List the chief distinguishing characteristics of Prokaryotes
1. DNA not enclosed, usually single circular chromosome
2. DNA contains no "histones"
3. Lack membrane enclosed organelles
4. Cell walls have polysaccharide "peptidoglycan"
5. Cells reproduce via binary fission
List the chief distinguishing characteristics of Eukaryotes
1. DNA in nucleus, separated by nuclear membrane, multiple chromosomes
2. DNA has protein "histones"
3. Organelles enclosed in membranes
4. Cell walls are simple
5. Cells reproduce via mitosis
Most bacteria range from ___ to ___ micrometers in diameter; and ___ to ___ micrometers in length
diameter: 0.2 - 2.0 micrometers
length: 2 - 8 micrometers
coccus
spherical shape of bacteria
bacillus
rod-shape of bacteria
What are the 3 basic shapes of bacteria?
coccus, bacillus, spiral
diplococci
cocci bacteria that remain in pairs after dividing
streptococci
cocci bacteria that form a chain pattern after dividing
tetrads
cocci bacteria that form a group of 4 after dividing
sarcinae
cocci bacteria that form a cube of 8 after dividing
diplobaccilli
pairs of bacilli after dividing
streptobacilli
chains of bacilli after dividing
coccobacilli
oval shaped bacilli, named so because they closely resemble cocci bacteria
vibrios
curved (sprial) rod-shaped bacteria
spirilla
corkscrew (helical) shaped spiral bacteria that are rigid
monomorphic bacteria
bacteria that maintain a single shape due to heredity
pleomorphic bacteria
bacteria that can take on different shapes, due to their heredity
List the possible structures external to a prokaryotic cell wall
1. glycocalyx
2. flagella
3. axial filaments
4. filaments
5. fimbriae
6. pili
Glycocalyx
a sugar coating secreted by prokaryotes that is viscous and gelatinous
Capsule
a type of glycocalyx that is organized and firmly attached to a cell wall of a prokaryote
Slime layer
a type of glycocalyx that is unorganized and loosely attached to the cell wall of a prokaryote
What is the purpose of a prokaryote's capsule?
It may protect the bacteria from phagocytosis by host cells
Extracellular polymeric substance (EPS)
a type of glycocalyx that helps cells in a biofilm attach to their target environment, and aids in communication among the biofilm cells
Flagella
long, filamentous appendages that propel bacteria
Atrichous
bacteria without flagella or other projections
Peritrichous
Flagella are found around the entire surface of the cell
Polar (re: flagella)
Flagella are found at one or both ends of the cell
Monotrichous
a single flagella is found at one pole of the cell
Lophotrichous
a tuft of flagella comes out of one pole
Amphitrichous
flagella are at both ends of the cell
What are the 3 main parts of a flagella?
filament, hook, basal body
Compare the flagella of a gram-negative bacteria from a gram-positive one
the basal body contains 2 pairs of rings (inner and outer) anchored to the plasma membrane; in a gram-positive bacteria, only the inner pair is present
A. Monotrichous polar
B. Lophotrichous polar
C. Amphitrichous polar
D. Petrichous
Label the bacteria based on the arrangement of its flagella
How does the prokaryote flagellum aid the bacteria to move?
The basal body of the flagella rotates, forming a bundle that pushes against the surrounding liquid, propelling the bacteria forward
motility
the ability of an organism to move by itself
Bacteria "Runs
term that describes the motility of some bacteria, in which the movement is in one direction
Bacteria "Tumbles
term that describes the motility of some bacteria, in which the movement in one direction is interrupted by these brief, random changes in direction caused by the reversal of flagellar rotation
What is the advantage of bacteria motility?
allows the bacteria to move toward favorable environments or away from unfavorable ones
Taxis
the movement of bacteria toward or away from a specific stimulis
chemotaxis
chemical stimuli that causes bacteria to move away/toward it
phototaxis
light stimuli that causes bacteria to move away/toward it
chemotactic attractant
a chemical signal that causes a bacteria to move toward it
chemotactic repellant
a chemical signal that causes bacteria to move away from it
serovars
variations within a species of bacteria
Spirochetes
a group of helical spiral bacteria have axial filaments (endoflagella) capable of movement
Axial filaments / Endoflagella
bundles of fibrils that arise at the ends of the cell beneath an outer sheath and spiral around the cell (i.e. flagella found inside the cell); these bundles allow for the movement of spirochetes
Fimbriae
hairlike appendages on bacteria that are shorter than flagella, these tend to adhere to each other and to surfaces outside the cell. They tend to be be at the poles of a bacteria, or evenly distributed across the surface.
Pili
hairlike appendages on bacteria allow for motility or DNA transfer, these are longer than fimbriae and number 1-2
Twitching motility
the type of movement of bacteria involving a pilus (pili) that makes contact with the surface of another cell, then retracts in a powerstroke
Gliding motility
the type of movement of bacteria involving smooth, gliding movement of myxobacteria
Conjugation (sex) pili
bacterial pili that are involved in the transfer of DNA from one cell to another
What is the function of a bacteria cell wall?
- prevents it from rupturing when water pressure inside the cell is greater than that outside the cell
- helps it maintain shape
- anchors flagella
- contributes to its ability to cause disease (invade hosts)
What distinguishes the cell wall of Gram-positive bacteria from Gram-negative
- Gram-positive bacteria's cell walls have many layers of peptidoglycan, forming a thick rigid structure
- Gram-positive bacteria cell walls contain teichoic acids which span the peptidoglycan layers
- Gram-negative bacteria's cell walls thin layers of pe
What is the function of teichoic acids in the cell walls of Gram-positive bacteria?
- bind and regulate the movement of (cations) ions in/out of the cell
- play a role in cell growth
- prevent damage to cell
- provides antigen specificity
Which type of bacteria are more resistant to mechanical breakage (Gram-positive or -negative)? Why?
Gram-positive; because the cell walls of gram-negative cell walls contain only a small amount of peptidoglycan
Protoplast
a Gram-positive cell that has undergone cell wall destruction by lysozyme
Spheroplast
a Gram-negative cell that has undergone cell wall destruction by lysozyme
L-forms of prokaryotes
prokaryotic cells that have lost their cell walls and swelled into irregularly shaped cells
osmotic lysis
rupturing of a prokaryotic cell due to strong osmotic pressure outside the cell
plasma membranes
a thin structure lying inside the cell wall, encloses the cell's cytoplasm
CARDS STOPPED AT P. 89 2ND COLUMN "PLASMA MEMBRANE
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