BIO 171 Module 5 TEST- Questions and Answers Portage Learning

QUESTION 1 Define the concept of universal precautions. Universal precautions means any and all samples, whether known or unknown, are to be treated as potentially hazardous (or pathogenic) materials. 

QUESTION 2 List at least 3 observations a researcher would be sure to note while assessing an unknown microbial sample. A lab researcher would be certain to note: Size and shape; Any observable motility; Gram status (positive or negative); The presence of any chemical reactions; Changes in color localized to the organism or the surrounding media; Capture (or draw) images of any of the characteristics described above 

QUESTION 3 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? 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. 

QUESTION 4 A facultative anaerobe is a microorganism capable of growth under what conditions? A facultative anaerobe is capable of growth under aerobic (with oxygen) and anaerobic (without oxygen) conditions. 

QUESTION 5 As Streptococcus is catalase negative would it thrive or die in the presence of peroxides? Why? 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 lysisIcell death 

QUESTION 6 Streptococcus is most often streaked onto: BLOOD AGAR Strep is often cultured on Blood agar plates to determine its hemolytic properties, which aids in the classification (and differentiation) process. 

QUESTION 7 True or False. The Lancefield groups are used to subdivide antigenic groups of gamma-hemolytic Streptococcus. FALSE. The Lancefield groupings are used to subdivide beta-hemolytic Strep. 

QUESTION 8 The distinctions for Lancefield subgroupings lie in its: (select all that apply) Carbohydrate composition of antigens 

QUESTION 9 Rheumatic fever displays hemolytic activity and occurs when is left untreated. Beta; Strep.Pharyngitis. Strep throat (also known as strep. Pharyngitis) can lead to Rheumatic fever if left untreated and displays beta-hemolytic activity. 

QUESTION 10 True or False. Under most circumstances, staphylococcus can be found in -30% of human population where it remains pathogenic. FALSE. While staphylococcus can be found in -30% of the human population, it remains non-symptomatic. 

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