New Evolution Lab 7

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Q24:  A 7 dilution is performed on a culture of bacteria in order to perform viable plate counts. From the dilution, *0.1 mL* of solution is plated on solid media, and 31 colonies of bacteria grow on the petri dish.  Assuming each colony came from a single bacterium, how many bacteria are in a single mL of the original culture? Express your answer to two decimal places using standard notation. Since only 0.1 mL is put on the plate, this counts as an extra dilution!!! Any time less than 1 mL is transfered, a dilution is being performed. Any time more than 1 mL is transfered, a concentration is being performed.

Clinical application: A 44-year-old man with HIV is receiving antibiotics through a intravenous catheter. The antibiotics are to help treat a kidney infection. The patient develops a fever. Subsequent cultures from the patient's blood, the needle tip, and from the insertion site all show growth of an organism with large oval-shaped cells. The cells reproduce by budding. (a) What is your guess about the identity of the pathogen? (b) How do you think the antibiotics may have contributed to this outcome? (c) What do you think the portal of entry was for this pathogen?

3. Please help answer this question and please show all work on how you got the answers. Thank you so much!! :)

7a. A petri plate is given to you with 80 colonies on it.  I tell you that I did five 10x dilutions and then plated 0.1 ml from my last tube to get 80 colonies on a plate.  How many living bacteria per ml were in that original sample?  Draw out (or describe) all of the dilutions I would have done to get this number. 7b. Again, I have a plate with 80 colonies on it, but I tell you that I did one 100x dilution and two 10x dilutions before I plated that 0.1ml from my last tube.  How many living bacteria per ml were in that original sample?  Draw out (or describe) all of the dilutions I would have done to get this number.   please include drawings. thank you

Naming and Classifying Microorganisms 1. Recognize the system of scientific nomenclature that uses two names: a genus and a specific epithet. 2. Differentiate the major characteristics of each group of microorganisms. 3. List the three domains. A Brief History of Microbiology 1. List at least four beneficial activities of microorganisms. 2. Name two examples of biotechnology that use recombinant DNA technology and two examples that do not. 3. Explain the importance of observations made by Hooke and van Leeuwenhoek. 4. Compare spontaneous generation and biogenesis. 5. Identify the contributions to microbiology made by Needham, Spallanzani, Virchow, and Pasteur. 6. Define bacteriology, mycology, parasitology, immunology, and virology. 7. Explain the importance of microbial genetics and molecular biology.

t Fall 2020 (page 2 of X elearn.squ.edu.om/mod/quiz/attempt.php?attempt3D1335328&cmid%3D697149&page3D1 System (Academic) The reason why Bacteria stain differently is mainly based on their: Select one: O a. Number and thickness of smear O b. Cell wall structure O c. Presence/absence of nucleus O d. Size O e. Origin In the image provided, the basic unit of life is represented in the.....

Escherichia coli Mycobacterium phlei Bacillus Micrococcus subtilis luteus A B Figure 1: Agar Slant Cultures of Bacteria (Gary E. Kaiser, Ph.D.- Professor of Microbiology) . Observe and describe the colour of the slant cultures (A-D) in fig 1. ( . Define the following terms: pure culture, sterile medium, inoculum, aseptic technique, and colony. What is the name of the cultures that you used . Where they gram negative or positive Define the following terms: psychrophile, mesophile, thermophile, and hyperthermophile.

Question:- Define the bacterial categories that each type of bacteria belongs to. You only have to name the categoriesNOT the actual species of bacteria Note: there will be more than one category . A bacterial species that grows best at 37 degrees Cand when a small amount of oxygen is present

Which cultures would be suitable for the transduction experiment and why？ Which cultures would not be suitable for the transduction experiment and why？

1) both streak plating and pour plating produce isoluated colonies. What is the underlying explanation for why both methods work; that is, what are both methods doing with repect to the bacterial cells? 2) If streak plates failed to produce isolated colonies, describe two things that you could do to improve your chance of generating isolated colonies. 3) Why do we care so much about producing isolated colonies? what is an isolated colony composed of? What can you do with an isolated colony?

ISOLATE #2 Isolation of Gram-positive Bacteria from the Nose and Skin – Part III – Use the results from your Gram stain (morphology and Gram stain result), along with the results you record in the table below to determine the genus of "Isolate #1" and "Isolate #2". Refer to Table 1 in “Isolation of Gram-positive Bacteria from the Nose and Skin – Part III. Additional Information to HELP Below! 1. MSA: Record the results for "Isolate #2 below: Results of Tests to determine the genera of "Isolate #2: a. Isolate #2: Cell Morphology (shape) Results & Interpretation (not just positive or negative, what do the results tell you about the unknown bacteria?) Appear to be rounded ball like, Bacteria is coccus shaped . Possible genera (genus) (there may be more than one) Test b. Isolate #2: Gram stain result Gram Postive. (The color I see on my screen is purple.) c. List at least two genera (not species) of bacteria that are consistent with the Gram reaction and morphology you observed. Morphology…

