2.1 Prokaryotes
Endospores
- Found everywhere - Resist most ordinary cleaning and sterilization methods - Use endospores to determine if autoclaves have the proper settings
Run-and-tumble Motion
- Used by bacteria - A form of movement in a semi-random fashion. - Progress in the right direction occurs when the average length of a run in the correct direction is longer than the average length of a run in the wrong direction.
All cells have
- genetic material - cytoplasmic matrix - cell membrane - chromosomes - ribosomes
Medical Significance of Endospores
-Endospores are resistant to alcohol based hand sanitizers -They can live for thousands of years -They can last in patient rooms for a long time -It is hard to destroy them -Some endospores are used to see if correct flaming methods are being used.
What makes an endospore so resistant?
-Extensive protein coat -Low metabolic activity -Low water content -Compounds to stabilize proteins (dipicolinic acid)
Biofilm Contributions
-Fimbriae -Flagella -Pili
Acid-Fast Bacteria
-contain mycolic acid (a wax) -resist decolorization by acids during staining -can be a pathogen (tuberculosis, leprosy)
Prokaryote Size
.5-.2 um
Eukaryote Ribosomes
80s Number in millions. Complex macromolecular machines that manufacture proteins and are scattered in cytoplasm.
Endospore
A highly resistant structure designed for survival of the species
Nucleoid
A non-membrane-bounded region in a prokaryotic cell where the DNA is concentrated.
Teichoic Acid
A phosphorylated polyalcohol found in the cell wall of some gram-positive Bacteria
Gram Stain (Hans Christian Gram)
A staining method that distinguishes between two different kinds of bacterial cell walls.
Capsule
A sticky layer that surrounds the cell walls of some bacteria, protecting the cell surface and sometimes helping to glue the cell to surfaces. One form of glycocalyx.
Biofilm
A surface-coating colony of one or more species of prokaryotes that engage in metabolic cooperation.
Endospores
A thick-walled protective spore that forms inside a bacterial cell and resists harsh conditions. Only gram-positive
Pili (Pilus)
A thin, hair-like projection that helps a prokaryote attach to surfaces.
Endotoxin
A toxic component of the outer membrane of certain gram-negative bacteria that is released only when the bacteria die.
are found in acid-fast bacterial cell envelopes
All of the following pertain to endotoxins, except they
Sporulation
Allows continuation of a species, not an individual
Nucleid
Archaea and bacteria do not have a nucleus, but a:
One
Bacteria have _____ supercoiled chromosome
Gram-Negative bacteria
Bacteria with a complex cell wall that is not detected by the immune system. They are more resistant to antibiotics.
Capsule Detection
Bacteria with capsules look wet or slimy
Plasmids
Can have 0 or many
Bacilli
Can only divide along the short plane.
Mycoplasma
Causes walking pneumonia
Chemotaxis
Cell movement that occurs in response to chemical stimulus
Nucleoid
Circular, non-membrane bound chromosome
Staphlo
Cluster
Vibrio
Comma shaped bacteria
Capsule
Covers the cell wall in prokaryotes.
Tindell
Created sterile equipment even with endospores
Gram Positive
Describing the group of bacteria that have a cell wall that is structurally less complex and contains more peptidoglycan than the cell wall of gram-negative bacteria. Gram-positive bacteria are usually less toxic than gram-negative bacteria. These stain purple.
Gram Negative
Describing the group of bacteria that have a cell wall that is structurally more complex and contains less peptidoglycan than the cell wall of gram-positive bacteria. Gram-negative bacteria are often more toxic than gram-positive bacteria. These stain pink
Alcohol
Dissolves membranes
Archaea
Do not follow gram - or + rules
Germination
Dormant endospores start metabolic activity and break hibernation.
Gram-Positive bacteria
Easier to detect by the immune system. Does not have a selectively permeable membrane, so it is easier to treat with antibiotics
Viable
Endospores remain viable for 1000s of years!
