Shared Flashcard Set

Details

SCCC Micro Final pt 2
SCCC Micro Final pt 1 - chapters before 16
135
Microbiology
Undergraduate 2
05/07/2012

Additional Microbiology Flashcards

 


 

Cards

Term
Fields studied by microbiologists
Definition

-prokaryotes (bacteria)

-fungi - yeast, mold

-protozoa

-helminths - worms

Term
Three basic bacterial shapes
Definition

coccus (pl. cocci) - spherical

bacillus (pl. bacilli) - rods

spirals

Term
Shapes of cocci
Definition

diplococci - pairs

streptococci - chains

tetrad - groups of 4

sarcinae - cubelike groups of 8

staphylococci - grapelike clusters

 

*strep (small) *staph (big)

Term
Shapes of bacilli
Definition

diplobacilli - form pairs

streptobacilli - chains

coccobacilli - ovals

pallisades - look like Chinese letters (ex Diphtheria)

Term
Shapes of Spirals
Definition

vibrio - curved

spirilla - helical, like a corkscrew with rigid bodies

spirochetes - flexible corkscrews

Term
Types of flagella
Definition

monotrichous - one

amphitrichous - tufts at both ends

lophotrichous - 2 or more at 1 end

peritrichous - flagella all over cell

Term
Axial filaments
Definition
bundles of fibrils that wrap around spirochetes to help them move
Term
Fimbrae
Definition
hairlike structures that help bacteria adhere
Term
Pili
Definition
join some bacterial cells so DNA can be transferred
Term
Prokaryotic Cell Walls
Definition

- semi rigid

- protects against lysis

- protects internal structures

- usually made of peptidoglycan

Term
Gram Positive Cell Walls
Definition

- Thick, many layers of peptidoglycan outside the plasma membrane

- Resists decolorization when gram staining

- Contain teichoic acid (allows for slide agglutination typing)

Term
Gram negative cell walls
Definition

- One, or just a few peptidoglycan layers outside the cell membrane

- Easily broken

- No teichoic acids

- Have outer membrane of phospholipid bilayer, used to determine strain or serovar

- Barrier for some antibiotics, enzymes, heavy metals, bile salts

Term
Atypical Cell Walls
Definition

No cell walls - Mycoplasma

Acid Fast cell walls - Mycobacterium (have a waxy lipid called "mycolic acid" in cell wall, resists staining. Must use heated carbolfuchsin)

Term
Methods of Identifying Organisms
Definition
- morphological characteristics
-staining
-biochemical tests
-serology
-phage typing
-DNA base composition
-DNA probes
Term
morphological characteristics
Definition

-what it looks like

-macroscopic & microscopic

Term
staining
Definition

-gram staining (+/-)

- acid fast (mycobacterium)

negative staining

Term
biochemical tests
Definition

-used to determine which enzymes an organism has

 

-must have pure culture

Term
serology
Definition

antigen-antibody reaction

 

-slide agglutination

-ELISA (Enzyme Linked ImmunoSorbent Assay)

Term
Phage typing
Definition
bacterial viruses only infect members of a particular species
Term
DNA base composition
Definition
(G+C) ratio
Term
DNA probes
Definition

contain DNA from a known organism

 

DNA strand is separated

 

-look to see if it hybridizes (forms base pairs with the unknown specimen, if it does, have identified specimen)

 

-works on mixed cultures

Term
DNA Fingerprinting
Definition

used to map nucleotide sequences

sometimes used to determinte the source of a nosocomial infection

Term
DNA hybridization
Definition
measures the ability of DNA strands from one organism to hybridize (bind through DNA base pairing) with the DNA strand of another organism. The more hybridization, the more closely related they are
Term
Bartonella henselae
Definition

Cat Scratch Fever

normal flora in cat intestines

serious infection - high fever

gram negative rods

direct contact or fleas

Term
Bordetella pertussis
Definition

Pertussis  - Whooping Cough

gram negative rods

vaccine DPT

forms a membrane in the throat

Term
Neisseria
Definition

gram negative diplococci

normal flora of mucus membranes

 

