Nokea
Which microbial group can resist acidic pH?
- A. yeast and molds
- B. bacteria
- C. E. Coli
- D. none of the above
Correct Answer: A
Rationale: The correct answer is A: yeast and molds. Yeast and molds can resist acidic pH due to their ability to maintain a stable internal pH through various mechanisms such as ion transport and cell wall composition. Bacteria, including E. coli, are generally more sensitive to acidic conditions. Choice D is incorrect as yeast and molds are known to thrive in acidic environments.
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For isolating Rickettsia, the sample is investigated via:
- A. Skin-allergy tests
- B. Serological methods for proving Ab
- C. Chick embryos, cell cultures, and lab animals
- D. None of the above
Correct Answer: C
Rationale: The correct answer is C because Rickettsia requires living cells for growth and replication. Chick embryos, cell cultures, and lab animals provide a suitable environment for Rickettsia isolation. Skin-allergy tests (A) and serological methods for proving antibodies (B) are not directly used for isolating Rickettsia as they do not support the growth of the bacteria. "None of the above" (D) is incorrect as option C involves the appropriate methods for isolating Rickettsia.
Which of the following is responsible for causing gonorrhea?
- A. Neisseria gonorrhoeae
- B. Chlamydia trachomatis
- C. Mycobacterium tuberculosis
- D. Treponema pallidum
Correct Answer: A
Rationale: Neisseria gonorrhoeae is the correct answer because it is the specific bacterium responsible for causing gonorrhea. It is a sexually transmitted infection that primarily affects the genital tract. Neisseria gonorrhoeae is transmitted through sexual contact and can lead to symptoms such as painful urination, discharge, and pelvic pain.
Chlamydia trachomatis (Choice B) is another sexually transmitted bacterium, but it causes chlamydia, not gonorrhea.
Mycobacterium tuberculosis (Choice C) is responsible for tuberculosis, a different infectious disease that primarily affects the lungs.
Treponema pallidum (Choice D) causes syphilis, another sexually transmitted infection that presents with distinct symptoms from gonorrhea.
Therefore, Neisseria gonorrhoeae is the correct choice for causing gonorrhea due to its specific association with this particular infection.
Which description matches most to adenoviruses:
- A. Middle sized, naked icosahedral capsid, double-stranded DNA
- B. Small-sized, enveloped capsid, ssRNA
- C. Large, enveloped capsid, double stranded DNA
- D. None of the above
Correct Answer: A
Rationale: Step-by-step rationale:
1. Adenoviruses are DNA viruses, so choices B and C (ssRNA and DNA) are incorrect.
2. Adenoviruses have a middle-sized, naked icosahedral capsid, making choice A the correct description.
3. Choice D is incorrect as adenoviruses do have specific characteristics, making "None of the above" an inaccurate option.
In summary, the correct answer A is supported by the fact that adenoviruses have a middle-sized, naked icosahedral capsid and contain double-stranded DNA. Choices B, C, and D are incorrect as they do not align with the characteristics of adenoviruses.
All of the following viruses are enveloped EXCEPT:
- A. Hepatitis C virus
- B. Hepatitis B virus
- C. Hepatitis A virus
- D. Hepatitis D virus
Correct Answer: C
Rationale: The correct answer is C: Hepatitis A virus. This is because Hepatitis A virus is a non-enveloped virus, while choices A, B, and D are all enveloped viruses. Enveloped viruses have a lipid bilayer membrane surrounding their protein capsid, aiding in their ability to infect host cells. Hepatitis C, B, and D viruses all possess this lipid envelope, making them enveloped viruses. Hepatitis A virus, on the other hand, lacks this lipid envelope and is classified as a non-enveloped virus. Therefore, the correct answer is C.
For the structure of rubella virus, it is true that
- A. has icosahedral type of symmetry
- B. is ssDNA virus
- C. does not have an envelope
- D. does not have glycoprotein spikes
Correct Answer: A
Rationale: Step 1: Rubella virus belongs to the Togaviridae family, which typically exhibits icosahedral symmetry.
Step 2: Icosahedral symmetry refers to a structure with 20 equilateral triangular faces, which is characteristic of many viruses, including rubella.
Step 3: Therefore, choice A is correct as rubella virus indeed has icosahedral type of symmetry.
Summary:
- Choice B is incorrect as rubella virus is an ssRNA virus, not ssDNA.
- Choice C is incorrect as rubella virus does have an envelope derived from the host cell membrane.
- Choice D is incorrect as rubella virus does have glycoprotein spikes on its surface.