Nokea
In a compound light microscope the lens closest to the eye is the __________ lens.
- A. ocular
- B. objective
- C. condenser
- D. stage
Correct Answer: A
Rationale: The correct answer is A: ocular lens. The ocular lens is the lens closest to the eye in a compound light microscope. This lens is responsible for magnifying the image produced by the objective lens. It typically has a magnification power of 10x. The objective lens, choice B, is positioned closer to the specimen and provides the primary magnification of the image. The condenser, choice C, is located beneath the stage and helps focus light onto the specimen. The stage, choice D, is where the specimen is placed for observation. Therefore, the ocular lens is the correct choice as it is the lens closest to the eye and responsible for further magnifying the image.
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What drug should be administered?
- A. Doxycycline
- B. Chloramphenicol
- C. Penicillin
- D. Streptomycin
Correct Answer: A
Rationale: The correct answer is A: Doxycycline. It is a broad-spectrum antibiotic effective against a wide range of bacteria, including those causing infections like Lyme disease and pneumonia. Doxycycline is often the first-line treatment for these infections due to its efficacy and low risk of resistance. Chloramphenicol (B) has serious side effects and is reserved for specific cases. Penicillin (C) is not effective against all bacteria and may not cover the specific infection. Streptomycin (D) is mainly used for certain types of bacterial infections and is not the optimal choice for the conditions mentioned in the question.
All of the following infections may recur during pregnancy except:
- A. Epstein-Barr virus infections
- B. herpes simplex virus infections
- C. streptococcal infections
- D. polyomavirus infections
Correct Answer: D
Rationale: The correct answer is D: polyomavirus infections. Polyomavirus infections do not typically recur during pregnancy because once the virus infects the body, it remains latent without causing recurrent infections. In contrast, choices A, B, and C can recur during pregnancy due to their ability to reactivate from latency or reinfect the host. Epstein-Barr virus infections (choice A) can lead to infectious mononucleosis, herpes simplex virus infections (choice B) can cause recurrent genital or oral herpes outbreaks, and streptococcal infections (choice C) can result in recurrent throat or skin infections.
A patient returning from Congo republic a week ago is with fever, headache vomiting and diarrhea, Three days after his admission to the infectious ward, despite antibiotic therapy, severe hemorrhagic syndrome developed and as well as CNS involvement, The diagnosis is hemorrhagic fever. Which of these viruses can be a causative agent?
- A. SARS CoV
- B. Lymphocytic choriomeningitis virus
- C. Ebola virus
- D. ECHO 9
Correct Answer: C
Rationale: The correct answer is C: Ebola virus. The patient's symptoms align with Ebola virus infection, including fever, severe hemorrhagic syndrome, and CNS involvement. Ebola virus is known to cause hemorrhagic fevers with high mortality rates.
A: SARS CoV causes Severe Acute Respiratory Syndrome, which typically presents with respiratory symptoms, not hemorrhagic fever.
B: Lymphocytic choriomeningitis virus usually causes a mild illness with flu-like symptoms, not severe hemorrhagic syndrome.
D: ECHO 9 virus is associated with aseptic meningitis, not hemorrhagic fever.
The anticodons are located in
- A. tRNA.
- B. rRNA.
- C. mRNA.
- D. ribosomes.
Correct Answer: A
Rationale: The correct answer is A: tRNA. Anticodons are sequences of nucleotides found on tRNA molecules that complement the codons on mRNA during translation. tRNA molecules carry specific amino acids to the ribosome based on the codon-anticodon pairing. Option B, rRNA, forms the structure of the ribosome and is not directly involved in anticodon recognition. Option C, mRNA, contains codons but not anticodons. Option D, ribosomes, are the site of protein synthesis but do not contain the anticodons themselves.
During a microscopy session, spiral-shaped bacteria with loose coils and pointed ends were observed in a blood smear. What is the most likely diagnosis?
- A. Syphilis
- B. Leptospirosis
- C. Relapsing fever
- D. Lyme disease
Correct Answer: B
Rationale: The correct answer is B: Leptospirosis. Spiral-shaped bacteria with loose coils and pointed ends are characteristic of Leptospira interrogans, the causative agent of Leptospirosis. This bacterium is typically found in contaminated water or soil and can infect humans through contact with infected animals or water.
Syphilis (Choice A) is caused by the spirochete Treponema pallidum, which has a more tightly coiled shape and does not typically appear loose or pointed. Relapsing fever (Choice C) is caused by Borrelia species, which are also spirochetes but do not have the loose coils and pointed ends described. Lyme disease (Choice D) is caused by Borrelia burgdorferi, which, like Relapsing fever, does not match the morphology described.