Nursing Elites

1. What is the role of transfer RNA (tRNA) in protein synthesis?

• A. Transcribes DNA into mRNA
• B. Decodes the genetic code on mRNA
• C. Carries specific amino acids to the ribosomes
• D. Modifies the structure of proteins

Correct answer: C

Rationale: A) Transcribes DNA into mRNA: This is the function of RNA polymerase, not transfer RNA (tRNA). tRNA is involved in protein synthesis, not transcription. B) Decodes the genetic code on mRNA: This is the function of tRNA during translation. tRNA molecules carry specific amino acids and recognize the codons on mRNA, ensuring the correct amino acid is added to the growing polypeptide chain. C) Carries specific amino acids to the ribosomes: This is the primary role of tRNA in protein synthesis. Each tRNA molecule is specific for a particular amino acid and carries it to the ribosome, where it is added to the growing protein chain. D) Modifies the structure of proteins: This is not a function of tRNA. Protein modification can occur after translation is complete and involves other cellular processes and molecules.

2. Which of the following structures is found in the nucleus of a cell?

• A. Mitochondria
• B. Endoplasmic reticulum
• C. Chromosomes
• D. Ribosomes

Correct answer: C

Rationale: Chromosomes, which contain genetic information, are found in the nucleus of a cell. They play a crucial role in cell division, gene expression, and inheritance. Mitochondria, responsible for energy production, are located in the cytoplasm, not the nucleus. The endoplasmic reticulum is mainly involved in protein and lipid synthesis and is not a component of the nucleus. Ribosomes, essential for protein synthesis, are found in the cytoplasm and on the endoplasmic reticulum, but not in the nucleus.

3. Which vitamin is produced when the skin is exposed to sunlight?

• A. Vitamin A
• B. Vitamin D
• C. Vitamin K
• D. Vitamin E

Correct answer: B

Rationale: Vitamin D is the correct answer. When the skin is exposed to sunlight, it triggers a process where a form of cholesterol in the skin is converted into vitamin D. This vitamin plays a crucial role in aiding calcium absorption in the gut, which is essential for maintaining strong and healthy bones. Vitamin A (Choice A) is important for vision and immune function but is not produced by sunlight exposure. Vitamin K (Choice C) is known for its role in blood clotting and bone metabolism, but it is not produced by sunlight. Vitamin E (Choice D) is an antioxidant that protects cells from damage but is not synthesized in the skin through sunlight exposure.

4. Which structure in the respiratory system serves as the 'windpipe' that conducts air from the larynx to the bronchi?

• A. Trachea
• B. Larynx
• C. Bronchi
• D. Alveoli

Correct answer: A

Rationale: The correct answer is the trachea. The trachea, commonly referred to as the 'windpipe,' is a vital structure in the respiratory system that connects the larynx to the bronchi. It is made up of cartilage rings that provide structural support, preventing collapse and ensuring the unobstructed flow of air into the lungs. The trachea plays a crucial role in facilitating the passage of air from the upper respiratory tract to the lower respiratory tract. The larynx is responsible for sound production and is located above the trachea. The bronchi are the two main branches that lead from the trachea into the lungs, further branching into smaller airways. Alveoli are the tiny air sacs where gas exchange occurs in the lungs, but they are not the structure that serves as the 'windpipe' for air passage in the respiratory system.

5. How does the potential energy of an object change when it is compressed?

• A. Potential energy decreases
• B. Potential energy increases
• C. Potential energy remains constant
• D. Potential energy becomes zero

Correct answer: B

Rationale: When an object is compressed, its potential energy increases. This is because work is done on the object to compress it, resulting in an increase in potential energy stored in the object as it is compressed against an opposing force. The potential energy is transformed and stored within the object due to the work done during the compression process, leading to an increase in its potential energy. Choice A is incorrect because compression involves doing work on the object, increasing its potential energy. Choice C is incorrect because compression involves a change in position and potential energy. Choice D is incorrect because compression does not reduce potential energy to zero; rather, it increases it due to the work done in compressing the object.

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