e.g. Mitochondria, E.R., Golgi complexes)
bacteria
collective term for layers surrounding the bacteria
cell envelope
found on the outer surface of the membrane, most important role is to protect the bacteria
cell wall
cell wall consist of what
peptidoglycan
used to differentiate whether bacteria are gram positive/negative
peptidoglycan
have a thick layer of peptidoglycan
gram positive bacterai
have a thin layer of peptidoglycan sandwitched between the surface membrane and plasma membrane
gram negative
helps maintain shape of the bacteria
cell wall
round shaped bacteria
cocci
rod shaped bacteria
bacilli
spiral shaped bacteria
spirilla
bacteria with multiple forms
pleomorphic
acts as a shield against phagocytosis and helps it adhere to surfaces
an important virulence factor
capsule
most important layer of cell envelope, encloses the cytoplasm
plasma membrane
gel-like substance consist mainly of water, cell components, enzymes, and various organic molecules
plasma membrane
acquires nutrients
eliminate waste
maintains constant, organized state
selectively permeable barriers
plasma membrane
in bacteria, this layer is important in respiration, photosynthesis, and synthesis of lipids and cell wall components
plasma membrane
sites of protein synthesis
ribosomes
present in cytoplasm or attached to plasma membrane
ribosomes
ribosomes that are attached to the plasma membrane
plasma membrane associated ribosomes
make proteins that reside in the cell envelope or proteins that will be transported outside the cell
plasma membrane associated ribosomes
irregularly shaped region that contains the cell chromosome
nucleoid
single circle of double stranded DNA but some can have linear and more than 1
chromosome
small, dsDNA that can exist dependently from the chromosome (can be linear or circular) has few genes
plasmids
often contain genes that have selective advantage
plasmids
hair-like structures that allow bacteria to attach to other cells
pili
shorter pili
fimbriae
long whip-like protrusions that allow bacteria to move
flagella
when starved for nutrients, these can develop dormant,heat and dessication resistant spores
endospores
most of the knowledge of endospores came from this
Bacillus subtilis
can replicate every 30-60 minutes
B. subtilis
inititates sporulation
starvation
a strategy used by many organisms, including bacteria, fungi, protozoa, algae, and ferns to survive conditions that are too harsh to sustain vegetative growth.
sporulation
8 morphological stages of sporulation
decision to use one of two potential polar division sites for septum formation
what stage
0
replication and formation of axial filament
what stage of sporulation
stage I
septation occurs
what stage of sporulation
stage 2
septation product which will ultimately become the spore
forespore
septation product where forespore is derived
mother cell
mother cell membrane engulfs forespore
what stage of sporulation
stage III
mother cell chromosome destruction
what stage of sporulation
stage IV
made up of thick peptidoglycan layer surrounding the forespore protoplast
cortex
provide heat resistance and maintaining dormancy to the spore
cortex
deposition of coat proteins
what stage of sporulation
stage V
maturation completing development
what stage of sporulation
stage VI
is a component that accumulates in the forespore protoplast during spore formation, contributing to the heat resistance of the developing spore.
dipicolinic acid
what stage does the dipicolinic proliferates
stage VI
maintains dehydration in the spore
dipicolinic acid
mother cell is called what in stage VII of sporulation
sporangium
mother cell releases spore
what stage of sporulation
VII
only 10-30 percent of a vegetative cell’s water content
dessicated spore
protects DNA in dessicated spores
small acid soluble proteins
program to wake the dormant cell and dissolve cortex of spore
germination
two categories of cells
eukaryotic and prokaryotic cells.
means “true nucleus”
eukaryotic
eu means
true
means “before nucleus”
prokaryotic
pro means
before
Organisms which are categorized in the domains of Bacteria and
Archaea belong to the ___cells.
prokaryotic cells
Fungi, animals, plants and organisms under the kingdom
Protista are under the category of ___cells.
eukaryotic
which is the selective barrier between its cytosol
plasma membrane
a semifluid jelly-like
substance inside
cytosol
carry the genes made of DNA (deoxyribonucleic acid) segments
chromosomes
complexes or units that
convert instructions from the genes to proteins
ribosomes
which is bigger P or E?
