contributes to the strength of a gram postive cell wall. antigen typing
Lipopolysaccharide- What are the (2) components of a LPS?
outter membrane on a gram (-) cell wall 1. O polysaccharide- O antigen used for serotyping 2. Lipid A
What is the chemical composition of a Endotoxin?
Lipid (Lipid A)
What is the chemical composition of a Exotoxin?
Overwhelming gram (-) infection from an Endotoxin causes (3)?
1.Fever 2.Shock 3.DIC
Every gram (-) infection causes same response bc?
Endotoxin- Lipid A is always present
Porins- proteins that act as channels. Function-allow some substances to pass through cell wall.
Why do gram (-) cell walls resist chemicals and antibiotics better than gram (+) cell walls? (2)features
1. LPS-outer lipid membrane 2.Porins- protein channels These preven chemicals and anitbiotics from penetrating.
(4) steps of a gram stain?
1.crystal violet-primary dye enters both cells. Stain cells purple 2. Iodine applied- mordant and forms larger moleules with crystal violet 3.Acetone OH applied * Thick peptidoglycan will hold the purple dye and will not wash out. gram + =purple *Thinner peptidoglycan layer will wash out and release the dye. gram-= colorless 4.Safranin dye= red Gram- cell will uptake the red dye bc it contains none. Gram + cell will not uptake the red dye becuase it saturated with purple dye.
The color of a negative gram stain and cell wall type? The color of a positive gram stain and cell wall type?
Negative gram stain= red thin peptidoglycan, LPS, and porins Postive gram stain = purple, thick peptidoglycan
What does a negative gram stain mean?
It means the subject of intrest does not stain.
What are the (4) characteristics of a Bacteria that lacks a cell wall?
1.Plemorphic-shape 2.Bacteria does not stain- red gram stain 3.Antibiotics will not work 4.Less protection from environmental extremes.
An example of a bacteria that lacks a cell wall?
Mycoplasma Pnuemoniae causes walking pnuemonia.
What are the effects of each envoriments on a cell? Isotonic soln Hypertonic soln Hypotonic soln
Isotonic soln- no effect on cell Hypertonic soln=Shrink Cell Hypotonic soln=Burst Cell
Hypertonic Soln effect on Cell Membrane
1. Plasma Membrane Shrinks
Hypertonic soln effect on a cell with no cell wall?
The Cell will be destroyed.
Hypertonic soln effect on a cell with a cell wall?
The cell will stop growing.
the bacteria stops growing?
What is used for stoping bacterial growth? (2)
1.high salt 2.high sugar These hypertonic solutions perserve food by preventing bacteria from growing by shrinking the cell membrane.
Hypotonic soln effect on a cell with no cell wall?
The cell w/no wall will burst and be destroyed. A cell w/wall will maintain itself.
Name this piece of internal equipment and function?
Spore-oval swelling at the end of rods Function- preserve the cell when external conditions threaten cell survival.
(3) Conditions when a bacteria turns into a spore?
1.Dry 2.No Food 3.other threat to cell's survival
When external conditions improve.
1 Spore= 1 Bacteria Why?
No reproduction takes place when a bacteria is in a sporulation.
Do Bacterial Spores Gram Stain?
No Bacterial Spores do not uptake the stain.
What does no cell wall mean about the bacteria?(4)
1.pleomorphic 2.Bacteria cant be gram stained 3.Antibiotics that attack cell walls do not work 4.Bacteria less protection from environmental conditions.
Name two membrane organelles that prokaryotes do not have in their cytoplasm?
1.Golgi Bodies 2.Endoplasmic Reticulum
What are Bacterial Ribosomes called? What is their function?
Bacterial Ribosomes are 70s Eukaryotic Ribosomes are 80s
Why do antibiotics attack bacterial ribosomes and not human ribosomes?
Antibiotics only target 70s Ribosomes bc their different from humans
What is the evidence suggesting that mitochondria and chloroplasts could have once free living?
1. both have 70s ribosomes 2.both have double membrane organellas due to endocytosis
What is endosymbiotic theory?
Mitochondria and chloroplasts are actually bacteria in origin.