micro lab final – Flashcards
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| What is the purpose of doing an API test? |
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| an identification system to test for enterics |
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| what is bacteriocidal? |
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| something that kills bacteria |
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| what do you look for while trying to identify a gram positive stain? |
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| Color differintiation |
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| Whats the gram stain procedure |
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| heat smear first, flood with crystal violet, iodine, acetone, safarin |
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| what is the purpose of using microbial metabolism or why is it important and what is the procedure? |
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| pg 74-75, to figure out jf bacteria is positive or negative for all the tests that are ran. Match results of bacteria to organism number in front of the book to see what it correlates with |
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| What are formulas for dilution factor? |
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| aliquot/ total volume |
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| How do you find concentration? |
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| stock X TDF, or ____________ |
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| what does it mean when a bacteria can metabolize nitrate? |
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| They are usually anaerobic |
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| What does the IMViC series test for? |
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| To differintiate between fecal and non fecal orgin |
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| What are the 2 functions of bacterial capsule? |
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| to keep from sticking to surfaces and to hold water in and to keep from being phagotized |
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| what are the functions of biofilms? |
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| anti microbial resistance |
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| what does faculatative anerobes mean |
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| it can grow in oxygen but prefers no oxygen |
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| what is a spectrum of action |
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| the range of bacteria an antibiotic can effect, narrow range is only certain bacteria, and broad range is many bacteria |
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| what does the minimal inhibit concentration tell you |
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| the amount of concentration needed to inhibit the growth of bacteria |
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| how do you know if your looking at a bacteria donor? |
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| resistance is located on the plasmid, chromosomes will not transfer |
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| what are the 5 characteristics of an enteric? |
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| -they grow on Mconkey's agar -they are gram - rods -they are oxidase negative -they ferment glucose and lactose -they are faculatative |
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| what are the 3 possible zones of inhibition that are noted on a mueller hinton agar plate? |
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| intermediate, succeptible, and resistant |
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| how can you determine if dentrification took place |
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| it produced bubbles, and you cant continue to use it after bubbles are produced |
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| what is reversion? |
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| pg 69- after it has eaten up all of the sugar it eats the amino acids which raises the pH and implies its more basic, its called reversion because it goes from red and turns yellow by fermentation of sugar then goes back to red after eating amino acids |
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| What test utilizes reversion |
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| the KIA test, which is sulfer metabolism. It differentiates between glucose and lactose fermentation |
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| what bacteria is in a chain and what is in a cluster? |
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| know the term staph, strep, coccus, bacillus |
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| KNOW THE PARTS ON A MICROSCOPE |
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| what happens when Dna is exposed to UV radiations? How is it repaired and what is it called |
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| DNA gets thymine dimers, photoreactivation is how its repaired. PG 92 |
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| How does UV light not kill endospores? |
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| endospores have a protective coat that UV light cant penetrate |
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| UNDERSTAND THE PROCESS OF TRANSCONJUGATION |
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| The total magnification on the 100X is? |
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| 1000X |
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| 2.) Put the following steps in order for a Gram Stain (Just put a number next to the following step): (4 points) i. Flood the stain with Iodine ii. Flood the stain with Safranin iii. Flood the stain with Crystal Violet iv. Create a smear v. Heat fix 2 |
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| create a smear, heat fix, flood with crystal violet, flood with iodine, flood with safarin |
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| define parfocal |
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| When using a microscope, you initially focus an object on the lowest objective by first using the coarse focus and finishing with the fine focus. After focusing in this manner on the lowest objective, it is possible to move to the next highest objective and use only the fine focus to focus the object on the next objective. This is due to microscope’s parfocal ability. |
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| What stain will be used in the capsule stain |
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| India ink |
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| What are 2 beneficial uses of a capsule? |
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| -avoids phagocytosis -can stick to surfaces which has a large immunological importance |
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| What are the formulas for dilution factor and total dilution factor? |
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| What are 3 environmental factors that affect growth rate |
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| -osmotic pressure -temperature -oxygen |
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| Name 2 out of 5 temperatures you incubated your bacteria at to test for optimal growth at varying temperature |
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| -5 -25 -37 -42 -55 |
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| at what temperature does Seretia Marcescens have a pinkish pigment |
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| 25 |
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| If you have isolated an enteric, what temperature is it likely to grow best at? |
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| 37 |
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| Why should you no shake the TSA tube |
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| it creates air bubbles which will make the environment no longer anaerobic |
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| Is MSA (mannitol salt agar) selective, differential or both |
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| both,it is selective for staphylococci and differential for Staphylococcus aureus from other staphylococci. Staphylococci is able to grow on MSA but do not ferment mannitol, so growth appears pink to red. S. aureus ferments the mannitol which produces acid and lowers the ph of a medium. This results in the bright yellow color |
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| what is the chromosomally mediated antibiotic being used for todays experiment? |
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| Naladixic acid/ rifampton |
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| On what type of agar will the hemolysis experiment be performed on |
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| blood agar |