Eukaryotes (Typically 10 – 100 μm _
Prokaryoties (Typically 1– 5 μm)
difference between prokaryotes and eukaryotes in genetic material
P - free floating in cytoplasm (nucleoid)
E - contained in a membrane bound nucleus
difference between prokaryotes and eukaryotes in # of chromosomes
P - single chromosome; usually circular in shape
E - multiple chromosome; generally in pairs
difference between prokaryotes and eukaryotes in presence of histone
P - absent
E - present
difference between prokaryotes and eukaryotes in ribosome sizes
P - smaller (70S)
E - larger (80S)
eukaryotic ribosomes (2)
70S
80S
eukaryotic ribosomes present in cytoplasm or attached to membranes
80S
eukaryotic ribosomes in mitochondria and chloroplast
70S
difference between prokaryotes and eukaryotes in membrane bound organelle
P - absent
E - present
difference between prokaryotes and eukaryotes based on its cell wall composition
P - based on peptidoglycan
E - (when present) is made up of cellulose or chitin
difference between prokaryotes and eukaryotes in presence of cili
P - absent
E - may be present
difference between prokaryotes and eukaryotes in present of flagella and its movement
P - if present provides rotating motility
E - if present provides whiplash motility
difference between prokaryotes and eukaryotes in presence of pili
P - present
E - absent
a prokaryotic cell, the genetic material is usually located in a region that is not
membrane closed, which is called a
nucleoid
On the other hand, the genetic material possessed by a eukaryotic cell is contained or found in a double membrane-bound organelle called the
nucleus
After some million years, after the rise of ____,
eukaryotes emerged in the earth, having complex structures of organelles and can support
aerobic metabolism as well as photosynthesis.
atmospheric oxygen
One good explanation on how the first simple eukaryotic cells have emerged to earth is
the
endosymbiotic hypothesis
states that the mitochondria and chloroplasts,
the organelles which is responsible for cellular respiration, came from a respiring prokaryote and
a cyanobacterium-like prokaryote.
endosymbiotic prokaryote
possess short amounts of DNA which are in a circular form, which is common to bacteria.
mitochondria
chloroplast
In the world of microbiology, the common and major groups of eukaryotes are the
protist (protozoa and algae)
fungi
have a true nucleus bounded by a double-layer membrane
eukaryotic cells
function as “passageways” for messenger RNA leaving the
nucleus out to the cytoplasm during the event of protein synthesis
pores in double layer membrane
The eukaryotic DNA is highly condensed and wrapped around proteins called
histones
possess a strong positive charge responsible in associating with the negatively charged
phosphate groups on the DNA, giving it a more compact shape
histone
is a complex system comprised of tubes. It is an
extensive network of membrane that makes up for more than half the total membrane in most
eukaryotic cells
endoplasmic reticulum
endoplasmic means
within the cytoplasm
reticulum means
little net
The endoplasmic reticulum is differentiated into two types
RER
SER
mainly possesses numerous ribosomes on its surface, resulting in a rough, granular
appearance when seen under an electron microscope, hence, the name.
rough endoplasmic reticulum
. The areas which do
not contain numerous amounts of ribosomes are known as the
smooth endoplasmic reticulum
function is to mainly synthesize protieins
RER
Proteins synthesize in the RER already have specified final
destinations, which is to the
Golgi apparatus
in contrast, is involved
in a large array of metabolic processes
SER
SER is involved in processes called (5)
lipid synthesis
carbohydrate
metabolism
calcium ion storage
detoxification of drugs and poisons
is a transport organelle, which consists of a set of flattened vesicles
golgi apparatus
The Golgi apparatus is a transport organelle, which consists of a set of flattened vesicles,
called
dictyosomes
is responsible for the modification, storage and sending
of the products formed in the endoplasmic reticulum
Golgi apparatus
, the membrane itself is extensive
in cells which are specialized in secretion
what organelle
Golgi apparatus
has a distinct structural directionality
Golgi stack
comprises of two sides, the cis face
and the trans face.
Golgi stack
face is the part which is usually located near the ER. Transport vesicles
from the ER move to the Golgi apparatus through this face
cis face
face gives rise to
vesicles that “pinch off” and travel to other sites
trans face
are membrane bound organelles which contain digestive enzyme
lysosomes
contain vesicles which possess hydrolytic enzymes that are responsible for digesting waste
products of the cell.
lysosomes
These hydrolytic enzymes have the potential to digest the whole cell, in a
process called a
autolysis
autolysis is being regulated by enclosing the enzymes
with the
lysosomal membrane
The hydrolytic enzymes and the lysosomal membrane are manufactured in the
RER
work at acidic environments, hence, not
very active when released into the cell since the pH of the cytosol is neutral in nature.
hydrolytic enzymes
enzyme pH of cytosol
neutral
lysosome digesting food
phagocytosis
lysosome breaking down damaged organelles
autophagy
are generally rod-shaped organelles enclosed by a double membrane
mitochondria
The
inner surface of the mitochondria is folded into finger-like projections called
cristae
These organelles
vary in numbers depending on which kind of cell they are present in, sometimes in singles or
may be found in large numbers
mitochondria
a are sites where cellular respiration occurs, which
is the metabolic process that uses oxygen to generate ATP by extracting energy from fats,
sugars, and other fuels.
