Which of the following have a fecal oral route of transmission?

Correct Answer: B

Rationale: The correct answer is B: Typhoid fever. Typhoid fever is transmitted through the fecal-oral route, meaning the bacteria from an infected person's feces can contaminate food or water and then be ingested by another person. This can lead to infection and illness. The other choices, diphtheria (A), syphilis (C), and spotted fever (D) are not transmitted through the fecal-oral route. Diphtheria is spread through respiratory droplets, syphilis is primarily sexually transmitted, and spotted fever is transmitted through tick bites. Thus, only Typhoid fever aligns with the fecal-oral route of transmission.

Correct Answer: A

Rationale: The correct serological test for diagnosing toxoplasmosis is the Complement Binding Assay (A) because it detects antibodies specific to the Toxoplasma gondii parasite. This test is highly sensitive and specific for toxoplasmosis. Choice B, Precipitation test, is not used for toxoplasmosis diagnosis but rather for other diseases like syphilis. Choice C, Neutralization test, is not specific for toxoplasmosis and is used for other types of infections. Choice D, Widal's test, is used for diagnosing typhoid fever and is not relevant for toxoplasmosis. In summary, the correct answer (A) is specific to toxoplasmosis, while the other choices are used for different diseases and are not suitable for diagnosing toxoplasmosis.

Correct Answer: A

Rationale: The correct answer is A: Bordetella pertussis. This bacterium is known for causing whooping cough due to its ability to produce toxins that damage the respiratory tract, leading to severe coughing fits. Clostridium tetani causes tetanus, Haemophilus influenzae can cause respiratory infections but not whooping cough, and Staphylococcus aureus is more commonly associated with skin infections. Therefore, A is the correct choice based on its specific association with the disease in question.

Correct Answer: C

Rationale: The correct answer is C: Gram-positive rod-shaped bacteria. Listeria monocytogenes is a Gram-positive bacterium, as it retains the crystal violet stain during the Gram staining process. The bacteria are rod-shaped, not spherical. Choice A is incorrect as Listeria monocytogenes is not Gram-negative. Choice D is incorrect as Listeria monocytogenes does fall under the category of Gram-positive bacteria. The key is to remember the characteristics of Listeria monocytogenes, which are Gram-positive and rod-shaped.

Correct Answer: B

Rationale: The correct answer is B: Endoplasmic reticulum. Prokaryotic cells lack membrane-bound organelles like the endoplasmic reticulum, which is present in eukaryotic cells. Prokaryotes do possess ribosomes for protein synthesis (A), a chromosome (C) for genetic material, and peptidoglycan (D) in their cell walls. The absence of endoplasmic reticulum is a key characteristic that distinguishes prokaryotic cells from eukaryotic cells.

Correct Answer: C

Rationale: The correct answer is C: Thermophiles. Thermophiles are bacteria that thrive in high temperatures, typically between 45-80 degrees Celsius. They have adapted to extreme heat environments and have enzymes that function optimally at high temperatures. Mesophiles (A) grow best at moderate temperatures, Psychrophiles (B) thrive in cold temperatures, and Halophiles (D) thrive in high salt concentrations. Therefore, only Thermophiles are specifically adapted to high temperatures, making it the correct choice.

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.

Correct Answer: A

Rationale: Step 1: Definition - A codon is a sequence of three nucleotides that code for a specific amino acid or signal the start/stop of protein synthesis. Step 2: Function - Codons are essential for translating genetic information into proteins. Step 3: Specificity - Codons are specific in their role of encoding amino acids. Step 4: Examples - Examples like AUG for methionine and UAA, UAG, UGA for stop codons illustrate codon functionality. Step 5: Summary - The correct answer is A (Codon) because it accurately describes the function and specificity of a three-nucleotide sequence in genetic coding. Choices B, C, and D are incorrect as they do not align with the definition and function of a codon.

Correct Answer: A

Rationale: The correct answer is A: Itraconazole. Itraconazole is an antifungal medication commonly used to treat candidosis. It works by inhibiting the synthesis of ergosterol, a key component of fungal cell membranes. This action disrupts the integrity of the fungal cell membrane, leading to cell death. Griseofulvin (B) is primarily used to treat fungal infections of the skin and nails, not mucous membranes. Nitrofungin (C) is not commonly used for candidosis treatment. Amphotericin (D) is a potent antifungal medication but is typically reserved for severe or systemic fungal infections due to its potential side effects.