Question

TSA medium with 5% sheep blood cells (RBCs) is used for determining the hemolytic capabilities of
an organism. Some bacteria produce exoenzymes that lyse red blood cells and degrade hemoglobin;
these are called hemolysins. Bacterial hemolysis includes.
a. Beta-hemolysin breaks down the RBCs and hemoglobin completely [β-hemolysis]
b. Alpha-hemolysin partially breaks down the RBCs and leaves a greenish color behind
c. No production of hemolysins equals no breakdown of RBCs and is called γ-hemolysis.
d. a and b
e. all the above

22. When asked to identify several unknown bacteria isolated from the WCCCD restroom, laboratory
analysts used microscopic, macroscopic, and biochemical tests in order to characterize the
unknowns. In order to determine the genus of their unknowns, it would be making most sense if the
analyst utilized which of the following documents.
a. Foundations in Microbiology, Tenth Edition, Talaro, McGraw-Hill
b. Benson’s Microbiological Applications, 13 th Edition, Brown, Alfred E
c. Bergey’s Manual
d. Techniques for Studying Bacteria and Fungi Manual
23. A rod-shaped, Gram-positive, spore forming with a chain arrangement is most likely to be
a. Staphylococcus aureus
b. Escherichia coli
c. Bacillus megaterium
d. Mycobacterium smegmatis
e. Micrococcus luteus
24. A rod-shaped, Gram-negative, bacteria that produces a green pigment is most likely to be
a. Escherichia coli
b. Micrococcus luteus
c. Proteus vulgaris
d. Pseudomonas aeruginosa
e. Euglena gracilis

Answer 1

Question 1:-

The right answer is option (e) All of the above

Explanation :- Hemolysis test is used to determine the presence of an enzyme called Hemolysin and this is of two types. The enzyme which break down cell of our blood is known as Beta Hemolysin and is produced by species like Staphylococcus aureus. On the other hand, Alpha Hemolysin do not break down red blood cells completely and is characteristic of bacteria like Streptococcus pneumoniae. Some bacteria are unable to lyse the red blood cells and are called gamma Hemolysin.

Question 22 :-

The right option is option (C) Bergey's manual

Explanation :- Bergey's manual was first published by David Bergey and it is the go to book for any researcher if they want to identify a prokaryotic organism. Whatever aspect you want to use to identify a given sample, Bergey's manual cover it and using that you can find out the given species. On the other hand, all the other books are Microbiology Textbook or labbooks while Bergey is a manual for identification.

Question 23 :-

The right option is option (c) Bacillus megaterium

Explanation :- Bacillus and Clostridium are the two genus of bacteria which are Gram positive rods and capable of forming spores.

On the other hand, Escherichia coli is Gram negative and non spore forming, Staphylococcus aureus is a coccus not rod shaped.

Mycobacterial species aren't stained by Gram stain while Micrococcus is also a coccus not a rod shaped bacteria.

Question 24:-

The right option is option (d) Pseudomonas aeruginosa

Explanation :- P. aeruginosa is capable of producing pigments like pyocyanin which make it appear greenish in cultures. While other options available aren't capable of producing green pigments.

Meanwhile Euglena isn't a bacterium but a protists which are considered eukaryotes.