Growth on the MSA and NA plates was recorded as “good growth”, “poor growth” or “no growth”. These are qualitative and, at least for the first two, subjective terms. What did you use to estabolish what constitued “good growth”?
- 1 What do you expect to see on the MSA and Na plates?
- 2 Why are growth characteristics more useful on agar plates than on agar slants?
- 3 Do you think the broth or the slant will give you the better smear?
- 4 Is MacConkey agar a defined or an undefined medium provide the reasoning behind your choice and explain why this formulation is desirable?
- 5 What did you use to establish what constitutes good growth?
- 6 Did you notice a difference in density of growth in NB tubes inoculated?
- 7 How should you record the growth on the EMB Na and MSA plates?
- 8 Why is the loop sterilized after the initial inoculum?
- 9 Why do we fix the smears before staining?
- 10 Why would you use a slant to store cultures but not to study?
- 11 What factors besides physical growth characteristics of bacteria are important when recording data about the bacteria?
- 12 What difference did you see between unwashed and washed skin?
- 13 Which type of culture media is best used to grow stock cultures of bacteria for storage?
- 14 How would you verify the purity of colonies growing on a culture plate?
- 15 Which ingredient would not be found in defined media?
- 16 Why is it important to check for growth of the organism before reading the result after incubation?
- 17 Does Bacillus subtilis grow on MSA?
- 18 How can I test my home for bacteria?
- 19 What bacteria will not grow on EMB Why?
- 20 What does a positive motility test look like?
- 21 What does CNA stand for in microbiology?
- 22 How would a microbiologist determine if their transfers had been successful?
- 23 Were the three different streak methods appropriate to the cell densities recovered?
- 24 What was the purpose of incubating the unopened plates?
- 25 What would happen if you did not sterilize your loop between streaks on your streak plate?
- 26 Why is it important to allow the Sterilised loop to cool fully between each successive streak on the plate?
- 27 What are some consequences of leaving a stain on bacterial smear too long?
- 28 What happens if you don’t heat fix slides?
- 29 Why is the loop sterilized after the initial inoculum?
- 30 Why is it important to sterilize your inoculating loop before and after each use?
- 31 What would happen if you didn’t heat fix a smear before performing the direct stain?
- 32 Why must the loop be flamed before entering a culture why must it be flamed after making an inoculation?
- 33 What is the primary use of slants?
- 34 How do we think bacteria reproduce and grow?
- 35 What type of growth is exhibited by bacteria?
- 36 Which type of culture media is best used to grow stock cultures of bacteria for storage?
- 37 Why are growth characteristics more useful on agar plates than agar slants?
- 38 What would you expect to happen if you forgot to remove the lids on all your plates?
- 39 What did you conclude from observing the plate that was exposed to UV radiation with the lid on?
- 40 How do you know if you have a pure culture?
- 41 Which is more rapid in proving the purity of a culture?
- 42 Can all bacteria grow on the same media?
- 43 What did you use to establish what constituted good growth?
- 44 What does comparing growth of a given organism?
- 45 Is it acceptable to read a positive test before incubation time is complete?
- 46 Does Bacillus grow on MSA?
- 47 Will Bacillus Grow on mannitol salt agar?
- 48 What grows on EMB?
- 49 What bacteria grows on EMB?
- 50 What is hanging drop method?
- 51 Is a motility test painful?
- 52 What is the dirtiest place in the house?
-
53
Which part of the house has the most bacteria?
-
53.1
Related Posts
- 53.1.1 Do growth factors speed up the cell cycle?
- 53.1.2 Do growth factors promote cell division?
- 53.1.3 Do fingers have growth plates?
- 53.1.4 Do genetic factors affect the growth of organisms?
- 53.1.5 Did railroads induce or follow economic growth?
- 53.1.6 Did the Industrial Revolution lead to population growth?
-
53.1
Related Posts
What do you expect to see on the MSA and Na plates?
Growth on the MSA and NA plates was recorded as “good growth”, “poor growth” or “no growth”. These are qualitative and, at least for the first two, subjective terms. What did you use to estabolish what constitued “good growth”?
Why are growth characteristics more useful on agar plates than on agar slants?