N. gonorrheae - gonorrhea

N. meninginitidis - meningitis

 

*N. gonorrheae has protein Opa that binds to CD4 lymphocytes and prevents the production of memory cells and immunity

Term
Pseudomonas
Definition

gram negative motile rods

can grow in water, on soap, in bottle caps

can grow in refrigerator

common nosocomial infection

can produce a blue-green pigment that smells like grapes

antibiotic resistant - gentamicin

Term
Escherichia coli
Definition

inhabits mammalian interstinal tract

wound infections & UTI

E. coli O157:H7 - causes diarrhea and produces a toxin that can shut down the kidneys

Term
Salmonella enterica
Definition

-2400 serovars

-found in intestinal tracts of poultry & cattle, found in reptiles

-can get inside plants we eat

-causes bloody diarrhea

Term
S. typhi
Definition

-causes typhoid fever

-high fever & headache

-can infect the liver & spleen

-some people become carriers (Typhoid Mary)

Term
Proteus
Definition

-many flagella

-swarming growth on media

-normal intestinal flora

-UTI & wound infections

-smells like chocolate cake

Term
Pasturella multocida
Definition

-wound infection from cat bites

-requires IV antibiotics

-causes cellulitis

Term
Haemophilus
Definition

-needs chocolate (hemolyzed blood) agar to grow in the lab

-very pathogenic

-smells mousey

Term
Haemophilus influenza
Definition
-meningitis, ear infection, epiglotitis, pneumonia
Term
Haemophilus ducreyi
Definition
-STD "chancroid"
Term
Haemophilus ageptycus
Definition
-pink eye
Term

Helicobacter spp.

Helicobacter pylori

Definition
-causes peptic ulcers and stomach cancer
Term
Clostridium
Definition

-spore forming anaerobes

-spores can live in the soil for years

 

C. tetani - tetanus (lockjaw)

C. botulinum - botulism

C. perfringens - gas gangrene

C. difficile - antibiotic resistant, normal intestinal flora, when antibiotics kill all good flora it takes over, often a nosocomial infection

Term
B.antracis (anthrax)
Definition

CDC must be notified

Three types of anthrax:

-Cutaneous (skin)

-Gastrointestinal

-Pulmonary

(if not treated can lead to septicemia - death rate 100%)

*potential for bioterror

Term
Staphylococcus aureus
Definition

-gram positive cocci

-grows in grape-like clusters

-yellow colonies

-can grow in salty meats

-grows in ocean

-produces toxins

-MRSA (pg 422)

-causes wound infections, food poisoning, toxic shock syndrome

Term

Streptococcus - beta hemolytic - Group A -

Streptococcus pyogenes

Definition

Group A

Strep. pyogenes

has M protein on surface that helps it avoid phagocytosis

causes most variety of diseases:

sore throats

scarlet fever

rheumantic fever (affects joints & heart)

impetigo

necrotizing fascitis - painful infection that can consume an inch of tissue an hour

Term
Listeria monocytogenes
Definition

grows in soft cheeses & deli meats

withstands refrigeration

should not be eated by pregnant women

can cause stillbirth

Term
Mycobacterium
Definition

-resist gram stain because they have waxy cells

-cells have mycolic acid

-require acid fast stain (carbol-fuchsin)

M. tuberculosis - tuberculosis

M. leprae -leprosy

Term
Spirochaetes
Definition

coiled gram negative

move using axial filaments

Treponema pallidum - syphilis

Borrelia spp. - Lyme disease

Term

YEAST

pseudohyphae

Definition

chains of buds that do not detatch

made by Candida albicans (causes thrush)

Term
Types of fungal infection
Definition

-systemic - can spread within body

-subcutaneous - under the skin
(ex. Sporothrix schenckii - causes sporotrichosis in punture wounds, common in farmers)

-superficial - fungi that infect hair, nail, and skin are called dermatomycoses

 