Use the data below to calculate the colony forming units per mL (CFU/mL) from a sample of bacteria after growing the sample in an incubator for 2 hours. Culture density (CFU/mL) = Time 1 hour 2 hours 1x 10-¹ 1 x 10-² 1x 10-³ 1x 104 number of colonies (dilution) x (volume plated, in mL) Dilution (before plating) Volume spread on plate (replicate plates) 1x 10-1 1x 10-² 1x 10-³ 1 x 104 0.1 mL 0.1 mL 0.1 mL 0.1 mL Number of colonies observed 0.1 mL 0.1 mL 0.1 mL 0.1 mL TNTC 660 101 8 TNTC 220 15 3 TNTC 783 115 7 TNTC 180 9 7

Im 100 4. You have a culture of yeast that is at a density of 8x10' cells/mL. You dilute the sample 1:10, then 1:1,000 again, and finally you dilute the sample an additional 1:5. You add 0.1 mL of the final dilution to a spread plate. Assuming that most of the cells in the original culture were living, how many colony- forming units do you expect to count on your pour plate the next day?

Identify the shapes and arrangements of the following bacteria observed under the microscope. Recall: look for the arrangement seen with most cells; you may see another arrangement that is less common. option: diplo, bacillus, negative, coccus, positive, staphylo, strepto. Gram stain   Cell arrangement    Cell Shape

Q10) What genera produce endospores? - What culture would have more endospores? A bacterium in broth culture for 24 hour or 72 hours? - How specifically does a flagella stain let us see the flagella? (they’re too thin to be seen with 1000X magnification)

Performing a bacterial isolation by streaking, using sterile (aseptic) technique, consider the expected outcome on the streak plate after the following: Two organisms were in the original sample. Organism G was present at twice the abundance of Organism H (so 2/3 of the original sample). The streak plate was generated using 4 areas (quadrants)- A, B, C & D. Area A was inoculated with a loop containìng 3 mìllion organisms from the original culture, which was mixed very well and considered to be homogeneous. Areas B, C & D were streaked from the previous area with a sterilized loop, with each streak transferring 2% of the organisms from the previous area (assume the relative abundance of the two organisms was maintained). What is the expected outcome in Area on this streak plate? 2d

Question:- Name ten examples of bacteria and give their colony morphology. ( indicate the media used for each)

There are two cultures of yeast cells in the pictures, one has been incubated for 6 hours and one has been incubated for 24 hours. After a 10x dilution by taking 100µl of each culture and adding it to 900 µl water in a microcentrifuge tube and 100µl sample from the tube was taken to view in the counting chamber. a) Count the total number of yeast cells for each culture respectively b) Calculate the concentration and density of yeast cells for each culture respectively

6a. A sample is given to you that contains 6 million cells per ml.  You must make a series of serial dilutions in order to get a countable number on a plate to prove that there are indeed 6 million cells per ml.  The plate that you eventually put a sample of bacteria on must have between 10 and 100 colonies for ease of counting.  What dilutions do you make to get this many colonies on a plate?  How many colonies do you have on that plate?  Show what dilutions you make (Write exactly how much liquid you move into each test tube and how much liquid was in the test tube, ex. Move 1 ml of culture into 9 ml of water – 10x dilution).  Don’t forget to tell me how much liquid you eventually put on your plate. (If you want to draw something out, you could draw then take a picture of it with your phone and submit the image along with the worksheet).   6b. Do the same problem as in 6a, but now you have to do it in 3 test tubes or less.  What dilutions do you do now?   please use drawings to help…

Someone can please help me to fill in the blanks by compare and contrast domain bacteria and domain arches using the chart below

Below are the results of streak for isolations of Bacterium 1 and Bacterium 2 before and after they were cryopreserved using glycerol stock. Identify if the culture is pure or not

Sample Station 2 • This is micrograph of a Gram stained bacterium. Look at the cells indicated by arrows, answer the following: A. What is the cell morphology? B. What is the cell arrangement? C. What is the Gram reaction of this organism?

Plaque assay (Bacteriophage Titer) Answer questions 2 & 3 2. Why don't bacteriophages continue spreading over the entire plate until all of the E. coli cells on the plate are lysed?  3. Why is it important that bacterial cells should be in the exponential growth phase for this experiment?

In the experiment by Bernard Davis, bacterial F+cells and F- cells were growing while separated by a filter. Filter pores allowed the passage of the liquid medium but not the bacteria cells. As a result: 1) prototype colonies grew well on minimal medium 2) F+ cells were converted to F- cells despite the physical separation  3)F- cells were converted F+ cells despite the physical separation  4)F+ cells were not converted to F- cells because of the physical separation  5) F- cells were not converted to F+ cells because of the physical separation  6)there was no growth of prototypes on minimal medium

Please answer fast Dilution Problem. A culture of Staphylococcus is diluted as follows: (1) 20mL are added to 80mL of water. (2) 10uL from (1) are then added to 9.99mL of water. (3) A 10-2 dilution is made from tube # (2). (4) 100uL from (3) are plated for a pour plate and incubated.   Growth Problem.A culture with approximately 2x103 cells/mL were incubated. After 3 hours, the number of cells had increased to 3x105. a) How long was the generation time in minutes?b) How many generations have occurred