List some reasons why growth characteristics are more useful on agar plates than on agar slats. The main reason is that on agar plates growth is in individual colonies, not confluent as on slants. While color and opacity are visible on each, some features, such as elevation, are less obvious.
Do you think the broth or the slant will give you the better smear?
More difficult to see in broth because you can only see if growth occurred on the top or bottom etc. Better in slant because you can observe different growth patterns.
Is MacConkey agar a defined or an undefined medium provide the reasoning behind your choice and explain why this formulation is desirable?
Is MacConkey agar a defined or an undefined medium? Provide the reasoning behind your choice and explain why this formulation is desirable. It is undefined due to the pancreatic digests of gelatin and casein, peptic digest of animal tissue, and bile salts in the medium.
What did you use to establish what constitutes good growth?
What did you use to establish what constituted “good growth?” The nutrient agar plate inoculated with the same organisms provided examples of what “good growth” for each organism looks like on a nonselective media.
Did you notice a difference in density of growth in NB tubes inoculated?
Answer and Explanation: Yes, a slight density difference is noticed and as more cells are transferred onto the NB tubes from nutrient broth (NB) and Nutrient agar (NA)…
How should you record the growth on the EMB Na and MSA plates?
Growth on the EMB agar and NA plates was recorded as “good growth,’ “poor growth,” or “no growth.” These are qualitative and at least for the first two, subjective terms.
Why is the loop sterilized after the initial inoculum?
Answer and Explanation: The loop is sterilized even after the agar plate is inoculated in order to avoid contamination.
Why do we fix the smears before staining?
Answer and Explanation: Bacterial smears are “heat fixed” on the microscope slide before staining to affix the cells to the slide so that they do not wash off…
Why would you use a slant to store cultures but not to study?
Slanting gives the bacteria a greater surface area on which to grow in a tube. Agar slants are also useful in maintaining bacterial cultures, more so than stacks of Petri dishes. Multiple cultures are easily placed into test tube racks and stored under refrigeration.
What factors besides physical growth characteristics of bacteria are important when recording data about the bacteria?
Three critical aspects of a description of bacterial growth are colony size, color, and shape.
What difference did you see between unwashed and washed skin?
the plate with the sample of the unwashed hands show the norma biota of the skin. in the washed skin we see less colonies of the normal biota of the skin. the hands that were scrub has lest colonies than the ones were not scrub.
Which type of culture media is best used to grow stock cultures of bacteria for storage?
The most common growth media for microorganisms are nutrient broths and agar plates; specialized media are required for some microorganisms. Some, termed fastidious organisms, require specialized environments due to complex nutritional requirements.
How would you verify the purity of colonies growing on a culture plate?
Pick up a load of bacteria from a culture plate using a sterile toothpick or flamed and cooled inoculating loop. Mix the bacteria in the KOH by stirring, and lift the toothpick or loop 1-2 cm from the slide after about 15 seconds. Production of a viscous string within 30 seconds is indicative of Gram negative bacteria.
Which ingredient would not be found in defined media?
By definition chemically defined media cannot contain either fetal bovine serum, bovine serum albumin, or human serum albumin as these products are derived from bovine or human sources and contain complex mixes of albumins and lipids.
Why is it important to check for growth of the organism before reading the result after incubation?
You must know the optimum growth temperature and lag time of the organism to do this. This decreases incubation time needed to see the result. In the gelatin hydrolysis lab, if the control is solid and an inoculated tube is liquid, is it acceptable to read the result before the complete incubation time has elapsed?
Does Bacillus subtilis grow on MSA?
Test | Mannitol Salt Agar |
---|---|
Reagents | MSA Plate |
370C | |
Observations | Growth of organism |
Results | Able to isolate Gram Positive bacterium |
How can I test my home for bacteria?
- Prepare a small sample of agar in the petri dish as directed on its package. …
- Use a sterile swab to take your samples. …
- Rub the swab containing your sample onto the prepared agar and close the petri dish.
- Place your petri dishes in an out-of-the way spot, out of direct light.
What bacteria will not grow on EMB Why?
Some strains of Salmonella and Shigella may fail to grow on EMB Agar. Some gram-positive bacteria, such as enterococci, staphylococci, and yeast will grow on this medium and usually form pinpoint colonies. Non-pathogenic, non-lactose-fermenting organisms will also grow on this medium.
