Lab Practical 2 Flashcards
what is the optimum growth temperature?
temp where bacteria have the fastest rate of binary fission; where their generation time is the fastest
what are mesophiles?
optimum growth temp of 20 and 50 degrees
what are psychrophiles?
bacteria that grow in the range -15 to 20 degrees
what are thermophiles?
45 to 80 degrees
what are hyperthermophiles?
67 to 105
what is prodigiosin?
red pigment protein produced by serratia marcescens
In the temperature on bacteria growth lab, what could go wrong?
you may have incubated at the wrong temperature
what is the optimal growth temperature of s. marcescens?
25 degrees
what is the optimal growth temp of e coli?
37 degrees
what is the danger zone of food safety?
40 degrees to 140 degrees farenheight
what is the peak growth of a pshycrophile?
0 degrees celcius
what is the peak growth of a thermophile?
80 degrees celcius
what is osmolarity?
a measure of how much solute is dissolved in the solvent
what is osmosis?
the movement of water into or out of a cell
what is an isotonic solution?
the concentration of solute inside and outside the cell is equal so there is no movement of water
what is a hypotonic solution?
the concentration of solute inside the cell is greater than outside the cell so there is a net gain of water for the cell
what happens if a cell only has a membrane in an hypotonic solution?
bursting
How can cells survive in a hypotonic solution?
the presence of a cell wall
what is a hypertonic solution?
there is more solute outside of the cell than inside so water moves outside of the cell.
what happens to cells in an hypertonic solution?
the cell shrinks
why doesn’t a jar of jam in the refrigerator spoil?
the concentration of sugar is so high that the solution is hypertonic and the bacteria cannot grow
what are halophiles?
bacteria capable of growing in high salt concentrations
what are osmophiles?
bacteria that can tolerate hypertonic solutions (both salt and sugar)
where do most halophiles live?
the ocean
what is the ultraviolet range?
400 and 4 nanometers
what is the greatest source of ultraviolet light?
the sun
what do pyrimidine dimers do?
cause mutations in the genes in DNA replication sometimes causing cancer
What is UV light used to treat?
wastewater, clean room disinfection, air in hospitals
what is non-ionizing UV light?
UV light that penetrates surfaces poorly
what is ionizing UV light?
UV light that penetrates surfaces
what needs to happen for a microorganism to be classified as resistant?
the concentration of a drug required to inhibit or kill the microbe is greater than can safely be achieved in a patient without causing side effects
what is the Kirby-Bauer antibiotic sensitivity test?
determines what the best antibiotic and dose to use for a patient
What is the accepted standard media used for the Kirby-Bauer?
Muellar-Hinton agar
what is the zone of inhibition?
where the antibiotic kills the microbe around the antibiotic disk
what are narrow spectrum drugs?
effective against a limited array of different microbes
what are broad spectrum drugs?
active against a wider range of different microbes
what are some broad spectrum drugs?
tetracycline and ciproflaxin
what are some narrow spectrum drugs?
penicillin and vancomycin
How can drug resistance be circumvented?
having antibiotics prescribed after a culture and susceptibility test and having patients finish all of their antibiotics
what are some good forms of antiseptics?
first aid antiseptic and iodine
what disinfectants work the best?
chlorine and lysol
if an agent had no effect does that mean that it is an ineffective form of disinfectant?
no because there is probably more bacteria on the media than what the product is normally used to treat
how was the disinfectant test biased?
the product must be absorbed into cotton and must be water soluble
what is sepsis?
growth of a microorganism in blood and other tissues
what is asepsis?
any practice that prevents the entry of infectious agents into sterile tissues to prevent infection
what is disinfection?
reducing pathogenic microbes in or on nonliving material to a level where they are no longer a hazard
what is sterilization?
removing or killing all the organisms and viruses on an object
what is bactericide?
destroys bacteria with the exception of endospores
what is fungicide?
destroys fungal spores, hypae and yeast
what is virucide?
inactivates viruses
what is sporicide?
kills bacterial spores
where does most of Houston’s drinking water come from?
surface water of the San Jacinto and Trinity rivers
what is a coliform?
gram-negative, lactose fermenting bacteria
why is e coli a good indicator of fecal contamination?
e. coli is not found in soil so if it is in water it must have come from sewage; it is easily grown outside laboratory conditions; e. coli survives longer outside the body than other organisms
what is the presumptive test?
tests for lactose
what is the confirmed test?
tests for the presence of gram negative bacteria
why are differential and selective agars used for the confirmed test?
they contain chemicals that are toxic to gram positive bacteria
what is a completed test?
identifies the species
Does a high MPN in the presumptive test mean the water is unsafe to drink?
no, you will not know if coliforms are present until the confirmed test
what are some sources of error on the fecal matter test?
not having enough water, contaminating your bottle or pipets, putting wrong amount of water in the test tubes or mislabeling
what is an example of a coliform?
e. coli
what is an example of a non-coliform?
Pseudomonas aeruginosa
what are some prokaryotic pathogens that can be present in sewage water?
e. coli
salmonella
shigella disentarie
vibrio cholera
what are some eukaryotic pathogens that can be found in sewage water?
giardia lamblia
entamoeba histolytica
cryptosporidum parvum
what are some viral pathogens that can be found in sewage water?
rotavirus, norwalk virus, hepatitis A
How can you be certain that your bacteria is e coli during the confirmed test?
because of the colors on the plate,
On the Levine EMB agar, what color is a positive result for e coli?
dark black colonies with a green sheen
On the endo agar, what color is positive for e coli?
dark red nucleated colonies
what is the bacterial count?
the concentration of bacteria present in milk
what is pasteurization?
kills certain types of organisms but does not sterilize the product
what is the flash method?