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| what is the name of the extracellular matrix that forms in a biofilm |
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| glycocylax |
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| what is the name of the pigment that Serratia marcescens produces |
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| what is the name of the type of genetic transfer done for quiz 8 |
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| conjugation |
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| What biosafety level is this micro lab |
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| 2 |
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| what does pathogenicity mean |
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| the ability to cause disease |
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| How do sterilization and disinfect differ |
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| Sterilization kills everything including endospores. Disinfection does not kill endospores |
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| why would you use a plate instead of broth to grow bacteria |
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| it allows you to somewhat distinguish between different types of bacateria due to the fact that you can see individual colonies and compare them. YOU CAN ALSO CREATE ISOLATED PURE GENETIC COLONIES. |
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| what is the purpose of using the streak plate method |
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| to isolate a pure genetic colonly |
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| the only lens that can handle oil is |
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| 100x |
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| gram negative bacteria have more or less peptidoglycan than gram positive bacteria |
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| less |
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| what is the name of the dye used in the capsule stain |
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| india ink |
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| name a type of bacteria shape |
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| cocci or bacillus/ rod |
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| what color is a gram negative bacteria under a gram stain |
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| pink |
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| what color should your bacteria stain during a gram stain if it is an enteric bacteria |
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| pink |
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| True/false/neither- if your bacteria was catalase negative, it is an enteric bacteria |
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| neither, catalase does not affect the status of an enteric |
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| what procedure is done during the protease enzyme to test for these enzymes? if your bacteria is positive for these enzymes, what should your result look like? |
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| After incubating for 24 hours, you refrigerate your gelatin tube for 5 minutes, a positive result will remain liquid due to the fact that the gelatin was utilized by the bacteria. a negative result will resolidify when frozen. |
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| what 2 things can KIA (kligers iron agar) test for |
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| -glucose/lactose fermentation -sulfer reduction |
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| what does a "cracl" in agar indicate |
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| gas production |
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| explain how to use the metabolic screening chart |
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| describe a positive rod and negative result for gelatin protease production. |
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| A positive result will remain liquid due to the fact that the gelatin was utilized by the bacteria. a negative result will resolidify when frozen. |
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| At what temperature are the Streptomyces griseus plates incubated? What is another name for this temperature |
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| 25 degrees. room temperature |
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| what does MIC stand for? explain what it means |
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| Minimal Inhibitory Concentration- the least amount or lowest concentration of an antibiotic needed to inhibit bacterial growth |
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| in order to create an anerobic environment in the API 20E series, what reagent is added |
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| Mineral oil |
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| Define bactericidal and bacteriostatic |
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| bactericidal kills bacteria bacteristatic inhibits growth |
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| what is the name of the substance produces by S. griseus that smells like dirt |
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| Geosmin |
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| Explain why the bacteria are put into saline solutions instead of water-hint- we discussed this in class when we put the meat into saline solutions |
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| 1.) Describe the difference between broad and narrow ranged antibiotics |
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| 2.) Why did we put the bacteria into saline solutions for the Muller Hinton plate and API 20E strip? |
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| 3.) What were the three zones of inhibition possible for the Muller Hinton plate? |
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| succeptible, intermediate, resistant |
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| 4.) Why did you not invert the Muller Hinton plate? |
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| 5.) What does the resistance profile of your antibiotic tell you about your bacteria’s ability to cause disease? |
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| 6.) A pyrimidine dimer forms between what two nucleic acids when exposed to UV? |
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| 7.) At what temperature does Seretia Marcescens have a pinkish pigment? |
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| 8.) What three environmental factors are you looking at in lab today? |
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| 9.) Name two of the five temperatures you will be exposing your bacteria to today. |
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| Why should you not shake the TSA tube? |
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| What does Serratia marcescens produce? |
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| Name the five common characteristics of enteric bacteria. |
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| Gram Negative rods Grows on Mac. Agar Anaerobic and Aerobic Glucose and Lactose Fermentation Oxidase Negative |
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| 2.) Why might catalase production be beneficial to pathogenic (disease-causing) bacteria? |
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| It can break down catalase into water oxygen which these products are not injurous to bacteria unlink hydrogen peroxide |
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| For the Oxidase Test, what indicates a positive result? If your bacteria is an enteric, what should the result of this test be? |
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| A positive result is indicated by a purple color change. An enteric should be negative and therefore there should not be a color change. |
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| During the hydrolysis of starch test, what reagent is used? Explain what a positive result of alpha-amylase on the starch plate looks like |
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| Iodine is the reagent used. On a positive plate, the starch in the plate is broken down by the produced alpha-amylase. Since there is no longer starch in the media, a clearing will form around the bacteria since there is not any starch to form an iodine starch complex. However, further away from the bacteria, where the alpha-amylase has not broken down the starch, the iodine will bind to and the starch and form a purple color. |
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| 5.)Explain why we used the process of serial dilution last week. Another way to think of this question is what is the ultimate reason for why we performed this process? |
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| Ultimately we want to find the stock concentration on the meat. By counting the number of colonies on a plate, it is possible to take the reciprocal of the dilution factor, multiply this by number of colonies, to find the stock concentration. |