What does a positive motility test look like?
Expected Results. Positive: Diffuse, hazy growths that spread throughout the medium rendering it slightly opaque. Negative: Growth that is confined to the stab-line, with sharply defined margins and leaving the surrounding medium clearly transparent.
What does CNA stand for in microbiology?
Medium | Selective Ingredients | Mechanism of Differentiation |
---|---|---|
CNA-blood | colistin and nalidixic acid (CNA) | If the bacteria grow and produce the enzyme hemolysin, they can digest the red blood cells in the media. Bacterial Enzyme: hemolysin |
How would a microbiologist determine if their transfers had been successful?
How do you know your transfer to agar slants were successful? Success is presence of growth. If any of your transfers were unsuccessful, suggest possible errors that may have been made in the transfer process. Failure is no growth; or growth of a wide variety of colonies, signaling contamination.
Were the three different streak methods appropriate to the cell densities recovered?
Were the three different streak methods appropriate to the cell densities recovered? In general, T-streaks and quadrant streaks are used for samples with expected high cell densities, which the S. epidermis and M. luteus cultures should have had, and therefore should have been appropriate.
What was the purpose of incubating the unopened plates?
What is the purpose of incubating the unopened plates? To use as a contol group. They will not change so one would have enough to control to study off of. If growth appears on the unopened plates what probably happend?
What would happen if you did not sterilize your loop between streaks on your streak plate?
What would a streak plate look like if you had not sterilized the loop between streaking into the new areas of the plate? While the number of bacteria colonies seen in each area may decrease, the numbers would not decrease enough for individual colonies to form.
Why is it important to allow the Sterilised loop to cool fully between each successive streak on the plate?
Never lay the loop down once it is sterilised, or it may again become contaminated. Allow the loop to cool a few seconds before contacting the inoculum to avoid killing the microorganisms.
What are some consequences of leaving a stain on bacterial smear too long?
. What are some consequences of leaving a stain on a bacterial smear too long (over-staining)? Consequences of over-staining are that the cell wall may be broken up or completely destroyed which would result in a loss of morphological characteristics of the bacterial cell.
What happens if you don’t heat fix slides?
If your slide is wet and you heat fix it, the bacteria will boil and the cellular morphology will be lost. If your slide is wet and fix it in methanol, it will most likely wash off the slide.
Why is the loop sterilized after the initial inoculum?
Answer and Explanation: The loop is sterilized even after the agar plate is inoculated in order to avoid contamination.
Why is it important to sterilize your inoculating loop before and after each use?
c Sterilise a wire loop by heating to red hot in a roaring blue Bunsen burner flame before and after use. This ensures that contaminating bacterial spores are destroyed.
What would happen if you didn’t heat fix a smear before performing the direct stain?
Heat-fixing the slide fixes the bacteria to the slide surface. If this step is not done, the bacteria in the smear would be washed off of the slide during the staining and decolorization steps.
Why must the loop be flamed before entering a culture why must it be flamed after making an inoculation?
Always flame the lip of the culture tube before inserting your sterile loop into the culture. This destroys any contaminating cells that may have been inadvertently deposited near the lip of the tube during previous transfers or by other means.
What is the primary use of slants?
Agar slants are commonly used to generate stocks of bacteria. Agar plates can be used to separate mixtures of bacteria and to observe colony characteristics of different species of bacteria (you will perform an experiment in this lab to illustrate this).
How do we think bacteria reproduce and grow?
Bacteria reproduce primarily by binary fission, an asexual process whereby a single cell divides into two. Under ideal conditions some bacterial species may divide every 10–15 minutes—a doubling of the population at these time intervals.
What type of growth is exhibited by bacteria?
In comparison to batch culture, bacteria are maintained in exponential growth phase, and the growth rate of the bacteria is known. Related devices include turbidostats and auxostats. When Escherichia coli is growing very slowly with a doubling time of 16 hours in a chemostat most cells have a single chromosome.
Which type of culture media is best used to grow stock cultures of bacteria for storage?
