Which of the following statements is true regarding polio vaccines:

Correct Answer: A

Rationale: The correct answer is A: Salk and Sabin vaccines are vaccines against polio. Both Salk and Sabin vaccines are indeed vaccines specifically developed to prevent polio. The Salk vaccine is an inactivated polio vaccine, while the Sabin vaccine is an oral live attenuated vaccine. Therefore, choice B is incorrect as the Sabin vaccine is live attenuated, not inactivated. Choice C is also incorrect because the Salk vaccine is inactivated, not live attenuated. Choice D is incorrect because not all statements are true; only statement A is accurate.

Correct Answer: C

Rationale: The correct answer is C, Meat-peptone agar, as it provides a simple nutritive media for bacterial growth. This agar contains meat extract and peptone, which are good sources of nutrients for bacterial growth. Glucose broth (A) is a liquid medium with glucose but lacks other essential nutrients. Ascites (serum) agar (B) is a selective medium used for detecting pathogens in clinical samples. Blood agar (D) is a differential medium used to distinguish different types of bacteria based on hemolytic reactions. Meat-peptone agar is the simplest and most general-purpose medium among the options provided.

Correct Answer: A

Rationale: The correct answer is A: Shigella dysenteriae. It is the likely causative agent because it is a non-lactose-fermenting, Gram-negative rod commonly associated with severe diarrhea. Shigella dysenteriae specifically causes bacillary dysentery. Other choices are incorrect because: B: Escherichia coli is a lactose-fermenting bacterium commonly found in the gut and not typically associated with severe diarrhea. C: Salmonella typhi causes typhoid fever, not severe diarrhea. D: Proteus mirabilis is a urease-positive bacterium associated with urinary tract infections, not severe diarrhea.

Correct Answer: A

Rationale: The correct answer is A: Ciprofloxacin. Pseudomonas aeruginosa is commonly resistant to Ampicillin, Cefazolinum, and Azithromycin. Ciprofloxacin is a fluoroquinolone antibiotic known for its efficacy against Pseudomonas aeruginosa. Its broad spectrum and ability to penetrate tissues make it the most advisable choice for treating secondary obstructive pyelonephritis caused by this pathogen.

Correct Answer: B

Rationale: The central dogma of molecular biology, which describes the flow of genetic information from DNA to RNA to proteins, was first proposed by Francis Crick. Crick, along with James Watson, discovered the structure of DNA in 1953, leading to the understanding of how genetic information is stored and transmitted. Ernst Ruska was a physicist who developed the electron microscope, not related to genetic information flow. Camillo Golgi was an Italian biologist known for the discovery of the Golgi apparatus, not central to the central dogma. Carl Bender is not a prominent figure in the field of molecular biology. In summary, Francis Crick is the correct answer as he played a pivotal role in introducing the central dogma of molecular biology.

Correct Answer: B

Rationale: I apologize for the confusion, but the correct answer to the question is actually A: microtubules. Microtubules are indeed shaped like hollow cylinders made out of tubulin proteins. They play a crucial role in cell structure, cell division, and intracellular transport. Microfilaments (choice B) are composed of actin proteins and are not shaped like hollow cylinders. Intermediate filaments (choice C) are more rope-like in structure and are made up of various proteins. Flagella (choice D) are whip-like structures used for cell movement and are not shaped like hollow cylinders.

Correct Answer: B

Rationale: The correct answer is B: Tuberculosis and mycobacterioses. Mycobacterium tuberculosis, the causative agent of tuberculosis, and other mycobacteria can survive in the soil for extended periods. Here's the rationale: 1. Mycobacteria have a waxy cell wall that provides resistance to harsh environmental conditions. 2. The slow growth rate of mycobacteria allows them to persist in the soil for long periods. 3. Tuberculosis and mycobacterioses are known to be transmitted through environmental exposure, including soil. 4. Colibacillosis and cholera (Choice C) are caused by enteric bacteria that do not survive well in soil. 5. Leptospirosis and plague (Choice D) are bacterial diseases transmitted through animal hosts and are not known to be soil-borne.

Correct Answer: A

Rationale: The correct answer is A: spleen. The spleen is not a component of the gastrointestinal tract; it is part of the lymphatic system. The pharynx, esophagus, and stomach are all part of the gastrointestinal tract responsible for digestion and absorption of food. The spleen's main functions include filtering blood, storing blood cells, and supporting the immune system, making it unrelated to the digestive process.

Correct Answer: B

Rationale: The correct answer is B: Cholera. Cholera is caused by Gram-negative curved rod-like bacteria called Vibrio cholerae, commonly found in contaminated water or food. The characteristic symptom of cholera is profuse watery diarrhea, which matches the patient's presentation. Typhoid fever (A) is caused by Salmonella typhi, which is not a curved rod-like bacteria. Diphtheria (C) is caused by Corynebacterium diphtheriae, a Gram-positive bacterium, and does not typically cause diarrhea. Intestinal form of plague (D) is caused by Yersinia pestis, which is not a curved rod-like bacteria and does not typically present with diarrhea.