BIOD 171 Module 4 Exam(2 Versions)(New, 2023-2024)/ BIOD171 Module 4 Exam:Portage Learning, Exams of Nursing

Download BIOD 171 Module 4 Exam(2 Versions)(New, 2023-2024)/ BIOD171 Module 4 Exam:Portage Learning and more Exams Nursing in PDF only on Docsity! M4: Module 4 Exam - Requires Respondus LockDown Browser + Webcam Attempt Time Score LATEST Attempt 1 28 minutes 98 out of 100 Score for this quiz: 98 out of 100 Submitted Aug 6 at 10:30am This attempt took 28 minutes. Question 1 2 / 2 pts True or False: Growth media is best suited for distinguishing between two similar species of bacteria. True Correct! False Growth media is designed to simply support (and not restrict) microbial growth. Question 2 2 / 2 pts A researcher is asked to determine which of two vials contains E coli and which contains salmonella. Knowing both are Gram-negative while only one of them is capable of fermenting lactose, which type of media would be best suited? Selective and Differential media Selective media Growth media Correct! Differential media Differential media distinguishes between two, often related, microbes. Question 3 10 / 10 pts What are the requirements of a fastidious microbe? Your Answer: A fastidious microbe is organism with complex growth requirements. If these growth requirements are not met, the organism will not grow. An enriched media must be to provide the correct nutrients to the organism to allow for growth. A fastidious microbe is an organism with complex growth requirements such that if absent it will not grow. Enriched medias thus contain these specific and essential nutrients required for the growth of a particular subset of microorganisms. Question 4 0 / 2 pts True or False: LB agar is classified as a non-selective, non-differential media. Correct Answer True You Answered False Question 5 5 / 5 pts What is agar used for in microbiology? Your Answer: Agar is used to create a solid, smooth surface on which microbes can grow. Agar is used to create a solid, smooth surface on which microbes can grow. Chocolate (cocoa) is never added to the media. The name is derived simply based on the color that actually comes from the presence of ‘cooked’ (lysed) red blood cells in the media. Question 10 5 / 5 pts A researcher is studying a strain of E. coli currently growing on a MacConkey plate. However, the researcher can’t remember if E. coli is Gram-positive or Gram-negative. Would a Gram stain be necessary to confirm? Why or why not? Your Answer: A gram stain would not be necessary. Only gram-negative microbes will grow on MacConkey agar. E.coli is a gram-negative. No. A Gram stain would not be necessary, as only Gram-Negative microbes will grow on MacConkey agar. Thus, E. coli is a Gram-Negative microbe. Question 11 10 / 10 pts In an attempt to detect the presence of the pathogenic strain of E. coli O157:H7, a researcher spread a culture onto a MacConkey agar with failed results. What type of agar should they (correctly) try next? Why? Your Answer: The next type of agar they should try is SMAC( sorbitoll mannitol agar). SMAC is used to detect E.coli 0257:H7. E.coli 0257:H7 is pathogenic and cannot ferment sorbitol. The non-pathogenic form of E.coli can ferment sorbitol and lactose. The microbe should be plated on SMAC (Sorbitol-MacConkey agar) as it is specifically formulated to detect O157:H7. Pathogenic E. coli (O157:H7) cannot ferment sorbitol while non-pathogenic E. coli can ferment both soribitol and lactose. Therefore, colonies that ferment (acidic conditions; non-pathogenic) can be differentiated from non-fermenters (neutral to basic conditions; pathogenic). Question 12 5 / 5 pts In Eosin Methylene Blue (EMB) agar, what color indicates the presence of E. coli? Your Answer: metallic green Metallic Green Question 13 2 / 2 pts Mannitol salt agar will turn what color in the presence of the pathogenic strain Staphylococcus aureus? Your Answer: yellow Correct Answer Yellow Pathogenic Staph aureus will turn the agar from red to yellow. Question 14 3 / 3 pts What is the process of spreading a bacterial culture onto a petri dish called? Your Answer: plating Plating Question 15 10 / 10 pts In order to visual individual colonies of bacteria would you culture your sample in a liquid media or on a solid (agar) media? Why? Your Answer: Solid media would need to be used. Cells are held in place and will be fixed to allow for individual colonies to grow. In nutrient broth, bacteria will mulitply and are free to move around in the broth. Solid (agar) media. The primary advantage is that cells are held into place. When grown in a nutrient broth, bacterial cells can multiply but are free to move around in solution. When grown on agar within a petri dish the fixed in such as way as to form colonies. Question 16 2 / 2 pts True or False: The