Nursing Elites

1. Which of the following is the cytoplasmic organelle that contains fluid-filled tubules for carrying and transporting substances?

• A. Endoplasmic reticulum
• B. Golgi apparatus
• C. Mitochondria
• D. Nucleus

Correct answer: A

Rationale: The endoplasmic reticulum is the correct answer. It is the cytoplasmic organelle that contains fluid-filled tubules responsible for carrying and transporting substances within the cell. The endoplasmic reticulum plays a crucial role in protein synthesis, lipid metabolism, and detoxification processes. The Golgi apparatus, although important in modifying, sorting, and packaging proteins for secretion or for use within the cell, does not primarily contain fluid-filled tubules for carrying and transporting substances. Mitochondria are responsible for generating ATP through cellular respiration, not for carrying and transporting substances. The nucleus contains the cell's genetic material and is involved in regulating cellular activities but does not contain fluid-filled tubules for transportation.

2. The Gram stain is a differential staining technique used to classify bacteria based on their cell wall composition. Gram-positive bacteria appear

• A. Pink
• B. Blue
• C. Red
• D. Purple

Correct answer: D

Rationale: The Gram stain is a differential staining technique that categorizes bacteria into two groups based on their cell wall composition: Gram-positive and Gram-negative. Gram-positive bacteria have a thick layer of peptidoglycan in their cell walls, which retains the crystal violet stain used in the Gram staining procedure. Consequently, Gram-positive bacteria appear purple under the microscope after staining. On the other hand, Gram-negative bacteria possess a thinner peptidoglycan layer and an outer membrane that can be penetrated by the counterstain safranin, leading them to appear pink or red. Blue is not typically used to describe the color of bacteria in a Gram stain, making it an incorrect choice.

3. What is the importance of RNA splicing?

• A. Removes introns from the mRNA molecule
• B. Adds the poly-A tail to the mRNA molecule
• C. Activates the mRNA molecule for translation
• D. Modifies the structure of the protein

Correct answer: A

Rationale: RNA splicing is a crucial process in gene expression where non-coding regions called introns are removed from the pre-mRNA molecule, and the remaining coding regions called exons are joined together to form the mature mRNA molecule. This process ensures that only the protein-coding sequences are retained in the mRNA for translation, allowing for the production of functional proteins. Therefore, option A is the correct answer as it accurately describes the importance of RNA splicing in generating mature mRNA molecules for protein synthesis. B) Adding the poly-A tail to the mRNA molecule is a post-transcriptional modification that occurs after RNA splicing and is not directly related to the process of removing introns. C) Activating the mRNA molecule for translation is typically achieved through the addition of a 5' cap and the poly-A tail, rather than through RNA splicing. D) Modifying the structure of the protein is not directly related to the process of RNA splicing, which primarily focuses on mRNA maturation by removing non-coding introns.

4. In an SN2 reaction, what affects the rate of the reaction?

• A. Only the concentration of the nucleophile
• B. Only the concentration of the electrophile
• C. Neither the concentration of the nucleophile nor the electrophile
• D. Both the concentration of the nucleophile and the electrophile

Correct answer: D

Rationale: In an SN2 reaction, the rate of the reaction is affected by both the concentration of the nucleophile and the electrophile. The rate-determining step involves the nucleophile attacking the electrophile, so the concentrations of both species will impact the reaction rate. Increasing the concentration of the nucleophile increases the frequency of nucleophilic attacks, while increasing the concentration of the electrophile provides more opportunities for the nucleophile to react. Therefore, the correct answer is that both the concentration of the nucleophile and the electrophile affect the rate of the SN2 reaction. Choices A, B, and C are incorrect as they do not consider the interplay between the nucleophile and the electrophile in determining the overall reaction rate in an SN2 mechanism.

5. Which of the following is an example of a commensal relationship between a microorganism and a human?

• A. Salmonella causing food poisoning
• B. taphylococcus aureus causing skin infections
• C. coli living in the gut
• D. Rabies virus causing neurological disease

Correct answer: C

Rationale: A commensal relationship is a type of symbiotic relationship in which one organism benefits, while the other is neither harmed nor benefited. In this case, E. coli living in the gut is an example of a commensal relationship because it can benefit from the environment in the gut without causing harm to the human host. Option A, Salmonella causing food poisoning, is an example of a pathogenic relationship where the microorganism causes harm to the host. Option B, Staphylococcus aureus causing skin infections, is also an example of a pathogenic relationship where the microorganism causes harm to the host. Option D, Rabies virus causing neurological disease, is another example of a pathogenic relationship where the microorganism causes harm to the host.

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