Nokea
The presence of flagella in bacterial cell represents:
- A. H-antigen
- B. O-antigen
- C. K-antigen
- D. None of the above
Correct Answer: A
Rationale: The presence of flagella in a bacterial cell represents the H-antigen. Flagella are protein structures on the cell surface that play a role in bacterial motility. The H-antigen refers to the flagellar antigen, which is involved in immune responses and bacterial identification. Option A is correct because flagella are specifically associated with the H-antigen.
Summarily, choices B and C are incorrect because the O-antigen and K-antigen are associated with lipopolysaccharide and capsule antigens, respectively, not flagella. Option D is incorrect as well because the correct association is with the H-antigen.
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Gram (+) bacteria ... MG-ribonucleate and Mg. deoxyribonucleate in:
- A. Proportion 4:1
- B. Proportion 2:1
- C. Proportion 8:1
- D. Proportion 1:1
Correct Answer: A
Rationale: The correct answer is A, proportion 4:1. Gram (+) bacteria have a higher ratio of MG-ribonucleate to Mg. deoxyribonucleate because ribosomal RNA is more abundant in actively growing bacterial cells. This higher proportion of MG-ribonucleate to Mg. deoxyribonucleate is essential for protein synthesis and growth. The other choices are incorrect because they do not reflect the higher ratio of ribosomal RNA to DNA in Gram (+) bacteria, which is crucial for their metabolic activities and cellular functions.
Which of the following bacteria is known for causing pneumonia?
- A. Streptococcus pneumoniae
- B. Mycobacterium tuberculosis
- C. Escherichia coli
- D. Pseudomonas aeruginosa
Correct Answer: A
Rationale: The correct answer is A: Streptococcus pneumoniae. This bacteria is known for causing pneumonia due to its ability to infect the lungs and cause inflammation leading to pneumonia symptoms. It is a common cause of community-acquired pneumonia. Mycobacterium tuberculosis (B) causes tuberculosis, not pneumonia. Escherichia coli (C) is associated with urinary tract infections and gastrointestinal infections, not pneumonia. Pseudomonas aeruginosa (D) is known to cause infections in immunocompromised individuals but is not a common cause of pneumonia.
A patient with diarrhea had stool culture revealing non-lactose-fermenting, Gram-negative rods. The bacteria produced gas in a nutrient broth. What is the most likely causative agent?
- A. Salmonella typhi
- B. Shigella dysenteriae
- C. Escherichia coli
- D. Proteus vulgaris
Correct Answer: D
Rationale: The correct answer is D: Proteus vulgaris. Non-lactose-fermenting, Gram-negative rods that produce gas in a nutrient broth are characteristic of Proteus species. Proteus vulgaris is known for its swarming motility and ability to produce hydrogen sulfide gas. Salmonella typhi and Shigella dysenteriae are Enterobacteriaceae that do not produce gas in a nutrient broth. Escherichia coli is a lactose-fermenting bacterium and would not be expected to produce gas in a nutrient broth.
The term used to indicate the extent to which a drug reaches its site of action is:
- A. bioactivity
- B. bioavailability
- C. bioremediation
- D. biostasis
Correct Answer: B
Rationale: The correct answer is B: bioavailability. Bioavailability refers to the extent and rate at which a drug reaches its site of action in the body. This includes factors such as absorption, distribution, metabolism, and excretion.
Rationale:
1. Bioactivity refers to the pharmacological effect of a drug, not how effectively it reaches its site of action.
2. Bioremediation is the process of using organisms to remove or neutralize pollutants, not related to drug delivery.
3. Biostasis refers to a state of equilibrium or balance in living organisms, not related to drug transport to its site of action.
In summary, bioavailability is the most appropriate term as it specifically addresses the process of a drug reaching its intended target within the body, distinguishing it from the other choices.
The United Nations estimates that by the year 2050 more than __________ of the world’s population will live in urban areas.
- A. 35%
- B. 56%
- C. 60%
- D. 69%
Correct Answer: D
Rationale: The correct answer is D (69%). The UN projects that by 2050, around 69% of the world's population will live in urban areas. This is based on current global urbanization trends and population growth rates. Urban areas are experiencing rapid population growth due to factors like rural-to-urban migration and natural population increase. Choices A, B, and C are incorrect because they underestimate the expected urban population growth by 2050. A (35%), B (56%), and C (60%) are too low compared to the projected 69%. Urbanization is a significant global trend, and it is essential to consider the implications of this shift for sustainability, infrastructure development, and resource allocation.