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ASU MIC 205 PENTON EXAM 1 NEWEST
2024-2025 ACTUAL EXAM COMPLETE 200
QUESTIONS AND CORRECT ANSWERS
(VERIFIED ANSWERS) |ALREADY GRADED
A+||BRAND NEW VERSION!!
What is an endospore? - CORRECT ANSWER -a dormant, tough, and temporarily non-reproductive structure produced by certain bacteria.
Why do bacteria make endospores - CORRECT ANSWER -to survive in unfavorable environments they can form endospores to protect their genetic material and essential cellular components until conditions improve.ex. depleted nutrients, extreme temps
What bacterial group discussed in class is medically important and form endospores?How does this relate to C. diff? - CORRECT ANSWER -Bacteria that form endospores such as bacillus and clostridia Is relevant medically because its resistant to treatment and can cause death 1 / 4
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It relates to C diff because they both are both G+, have endospores that are hard to treat and have the same symptoms
What does it mean for a bacterial growth medium to be selective? - CORRECT ANSWER -A selective growth medium is designed to inhibit the growth of certain types of bacteria while allowing others to grow This is achieved through the addition of specific substances, such as antibiotics or specific nutrients, that favor the growth of target organisms
What does it mean for a bacterial growth medium to be differential? - CORRECT ANSWER -allows multiple types of bacteria to grow but contains specific indicators that help distinguish between them based on their biochemical characteristics. These indicators can change color or produce a precipitate in response to specific metabolic activities.
Understand the selective aspects of MacConkey's agar (MAC). - CORRECT ANSWER -effectively isolate Gram-negative bacteria by inhibiting Gram-positive bacteria through the inclusion of bile salts and crystal violet, facilitating further analysis and identification of clinically relevant pathogens
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Understand the differential aspects of MacConkeys agar (MAC)
- CORRECT ANSWER -enable the identification and
differentiation of lactose fermenting and non-fermenting Gram- negative bacteria
What information does MAC provide about bacteria growing on this medium? - CORRECT ANSWER -Lac+ produce lactic acid, lowers the pH, changing the colonies to pink (due to a pH indicator-neutral red)Lac - do not ferment lactose, no lactic acid produced, white
What makes Mannitol Salt agar (MSA) selective? - CORRECT ANSWER-MSA contains a high concentration of salt (7.5% sodium chloride), inhibiting the growth of most bacteria except halophilic organisms like Staphylococci.
How does Mannitol Salt agar (MSA) function differentially? - CORRECT ANSWER -MSA differentiates between mannitol fermenters and non-fermenters based on color changes in the medium, aiding in identifying pathogenic Staphylococcus species.
What information does MSA provide about bacteria growing on this medium? - CORRECT ANSWER -If organism can ferment mannitol, acid produced turns the phenol red to yellow. 3 / 4
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What specific bacteria can be identified in Mannitol salt agar (how are they clinically important)? - CORRECT ANSWER - GRAM +, Staphylococcus aureus
What type of clinical samples is plated on Blood agar (BAP)? - CORRECT ANSWER -Not used selectively Used to grow a variety of bacteria and then be able to tell them apart by how they react to the blood in the plate
What broad type ofbacteria are we looking for from a sample plated on BAP? - CORRECT ANSWER -looking for bacteria that can perform hemolysis and the lysis of red blood cells; differentiate STREP
Beta: - CORRECT ANSWER -they lyse (break down release
contents) red blood cells, leading to a clear zone around the colonies on blood agar.
Alpha - CORRECT ANSWER -these bacteria partially lyse (break down release contents) red blood cells, resulting in a greenish discoloration around the colonies due to the reduction of hemoglobin to methemoglobin.
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