2.1 Prokaryotes

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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


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