Nokea
The typical site for replication of DNA viruses is:
- A. Nucleus
- B. Cytoplasm
- C. Endoplasmic Reticulum
- D. Golgi Apparatus
Correct Answer: A
Rationale: The correct answer is A: Nucleus. DNA viruses replicate in the host cell's nucleus because they require access to the host cell's DNA replication machinery. The nucleus contains the necessary enzymes and factors for DNA replication to occur accurately. The DNA viruses need to utilize these host cell components to replicate their own genetic material.
Summary of why other choices are incorrect:
B: Cytoplasm - Cytoplasm lacks the necessary enzymes and machinery for accurate DNA replication.
C: Endoplasmic Reticulum - ER is involved in protein synthesis and processing, not DNA replication.
D: Golgi Apparatus - Golgi apparatus is responsible for processing and packaging proteins, not DNA replication.
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Acne is caused by:
- A. Staphylococcus aureus
- B. Staphylococcus epidermidis
- C. Streptococcus pyogenes
- D. Propionibacterium acnes
Correct Answer: D
Rationale: The correct answer is D: Propionibacterium acnes. This bacterium plays a key role in acne formation by colonizing hair follicles, leading to inflammation and acne lesions. It produces fatty acids that contribute to the development of acne. Staphylococcus aureus (A) and Staphylococcus epidermidis (B) are not directly linked to acne. Streptococcus pyogenes (C) is associated with skin infections but not acne. In summary, Propionibacterium acnes is the primary bacterium responsible for acne due to its ability to induce inflammation and follicular blockages.
Viruses cannot multiply in:
- A. Artificial nutrient media
- B. Living cells
- C. Human embryonic cells
- D. Bacteria
Correct Answer: A
Rationale: The correct answer is A: Artificial nutrient media. Viruses are obligate intracellular parasites, meaning they require living host cells to replicate. They cannot multiply in artificial nutrient media as they lack the cellular machinery necessary for viral replication. Living cells, including human embryonic cells and bacteria, provide the required cellular environment for viruses to replicate. Therefore, options B, C, and D are incorrect as they all contain living cells that can support viral multiplication.
Which are the most suitable materials for isolation of polio viruses?
- A. feces, duodenal and bile content
- B. blood, sputum, and urine
- C. only feces
- D. feces, nasopharyngeal swabs, and cerebrospinal fluid
Correct Answer: D
Rationale: The correct answer is D because polio viruses are primarily found in the gastrointestinal tract and respiratory secretions. Feces contain the highest concentration of the virus, while nasopharyngeal swabs and cerebrospinal fluid can also contain the virus. Blood, sputum, and urine do not typically contain high levels of polio virus. Choice A is incorrect as bile content is not a common site for polio virus isolation. Choice C is incorrect because only testing feces may not provide a comprehensive picture of the infection.
The bacteria responsible for anthrax is:
- A. Bacillus anthracis
- B. Clostridium tetani
- C. Mycobacterium tuberculosis
- D. Streptococcus pneumoniae
Correct Answer: A
Rationale: The correct answer is A: Bacillus anthracis. This bacterium is known to cause anthrax, a serious infectious disease in humans and animals. Bacillus anthracis is a gram-positive, spore-forming bacterium that produces toxins leading to the characteristic symptoms of anthrax. Clostridium tetani causes tetanus, Mycobacterium tuberculosis causes tuberculosis, and Streptococcus pneumoniae causes pneumonia, none of which are related to anthrax. Therefore, based on the specific pathogen responsible for anthrax, Bacillus anthracis is the correct answer.
The term used to describe an inflammation of the saclike membrane surrounding the heart is:
- A. peritonitis
- B. pericarditis
- C. myocardial infarction
- D. anemia
Correct Answer: B
Rationale: The correct answer is B: pericarditis. Pericarditis refers to inflammation of the pericardium, the sac-like membrane surrounding the heart. This condition can cause chest pain, fever, and other symptoms related to the heart. Peritonitis (A) is inflammation of the peritoneum, not the pericardium. Myocardial infarction (C) is a heart attack caused by a blockage in the coronary arteries, not inflammation of the pericardium. Anemia (D) is a condition characterized by a deficiency of red blood cells or hemoglobin, not related to inflammation of the pericardium.