mitochondria
which can be observed in plants and algae, are specialized cells which are
also sites of photosynthesis
chloroplast
are flatted membranous sacs arranged into stacks
called grana.
thylakoids
thylakoids arranged into stacks
grana
These thylakoids contain the photosynthetic pigment of the plant called the
chlorophyll
responsible for converting solar energy to chemical energy when it is used
to synthesize organic compounds particularly sugars from carbon dioxide and water.
chloroplast
are organelles derived from the Golgi apparatus.
vacuoles
are
responsible for storing various nutrients and waste products.
vacuoles
is the rigid protective layer that surrounds the cell
cell wall
Some organisms that do have cell walls are
fungi
algae
plants
provide form and strength to the cell
cell wall
The cell walls of algae, plants and some lower
members of fungi are composed of
cellulose
chain of glucose molecules
cellulose
fungi that have a different composition of cell wall in yeast and mushroom
chitin
a polymer of N-acetylglucosamine is the primary component of
the cell wall.
chitin
is also observed as a major component of crustacean and insect
exoskeletons, whose functions are for strength and rigidity.
chitin
In eukaryotes without cell walls, the _____ becomes the outermost layer of
the cells.
plasma membrane
acts as selective barrier which allows the passageway of important molecules
into the cell.
plasma membrane
The plasma membrane is comprised of lipid structures containing
two chains of fatty acids and phosphate group
Each phospholipid molecule is
composed of two regions
hydrophilic head
hydrophobic tail
which is composed of the phosphate group and
glycerol
hydrophilic head
which is composed of the two fatty acid chains
hydrophobic tail
It can be noticed that when a phospholipid is
dropped into a body of water, a __would form
micelle
which is an aggregate with the hydrophilic
head in contact with the solvent, while the hydrophobic tail is being protected inside away from
the solvent.
micelle
is an extensive network of fibers that can be observed in the cytoplasm.
cytoskeleton
function is to support the cell’s shape and for mechanical support.
cytoskeleton
very important part
of the cell since some eukaryotes lack cell wall
cytoskelton
cytoskeleton is comprised of three types of
molecular structures
microtubules
microfilaments
intermediate filaments
are the main components of eukaryotic cells in regard to motility
flagella
cilia
is a
lash-like appendage which provides movement or locomotion in certain eukaryotic cells
flagellum
cells that have flagella
flagellates
It functions also as sensory organelles
to temperatures and chemicals in the surroundings of the cell
cilia
on the other hand, can be
described as short flagella. B
cilia
Both appendages are attached to the plasma membrane and the
bases are anchored to the cell by a
basal body
is the classification of organisms that possess simple characteristics in their cells.
prokaryote
a type of prokaryotes,
were also observed with their differences in shape and arrangement.
bacteria
three basic shapes of bacteria
rod
spherical
curved (spiral)
Bacterial cells also remain attached in an arrangement depending on the plane of ___,
which is a characteristic of their genera
fission
some bacteria can be arranged in
pairs (diplo)
groups of four (tetrad)
three dimensional cubes (sarcina)
chains (streptococcus)
or irregular (staphylococcus)
paired cocci
diplococci
grape-like cocci
staphylococci
chains of cocci
streptococci
3D cube cocci
sarcina
groups of 4 in cocci
tetrad
Most bacteria secretes a
glycocalyx
a slimy or sticky material on their cell surface made
of polysaccharide or proteins.
glycocalyx
glycocalyx that is a more organized
matrix, otherwise, an easily deformed
capsule
functions as a
protective layer that enables bacteria to resist phagocytosis by the host immune system
capsule
Its polysaccharide nature allows it to bind water
and likely resist desiccation
capsule
what gram positive bacteria has a polysaccharide type 11, glucose, glucoronic acid, other types, various sugars and amino sugars
S. pneumoniae
what gram positive bacteria has the polysaccharides of hyaluronic acid (group A), others containing amino sugras, uronic acids
Streptococcus spp.
what gram positive bacteria has the glutamyl polypeptide
bacillus anthracis
what gram negative bacteria has the polybosephosphate
Haemophilus influenzae
which gram negative bacteria has the polysaccharides sugars such as hexoses, fucose, uronic acids
Klebsiella spp.
