01 - Generalities Flashcards by Jasper Viloria

non-SI unit for sedimentation rate; how fast is 1 unit?

svedberg unit = 10^-13 s (100 fs)

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content of bacterial cell wall

peptidoglycan

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content of fungal cell wall

chitin

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The only bacteria with sterols in their membranes

Mycoplasma

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jumping genes

transposons

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What are prions?

naked proteins, same sequence as certain normal human cell surface proteins but have folded differently

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vacuolated neurons with loss of function and the lack of an immune response or inflammation

spongiform encephalopathies

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etiology and manifestation of Creutzfeldt-Jakob disease

Infection -> dementia

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etiology and manifestation of Kuru disease

Cannibalism -> cerebellar disorders

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another name for mad cow disease

bovine spongiform encephalopathy

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how to disinfect tools from prions?

5% hypochlorite solution or 1.0 M sodium hydroxide or autoclaved at 15 psi for 1 hour

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three shapes of bacteria and their descriptions

cocci - spheres
bacilli - rods
spirochetes - spirals

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arrangement of cocci and their descriptions:

diplococci - pairs
streptococci - chains
staphylococci - clusters

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All bacteria have a cell wall composed of peptidoglycan except:

Mycoplasma (have sterols in their cell membranes)

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what enzyme cross-links the peptidoglycan?

transpeptidase

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Units of the sugar backbone in peptidoglycan?

NAM and NAG

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reason for resistance of MRSA?

alteration of the penicillin-binding protein

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This drug targets the ala-ala residues of the peptidoglycan

Vancomycin

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These bacterial cell wall proteins facilitate the passage of small, hydrophilic molecules into the cell

Porin proteins

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Lysozymes are enzymes that kill bacteria by cleaving which part of the cell wall?

Beta 1->4 glycosidic bond betweeen NAG and NAM (in peptidoglycan)

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Gram (+) vs Gram (-):

Peptidoglycan is thicker in

Gram (+)

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Gram (+) vs Gram (-):

techoic acids are present in

Gram (+)

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Gram (+) vs Gram (-):

lipopolysaccharide is present in

Gram (-):

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another name for lipopolysaccharide:

endotoxin

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Gram (+) vs Gram (-): periplasmic space

Gram (-):

What comprises an endotoxin?

lipid A and O antigen

Which Gram (+) bacteria have an endotoxin?

None, except for Listeria monocytogenes

steps in gram staining

1. crystal Violet 2. Iodine 3. Acetone 4. Safranin VIAS

Enumerate: | Bacteria that cannot be seen in gram staining; why can't we do gram staining; alternative approaches to detection

1. Mycobacteriae - too much lipid in cell wall so dye cannot penetrate - acid fast staining 2. Spirochetes - too thin to see - darkfield microscopy 3. Mycoplasma - no cell wall - do serologic studies 4. chlamydiae - intracellular and very small - giemsa stain 5. rickettsiae - intracellular and very small - giemsa stain 6. Legionella - poor uptake of red counterstain - silver stain

Oldest acid-fast staining method, which requires heating the specimen during the procedure.

Ziehl-Neelsen procedure

Which component of the gram (-) cell wall reduces its susceptibility to lysozymes?

outer membrane

Ribosomes of prokaryotes:

30S + 50S = 70S

Ribosomes of eukaryotes:

40S + 60S = 80S

invagination of the plasma membrane

mesosome

space between the plasma membrane and the outer membrane

periplasmic space

what is the function of the mesosome?

participates in cell division and secretion

what is the function of the periplasmic space?

contains many hydrolytic enzymes e.g. Beta-lactamases

This component protects the bacteria against phagocytosis

capsule

this component mediates adherence to surface and is responsible for the formation of biofilms

glycocalyx

These components are resistant to heat and chemicals

spores

Extrachromosomal, double-stranded, circular DNA capable of replicating independent of the bacterial chromosome

plasmid

site of nutrients in the cytoplasm

granule

What bacteria form spores?

Gram-positive rods, especially Bacillus and Clostridium, which are also exotoxin-forming

This bacteria has a protein capsule instead of a polysaccharide capsule: What is it made of?

Bacillus anthracis | - polypeptide of D-glutamate

Term for fusion of plasmids with the bacterial chromosome:

episomes

Function of the plasmid

for antibiotic resistance and formation of new toxins

toxic proteins produced by certain bacteria that are lethal for other bacteria

bacteriocins

Process of killing all microbial forms, plus spores

sterilization

Process of applying chemicals on inanimate objects to kill some bacteria

disinfection

Process of killing bacteria present in living tissues

antisepsis

Physical removal of microorganisms

De-germing

Process of lowering the bacterial count

Sanitization

Chloramphenicol is bacteriostatic except for the following microorganisms: (4)

1. Neisseria meninigitides 2. Bacteroides fragilis 3. Streptococcus pneumoniae 4. Haemophilus influenza No Boyfriend Since Highschool

Why are alcohol-based sanitizers ineffective against Clostridium?

because it can form spores

Enumerate the 4 phases of bacterial growth, and expain

1. Lag phase 2. log phase (exponential phase) 3. stationary phase 4. death phase (decline phase)

Phenomenon of a continued antibiotic effect despite its total elimination from the body

Post-antibiotic effect

substrate and product of superoxide dismutase:

- superoxide | - hydrogen peroxide and oxygen

substrate and product of catalase:

- hydrogen peroxide | - water and oxygen

substrate and product of peroxidase:

- hydrogen peroxide | - water

Completely dependent on oxygen for ATP-generation

obligate aerobes

use fermentation but can tolerate low amounts of oxygen due to presence of SOD

microaerophiles

utilize oxygen if present, but can use fermentation in its absence

facultative anaerobe

exclusively anaerobic but insensitive to the presence of oxygen

aerotolerant anaerobe

cannot grow in the presence of oxygen

obligate anaerobes

What enzymes do obligate anaerobes lack?

SOD, peroxidase, and catalase

examples of aerotolerant anaerobes

propionibacterium, lactobacillus

examples of obligate anaerobes

Actinomyces, Bacteroides, Clostridium

examples of obligate aerobes

``` Nocardia Neisseria Pseudomonas Mycobacteria Bordetella/Brucella/Bacillus cereus Legionella ``` Nosy and Nagging Pests Must Breathe Breathe Breathe Lots (of oxygen)

DNA transferred from one bacterium to another

Conjugation

DNA transferred by a virus from one cell to another

Transduction

Purified DNA taken up by a cell

Transformation

Normal flora of the skin

Staphylococcus epidermidis

Normal flora of the nose

Staphylococcus aureus

Normal flora of the mouth

viridans Streptococci

Normal flora of dental plaques

Streptococcus mutans

Normal flora of the colon

Bacteroides, E. coli

Normal flora of the vagina

Lactobacillus vaginalis, E. coli, Streptococcus agalactiae

01 - Generalities Flashcards

(77 cards)