Microbiology Chapter 4.txt

• Bacillus
• Coccus
• Spirals

• Rod shaped
• Single or strepto only, no chains

• Sphere
• Cocci
• Single, occasional pairs, tetrad (group of four), cluster and chain

• Vibrios
• Spirilla
• Spirochetes
• Never in clusters or chains

comma

Rigid cell wall, flagella on each end for movement

• Flexible cell wall
• Moves like a snake
• Syphilis

• Flagella
• Pili
• Glycocalyx - Slime Layer and Capsule - protects, hides things that antibodies can be made against.
• Cell wall

• Protects, hides things that antibodies can be made against.
• Makes it too big to be engulfed by phagocytes

• Strength and shape
• N acetyl glucosamine
• N acetyl muramic Acid
• Teiocholic acid

• Pili are protein fibers extending from the surface of many prokaryotes
• Attach cells to surfaces
• Form biofilms and microcolonies
• Some bacterial species have conjugation pili, used to transfer genetic material between cells, like plasmid, pieces of DNA that have antibiotic resistance

• Location & number determined by genetics
• Prokaryotic flagella are long appendages extending from the cell surface
• Flagella can be used for cell motility
• Prokaryotic flagella contain a helical filament, a hook, and a basal body
• Bacteria exhibit chemotaxis, moving up the concentration gradient of a chemical attractant
• Some prokaryotes move without flagella by gliding across a solid surface
• Spirochetes contain endoflagella, which move the cell through torsion exerted on the cell by endoflagellar rotation

Cells will move towards nutrients (move up the concentration gradient)

single flagella

Flagella on both ends

Flagella on one end

Flagella all over

• Not all bacteria have this candy coating
• Polysaccharide composition (complex carbs with some minor small proteins)
• When it's thick it's considered a slime layer or capsule
• Can help with attachment
• Mostly for protection

• Capsule
• Cell wall
• Cell membrane
• Cell wall
• Keeps the cell from bursting
• A tough and protective external shell
• The cell wall protects the cell from injury, and to maintain cell shape and water balance

• 3 proteins, Nag, Nam & teichoic acid
• Nag and Nam are tied like ropes and the teichoic acid binds them together
• A thick peptidoglycan cell wall containing teichoic acid

• Only 1 layer of Nag & Nam between the outer membrane and cell membrane
• Thinner than G+
• Has an outer membrane
• Without teichoic acid, it doesn't hold the crystal purple stain
• A two-dimensional peptidoglycan layer and no teichoic acid

Prevents the making or repair of the peptidoglygan layer so it's more effective against G+

• Separated from the cell membrane by the periplasmic space
• Contains proteins called porins that selectively allow small molecules into the periplasmic space

• Made of triglycerides - 3 fatty acids and 1 glycerol
• Permeability barrier
• The cell membrane is a fluid layer of phospholipid and protein (the fluid mosaic model)
• The phospholipid molecules are arranged in a bilayer
• Antimicrobial substances may disrupt or dissolve the bilayer

• Cell wall synthesis
• Energy metabolism
• DNA replication
• Sensation of stimuli
• Molecule transport

• Hydrophobic fatty acid chains in the phospholipids form a permeability barrier
• 2 layers facing each other
• ooooooooo o = a glycerol
• |||||||||||||||||||||| = 2 fatty acids and a phosphate for each glycerol
• ooooooooo o = a glycerol

Proteins that form pores in the outer membrane that selectively allow small molecules into the periplasmic space

• Cytoplasm
• Ribosomes
• Chromosome
• Metachromatic granules
• Magnetosome
• Plasmids
• The nucleoid region
• A central subcompartment in the cytoplasm where DNA aggregates

• The chromosome is usually a closed loop of DNA and protein
• Only 1
• Circular

• Smaller pieces of DNA
• Non-essential info
• Small, circular
• Exchanged through the sex pilus
• Each plasmid is a closed loop, containing 5-10 genes
• Can be used as vectors in genetic engineering
• R plasmids carry genes for resistance to antibiotics

• Dark staining
• Blobs of phosphate
• Found in diptheriae

The complete set of genes is called the genome

Most cells have only one copy of each gene (are haploid), so cannot undergo mitosis like eukaryotes

There are hundreds of thousands of ribosomes, used for protein synthesis

Inclusion bodies store nutrients or building blocks for cellular structures

• Destroys peptidoglycan layer of cells
• It's more effective in killing G+ because G+ has lots of PG

Some aquatic bacteria use gas vesicles to float on the water�s surface

Magnetosomes contain crystals of magnetite or greigite, allowing cells to respond to magnetic fields

• Phylogenetically related to G+
• No cell wall
• Believed that they once had a cell wall but lost it because of their parasitic relationship with their host.

• Peptidoglycan Both
• Teichoic acids G+
• Outer Membrane G-
• Lipopolysaccharids (LPS) G-
• Porin proteins G-
• Periplasm G-

The mosaic of phospholipids and proteins are not cemented into place but rather they can move laterally in the membrane

• Thought it didn't exist until recently
• Proteins homologous to those in eukaryotic cytoskeletons are present

It forms filaments similar to those found in microtubules. It regulates cell division. Localizes around the neck of the dividing cell where it recruits other proteins needed for the deposition of a new cell wall between the dividing cells.

Can help determine cell shape

A homolog to eukaryotic intermediate filaments, also assists in cell shape

• An entity with similar attributes due to shared ancestry
• How many phyla are in the domain Bacteria?
• The majority of the 18 phyla of Bacteria play a positive role in nature

Contain the largest and most diverse group of species, including E. coli and many human pathogens

Consist of many gram-positive species, such as Bacillus, Clostridium, Staphylococcus, and Streptococcus

Include Streptomyces, the genus that produces the antibiotic streptomycin

Carry out photosynthesis using chlorophyll, responsible for the appearance of oxygen in Earth�s early atmosphere

Are extremely small, mostly pathogenic bacteria

• Contain many extremophiles
• methanogens (live in anoxic environments)
• extreme halophiles (salt-lovers)
• thermoacidophiles (grow at high temperatures with low pH)

Tend to grow in hot, acidic environments such as hot springs and volcanic vents

• Provides Mechanical Strength
• No archaea have peptidoglycan in the cell wall, but some have pseudopeptidoglycan
• Others have polysaccharides, proteins, or both

• Hydrophobic lipid tails are attached to glycerol differently in archaea
• Fatty acids are usually absent
• Adjacent lipid tails are bound together forming a lipid monolayer, instead of a bilayer

Can be passive (facilitated diffusion) or active (active transport)

Passive transport of molecules