what gram negative bacteria has the N-acetylmannosamine phosphate polymer and sialic acid polymers
Neisseria meningitidis
The most observed extracellular structures are the
flagella
are thin hair-like
structures which are used for motility of a cell, regardless whether eukaryotic or prokaryotic
flagella and motility
single flagellum at one end
monotrichous
flagellum on both end
amphitricohus
many flagella on one end
lopotrichous
numerous flagella surrounding
the cell
peritrichous
As the flagellum’s function is for locomotion, it greatly relies in energy driven by the
basal body
A clockwise rotation of a single flagellum will result into “__” of the cell
tumbling
On the other hand, if the cell’s flagella rotates counterclockwise, it results in
“___” to a straight line.
running
Other extracellular structure which can be noticed in a bacterial cell is the
pili
are the structures which resemble short flagella.
pili
they are not used with motility, which
makes them different from the flagella
pili
used for anchorage or “sticking” of the
bacterium in a specific surface
pili
Attachment pili are sometimes called
fimbriae
which is a term
mostly used in order to differentiate attachment pili to a sex pili,
fimbriae
which functions in transfer of
genetic information by means of conjugation.
sex pili
Similar to eukaryotes, prokaryotes also possess a
plasma membrane
Analogous to sterols of the cell membrane are
hopanoids
which strengthen the
membranes of bacteria
hopanoids
have variations in
their cell membranes not found in the other two domains
archaea
archaea hydrophobic sides are attached to the hydrophilic heads by what linkages
ether
archea membrane is composed of repeating units of
5-C hydrocarbon isoprene
20-C unit of isoprene
phytanyl group
40-C unit of isoprene
biphythanyl
the cytoplasmic membrane of Archaea can be
constructed with
glycerol diether
diglycerol tetraethers
s twice the former but the ends
pointing inward become covalently linked
diglycerol tetraethers
serve its
purpose to Archaeans living in extreme conditions such as the hyperthermophiles.
lipid monolayers
Among the critical functions of the prokaryote membranes are (3)
permeability barrier
anchor to membrane proteins
major site of energy conservation
Small uncharged molecules can pass through membranes by ____ except
charged ions.
simple diffusion
while polar, does freely pass the membrane in both directions
water
dedicated transport proteins for water
aquaporins
its aquaporin adjusts movement of water across its membrane in varying osmotic
conditions
E. coli
help accumulate solutes against concentration gradient, which never
would occur had diffusion been the only mechanism to so.
transport proteins
consists only of a membrane
spanning transport protein;
simple transport
involves a series of proteins in the transport
event
translocation
consists of three components: a substrate-binding protein, a
membrane-integrated transporter, and an ATP-hydrolyzing protein
ABC system
All transport systems require energy in some form, either from
proton motive force
ATP
involves transport proteins
such as uniporters, symporters and antiporters, whose functions is owed to their names.
simple transport
is a well-studied symporter for lactose using the energy of the protons as the
driving force, which puts is in the indirect active transport category
Lac permease
transporter in E.coli that is used for lactose using energy of protons
Lac permease
modifies
the substance during the uptake by phosphotransferase system.
group translocation
provide the energy (phosphate) which is cascaded from the five-protein system to glucose
(sample molecule) during transport.
phosphoenolpyruvate (PEP)
are found in gram-negative and
employs the periplasmic-binding proteins, membrane transporter and ATP-hydrolyzing proteins.
ATP-binding Cassette (ABS transport system)
About ___ABC transport systems have been identified in prokaryotes for the uptake of organic
compounds such as sugars and amino acids, and inorganic nutrients.
200
Gram positives have ABC
transport systems involving ___ proteins of their cell membranes and do the same just as
in the gram negatives.
peripheral
While there is a specific area where the genetic materials of prokaryotes can be found,
the absence of a nuclear membrane make it indistinguishable. It is, thus, found in an area called
nucleoid region
Generally, the nucleoid or the bacterial chromosome of the prokaryotes is constituted in
a closed circular shape of what kind of DNA
double-stranded DNA
However, not all bacteria conform to a circular structure of DNA. Some bacteria also do possess
linear chromosomes such as
Streptomyces coelicolor
Some bacteria also contain additional DNA
in a form of
extrachromosomal plasmids
fundamental internal structures of
prokaryotic cells. These structures are comprised of complex proteins and RNA.
ribosomes
the site of protein synthesis, where an mRNA is being translated into a protein
ribosomes
Foremost, ribosomes are
measure with
Svedberg units
a prokaryotic ribosome has only
70s
All ribosomes are composed of two unequal subunits.