 

Term
Tinea capitis
Definition
fungal infection of hair and scalp
Term
Tinea unguium
Definition
fungal infection of the nails
Term
Tinea cruris
Definition
fungal infection of the groin (jock itch)
Term
Tinea pedis
Definition
fungal infection of the feet (athlete's foot)
Term
Tinea corporis
Definition
fungal infection of the body (ringworm)
Term
Tinea barbae
Definition
fungal infection of the beard
Term
Protozoa - basic info
Definition

-unicellular

-some can form a cyst and survive outside a host

-most reproduce asexually

Term
[image]
Definition

malaria life cycle

 

The life cycle of malaria parasites in the human body. A mosquito infects a person by taking a blood meal. First, sporozoites enter the bloodstream, and migrate to the liver. They infect liver cells (hepatocytes), where they multiply into merozoites, rupture the liver cells, and escape back into the bloodstream. Then, the merozoites infect red blood cells, where they develop into ring forms, trophozoites and schizonts which in turn produce further merozoites. Sexual forms (gametocytes) are also produced, which, if taken up by a mosquito, will infect the insect and continue the life cycle. 

Term
protozoa - Toxoplasma gondii
Definition

-transmitted from cats to humans by fecal-oral contact

-can cause birth defects if mom has her first exposure in the 1st trimester

-causes toxoplasmosis

 

Term
platyhelminths - flukes
Definition

-flat, leaf-shaped bodies

-oral sucker

-can infect:

lungsParagonimus westermani (worldwide)

liver - Clonorchis sinensis (immigrant populations)

blood - Schistosoma spp. (worldwide)

Term
Platyhelminths - cestodes - tapeworms
Definition

-intestinal parasites

-the head is called the scolex that attaches to the intestines

-they do not digest the host tissue but absorb undigested food

-the body made of proglottids

-proglottids contain the male and female structures that produce eggs

Term
scolex
Definition
head of a tapeworm that attaches to the intestines
Term
proglottids
Definition

makes up the body of a tapeworm

contains male and female structures that produce eggs

Term
[image]
Definition
pinworm life cycle
Term
viruses-structure
Definition

-obligate intracellular parasites

-have DNA or RNA, not both

-may be single or double stranded

-nucleic acid are covered with a coat made of protein called the capsid

-capsid made of sub-units called capsomeres

-some have an outer envelope

-virus = nucleic acid

-virion = nucleic acid + capsid + envelope

-envelopes may have spikes that help them attach to host cells

-spikes may cause hemagglutination (lysis of red blood cells) (ex: influenza)

Term
capsid
Definition

-covers the nucleic acid in a virus

-made of protein

Term
capsomeres
Definition
sub-units of the capsid in viruses
Term
virus vs. virion
Definition

virus = nucelic acid

virion = nucleic acid + capsid + envelope

Term
spikes
Definition

some viruses have envelopes with spikes

helps them attach to host cells

spikes may cause hemagglutination

Term
viral cultures
Definition

-must use living cells

-animals (mice)

-cell cultures from animal cells

-embryonated (fertile) eggs

Term
viral cultures - cell cuture
Definition

-animal cells grown in a nutrient solution adhere to walls of container

-a virus is introduced

-it causes the cells to deteriorate and is called the cytopathic effect (CPE)

-two types of cell cultures

-primary: includes diploid cell lines from embryo, live for ~100 generations

-continuous cell lines: from cancer cells, "immortal" (HeLa)

Term
viral cultures - embryonated (fertile) eggs
Definition
used for some vaccines
Term
[image]
Definition
viral cultures - embryonated (fertile) egg
Term

viral multiplication - bacteriophages

2 types are:

Definition

-lytic cycle

-lysogenic cycle

Term

viral multiplication - bacteriophages

LYTIC CYCLE

Definition
  1. attachment - virus attaches to cell wall or cell membrane proteins
  2. penetration - viral DNA or RNA is injected
  3. biosynthesis - replicate in cytoplasm ribosomes
    -virus stops host protein synthesis by: destruction of host DNA or interfering with transcription or translation
    -uses host ribosomes and nucleotides to replicate
    -capsid proteins are made, but all the parts are separate
    -this is called the eclipse period
  4. maturation - virions are assembled
  5. host cell lyses and many viruses are released
Term

viral multiplication - bacteriophages

LYSOGENIC CYCLE

Definition
  1. DNA or RNA penetrates the cell
  2. the viral DNA inserts itself into the host DNA and does not replicate (latency)
  3. viral DNA is incorporated into cell progeny
  4. when conditions are right, the lytic cycle occurs
Term
[image]
Definition
lytic & lysogenic cycles
Term
multiplication of animal viruses
Definition
  1. attachment to proteins or glycoproteins on cell membrane
  2. entry into the cells is by endocytosis or fusion (viral envelope fuses with plasma membrane and the capsid)
  3. uncoating - enzymes separate the nucleic acids from the protein coat
  4. biosynthesis - A: DNA viruses replicate their DNA in the nucleus and their capsid proteins in the cytoplasm
    B: RNA viruses multiply in the host cells cytoplasm
  5. maturation - assembly of capsid and virion
  6. release - A: budding - viral capsid with enclosed nucleic acids pushed through the plasma membrane. The plasma membrane is now the virus's envelope. May not kill host cell
    B: Non-enveloped viruses exit through ruptures in the host's cell. Usually kills the cell
Term
Prions - basic info
Definition

-infectious particle made of protein

-misfolded protein

-can survive autoclaving (steam under pressue of 120 degrees C for 20 minutes)

-must be killed by incineration

Term
reaction rate is increased by:
Definition

-temperature (up to a point)

-pressure (increases)

-increased concentration

-enzymes speed the rate

-pH must be "optimal"

Term
reaction rate is slowed by:
Definition
inhibitors
Term
Enzymes - aka catalysts
Definition

-proteins that speed chemical reactions by lowering the activation energy without being changed

-allow reactions to occur at a temperature that is compatible with life

-most enzymes end in "ase"

Term
Enzymes - specificity
Definition

-only catalyze one reaction

-they are large, three dimensional proteins with a primary, secondary, tertiary, quarternary structure

(primary-sequence amino acids, secondary-alpha helix and b pleated sheets, tertiary-unique 3D structure caused by folding by interaction of side chains, quarternary-two or more proteins)

-only one area with its specific substrate (lock and key)

Term
[image]
Definition
enzyme & substrate
Term
[image]
Definition
enzyme feedback inhibition
Term
enzyme feedback inhibition
Definition

-the end product of an enzymatic reaction binds to an allosteric site on the first enzyme in the reaction

-this changes the shape of the active site so the first enzyme can no longer function

Term
enzymes - active site
Definition
the part of the enzyme where the subsrate binds and undergoes a chemical reaction
Term
enzyme - allosteric site
Definition

an area of an enzyme that is NOT where the enzyme binds to the substrate

 

(changes shape of enzyme, substrate unable to bind)

 

Term
enzymes - efficiency
Definition

-reactions with enzymes occur 1 billion times faster than reactions without them!

-one enzyme can catalyze up to 500,000 reactions per second

Term
enzymes - components - basic info
Definition

-some enzymes act alone

-some need a helper

Term
enzyme-substrate complex 
Definition
formed during the temporary binding of the substrate to the active site of the enzyme
Term
enzymes - products
Definition
the substance(s) that is formed as the result of a chemical reaction
Term
enzymes - competitive inhibitor
Definition

binds to the active site of the enzyme and blocks the substrate from binding.

