Microbiology Exam 1 Cedarville University--Dr. Collins

What are the three domains of life?

Bacteria, Archaea, Eukarya

According to evolutionary theory, what does all life forms evolve from?

Common ancestors

How was spontaneous generation disproved?

Francesco Redi conducted an experiment with maggots and meat in a jar...placed cap on jar with meat inside and proved that no maggot just appeared..they had to fly in themselves

What scientist disproved spontaneous generation?

Francesco Redi

What is the first Koch postulate?

microbes must be present in every case of the disease but not in healthy animal (pathogenic in unhealthy people but not healthy people)

What is the second Koch postulate?

Suspected microbe must be isolated and grown in pure culture (just the microorganism, no contamination)

What is the third Koch postulate?

Same disease must result when pure culture inoculated into healthy host (entered into)

What is the fourth Koch postulate?

Same microbe isolated from infected host

Who demonstrated the role in microbes causing disease?

Robert Koch

What is the first exception to the postulates?

some individuals may be immune --healthy host (Typhoid Mary)

What is the second exception to the postulates?

not everything can be grown in pure culture-viruses-M. leprae-lepracy

What is the third exception to the postulates?

Some microbes can cause various diseases

What is the fourth exception to the postulates?

various organisms can cause the same disease

What is the fifth exception to the postulates?

Might not be ethical-HIV

Who discovered vaccines?

Louis Pasteur

What was the first vaccine?

chicken cholera

What did Pasteur use to test his vaccines?

chickens

What did Pasteur do with the chickens for his vaccines

He took some of the microorganisms with a disease and put it into another chicken, but left it non-pathogenic (attenuated)

What are the three types of anthrax?

cutaneous, pulmonary, gastrointestinal

What is the common characteristic associated with the cutaneous anthrax?

black skin ulcer

What is the common characteristic associated with the pulmonary anthrax?

flu-like symptoms--cough, chest discomfort,etc

What is the common characteristic of gastrointestinal anthrax?

Nausea, vomiting, diarrhea

What is the treatment for those with anthrax?

60 day course of antibiotics

What are the four types of light microscopy?

Compound

Darkfield

Fluorescence

Confocal

When would you use electron microscopy?

When looking at a virus and/or cross sections of cells

What is the difference between light microscopy and electron microscopy?

Light uses a visible light to observe objects; electron used magnetic lenses with electron beam

How do you calculate total magnification?

ocular lens x objective lens

What is the ability of lenses to distinguish two points?

Resolution

How has anthrax been used in warfare?

Royal air forced bombed the land of gurnard island and caused quarantine for many years (40?)

What are the various types of bacterial shapes?

Cocci

Rod

spirilla

vibrio

spirochete

pleomorphic

What bacterial structure are involved in attachment?

glycocalyx

Flagella

pili

How does glycocalyx contribute to virulence?

-capsules prevent phagocytosis

-extracellular polymeric substance helps form biofilms

How does glycocalyx help an organism evade the immune system?

helps exclude antibiotics and viruses--capsule with strong resistant layer

What are the three components of flagellum?

Basal body

Hook

Filament

What are the four different flagella positions?

monotrichous

amphitrichous

lophotrichous

peritrichous

What is the function of pili?

transfer genetic material (sex pili)

Twitching movement

attachment to surfaces

What is bacterial taxis?

cell directed movement

five type--each goes with where the cell will go

What is the type of bacterial taxis that goes to chemical?

chemotaxis

What is the type of taxis that goes to the temperature?

Thermotaxis

What is the type of taxis that goes to light?

phototaxis

What is the type of taxis that goes to air/oxygen?

Areotaxis

What is the type of taxis that goes to solid concentration like salt?

Osmotaxis

Where do the cells move through during bacterial taxis?

chemoreceptors

What type of cell has a thick peptidoglycan layer in the cell wall?

gram positive

What type of cell has a thin layer of peptidoglycan in the cell wall?

gram negative

Which cell has an extra layer to the cell wall?

gram negative

what is the extra layer of a gram negative cell called?

outer membrane

What component do gram positive cells have that gram negative cells do not?

peptide interbridge between amino acids

What is the most prevalent type of tuberculosis?

latent

Inactive form of TB

latent

How can mycobacterium tuberculosis be detective in an infected individual?

Skin test-raised and red (purified)

Protein derivative from organism (PPD)

Blood interferon (gamma release assay-signal of infected body)

Chest x-ray

What did the Miller-Urey experiment demonstrate?

evidence for a need for a designer

one can produce amino acids from nothing, or old chemicals, but could not produce proteins or cells

Disproved abiogenesis

What is the function of LPS?

Stabilize outer membrane

attach to surfaces

biofilm formation

create additional permeability layer

protects bacteria from host immune system

endotoxins (toxin that is a part of the material cell)

O antigen given

What does the extra permeability layer do?

helps with resistance to any entry of salts, antibiotics, other toxic substances

What is antigenic variation?

cells can change their o antigen, antibodies created by the human body will not attach to the new o antigen, way to avoid immune system

How does antigenic variation help with pathogenicity?

Avoids immune system way

What are the components of the archaea plasma membrane?

fluid mosaic model

Interspersed lipid bilayer-20% peripheral and 80% integral proteins (with specific function)

What are the components of the bacterial plasma membrane?

Unique lipids- isoprene units

Ether linkages to glycerol

some may have a monolayer instead of bilayer

What is the function of the cytoskeleton?

Cell division

localize proteins

Cell shape

What is the function of the inclusion bodies?

storage for cells

What are the two types of inclusion bodies

organic

inorganic

What does the plasmid DNA encode for?

antibiotics resistant genes

toxin resistant genes

Why do some bacterial cells form endospores?

nutrient depletion

desiccation--not enough water

What makes endospores so resistant?

calcium

small acid-solluable DNA binding proteins

dehydrated core

spore coat and exosporium protect

What is an opportunistic pathogen?

one that invades the tissues when the body defenses are suppressed (immune system compromised--causes illness)

How does P. aeruginosa exhibit antibiotic resistance?

efflux pumps

beta-lactamases (enzymes that break down penicillins)

Mutants

Protection in biofilms

What does noscomial infection mean?

when a person goes into a hospital and comes out with an infection

What are biofilms?

a thin, slimy film of bacterial colonies that adheres to a surface.

What are P. aeruginosa virulence factors?

proteases, exotoxin A, hemolysins

Where is the most common place to find a P. aeruginosa infection?

Respiratory tracts