Prokaryotes are comprised of a subunit of
50s and 3-s
eukaryotes are composed of what subunits
60S and 40s
Bacteria, like other prokaryotic and some eukaryotic cells such as plants, have a
protective layer in their cells which provides structural rigidity and strength which are called
cell walls
protects bacterial cells against lysis
cell wall
can be caused by pressures in the activities
of transport systems of the cell.
lysis
Generally, species of bacteria are divided into two major classifications in regards with
their cell wall structures. These are called G
gram positive
gram negative
Basically, the cell wall structure of a
Gram-__bacteria is very much more chemically complex, consisting of two layers
negative
On the
other hand, the cell wall of a Gram-___bacteria is comprised of only a single type of molecule
but very much thicker than its counterpart
positive
is a polysaccharide which is made up of N-acetylglucosamine and N
acetylmuramic acid –
peptidoglycan
amino acids in peptidoglycan
L-alanine,
D-alanine, D-glutamic acid, and either lysine or DAP (diaminopimelic acid).
L-alanine,
D-alanine, D-glutamic acid, and either lysine or DAP (diaminopimelic acid). Such molecules are
responsible for the formation of a repeating structure called the g
glycan tetrapeptide
The chains of sugars connected by the glycosidic bonds are linked by the cross-links
of
amino acids
typically obtain cross linkages by a peptide formation from the carboxyl
group of D-alanine to the amino group of DAP.
gram negative
occurs through a peptide interbridge, in which the numbers and types of amino
acids in that interbridge vary between species.
gram positive
In the cell wall of a Gram-positive bacteria, ____comprises about 90% in the structure
itself, mostly having several sheets stacked one after another.
peptidoglycan
peptidoglycan contain acidic polysaccharides known as
teichoic acid
which
contain phosphate groups that are responsible for an overall negative charge of the cell surface.
teichoic acid
This actually makes the cell wall of Gram-negative bacteria to be less sturdy.
thinner peptidoglycan
the structure is more complex because there is a second phospholipid bilayer
observed outside of the peptidoglycan layer, which is more permeable than the inner cytoplasmic
membrane.
gram negative bacteria
In addition, the second phospholipid bilayer contains special
types of molecules called
lipopolysaccharides
which helps support the bacterial cell by protecting
it from certain drugs and antibodies in the immune system.
lipopolysaccharides
This outer membrane is connected
from the peptidoglycan layer by molecules called
lipoproteins
which functions as anchorage and
hold the outer membrane via covalent bonds of the bacteria to itself.
lipoproteins
Moreover, one function of the outer membrane is to keep the
proteins whose activities are being done outside the cytoplasmic membrane from going away.
Therefore it is contained in a region between the outer surface of the cytoplasmic membrane
and the inner surface of the outer membrane called the
periplasm
The reason why the outer membrane is relatively permeable to some molecules is because of
channels embedded in the membrane which are known as
porins
porins are divided in two
nonspecific porins
specific porins
which form water-filled channels making any small substance to
pass,
nonspecific porins
which contain binding sites for specific types of molecules.
specific porins
In Gram staining procedure, the crystal violet-iodine
complex forms outside/inside the bacterial cell.
inside
by applying ___, the crystal violet-iodine
complex becomes extracted from the Gram-negative bacteria but not from the Gram-positive
bacteria.
alcohol
dehydrates the thick peptidoglycan layer of
the Gram-positive cell wall, resulting in the closure of pores in the layer itself and preventing the
escape of the crystal violet-iodine complex, hence, the violet coloration.
alcohol
This makes the Gram-negative bacteria readily accept the
counterstain
safranin
Certain species of bacteria, such as ___and __, produce structures called
endospores.
Bacillus
Clostridium
are highly differentiated, dormant forms of the cells which function as
survival structures that enables the organism equipped with it highly resistant to extreme
conditions such as very high temperature, harsh chemicals, pH, as well as radiation,
endospores
endospores is highly resistant to
very high temp
harsh chemicals
pH
radiation
compartmentalized interior but no cell wall
animal cell
non-compartmentalizd in interior has a cell wall
bacterial cell
two major structures in bacterial cell
chromosomes
ribosomes
has a + outer membrane in bacteria
gram-negative
has a - outer membrane in bacteria
gram positive
with no nuclear membrane
prokaryotes
single-celled, microscopic organism
prokaryotes
a bacillus-shaped
bacterium 80 µm diameter; 200-600 µm long;
Epulopiscium fishelsoni
a spherical
bacterium between 100 and 750 µm
diameter
Thiomargarita nambiensis
generally much smaller
eukaryotic cells.
