BIOD 171 Module 5 Exam Portage Learning

Ques 3 / 3 pts tion 1 Your Answer: Define the concept of universal precautions. Any and all samples, known or unknown, that are to be treated as potentially hazardous materials Universal precautions means any and all samples, whether known or unknown, are to be treated as potentially hazardous (or pathogenic) materials. Ques 3 / 3 pts tion 2 Your Answer: List at least 3 observations a researcher would be sure to note while assessing an unknown microbial sample. While assessing an unknown microbial sample, a reasearcher should note the size and shape, observable motility and the presence of any chemical reactions along with gram status. A lab researcher would be certain to note: 1. Size and shape 2. Any observable motility 3. Gram status (positive or negative) 4. The presence of any chemical reactions 5. Changes in color localized to the organism or the surrounding media 6. Capture (or draw) images of any of the characteristics described above Ques 5 / 10 pts tion 3 2/22/22, 3:46 PM M5: Module 5 Exam- Requires Respondus LockDown Browser: Essential Microbiology with Lab- Kephart Your Answer: While observing an unknown sample of limited amounts, a researcher must determine the following observations: (1) the presence of any motility and (2) its Gram status using the same sample—the liquid sample cannot be divided. Which would you determine first and why? First, I would determine the motility because by properly documenting observations, it helps to identify causative agents and selecting appropriate treatments against foreign microbes. You must determine motility before determining the Gram status. Motility requires a wet mount, while Gram staining requires heat fixing the sample. If one were to begin with the Gram stain the heat fixation process would kill the organism, making any observations regarding motility impossible. The correct approach would be to place the liquid culture on a glass slide and determine its motility status. Next, the same liquid culture can be heat fixed and Gram stained. Ques 3 / 3 pts tion 4 Your Answer: A facultative anaerobe is a microorganism capable of growth under what conditions? It is capable of growth in both the presence or absence of oxygen. A facultative anaerobe is capable of growth under aerobic (with oxygen) and anaerobic (without oxygen) conditions. Ques 10 / 10 pts tion 5 Your Answer: As Streptococcus is catalase negative would it thrive or die in the presence of peroxides? Why? It dies in the presence of peroxides because it cannot break down peroxides and needs to be cultured on BAP. Streptococcus would not survive in the presence of peroxides—it is unable to breakdown peroxides (catalase negative). Left unchecked, peroxides would damage the cellular integrity of Strep causing lysis/cell death. Ques 2 / 2 pts tion 6 Streptococcus is most often streaked onto: 2/22/22, 3:46 PM M5: Module 5 Exam- Requires Respondus LockDown Browser: Essential Microbiology with Lab- Kephart Chocolate agar Blood agar Correct! Strep is often cultured on Blood agar plates to determine its hemolytic properties, which aids in the classification (and differentiation) process. EMB agar Spirit Blue agar Ques 0 / 2 pts tion 7 True or False. The Lancefield groups are used to subdivide antigenic groups of gamma-hemolytic Streptococcus. True You Answered False Correct Answer Ques 0 / 2 pts tion 8 The distinctions for Lancefield subgroupings lie in its: (select all that apply) Carbohydrate composition of antigens Correct! Carbohydrate composition of antigens present in the cell wall determines the Lancefield groupings (A, B, C, etc). Note, ALL strep under Lancefield groupings are (by definition) catalase negative and beta-hemolytic. Thus, answers A and C cannot be used to subdivide streptococcal species. Catalase activity All of the above Hemolytic activity You Answered Ques 2 / 2 pts tion 9 Left untreated, strep throat can progress to ______ , which displays _____ hemolytic activity. Strep. Pharyngitis; alpha Strep. Septicemia; gamma Rheumatic fever; beta Correct! Strep throat (also known as strep. Pharyngitis) can lead to Rheumatic fever if left untreated. Strep. Pharyngitis displays beta-hemolytic activity. 2/22/22, 3:46 PM M5: Module 5 Exam- Requires Respondus LockDown Browser: Essential Microbiology with Lab- Kephart Strep. Pharyngitis; beta Ques 0 / 2 pts tion 10 True or False. Under most circumstances, staphylococcus can be found in ~30% of human population where it remains pathogenic. True You Answered False