visualization of colonies on a petri dish represents bacterial cells that have often multiplied a million times over. Correct! True To form a bacterial colony the initial cell must have multiplied many times over, often greater than a million, in order for the naked eye to resolve it. False Question 17 2 / 2 pts True or False. The purpose of a quadrant streak is to produce individual colonies of a bacterial population. Correct! True The purpose of the quadrant streak is to generate individual colonies such that a single (pure) bacterial sample can be isolated. False Question 18 5 / 5 pts To be considered a pure culture, the sample (1) can be traced back to a single cell and (2)__________ ? Your Answer: free from any external contaminates The culture must also be free from external contaminants. Simply put, a pure sample would never contain multiple bacterial species (ie) Strep and Staph. Question 19 5 / 5 pts A dilution gradient is formed when carrying out what generalize plating strategy? LB media. All other options (A, C and D) are all forms of selective media, meaning they may potentially inhibit the growth of the unknown sample. The culture should be first expanded and then place onto selective/differential agar plates. Quiz Score: 98 out of 100 5/1/22, 6:14 PM M4: Module 4 Exam - Requires Respondus LockDown Browser + Webcam: Essential Microbiology with Lab-2021-Bowman https://nursingabc.instructure.com/courses/902/quizzes/23548?module_item_id=135785 1/13 M4: Module 4 Exam - Requires Respondus LockDown Browser + Webcam Due No due date Points 100 Questions 24 Time Limit 60 Minutes Requires Respondus LockDown Browser Attempt History Attempt Time Score LATEST Attempt 1 36 minutes 98 out of 100 Score for this quiz: 98 out of 100 Submitted Apr 21 at 9:47pm This attempt took 36 minutes. 2 / 2 ptsQuestion 1 True or False: Differential media is best suited for distinguishing between two similar species of bacteria. True Correct! Growth media does not contain restrictive factors, while selective media is best used to encourage the growth of one microbe while simultaneously discouraging the growth of the other. Since two similar species of microbes are being studied they must be differentiated under similar but just slightly different conditions (differential media). False 2 / 2 ptsQuestion 2 5/1/22, 6:14 PM M4: Module 4 Exam - Requires Respondus LockDown Browser + Webcam: Essential Microbiology with Lab-2021-Bowman https://nursingabc.instructure.com/courses/902/quizzes/23548?module_item_id=135785 2/13 A researcher is asked to determine which of two vials contains E coli and which contains salmonella. Knowing both are Gram-negative while only one of them is capable of fermenting lactose, which type of media would be best suited? Growth media Selective media Differential media Correct! Non-selective and non-differential media 10 / 10 ptsQuestion 3 Your Answer: What are the requirements of a fastidious microbe? A fastidious microbe is an organism with complex growth requirement such that if absent will not grow; hence enriched media contains these specific and essential nutrients for the growth of particular subset of microorganisims. A fastidious microbe is an organism with complex growth requirements such that if absent it will not grow. Enriched medias thus contain these specific and essential nutrients required for the growth of a particular subset of microorganisms. 2 / 2 ptsQuestion 4 5/1/22, 6:14 PM M4: Module 4 Exam - Requires Respondus LockDown Browser + Webcam: Essential Microbiology with Lab-2021-Bowman https://nursingabc.instructure.com/courses/902/quizzes/23548?module_item_id=135785 5/13 CNA agar restricts Gram-Negative microbes therefore only Gram- Positive microbes will grow. Mycobacteria Gram-Negative Gram-Positive and Gram-Negative 2 / 2 ptsQuestion 9 True or False: Chocolate (cocoa) is not a component of Chocolate agar plates. True Correct! The name is derived simply based on the color that actually comes from the presence of ‘cooked’ (lysed) red blood cells in the media. False 5 / 5 ptsQuestion 10 Your Answer: An unknown microbe is streaked onto a MacConkey agar plate. After an overnight incubation at 37°C, growth is observed. Would a Gram stain be necessary? Why or why not? No, a Gram stain will not be necessary because MacConkey agar only allows the growth of Gram-negative bacteria; so the unknown microbe will be a Gram-negative microbe 5/1/22, 6:14 PM M4: Module 4 Exam - Requires Respondus LockDown Browser + Webcam: Essential Microbiology with Lab-2021-Bowman https://nursingabc.instructure.com/courses/902/quizzes/23548?module_item_id=135785 6/13 No. A Gram stain would not be necessary, as only Gram- Negative microbes will grow on MacConkey agar. 10 / 10 ptsQuestion 11 Your Answer: In an attempt to detect the presence of