The most common growth media for microorganisms are nutrient broths and agar plates; specialized media are required for some microorganisms. Some, termed fastidious organisms, require specialized environments due to complex nutritional requirements.
Why are growth characteristics more useful on agar plates than agar slants?
Why are growth characteristics more useful on agar plates than on agar slants? Why are agar slants better suited than agar plates to maintain stock cultures? Slants are better suited because they can be capped, preventing the agar and culture from drying out.
What would you expect to happen if you forgot to remove the lids on all your plates?
What would you expect to happen if you forgot to remove the lids on all your plates when you put them under the UV lamp? Why? The UV light will not damages the DNA and the microorganisms will grow. Since, UV light will not go through plastic, glass, and many other materials.
What did you conclude from observing the plate that was exposed to UV radiation with the lid on?
**What did you conclude from observing the plate that was exposed to UV radiation with the lid on? It had poor penetrating ability.
How do you know if you have a pure culture?
Each colony represents the descendants of a single bacterial cell, and therefore, all of the cells in the colonies are clones. Therefore, when you transfer a single colony from the streak plate to new media, you have achieved a pure culture with only one type of bacteria.
Which is more rapid in proving the purity of a culture?
Streak plate – the original culture is directly diluted across an agar surface using and inoculating loop. This is a simple & rapid method.
Can all bacteria grow on the same media?
All microorganisms cannot grow in a single culture medium and in fact, many can’t grow in any known culture medium. Organisms that cannot grow in the artificial culture medium are known as obligate parasites.
What did you use to establish what constituted good growth?
What did you use to establish what constituted “good growth?” The nutrient agar plate inoculated with the same organisms provided examples of what “good growth” for each organism looks like on a nonselective media.
What does comparing growth of a given organism?
What does comparing growth of a given organism in the three media tell you? Comparison of growth of a given organism in the respective media gives information about the nature of the organism in terms of its relative fastidiousness or non-fastidiousness.
Is it acceptable to read a positive test before incubation time is complete?
It is acceptable to read a positive test before the incubation time is complete, because that means that the organism has already produced casein, and it is usually quite apparent.
Does Bacillus grow on MSA?
Some group D enterococci may exhibit growth with mannitol fermentation; however, catalase test and gram morphology should distinguish between enterococci and staphylococci. Prolonged incubation (≥ 48 hours) may also allow growth of Micrococcus, Bacillus, and some species of Serratia.
Will Bacillus Grow on mannitol salt agar?
The large colonies at the center of the plate are Bacillus cereus. Although these organisms grow well on nutrient agar, they are not halophiles so will not grow on mannitol salt agar.
What grows on EMB?
Some gram-positive bacteria, such as enterococci, staphylococci, and yeast will grow on this medium and usually form pinpoint colonies. Non-pathogenic, non-lactose-fermenting organisms will also grow on this medium.
What bacteria grows on EMB?
Organism | Colonial appearance on EMB agar |
---|---|
Enterobacter aerogenes | Colonies are 4-6mm in diameter, raised and mucoid, tending to become confluent. No metallic sheen, grey-brown centers by transmitted light |
Salmonella and Shigella spp | Translucent and colorless colonies |
Pseudomonas spp | Colorless irregular colonies |
What is hanging drop method?
The hanging drop technique is a well-established method for examining living, unstained, very small organisms. The traditional procedure employs a glass slide with a circular concavity in the centre into which a drop of fluid, containing the ‘microorganisms’, hangs from a coverslip.
Is a motility test painful?
Although esophageal manometry may be slightly uncomfortable, the procedure is not painful because the nostril is numbed. Once the tube is placed, patients talk and breathe normally. Side effects of an esophageal motility test are generally minor and include: Mild sore throat.
What is the dirtiest place in the house?
According to the 2011 NSF International Household Germ Study, the kitchen is the dirtiest area in the entire home. A family of bacteria that includes salmonella and E. coli was found in more than 75% of dish sponges and rags.
Which part of the house has the most bacteria?
The kitchen is the dirtiest room in a house, but germs also collect in the bathrooms, particularly in toothbrushes. Home offices are bacteria-ridden thanks to heavily-touched objects like keyboards and phones. Also on the list is living room carpet, washing machines, and food and water bowls for pets.