71.6 degrees Celsius for 15 seconds
why could milk that has always been properly refrigerated have a high bacteria count?
Because the milk has not been properly sterilized and bacteria can still reproduce in refrigeration. Also someone could have drank directly from the container
Does the batch or flash method sterilize milk?
no
does the ultra high temperature method sterilize milk?
yes
why is milk a more suitable vehicle of disease than water?
it carries more nutrients allowing the bacteria to feed more proteins
what are some infectious diseases that can be transmitted from cows?
brucella, tuberculosis, listeriosis
what are dental caries?
tooth decay
why do you form dental caries?
production of lactic acid by bacteria in the presence of high levels of sugar
what is a good method to test for tooth decay?
M.L. Snyders caries suseptibility test
what indicates the presence of acid production in M. L. Snyder’s susceptibility test?
bromcresol green
what factors could affect the reliability of M. L. Snyder’s test?
not using enough spit, and it is best to do this test a few hours after brushing
To increase the validity of M.L. Snyders test, how many times should it be performed?
three times over the course of 72 hours
what are some benefits of chewing sugar free gum?
more saliva is produced diluting the acids in your mouth and the stickiness pulls the bacteria from your teeth
What is trichinella spirosis?
Cause trichinosis when ingesting raw or undercooked pork.
What phylum is trichinosis spiralis?
Nematoda
What are the symptoms of trichinosis spiralis?
Nausea, vomiting, abdominal pain, diarrhea, itchy skin, muscle aches, headaches
What phylum is enterobius vermicicularis?
Nematoda
What is enterobius vermicicularis?
Pinworm. Causes itching around the anus and difficulty sleeping due to the female laying her eggs. Common in children.
What is taenia saginata?
Tapeworm. Results from eating undercooked beef.
What is the phylum for taenia saginata?
Platyhelminthes
What is the class of taenia saginata?
Cestoda
What is the head of a tapeworm called?
Scolex
What are the individual segments of a tapeworm called?
Proglottids
What structures are found on the tapeworm?
Hooks and suckers
What are the symptoms of tapeworm?
Abdominal pain, weight loss, proglottids in the feces
What is amoeba proteus?
Non pathogenic cousin of enteramoeba histolytica which causes amebiasis.
What are the symptoms to amebiasis?
Cramping, pain, dysentery.
What are the structures on amoeba proteus?
Pseudopods and nucleus
What phylum and class is amoebas proteus
Platyhelminthes Cestoda
What is trichomonas vaginalis?
Causes trichomoniasis, a sexually transmitted disease caused by a flagellated protozoan.
What are the symptoms of trichomonas vaginalis?
If they occur, inflammation of the mucus membranes of the urethra and vagina. Causes purelent discharge in females and dysuria in males.
What are the structures of trichomonas vaginalis?
Nucleus flagella
What class and phylum is trichomonas vaginalis in?
Platyhelminthes Cestoda
What is trypanosoma Brucei?
Causes sleeping sickness being transmitted by the tsetse fly in rural Africa.
What phylum and class does trypanosoma Brucei belong to?
Platyhelminthes Cestoda
What are the symptoms of trypanosoma Brucei?
Fever, headaches, muscle pain, extreme fatigue
What does trypanosomes Brucei do?
Crosses the blood brain barrier and causes neurological damage.
What two species are in the kingdom fungi?
Penicillium rhizopus
What are the structures of penicillium?
Conida with spores and mycelium
What are the structures of rhizopus??
Mycelium and sporangium with spores.
In the Durham test what is a positive result for acid??
Red
In the Durham test what is a negative result for acid?
Yellow
In the Durham test what is a positive result for co2?
Air bubble
In the Durham test what is a negative for co2?
No air bubble
What is the indicator of pH in the Durham test?
Phenol red
During the methyl red test, what is the results for mixed acid fermentation?
Red is positive
Yellow is negative.
In the urea hydrolysis test, what colors are the result?
Bright pink– positive for urease
Orange– negative for urease
What are the results for kligler’s iron agar?
Black is positive
Red, yellow or half and half is negative.
What reagent is used for mixed acid fermentation?
Methyl red in the mrvp tube.
What are the results in the vogues proskauer test?
Red is postive
Yellow is negative.
What reagent is used for the vogues proskauer test?
Vp-a vp-b
What are the results from the tryptone test?
Red oily layer is positive
Yellow oily layer is negative
What reagent is used in the tryptophan test?
Indole
What are the results of the Simmons citrate test?
Blue is positive
Green is negative.
What are the results of the phenylalanine test?
Green is positive
Yellow is negative.
What is the reagent used in the phenylalanine test?
Ferric chloride
What are the results of the nitrate reduction test?
Red is positive
Yellow is negative
What reagents are used for the nitrate reduction test?
Nitrase a and b
What does the durham test test for?
sugars the organism can ferment
what does the mixed acid fermentation test for?
mixed acids
what does the Vogues-Proskauer test for?
2, 3 butanediol fermentation
what does the catalase test for?
catalase
what is the reagent for catalase?
hydrogen peroxide
what does the citrate utilization test for?
citratase
what is metabolism?
all chemical reactions that take place in a cell
what is anabolism?
a building up reaction that requires energy
what is catabolism?
breakdown of large organic molecules that releases energy
what are obligate aerobes?
humans– must have oxygen to survivve
what are obligate anaerobes?
bacteria living deep underground that do not need oxygen to survive
what are facultative anaerobes?
can live with or without oxygen
what is anaerobic respiration?
most efficient catabolic process for extracting energy from a carbon source
what does the nitrate reduction test for?
aerobic respiration