the pathogenic strain of E. coli O157:H7, a researcher spread a culture onto a MacConkey agar with failed results. What type of agar should they (correctly) try next? Why? The type of agar to be used would be SMAC agar (sorbitol MacConkey agar) this is the agar that is suitable to grow pathogenic strain of E. Coli because it cannor ferment sorbitol. The non-pathogenic strain of E. coli although can ferment both lactose and sorbitol hence, SMAC can be used as a differential agar to distinguish between them. The strain that is able to ferment sorbitol will be the non-pathogenic strain which will bring about an acidic Ph, on the other hand, the pathogenic strain is unable to ferment sorbitol and hence brings about a neutral to basic Ph. Thus, the pathogenic strain of E. coli 0157:H7 is able to be detected and distinguisehed as it does not ferment sorbitol The microbe should be plated on SMAC (Sorbitol-MacConkey agar) as it is specifically formulated to detect O157:H7. Pathogenic E. coli (O157:H7) cannot ferment sorbitol while non-pathogenic E. coli can ferment both soribitol and lactose. Therefore, colonies that ferment (acidic conditions; non- pathogenic) can be differentiated from non-fermenters (neutral to basic conditions; pathogenic). 5/1/22, 6:14 PM M4: Module 4 Exam - Requires Respondus LockDown Browser + Webcam: Essential Microbiology with Lab-2021-Bowman https://nursingabc.instructure.com/courses/902/quizzes/23548?module_item_id=135785 7/13 5 / 5 ptsQuestion 12 Your Answer: In Eosin Methylene Blue (EMB) agar, what color indicates the presence of E. coli? Metallic Green Metallic Green 0 / 2 ptsQuestion 13 Your Answer: Mannitol salt agar will turn what color in the presence of the pathogenic strain Staphylococcus aureus? Dark purple to black orrect Answer Yellow Pathogenic Staph aureus will turn the agar from red to yellow. 3 / 3 ptsQuestion 14 What is the process of spreading a bacterial culture onto a petri dish called? 5/1/22, 6:14 PM M4: Module 4 Exam - Requires Respondus LockDown Browser + Webcam: Essential Microbiology with Lab-2021-Bowman https://nursingabc.instructure.com/courses/902/quizzes/23548?module_item_id=135785 10/13 The culture must also be free from external contaminants. Simply put, a pure sample would never contain multiple bacterial species (ie) Strep and Staph. 5 / 5 ptsQuestion 19 Your Answer: A dilution gradient is formed when carrying out what generalize plating strategy? Quadrant streak (Phase dilution) A quadrant streak. The resulting gradient should always contain within it the growth of individual colonies. 5 / 5 ptsQuestion 20 Your Answer: In what phase of a dilution streak would you expect to find the lowest concentration of bacteria, P2 or P4? P4 5/1/22, 6:14 PM M4: Module 4 Exam - Requires Respondus LockDown Browser + Webcam: Essential Microbiology with Lab-2021-Bowman https://nursingabc.instructure.com/courses/902/quizzes/23548?module_item_id=135785 11/13 P4 (Phase 4) would contain the lowest concentration of bacteria. The phases rank (from highest to lowest), P1 > P2 > P3 > P4. 2 / 2 ptsQuestion 21 True or False. When performing a dilution streak a new (or sterilized) loop is not required for each phase as long as the bacterial culture is pure. True False Correct! A new or sterilized loop is absolutely required for each phase. Failure to do so would prevent the establishment of a dilution gradient, as the same bacterial concentration would be spread across both phase regions, regardless of whether or not the culture is pure. 5 / 5 ptsQuestion 22 Your Answer: In order to encourage growth of a slow growing microbe what might a researcher do during a phase dilution streak? The resercher might use a 3 phase dilution streak instead of four, and also the research could use the sterile loop and go through the previous phase more than once. Instead of once normally done. 5/1/22, 6:14 PM M4: Module 4 Exam - Requires Respondus LockDown Browser + Webcam: Essential Microbiology with Lab-2021-Bowman https://nursingabc.instructure.com/courses/902/quizzes/23548?module_item_id=135785 12/13 A researcher may either (1) opt to perform only a 3-phase dilution streak or (2) pass the loop through the previous phase multiple times (as opposed to only once). 2 / 2 ptsQuestion 23 True or False. To restrict the growth of a pathogenic microbe a researcher might decrease an incubator from 37°C to 25°C. True Correct! Pathogenic strains of bacteria tend to grow faster than non- pathogenic strains at 37°C, so researchers may set incubators at 25°C to restrict its growth. False 5 / 5 ptsQuestion 24 Your Answer: When given an unknown bacterial sample the first step is to expand the current bacterial population. Which form of media best suites this need? Why? 1. MSA agar 2. LB media 3. MacConkey agar 4. Columbia CNA agar