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| 1.) What is selective media? What is Differential Media? Can a media be both? (2 points) |
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| Selective media incorporates some compound that will inhibit the growth of some organisms but allow others to grow. Differential media allows you to distinguish between different types of organisms growing on media |
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| 2.) What is MSA selective for? What does it differentiate for? |
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| It is selective for gram negative bacteria and differentiates the lactose non -fermenters (white) from the lactose fermenters (red) |
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| 3.) Give a one sentence description of the Metaproject. |
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| To isolate and identify an enteric bacteria found on the meat product selected |
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| 4.) What is the importance of a bacterial plate count in relation to food? |
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| A higher bacterial count may suggest that the food is unfit to eat and may cause illness |
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| 5.) What type of agar will be used to plate the meat? |
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| Both nutrient agar and macconkey agar |
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| 6.) The initial stock concentration of a tube is 4*108 . 10mL is taken from this solution and placed into a second tube containing 90mL already in it. This process is repeated four more times. What is the final concentration of the last tube. For full credit, please show all of your work |
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| 4X10^3 |
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| 7.) A plate has 200 colonies on it. What is the stock concentration if 10mL was added to 90 mL five times from the stock concentration? |
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| 2X10^7 |
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| Is E. coli gram + or - |
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| Negative |
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| Is B lichen gram + or - |
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| + |
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| What is the purpose of heat fixation |
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| Kill the bacteria and stick the smear to the slide |
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| Ex of selective conditions |
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| Antibiotics, dyes, inhibitory compounds |
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| Ex of differential medium and definition |
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| Substances that causes bact to take on the appearance that distinguishes it from other bact. Ex: when staphylococcus aureus grows on mannitol salt agar it ferments mannitol changing a pH indicator from red to yellow and other staphylococcus species cannot ferment mannitol so their growth results in no ph change this no color change |
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| What does eosin and methylene blue do to bact? |
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| Inhibits gram + growth |
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| What is catabolism |
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| Provide energy needed to drive the bio synthetic (anobolic) reactions required to construct new celles |
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| Aerobic respiration |
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| Max energy extracted when free oxygen is available as an electron acceptor |
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| Fermentative org |
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| All yellow culture tube, bubble or no bubble , acid, gas |
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| Faculative org |
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| Bottom of tube yellow, top 1/2 red, acid |
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| Aerobic org indicating incomplete oxidation of substrate |
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| Bottom of tube red, top yellow, no bubble no gas, |
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| Aerobic org showing growth |
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| All red with slight turgidity, |
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| All red and no turgidity |
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| No reaction and now growth |
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| How to test for hydrolysis of starch |
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| To Test for amylase flood plate with iodine and allow it to bind with starch. Clear zones indicate positive |
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| Hydrolysis of triglycerides, what's a positive result |
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| Clearing of emulsion is a positive sign of lipase. |
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| Why do bact produce the enzyme catalase |
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| Protective factor from the hydrogen peroxide produced during oxygen metabolism. It can rapidly break down hydrogen peroxide into water and oxygen, preventing it from causing any problems. Streptococcus does not produce catalase |
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| What is the enzyme oxidase test for |
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| Cytochrome oxidase. It occurs in bacteria that carry out respiration where oxygen is the terminal electron acceptor, so the test differentiates between bact that have cytochrome and uses oxygen as final acceptor and those that don't |
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| What was the positive control for nitrate reduction |
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| B lichen |
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| What was the negative control for nitrate reduction |
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| M Luteus |
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| How to test for production of nitrate reeducate |
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| The bact is grown in a nitrate rich medium and the tested for nitrite prescense after incubation. After adding alpha naphthylamine the presence of pink or red indicates presence of nitrites |
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| What is control negative for protease Control positive |
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| - is m lutues + is b lichen |
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| If gelatin solidifies in protease exp... |
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| Then no protease, prot - |
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| If gelatin was broke down in protease... |
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| It liquified and stays liquid it's protease positive |
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| How to test for suffer metabolism |
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| Looking for presence of h2s by media KIA it tests for fermentation of glucose and lactose |
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| Glucose + lactose |
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| All yellow |
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| Color of suffer reduction and fermentation |
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| Black |
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| If gelatin solidifies in protease exp... |
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| Then no protease, prot - |
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| If gelatin was broke down in protease... |
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| It liquified and stays liquid it's protease positive |
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| How to test for suffer metabolism |
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| Looking for presence of h2s by media KIA it tests for fermentation of glucose and lactose |
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| Glucose + lactose |
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| All yellow |
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| Color of suffer reduction and fermentation |
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| Black |
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| Suffer + = |
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| Salmonella= red slant yellow butt |
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| Sulfer -= |
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| E coli = all yellow |