It competes for the active site of the enzyme, so the rate of reaction is dependent on the concentration of substrate and the concentration of inhibitor

Term
enzymes - non-competitive inhibitor
Definition
binds to the allosteric site on the enzyme and changes the shape of the active site so that the substrate cannot bind to it
Term
enzymes - cofactors
Definition

-the protein part is called an apoenzyme

-the other part is called a cofactor

-many cofactors are minerals like iron, zinc, magnesium, and calcium

 

Term
enzymes - cofactors - fevers
Definition

-"feed a cold, starve a fever"

-colds caused by viruses

-fevers often caused by bacteria

-fever makes environment unfavorable to bacteria that are infecting you

-liver sequesters iron and zinc (cofactors for bacteria) when we have a fever

Term
enzymes - coenzymes
Definition

-a cofactor is called a coenzyme if it is an organic molecule

-conenzymes are usually a vitamin

Term
holoenzyme
Definition
apoenzyme + cofactor (coenzyme)
Term
coenzymes - examples
Definition

-ex: niacin - vitamin B3 is part of the coenzymes NAD+ (in catabolic reactions) and part of NADP+ (in anabolic reactions)

-they are electron carriers

 

-ex: riboflavin - vitamin B2 is part of the coenzymes FMN + FAD which are also electron carriers in cellular respiration

 

ex: pantothenic acid - another B vitamin is part of CoA in the Krebs cycle in cellular respiration. It is ubiquitous (everywhere)

 

They are all involved in obtaining energy from food

Term
growth requirements for microbes - chemical - oxygen
Definition

-obligate aerobes - require O2

-microaerophiles - require O2 but in concentrations lower than air

-faculative anaerobes - use O2 but can survive without it

-capnophiles - aerobes that require O2 and a high CO2 atmosphere

-obligate anaerobes - do NOT require O2, and many are harmed by it

-aerotolerant anaerobes - do not use O2 but tolerate it

some obligate anaerobes use O2 and produce hydrogen peroxide (H2O2) which kills them because they don't make catalase which breaks down H2O2

Term
selective media
Definition

-stop the growth of some bacteria to isolate others

ex - Sabouraard's Dextrose agar pH=5.6

-this inibits most bacteria and allows fungi to grow

ex - mannitol salt

-inhibits most bacteria except Staphylococcus

Term
differential media
Definition

help to distinguish pathogenic bacteria by looking for special colony characteristics

ex-mannitol salts-differentiates Staph. aureus from other Staph. organisms - S. aureus ferments the mannitol turning the medium yellow

ex-Beta hemolytic Strep. Group A-O make a clear ring around their colon on blood agar

ex-Salmonella are black on peptone ion agar 

Term
enrichment media
Definition
-selective and provides nutrients to encourage growth of pathogens
Term
sterilization
Definition
destruction of all forms of microbial life including spores (and viruses). Prions are not killed.
Term
disinfection
Definition
destruction of all pathogenic microbes except spores
Term
antisepsis
Definition
disinfection of living tissue
Term
sanitization
Definition
lowering the number of microbes on a surface to a safe public health level
Term
-cide
Definition
means kill
Term
-stat, -stasis
Definition
"stop" growth. Growth may resume after agent is removed
Term
sepsis
Definition
bacterial contamination (of blood) 
Term
asepsis
Definition
a non-contaminated state
Term
list of relationships between flora and host
Definition

-antagonism

-symbiosis

Term
antagonism (definition)
Definition

competition between normal flora and pathogens

ex. - E. coli produces proteins that inhibit the growth of Salmonella and Shigella

ex. - Acidophilis spp. lower the pH of the vagina to ~pH 4 so yeast cannot grow

Term
How do host flora make the environment unsuitable for pathogens?
Definition

-competing for nutrients

-producing harmful substances

-affecting pH

-affecting oxygen availability

Term
What happens when host flora are reduced or removed from use of broad spectrum antibiotic therapy?
Definition

-yeast (Candida) may colonize the mouth and vagina

-Clostridium difficil can infect the intestines (common nocosomial infection)

Term
symbiosis (definition)
Definition
relationship where at least one organism depends on the other
Term
symbiosis - types
Definition

