Chapter 4 Functional Anatomy of Prokaryotic Cells Flashcards
What are the characteristics of prokaryotes?
*single, circular chromosome located in non-membrane bound nucleoid region
*lack organelles
*lack prominent cytoskeleton
*non-cellulosic cell wall
*divide by binary fission
*domains Bacteria and Archea
What are chacterstics of Eukaryotes?
*multiple, linear chromosome located in a membrane bound nucleus
*membrane-bound organelles
*extensive, organized cytoskeleton
*Cell division: mitosis meiosis
*cell walls of cellulose
*domain Eukarya
What does the bacterial cell cytoplasm contain?
*protiens, RNA, macromolecules
*Water
*Inorganic ions
*small organic molecules
*nucleoid:DNA
*ribosomes
*plasmids
*inclusions
what are the external structure of bacterial cell?
*pili
*fimbriae
*Flagellum/flagella
*glycocalyx
What does the inner cell membrane of a bacterial cell contain?
*phospholids
*proteins-transport enzymes
*maintain gradients
What is a bacterial cell wall composed of ?
peptidoglycan
Does the gram-positive of bacteria cell have thick or thin cell wall?
thick cell wall
What does the following characteristics describe…..
*thin cell wall
*outer cell membrane
*lipopolysaccharide
Gram-negative bacteria
What is the general term for extracellular polysaccharide-protein secretions?
glycocalyx
Describe Capsules
more organized and tightly associated to the cell
Describe slime layer
a looser assemblage
what allows for resistance to phagocytosis as virulence factor ?
Capsule and slime layer
What serves to provide motility via rotary motion like propeller?
Flagella
what is H antigen?
flagellin protein
what is the flagellar motion?
clockwise (TUMBLE)
counter-clockwise rotary motion (RUN)
What are axial filaments?
protein fibers attached to both poles of cell and wrap around the cell underneath an outer sheath
What are fimbriae and pili comprised of ?
comprised of protein pilin
what are hair-like appendages, shorter than flagella?
Fimbriae and Pili
what is fimbriae used for?
*for attachment to surfaces or cells
*important in biofilm formation
*can be virulence factor
What is pili used for?
*In DNA transfer (conjugation using sex pilus)
what does the bacteria cell wall do?
*provides protection
* confers shape
*helps withstand changes in osmotic pressure
What is linked to plasma membrane in gram postive?
Lipoteichoic acids
what is linked to peptidoglycan in gram positive cells?
Wall teichoic acids
are teichoic acids positively or negatively charged?
negatively
describe gram-negative bacteria:
only 1 to a few peptidoglycan layers; bonded to an outermsmbrane via lipoproteins
what does the gram-negative outer membrane consist of ?
Porins:permit entry of metabolically important molecules
what is the function of gram-negative outer membrane?
provides a barrier to certain antibiotics and other antimicrobial agents; a defense against complement and phagocytosis
what does the LPS of the outer membrane consist of?
- core polysaccharide
*Lipid A
*O polysaccharide
what is released when cell dies; functions as endotoxin?
lipid A
what is linked to core polysaccharide; composed of multiple sugars; confers antigenicity?
O polysaccharide
what is between the inner membrane and outer membrane?
periplasm
what is the smallest bacteria that lack cell wall?
mycoplasma
what is Archie cell wall comprised of ?
pseudomurien
Which statement(s) among A – F is true?
A. Pasteur’s Germ Theory of Fermentation explains the
nature of infectious disease.
B. Ecologically speaking, you are considered a producer.
C. The common cold virus: example of an EID (emerging
infectious disease)
D. Handwashing with soap = sterilizing method
E. Vaccines work by stimulating your body to produce
antigens.
F. Some microbe types can “eat” completely inorganic
materials for energy.
F. Some microbe types can “eat” completely inorganic
materials for energy.
The most abundant molecule in a prokaryote
cell would be…
A. DNA
B. Protein
C. Water molecules
D. RNA
E. Lipids (fats)
protein
ribosome
sites of protein synthesis; consist of ribsomal RNA’s and proteins
-assembled into subsunits, large and small that combine to forms the larger functional ribsome
-polyribsome formation
30s+50s=70s
-antibotic targets
what is porins?
permit enetry of metabolically important molecules
membrane proteins provide functionality :
-transport
-structural support
-metabolic activity
-communication
Passive diffusion
simple diffusion & facilitated diffusion: osmosis (diffusion of water)
concentration gradient
molecule diffuses passively down their gradient High concentration-> low concentration
Simple diffusion through
the lipid bilayer
osmosis
diffusion of water across membrane; water molecules move towards area of high solute concentration
hypotonic
:water moves into the cell. If the cell wall is strong, it contains the swelling.If the cell wall is weak or damaged, the cell bursts(osmotic lysis)
Active transport
requires energy input; for transport of molecules moving against their concentran gradients(low conntration)-> high conentration
hypertonic
water moves out of the cell, causing its cytoplasm to shrink (plasmolysis)
isotonic
no net movement of water occurs
what are cytoplasms solutes?
Solutes: waters, proteins, ions, sugars, lipids
what is chemotaxis?
the migration of cells toward attractant chemicals
what kind of movement do axial filaments produce?
produces corkscrew motion
Polysaccharide granules:
glycogen, starch to glucose polymers
Metachromatic granules (volutin):
stores inorganic phosphate
Lipid inclusions:
PHB (polyhydroxybutyrate)
Sulfur granules:
from oxidation of H2 S (lithotrophy)
H2S -> S 0 (insoluble granules)
Magnetosomes (for magnetotaxis)
Move down to depths of lower oxygen
Comprised of magnetite (Fe3O 4) crystals
– Orient along the magnetic field
– Bacteria are anaerobic or microaeroph
Gas vacuoles are used for?
to maintain proper depth
for optimum O2 , light, nutrient
what are carboxysomes?
protein-covered bodies
containing Rubisco, the CO2 fixation enzyme;
found in photo-, chemo-autotrophs
what are chromatophores?
containing photosynthetic pigments
enzymes involved in photosynthesis
how are endospores formed?
Under environmental stress
members of what genera form endospores?
members of
the genera Bacillus and Clostridium
endospores are highly resistant to what?
heating,
freezing,
radiation,
chemicals,
loss of water
Morphologies of
endospore-forming
bacteria
terminal, subterminal, central, swollen, non-swollen
REMBER PICTURE
what is the origin of eukaryotes to prokaryotes?
Endosymbiont theory
what is the evidence for Endosymbiont theory?
-have size similar to bacteria
-posses circular DNA (like bacteria)
-Can duplicate themselves
-affected by antibiotics that inhibit bacteria
Mycobacterium cell wall
acid-fast – contains waxy mycolic acids external to the peptidoglycan cell wall
