Medical Bacteriology Flashcards by Sydney Millman

Name all the characteristics that cellular life has in common:

Cell Membrane: that regulates the flow of nutrients and wastes that enter and exist the cell
DNA: for genetic material
RNA molecules
Protiens: all enzymes
Basic Chemicals: lipids, minerals, protiens, vitamins
Reproduction
Energy

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Differentiate between Prokaryotic Cells and Eukaryotic Cells

Prokaryotic: NO nucleus NO RNA processing NO organelles but YES cell wall
Eukaryotic: YES nucleus, YES RNA processing, YES organelles, and no cell wall in animals

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What is cell structure is called the bacteria’s motor? and why?

Flagellum

- because it helps bacteria move from one place to another

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Describe flagellum

long structure that extends beyond the cells surface

-it arranges itself differently depending on the species

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Function of Flagellum

responsible for the movement; rotation propels bacterium through the enviroment

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Is flagellum used in chemotaxis? Y/N?

YES! it generates movement towards or away from substance;

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What defines positive and negative chemotaxis?

movement towards a favourable stimulus is postive taxis

movement away from a favourable stimulis is negative taxis

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What are Axial Fillaments?

They have a similar function of the flaggelum (its a type of flagella)
It runs lenghwise along the cell way and makes snake like movement

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How can you describe the movements of the axial fillaments?

snake like……

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What is fimbria?

sticky like projections that are distrubuted over the surface of cells; 100’s of them.
— used by bacteria to adhere to one another, to hosts and to substances in the environment

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Fimbria is longer then flagellum T or F

F: fimbria is shorter

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Is it true that fimbrae has a virulent factor?

Yes, it can have a virulent factor that is a danger to our system

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Describe the “pulling something with a rope” analogy?

Bacteria uses the fimbria to move across or towards another substance or cell ; so its like pulling something wit ha rope

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Describe 0.157 E-coli

type of ecoli that can be involved in food and water poisoning
enters into the blood stream and can affect our immune system and cause great damage
effects the efficiency of the fimbrae
very pathogenic

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Long hollow tubes
Longer then fimbrae but shorter then flagellum
Bacteria have typically 1 or 2 per cell but not everyone has it at all
WHAT AM I?

PILLI !!!

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What is pilli’s main function?

Pilli’s main function is to join to bacterial cells and mediate the transfer of DNA from one cell to another (conjugation)

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Sticky substance surrounding the outside of the cell is called…

CAPUSLE/SLIME layer

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What is the capusle and slime layer composed of?

polysaccharides, polypeptides and glycoprotiens; very sugary

Why are capsule and slime layers only normally observed in nature and not labs?

lab cells arent under any real life stress that nature cells are ; so the lab cells have no real threat or reason to have the protection from the capsule/slime layers

What are the differences between the capsule and slime layer?

CAPSULE: thick layer and firmly attached to the cells surface
SLIME: thin layer and loosely attached to the cells surface

TRUE OR FALSE: slime layer and capsule layer are always BOTH present

FALSE! you can only have one!!!!

What are some functions of the capsule/slime layer??

mediate adherence of cells to each-other and surfaces
protect bacterial cells from engulfment
protect cells from drying
reserve for carbohydrates

A complex aggregation of microorganisms growing on a solid substance (a colony of one or more bacterias)

BIOFILM

mediated by fimbria and capsules
much more resistant then planktonic cells to antimicrobial agents and the hosts immune response

How can biofilm be dangerous and life threatening?

when biofilm spreads in implants, tubes and wires (catheters ect) = INFECTION or when cystic fibrosis patients cant cough up their mucous; it gets stuck in lungs and biofilm develops

Biofilm is:

an organized layered system of bacteria and microbes attached to cell surface

True or False: Cells without a cell wall burst if put in a hypotonic solution but a cell with a cell wall, wouldn't

TRUE! - cell walls resist osmotic pressure :)

Prokaryotic Cell Walls....

allow resistance of osmotic stress provide structure and shape assist in some cells from attatching to others its only found in prokaryotic so we can target cell wall of bacteria with antibitoics

What is a bacterial cell wall made up of?

Peptidoglycan!!

features of Peptidoglycan:

``` single macromolecule highly cross linked surrounds cell all over from all directions provides rigidity and it determines the bacterial shape ```

Structure of peptidoglycan consists of two alternating sugars which are...

NAG & NAM

NAG AND NAM are linked to eachother with 5 main amino acids : name them

L-aline D-glutanic acid L-lysine/diaminopimelic acid D-aline x 2

What amino acids arent synthesized by mammals?

Muramic acid D-amino acids and diaminopimelic acid.

Describe the cell wall of a gram positive bacteria:

Thick layer of peptidoglycan (40-50 layers) and a plasma membrane

Describe the cell wall of a gram negative bacteria?

1. Outermembrane 2. Periplasmic space that carries a thin layer of peptidolycan (2-3 layers) 3. Plasma Membrane

You know if the gram is negative because the color after the stain is ...

PINK! its pink because since the layer of the wall is so thin, the crystal violet stain is washed away and its pink

the gram stain is positive because the color is..

PURPLE: because it becomes trapped inside the thick thick layer so its not washed away, it becomes dehydrated

What is Teichoic and Lipoteichoic acid and where would we find it?

Teichoic acid: connects the layers of peptidoglycan together Lipteichoic acid: connects cell wall to plasma membrane we find this in GRAM POSITIVE BACTERIA

Is it gram positive or negative where we find a thin layer of peptidoglycan covered by membrane composed of phospholipids, integral proteins and lipopolysaccharides?

NEGATIVE bitch.

Jelly like in nature Between the outermembrane and plasma membrane containing peptidolglycan, water, enzymes, nutrients an digestive enzymes; I also turn pink :)

Periplasmic space

Toxins are..

chemicals produced by the pathogen that harm tissues or trigger host immune response that causes damage

rod like = spiral = spherical=

baccilus spirrilum and coccus

``` Exotoxins are usually released by: a) endotoxins b: gram negative C: gram positive d: gramcrackers ```

C: gram positive bacteria

What are exotoxins?

protiens secreted from a live pathogen that sends abnormal signals to the cell to make them loose essential things they need to survive - can destroy cellular and extracellular strcutres - can affect the nervous system causing paraylsis - bacteria resides in one side of the body but the molecules of toxins travel and bring it everywhere - MRSA for example

talk about MRSA/staph aureus :

MRSA: causes abcesses, cellulitis, invasive infections (pneumonia, h1n1) and necrotizing facilities ( fleash eating disease - from injection with MRSA on it ) - it is antibiotic resistant STAPH AUREUS: influenza ; shows on xray and can be treated ;