prokaryotic cells
very complex despite their small size
prokaryotic cell
what size is more advantageous
small
diameter may be
insufficient to house
cells’ essential
components – limit for
small sizes
0.1 um
Higher/Lower Surface/Volume
ratio support faster rate of
nutrient exchange
Higher
means
immediate expression of
mutations - raw material
for rapid growth and
evolution
smaller size
example of straight rod
escherichia
example of branching rod
actinomyces
spore forming rod
bacillus
club shaped rod
corynebacterium
two cells that did not separate
diplococci
example of diplococci
neisseria
streaking will
spread them in
clusters
staphylococcus
is a measure of viable colonogenic cell numbers in CFU/mL
colony forming unit
Gram-positive, coccus
prokaryote (dividing).
streptococcus pyogenes
Agents of: pharyngitis, food
poisoning, puerperal
fever (childbed fever),
scarlet fever, rheumatic
fever, skin and wound
infections
streptococcus pyogenes
other shapes of bacterias
stellar
square and flat
triangular
variable
coccoid
pleomorphic bacterium
rhizobium
corynebacterium
typical plasma membrane of prokaryotes has the ff (5)
phospholipid bilayer
peripheral proteins
integral proteins
carbohydrates
sterols (cholesterol)
phospholipid + coline =
phosphatidylcholine
seen in animal cell
membranes
cholesterol
found in eucalyptus
and plants
phytosterol
phytosterol is composed of
campesterol
sitosterol
stimgasterol
what lipid are present only in e coli
phosphatidylglycerol
not present in e. coli among human erythrocyte, human myelin, beef heart mitochondria
phosphatidylserine
present in archeal cell membrane
glycerol diether
version of fatty acid in archea
phytanyl
2 phytanyl covalently linked on their hydrophobic
ends.
biphytanyl
because of this, archea can survive extreme
conditions
lipid monolayer of biphytanyl
position of ___make it difficult for phospholipid to become solid at colder temperature
cholesterol
makes the bilayer less liquid in high temp
cholesterol
functions of bacterial membrane
selective permeability
Protein anchor
Breakdown of nutrients and
production of energy
DNA replication
function of bacterial membrane that prevents leakage and functions as a gateway for transport of nutrients into and out of the cell
permeability barrier
Transport systems are
established in the membrane for
this purpose
selective barrier
not allowed to pass in a selective barrier
charged ions
general charge of the cell is always maintained as
negative (-)
crystal violet and safranin are charged
negative (-)
odorless, colorless (replaces oxygen in RBC)
nitric oxide
function of bacterial membrane that is the site of many proteins involved in transport, bioenergetics and chemotaxis
protein anchor
function of bacterial membrane that is the site of generation and use of proton motive force
energy conservation
the free energy per mol required to move protons outward across the membrane
proton motive force
infoldings of
plasma membrane in
prokaryote
chromatophores/thylakoids
a type of membrane transport that does not require energy to move substances across cell membranes
passive transport
is the movement of molecules from a region of lower concentration to a region of higher concentration with the use of energy.
active transport
high to low – towards equilibrium
simple diffusion
passive diffusion is made up of
simple diffusion
facilitated diffusion
diffusion with
transporters (permeases)
towards equilibrium
facilitated diffusion
uses ATP, Against
concentration gradient
For non-equilibrium;
Unidirectional
Ions and simple sugar
active processes
require energy in
some form, either
from the proton
motive force, or
ATP, or some other
energy-rich
organic compound
transport system
- could indirectly
be active transport,
facilitated by protons
simple transport
type of transport system in prokaryotes that is driven by energy in the proton motive force
simple transport
type of transport system in prokaryotes that has the chemical modification of the transported substance driven by phosphoenolpyruvate
group translocation
type of transport system in prokaryotes that has periplasmic binding proteins involved and energy comes from ATP
ABC system
simple facilitated transporter that is unidirectional
uniporter
movement of
a molecule towards a
direction facilitates
movement of another
molecule in opposite
direction
antiporters
cotransport two
molecule –same direction
symporters
what transporters are involved in indirect active transport
antiporters
symporters
involves a transport system coupled to an exergonic chemical reaction, most commonly the hydrolysis of ATP
direct active transport
involves the coupled transport of solute S and ions-protons, which in this case, the exergonic movement of protons provides the energy to move the transported solute against the concentrated gradient or electrochemical potential
indirect active transport
indirect active transport is also known as
secondary active transport
enzymes /transport proteins along the cell membrane
- allow protons to tag along a lactose
lac permease
lac permease is an example of
symporter
provide the
energy (phosphate)
which is cascaded
from the five-protein
system to glucose
(sample molecule)
during transport.
phosphoenolpyruvate
ABC means
ATP-binding casette
ABC transporters
contain three interacting
components
▪ periplasmic-binding
proteins
▪ membrane transporter
▪ ATP-hydrolyzing
proteins.