-commensalism

-mutualism

-parasitism

Term
commensalism
Definition
one benefits one is unaffected
Term
mutualism
Definition
both benefit
Term
probiotic
Definition

live bacteria that are ingested or applied that have a beneficial effect

ex - lactic acid bacteria in the intestine inhibit growth of pathogens

Term
prebiotic
Definition
chemicals that promote the growth of probiotic bacteria
Term
parasitism
Definition
one benefits, one is harmed
Term
opportunists
Definition
take advantage!
Term
when do opportunists take advantage?
Definition

-suitable location: bacteria in the intestine can cause infection when in the urinary tract or wounds

-immunosuppressed state: chemotherapy or AIDS. Organism normally present become pathogenic

-after broad spectrum antibiotics

Term
Etiology of Disease: Some diseases are caused by:
Definition

A) some diseases are only caused by one organism (ex. syphilis-Trepanoma pallidum, leprosy-Mycobacterium leprae, tetanus - Clostridium tetani)

B) some dieases can be caused by many different organisms (pneumonia, UTIs, sepsin, meningitis)

Term
spread of infection - reservoirs - list
Definition

humans

animals (zoonoses)

soil

water

Term
spread of infection - reservoirs - humans (examples)
Definition
colds, Hep. A (fecal-oral), Hep. B (blood-blood)
Term
spread of infection - reservoirs - animals (examples)
Definition

Pasturella multocida - cat bites

Rabies - mammals

Malaria - mosquitoes

Tularemia -hamsters

Tapeworms

Leprosy - armadillos

Term
spread of infection - reservoirs - soil (examples)
Definition

tetanus

Necator americanus (hookworm)

Term
spread of infection - reservoirs - water (examples)
Definition
cholera
Term
Penetration of host defenses - cell walls
Definition

Strep. pyogenes makes M protein that helps attachment and avoid phagocytes

Neisseria gonorrhoeae has protein called Opa to attach, invade, and grow inside WBC. Opa attaches to CD4-lymphocyte, it prevents production of "memory cells" (lifelong immunity where we "remember" antigens we were exposed to)

Mycobacterium have waxy cell wall (mycolic acid) to resist phagocytosis

Term
Penetration of host defenses - enzymes - list
Definition

coagulase

streptokinase

hyaluronidase

collagenase

Term
Penetration of host defenses - enzymes - coagulase
Definition

Staph makes coagulase

coagulase causes the formation of fibrin clots which wall off the infection

Term
Penetration of host defenses - enzymes - streptokinase
Definition

Strep. pyogenes (Group A Strep) makes streptokinase which breaks clots and helps infection spread

streptokinase is given to heart attack and stroke victims to prevent formation of clots.

Blood vessels get plaque made of cholesterol, fat, fibrin, and calcium. Platelets stick to plaque and initiate clot formation which contains fibrin. Streptokinase helps break up fibrin. (now TPA (tissue plasminogen activator) is used)

Term
Penetration of host defenses - enzymes - hyaluronidase
Definition

made by Strep. and Clostridium

hyaluronidase digests hyaluronic acids

hyaluronic acids holds cells together

hyaluronidase destroys tissue to help infection spread

Term
Penetration of host defenses - enzymes - collagenase
Definition

Clostridium makes collagenase

collagenase destroys collagen, destroys tissue, & keeps antibiotics away (destroys blood vessels through which antibiotics travel to reach infection)

Term
Penetration of host defenses - antigens
Definition

antigens trigger antibody production - proteins, sugars, nucleic acids

Antigenic variation - some pathogens can change surface antigens and our antibodies no longer recognize them

ex. Influenza, AIDS, Neisseria

Term
Exotoxins
Definition

-secreted actively from viable microbes (on the inside)

-heat labile, protein

-high specific activity

-very toxic

-toxoidable - can be denatured to remove toxicity and retain antigenicity (ex. to make vaccine)

Term
Endotoxins
Definition

-part of the bacterial architecture (on the cell wall)

-heat stabile, lipid/sugar

-low specific activity

-variable toxicity

-nontoxoidable - chemical composition prohibits molecular modification

Supporting users have an ad free experience!