Microbiology Lab Exam Study Guide
Questions with Complete Solutions
What is the purpose of aseptic technique in microbiology?
✔✔To prevent contamination of microbial cultures and the environment.
What type of bacteria will not grow on a MacConkey agar plate?
✔✔Gram-positive bacteria.
What is the primary function of a Gram stain?
✔✔To differentiate bacteria into two groups: Gram-positive and Gram-negative.
What is the function of the bacterial capsule?
✔✔To protect the bacterium from phagocytosis and enhance its virulence.
How is an antibiotic susceptibility test performed?
✔✔By placing antibiotic-impregnated discs on an agar plate inoculated with the microorganism.
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,What does a positive result in a catalase test indicate?
✔✔The presence of catalase enzyme, which breaks down hydrogen peroxide.
What is a pure culture?
✔✔A culture containing only one species of microorganism.
What is the purpose of an inoculating loop in microbiology?
✔✔To transfer microorganisms from one medium to another.
What type of bacteria produce endospores?
✔✔Bacillus and Clostridium species.
What is the role of the ribosome in a bacterial cell?
✔✔To synthesize proteins from RNA.
What is the difference between an obligate aerobe and an obligate anaerobe?
✔✔An obligate aerobe requires oxygen, while an obligate anaerobe cannot tolerate oxygen.
2
, What does an oxidase test determine in microbiology?
✔✔It identifies bacteria that produce cytochrome c oxidase.
What is the function of agar in microbiological media?
✔✔To solidify the medium and provide a surface for microbial growth.
What is the purpose of performing a streak plate?
✔✔To isolate individual bacterial colonies from a mixed culture.
What is the role of the bacterial cell membrane?
✔✔To regulate the movement of substances into and out of the cell.
What are obligate intracellular parasites?
✔✔Microorganisms that can only replicate inside a host cell.
What is the difference between a virus and a bacterium?
✔✔Viruses are not cellular and require a host to replicate, while bacteria are cellular organisms.
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Questions with Complete Solutions
What is the purpose of aseptic technique in microbiology?
✔✔To prevent contamination of microbial cultures and the environment.
What type of bacteria will not grow on a MacConkey agar plate?
✔✔Gram-positive bacteria.
What is the primary function of a Gram stain?
✔✔To differentiate bacteria into two groups: Gram-positive and Gram-negative.
What is the function of the bacterial capsule?
✔✔To protect the bacterium from phagocytosis and enhance its virulence.
How is an antibiotic susceptibility test performed?
✔✔By placing antibiotic-impregnated discs on an agar plate inoculated with the microorganism.
1
,What does a positive result in a catalase test indicate?
✔✔The presence of catalase enzyme, which breaks down hydrogen peroxide.
What is a pure culture?
✔✔A culture containing only one species of microorganism.
What is the purpose of an inoculating loop in microbiology?
✔✔To transfer microorganisms from one medium to another.
What type of bacteria produce endospores?
✔✔Bacillus and Clostridium species.
What is the role of the ribosome in a bacterial cell?
✔✔To synthesize proteins from RNA.
What is the difference between an obligate aerobe and an obligate anaerobe?
✔✔An obligate aerobe requires oxygen, while an obligate anaerobe cannot tolerate oxygen.
2
, What does an oxidase test determine in microbiology?
✔✔It identifies bacteria that produce cytochrome c oxidase.
What is the function of agar in microbiological media?
✔✔To solidify the medium and provide a surface for microbial growth.
What is the purpose of performing a streak plate?
✔✔To isolate individual bacterial colonies from a mixed culture.
What is the role of the bacterial cell membrane?
✔✔To regulate the movement of substances into and out of the cell.
What are obligate intracellular parasites?
✔✔Microorganisms that can only replicate inside a host cell.
What is the difference between a virus and a bacterium?
✔✔Viruses are not cellular and require a host to replicate, while bacteria are cellular organisms.
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