Found in gram neg and
gram positive bacteria
what transport
ABC transporters
Important because some
bacterial enzyme are designed to
function outside cell
protein export in prokaryotes
proteins designed to function outside cell
exoenzymes (amylase, cellulase, periplasmic enzymes)
which are specific in
the types of proteins exported
translocases
A mass
aggregates of
prokaryotic
chromosome
nucleoid
Composed of
housekeeping
genes
nucleoid
nucleoid is diploid/haploid
haploid
shape of bacterial chromosome
Supercoiled
Supercoiling is added
or removed by
topoisomerases
function as energy
reserves and as
reservoirs of structural
building blocks
cell inclusions
insoluble forms in cell
cell inclusion
function as phosphate reserves
metachromatic granules
function as glycogen and starch reserves
polysaccharides granules
function in non equilbirium, tried to put them inside the cytoplasm
polysaccharide granules
cell inclusion that function as energy reserves (2)
lipid inclusions
sulfur granules
cell inclusion that function as ribulose 1,5-diphosphate carboxylase for CO2 fixation
carboxysomes
cell inclusion that function as protein covered cylidners
gas vacuoles
cell inclusion that function as iron mineral magnetite (Fe3O4)
magnetosomes
small gas-filled
structures made of protein that
confer buoyancy on cells.
gas vesicles
decrease the density of cells
gas vesicles
allows organisms in water to
position themselves for optimum
light harvesting.
gas vesicles
common in many species of
cyanobacteria
gas vescicles
are
intracellular particles of the
iron mineral magnetite (Fe3
O4 ) that allow organisms to respond
to a magnetic field
magnetosomes
structures that are external to the cell wall include
glycocalyx
flagella
fimbriae and pili
substances that surrounds the cells outside the cell wall
glycocalyx
May be up to 10 µm thick
glycocalyx
types of glycocalyx
capsule
slime layer
- thick layer of viscous gel
capsule
amorphous glycocalyx
slime layer
Not required for viability
glycocalyx
a glycocalyx for biofilm protection and communication
extracellular polymeric substance
have a role in adherence, virulence, protection, securing nutrients, and cell-to-cell recognition.. The capsule is unstained and appears as a halo around the cell.
capsules
medical importance of capsule
inhibit ingestion and killing by phagocytes
attachment
can be absorbed as food
against dehydration
prevent moving out of nutrients
causes pneumonia if capsule is present
streptococcus pneumoniae
colonize respiratory tract if with capsule.
Klebsiella pneumoniae
For motility (taxis)
About 15-20 nm thin
flagella
proteins helps identify certain pathogenic bacteria
flagellar
food borne epidemics are caused by this strain of flagellated bacteria
E.coli O157:H7
parts of flagella (3)
filament
hook
basal body
made of globular protein flagellin in chains to form a hollow core
filament
end of the filament
hook
anchors flagellum to cell wall and plasma membrane through series of rings
basal body
how many rings does the gram negative cell wall have
4 rings
what rings of the gram negative cell has them outside the peptidoglycan layer
L ring
P ring
what rings of the gram negative cell has them outside the peptidoglycan layer
MS ring
C ring
drives the flagellar motor rotation
proton motive force
An appreciable speed of about 60 cell lengths/second can be achieved.
proto motive force
how many rings does a gram positive flagellate have
2 rings
Diameter measures on 10-13 nm
Rotates similarly like in bacteria
Several different flagellin
Archaea bacteria
genes for this bear no resemblance to bacteria.
Archea Flagella
Appears that ATP is source of energy
Archea Flagella
Endoflagella
Bundles of fibrils that arise at the end of cell
With similar structure to flagella
axial filaments
its rotation propels spirochetes in a spiral movement.
axial filaments
Pattern useful in identifying bacteria.
flagellar distribution
the arrangement in which the flagella are present throughout the body of the cell, all of which are directed in different ways.
peritrichous
A single flagellum at one end or the other. These are known as polar flagellum and can rotate clockwise and anti-clockwise.
monotrichous
have multiple flagella located at the same spot on the bacteria’s surfaces which act in concert to drive the bacteria in a single direction.
lopotrichous bacteria
are polar flagella located on opposite sides of the bacteria.
amphitrichous flagella
patterns of motility
reversible flagella
unidirectional flagella
Both made of pilin proteins
fimbriae and pili
3 to 10 µm; few to hundreds in a cell; for attachment to environments; pellicle or biofilm
fimbriae
fimbriae helps this bacteria to colonize mucous membrane
Neisseria gonorrhoeae
9 to 10 µm; 1 to 2 per cell;
required for bacterial genetic exchange during conjugation; genetically determined by sex factors or conjugative plasmids
pili
Adhesion to specific tissues
May also function for twitching motility (type IV pili)
pili
what pili function for twitching motility
type IV
do not employ rotating flagella but instead creep along a solid surface by any of several possible mechanisms.