Amphitrichous
Flagella at both ends of cell
Ferdinand and Kohn
Found endospores
Bacterial Endospores
Function in the survival of a species
Acid-Fast Bacteria
Gram +, but have unique lipids that compose most of their cell wall. Hard to stain Need to use heat (acid-fast) stain
Spirilla
Gram Negative
Spirochetes
Gram Negative
Endospore Germination
Happens when conditions are favorable
Endospore Formation
Harsh conditions cause formation
Outer Membrane
In Gram-negative bacteria, a membrane external to the cell wall.
Periplasmic Space
In Gram-negative cells, the space between the cell membrane and the outer membrane containing peptidoglycan and periplasm.
Conjugation
In bacteria, the direct transfer of DNA between two cells that are temporarily joined.
Rubbing Alcohol
Kills both gram + and - bacteria
Lipopolysaccharides (LPS)
Lipid portion (endotoxin) may become toxic when released during infections May function as receptors and blocking immune response Contain porin proteins in upper layer - regulate molecules entering and leaving cell
Peptidoglycan
Long chains of glycans connected by peptids
Ribosomes
Made of RNA
Flagellum
Major locomotor structure
Pleomorphic
Many shapes
Plasmid DNA
Non-essential DNA that makes certain bacteria more resistant to antibiotics or more resistant to oxidation
Cell wall
Not all cells have a
Archaeon (Archaea)
One of the two divisions of prokaryotes, often found in hostile environments such as hot springs or concentrated brine.
Endospores
Only Gram + and only produced by bacillus shaped
Flagellum
Only in aquatic environments
Arrangement
Paired arrangement (diplo) Grape-like clusters (Staphylo) Chains (Strepto)
Mycoplasmas
Pleomorphic No cell wall Extremely small
Porins
Proteins that allow the passage of certain ions and small polar molecules through membranes.
Removal of Peptidoglycan
Results in the failure of a cell
Bacillus (Bacilli)
Rod shaped bacteria
Archaea Ribosomes
Same size and function as bacteria, but different proteins
Fimbria (Fimbriae)
Small, bristle-like fibers sprouting off the surface of many bacterial cells. Allow tight adhesion between fimbriae and epithelial cells, allowing bacteria to colonize and infect host tissues.
Prokaryotes
Smallest living things
Periplasmic Flagella
Spirochetes
Endospores are Resistant to
Temperature, pH, oxygen, salt, lack of water, lack of nutrients, chemicals, radiation, antibacterial agents
Eukaryotes
Usually 10x bigger than prokaryotes
Vegetative Cell
a cell that has not formed spores or other resting stages
Slime Layer
a glycocalyx that is unorganized and loosely attached to the cell wall
Slime Layer
a glycocalyx that is unorganized and loosely attached to the cell wall.
Viability
ability to germinate
Cell membrane
all cells are surrounded by a thin flexible barrier
Mycoplasmas
bacteria that naturally lack a cell wall
Coccus (Cocci)
berry-shaped bacterium or sphere shaped
Strepto
chains
Lophotrichous
cluster of flagella at one or both ends
Lipoproteins
clusters of lipids associated with proteins that serve as transport vehicles for lipids in the lymph and blood
Lysis
destruction
Paired
diplo
Sporulation
endospore formation
Peritrichous
flagella distributed over the entire cell
Cell Envelope
includes plasma membrane, cell wall, and glycocalyx
Flagellum (Flagella)
long, tail-like projection with whiplike or propeller motion that helps a cell move
MRSA
methicillin-resistant staphylococcus aureus
Monotrichous
one flagella
Diplo
pairs
Peptidoglycan (PG)
qA network of polysaccharide chains cross-linked by short peptides that forms the rigid part of bacterial cell walls. Gram-negative bacteria have a smaller amount of this rigid structure than do gram-positive bacteria.
Bacteria (Bacterium)
single-celled or noncellular spherical or spiral or rod-shaped organisms lacking chlorophyll that reproduce by fission
Ribosomes
site of protein synthesis
Spirochetes
spiral-shaped GRAM NEGATIVE bacteria that have flexible walls and are capable of movement
Grape-like
staphylo
Chains
strepto
Bacteria ribosomes
structure: large and small 70s subunits made up of proteins and rRNA function: site for protein synthesis (translation) location: cytoplasm
