Nokea
Which of the following bacteria are unable to synthesize ATP?
- A. Chlamydia
- B. Enterococci
- C. Rickettsia
- D. Staphylococci
Correct Answer: A
Rationale: The correct answer is A: Chlamydia. Chlamydia lacks the essential enzymes for ATP synthesis and relies on host cell ATP. Enterococci, Rickettsia, and Staphylococci possess the necessary enzymes for ATP synthesis through cellular respiration. Chlamydia's inability to synthesize ATP makes it dependent on the host cell for energy production, distinguishing it from the other bacteria listed.
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What is the primary mode of transmission for tetanus?
- A. Ingestion of contaminated food
- B. Inhalation of droplets
- C. Contaminated wounds
- D. Direct physical contact
Correct Answer: C
Rationale: The correct answer is C: Contaminated wounds. Tetanus is caused by the bacterium Clostridium tetani, which enters the body through breaks in the skin such as wounds or cuts. The bacteria produce a toxin that affects the nervous system, leading to muscle stiffness and spasms. Ingestion of contaminated food (choice A) is not a mode of transmission for tetanus. Inhalation of droplets (choice B) is more relevant for respiratory infections. Direct physical contact (choice D) is not the primary mode of transmission for tetanus as the bacteria need a portal of entry such as a wound to cause infection.
Which of the following antibodies indicates acute measles infection
- A. Anti-mumps IgM
- B. Anti-rubella IgM
- C. Anti-measles IgM
- D. Anti-CMV IgM
Correct Answer: C
Rationale: The correct answer is C: Anti-measles IgM. During acute measles infection, the body produces IgM antibodies specific to the measles virus. This indicates a recent or current infection.
A: Anti-mumps IgM and B: Anti-rubella IgM are specific to mumps and rubella viruses, respectively, not measles.
D: Anti-CMV IgM is specific to cytomegalovirus, not measles.
In summary, choice C is correct because Anti-measles IgM is the specific antibody indicating acute measles infection, while the other choices are antibodies related to different viruses.
Which bacteria are known for producing toxins that can lead to foodborne illnesses?
- A. Clostridium botulinum
- B. Salmonella enterica
- C. Escherichia coli
- D. All of the above
Correct Answer: D
Rationale: The correct answer is D because all three bacteria (Clostridium botulinum, Salmonella enterica, Escherich:ia coli) are known to produce toxins causing foodborne illnesses. Clostridium botulinum produces botulinum toxin, causing botulism. Salmonella enterica produces toxins leading to salmonellosis. Escherichia coli can produce toxins like Shiga toxin causing food poisoning. Choices A, B, and C are incorrect because each bacterium is individually known to produce toxins causing foodborne illnesses, thus the correct answer is D.
Acute hemorrhagic cystitis may be due to:
- A. Parvovirus B19
- B. CMV
- C. Adenovirus
- D. Herpesvirus type 2
Correct Answer: C
Rationale: Rationale for choice C (Adenovirus) being correct:
1. Adenovirus is a common cause of acute hemorrhagic cystitis.
2. Adenovirus infects the bladder epithelium, leading to inflammation and bleeding.
3. Symptoms include hematuria and bladder pain.
4. Diagnosis is confirmed through viral culture or PCR testing.
Summary of why other choices are incorrect:
A: Parvovirus B19 - More commonly associated with erythema infectiosum (fifth disease) and aplastic anemia.
B: CMV - Known to cause congenital infections, mononucleosis, and retinitis, not typically associated with hemorrhagic cystitis.
D: Herpesvirus type 2 - Commonly causes genital herpes, but not typically associated with acute hemorrhagic cystitis.
A scientist identifies a strand of RNA that can be directly used to code for important viral proteins during viral replication. What have they found?
- A. RNA major
- B. -RNA
- C. (+RNA)
- D. RNA minor
Correct Answer: C
Rationale: The correct answer is C: (+RNA). This indicates that the scientist found a positive-sense RNA strand that can be directly translated by host cell machinery to produce viral proteins. Positive-sense RNA can act as messenger RNA, allowing immediate protein synthesis during viral replication. Choice A (RNA major) and D (RNA minor) are not standard terms used to describe RNA strands in virology. Choice B (-RNA) indicates a negative-sense RNA strand, which requires transcription to form a complementary positive-sense strand before protein synthesis. Thus, the identification of a strand of RNA that directly codes for viral proteins aligns with the characteristics of a positive-sense RNA strand.