gliding motility
can occur from slime secretion or by a ratchet-protein mechanism that moves the outer membrane of the cell.
gliding motility
repeated extension and retraction of pili
twitching motility
Maintaining the cell’s characteristic shape - compensates for the flexibility of the phospholipid membrane and keeps the cell from assuming a spherical shape
bacterial cell wall
Countering the effects of osmotic pressure - responsible for keeping the cell from bursting when the intracellular osmolarity is much greater than the extracellular teichoic osmolarity
bacterial cell wall
cell wall Providing attachment sites for
bacteriophage
attached to the outer surface of the wall are like landing pads for viruses that infect bacteria
teichoic acids
Providing a rigid platform for surface appendages - flagella, fimbriae, and pili all emanate from the wall and extend beyond it
Contributes to virulence
Site of action of antibiotics
Differentiates major types of bacteria
cell wall
Thick peptidoglycan
Teichoic acids (lipo and wall)
gram positive
Outer membrane (phospholipids, lipopolysaccharide, porins)
Periplasmic space (thin peptidoglycan, lipoproteins, enzymes)
gram negative
connected by peptide interbridge
glycan tetrapeptide units
which gram reaction have interbridges
gram positive
bonds NAM and NAM together
peptide bonds
bonds NAM-NAG
B-1,4 glycosidic bonds
Sensitive to lysozyme found in animal secretions
B,1-4 glycosidic bonds
acidic component of gram positive cell wall
teichoic acid
links to plasma membrane
ipoteichoic acid
what teichoic acid links to peptidoglycan
wall
its outermembrane has Lipopolysaccharides (LPS), lipoproteins, phospholipids
gram negative
– contains unusual sugars, and provide stability in gram negative bacteria
core polysaccharide
antigenic (E. coli O157:H7)
o-polysaccharide
NOT a typical phospholipid
Has endotoxin properties, which may cause violent symptoms in humans
lipid A in gram negative
Cause intestinal symptoms (gas, diarrhea, vomiting).
lipid A
Gel-like consistency
contains various proteins involved in important cellular functions (hydrolytic, chemoreceptors)
periplasm
Channel for solutes (nucleotides, disaccharide, peptides etc.)
porins
Protection from phagocytes, and complement system.
Barrier to antibiotics, lysozyme, detergents, dyes
gram negative outer membrane
Lack cell walls
Sterols in plasma membrane
mycoplasma
Mycolic acid (wax)
Thin peptidoglycan
mycobacterium
variations of cell wall in archea
a. Wall-less
b. Walls of pseudomurein (N-acetyltalosaminuronic acid (NAT) instead of NAM).
c. made of polysaccharides
d. S-layer (paracrystalline)
instead of NAM, archea has what
n-acetyltalosaminuronic acid (NAT)
The backbone of pseudopeptidoglycan is linked by b-1,_bonds instead of the b-1,4 bonds of peptidoglycan
b-1,3
digests disaccharide in peptidoglycan
lysozyme
inhibits peptide bridges in peptidoglycan.
penicillin
The Gram positive cell without a wall is a
protoplast
is a wall-less Gram-negative cell.
spheroplast
forms are wall-less cells that swell into irregular shapes.
L forms
are susceptible to osmotic lysis.
protoplast and spheroplast
-resistant to
Extreme Heat
UV radiation
Desiccation
Chemical disinfectants
endospores
endospores are found in gram negative
Coxiella burnetiid
endospores are found in genera
Clostridium and Bacillus
– thin protein covering of endospore
exosporium
part of endospore that is made of spore-specific protein
spore coat
part of endospore that has loose peptidoglycan
cortex
part of endospore that has a wall, membrane, cytoplasm, nucleoid, ribosomes, and others
core
resistance factors for endospore
heat-stable enzymes
Ca-dipicolinic acid (DPA)
Protoplast dehydration
Small acid-soluble spore protein (SASPs)
Binds free water and help dehydrate; intercalates with DNA, protect it from heat denaturation
Ca-dipicolinic acid
Increases heat resistance, H2O2 resistance, and keep enzymes inactive.
protoplast dehydration
protect DNA from ultraviolet radiation, desiccation, and dry heat and also serve as a carbon and energy source during germination.
small acid-soluble spore protein (SASPs)
reduce water availability within the endospore, thus helping to dehydrate it
calcium DPA complexes
These complexes also intercalate in DNA, stabilizing it from heat denaturation.
calcium dpa complexes
endospore morphology
central endosphore
terminal endospore
lateral endospore
