Micro Chap 4/Exam 1

• Eukaryotes: multiple, linear chromosomes
• Prokaryotes: single, circular chromosome

• Eukaryotes: histones
• Prokaryotes: non-histones

• Eukaryotes: have mambrane enclosed organelles
• Prokaryotes: do not

• Eukaryotes: (if present) simple molecules
• Prokaryotes: complex molecules

• Eukaryotes: mitosis or meiosis
• Prokaryotes: binary fission

• Eukaryotes: fungi, protists, plants, animals
• Prokaryotes: Bacterium and archea

• coccus: round
• bacillus: rods (Sticks)
• spiral: spiral
• spirillum: spiral with no axial filaments
• vibrio: comma shaped

• Diplococcus: pairs of coccus
• Streptococcus- chain of coccus
• Tetrads: four coccus
• Staphylococcus: grape like clusters of coccus

• Diplobacillus: pairs of bacillus
• Streptobacillus: chain of bacillus
• Coccobacillus: very short rods that may look like coccus (when in doubt, its a rod)

They are clues to the MOs identity

made of water, proteins  and polysaccarides-means "sugar coating"

its a sticky, gelatinous polymer made inside the cell and secreted to the surface

• Capsule: if the glycocalyx is well organized and firmly attached to the cell wall
• -protect against phagocytosis from host, making ti more pathogenic

• Biofilm: if it is unorganized and only loosely attached to the cell wall (slime layer)
• -helps keeps cells lumped together and attached to a surface (attachment allows bacteria to grow)

They are long filament appendages that propel bacteria. Composed of protein molecules

Move by rotating the filament on a hook attached to the basal body

• the ability of an organism to be able to move by itself
• -towards good environments or away from danger

Axial filaments (endoflagella) located under the outer sheath

creates a corkscrew motion that can burrow through tissues

fimbrae are "sticky whisker" protein filaments that allow adhesion

this makes them more pathogenic because they hang out longer

The major function of the cell wall is to maintain osmotic pressure and prevent against lysis in hypotonic environments (50psi)

consists of very strong peptidoglycan

• -Made of protein and sugar chains
• -Very strong and permeable
• -Created by Nag/Nam chains (n-aceytlglucosamine and n-acetylmuramic acid-both modified glucose)
• -Also composed of Teichoic acid and peptide cross links

• -Thick layer of peptidoglycan
• -Teichoic acids

small molecules may pass through this tunnel in either direction (water, sugar, ions, and amino acids)

• -Thin peptidoglycan layer
• -out membrane (phospholipid bilayer)
• -Lipopolysaccaride (LPS) consisting of Lipid A and o polysaccarides
• -porins

contrinutes to the cells negative surface charge and protects against phagocytes and complement

• Lipid A is is the endotoxin in gram - cells.  Free Lipid A molecules in an animal's blood can cause shock!
• -when bacterial cells grows, some lipid A is freed
• -once treated, dead cells denigrate and release Lipid A

• Proteins secreted from the cell which are usually very toxic.
• -Gram + cells produce exotoxin, but some Gram - as well
• -botulinum toxin and tetanus toxin are two

• An enzyme found in tears, saliva, other secretions
• -break the Nag/Nam connection
• -this works on the Gram + cells, but not on the Gram - cells because the cell membrane protects the peptidoglycan

• Penicillin inhibits the formation of the peptide cross-links in new and growing cells, causing lysis
• -works on gram +
• -we have created ampacillin for Gram - cells

Phospholipid bilayer- a differentially permeable barrier composed of the lipid bilayer (polar head and nonpolar fatty acid tails), integral proteins, and peripheral proteins

• It functions as a deferentially permeable barrier
• -carbon dioxide, oxygen pass through freely while water, ions, sugars, amino acids, and proteins bounce off

Membrane proteins: most are transporters

Molecules pass directly through the PBL (oxygen and carbon dioxide)

• Molecules are assisted across the membrane by substrate specific transport proteins 
• -monosaccarides, amino acids, vitamins, ions
• *no ATP used because it follows the concentration gradient, however it does also occur against the gradient

Water moves across membrane both by simple diffusion and by passing through aquaporin proteins

• 1. If the cell wall is damaged and cell is in a hypotonic ECF, the cell bursts
• 2. Bacteria in hypertonic environments grow poorly

• Protein pumps that are substrate specific carry ions, sugars, amino acids, and sometimes antibiotics across the membrane
• *uses ATP
• -against concentration gradient

• -This always deals with the amount of substrate in the ECF.  
• -If there is more substrate in the ECF, it ishypertonic and water will leave the cell.  
• -If there is more subtrate in the cell, the ECF is hypotonic and water will enter the cell

• -Bacterial chromosome is located in the Nucleoid
• -a single, continuous, circular thread of double stranded DNA (no envelope or histones)
• -attached to the plasma membrane

• A plasmid is a small, circular, double stranded DNA molecule that are extrachromosomal genetic elements
• -replicates independently of chromosomal DNA
• -not essential to survival
• -may be transferred to another bacteria

• Advantages: may carry genes for
• -antibiotic tolerance
• -tolerance to toxins
• -production of toxins
• -synthesis of protiens
•  

• Function: site of protein synthesis
• Composed of: 2 sub-units, consisting of protein and ribosomal RNA (rRNA)

50S+30S=70S ribosome

Svedberg measure of density

• prokaryotic is 70S while Eukaryotic are 80S
• -certain antibiotics can interfere with protein synthesis in 70S while not harming host

• Inclusions: reserve deposits
• 1. metachromatic granules: hold polyphosphate for ATP production
• 2. polysaccaride molecules: contain glycogen and starch
• 3. Lipid inclusions: lipid nutrient reserves

• Bacillus-respiratory problems (B. anthracis for example)
• Clostridium-digestive problems (C. difficile causes major diarrea)

Sporulation is triggered when a key nutrient, such as carbon dioxide or nitrogen is depleted for unavailable

• 1. sporeseptum begins to isolate newly replicated DNA and small protein of cytoplasm
• 2. Plasma membrane starts to surround DNA, cytoplasm, and membrane isolated in step 1
• 3.  Spore septum surrounds isolation portion forming endospore (forming 2 membranes)
• 4. Peptidoglycan layer forms between membranes
• 5. Spore coat forms
• 6. endospore is freed from cell
• 

• Endospore only contains the essentials: DNA, small amounts of RNA, ribosomes, and enzymes
• -surrounded by spore coat and peptidoglycan later
• -dehydrated

• Germination takes the endospore from dormant to vegetative
• - triggered by physical or chemical damage to the endospores coat
• -causes endospores enzymes to break down extra outer spore coat and water enters

• Vegetative cells are easy to kill, but endospores are not.  Their thick spore coat keeps out antibiotics and makes it very hard to treat while endospores are dormant.
• -hardest MO to treat

The endospore is only one cell.  It is not  means of reproduction, but of survival

• The idea that mitochondria and chloroplasts used to be bacteria
• -both have their own circular DNA
• -both are enclosed with a double membrane (PLB)
• -both have 70S ribosomes

• Advantages for the small cells:
• -big cell is a source of nutrients
• -big cell is a source of protection

• Advantages for big cells:
• -small cells produce more ATP