Nursing Elites

1. What is the function of introns in eukaryotic genes?

• A. They code for protein sequences.
• B. They are involved in gene regulation.
• C. They are removed during mRNA processing.
• D. They are non-functional remnants of ancient DNA.

Correct answer: C

Rationale: A) Introns do not code for protein sequences. Exons are the segments of DNA that code for proteins. B) While introns can indirectly influence gene regulation, their primary function is not directly involved in gene regulation. C) Introns are non-coding regions of DNA that are transcribed into pre-mRNA but are removed during mRNA processing through a process called splicing. This allows only the exons to be included in the mature mRNA that will be translated into proteins. D) While introns were once thought to be non-functional remnants of ancient DNA, research has shown that they can have regulatory functions and play a role in gene expression.

2. What is the difference between a phylum and a class?

• A. Phylums are broader and more general
• B. Classes are broader and more general
• C. They are synonyms, used for the same groups
• D. Phylums are for plants, classes are for animals

Correct answer: A

Rationale: In biological classification, a phylum is a higher taxonomic rank than a class. A phylum is a broader category that encompasses multiple classes within it. It represents a group of organisms sharing a common body plan or evolutionary history. On the other hand, a class is a more specific category within a phylum that includes organisms with similar characteristics. Therefore, phyla are broader and more general compared to classes. Choice B is incorrect because classes are more specific categories within phyla. Choice C is incorrect as phyla and classes are distinct hierarchical levels in taxonomy. Choice D is incorrect because phyla and classes are not restricted to specific types of organisms; they can apply to various organisms across the biological kingdom.

3. Which of the following can weaken the immune system and increase susceptibility to infections?

• A. Regular exercise
• B. Balanced diet
• C. Chronic stress
• D. Adequate sleep

Correct answer: C

Rationale: Chronic stress can weaken the immune system by increasing the production of stress hormones like cortisol, which can suppress the immune response. This suppression can make individuals more susceptible to infections and illnesses. Conversely, regular exercise, a balanced diet, and adequate sleep actually support a healthy immune system and help strengthen it. Choices A, B, and D are incorrect as they are factors that generally contribute positively to the immune system. Regular exercise, a balanced diet, and adequate sleep are crucial for maintaining overall health and boosting the immune system rather than weakening it.

4. Which property of matter measures the amount of space occupied by an object?

• A. Mass
• B. Density
• C. Weight
• D. Volume

Correct answer: D

Rationale: Volume is the property of matter that measures the amount of space occupied by an object. Mass refers to the amount of matter in an object, weight is the force of gravity acting on an object, and density is the mass of an object per unit volume. Volume specifically quantifies the space occupied by an object, making it the correct answer in this context.

5. Which type of epithelium lines the inner surface of the oral cavity, providing a barrier against external insults?

• A. Simple squamous epithelium
• B. Stratified squamous epithelium
• C. Simple columnar epithelium
• D. Pseudostratified columnar epithelium

Correct answer: B

Rationale: The oral cavity is constantly exposed to mechanical stress and potential injury from food particles and other external factors. To protect against these insults, a strong and resilient epithelium is needed. Stratified squamous epithelium is the best choice for lining the oral cavity due to its multiple layers of cells. This type of epithelium provides a robust barrier that can withstand abrasion and protect the underlying tissues. Simple squamous epithelium (choice A) is too thin and not suitable for a protective function. Simple columnar epithelium (choice C) is more suited for absorption and secretion functions, not protection against mechanical stress. Pseudostratified columnar epithelium (choice D) is found in respiratory passages and functions in mucociliary clearance, not in providing a protective barrier against external insults in the oral cavity.

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