Nursing Elites

1. What is the main function of valence electrons in chemical bonding?

• A. They are responsible for holding the nucleus together.
• B. They are involved in forming bonds with other atoms.
• C. They determine the element's physical properties.
• D. They play no role in chemical reactions.

Correct answer: B

Rationale: They are involved in forming bonds with other atoms. Valence electrons occupy the outermost energy level and are readily involved in attracting other atoms through sharing or transferring electrons, forming chemical bonds.

2. What is the net ionic equation for the reaction: 2HCl(aq) + Ba(OH)2(aq) → 2H2O(l) + BaCl2(aq)?

• A. 2H+(aq) + 2OH-(aq) → 2H2O(l)
• B. 2HCl(aq) + Ba(OH)2(aq) → BaCl2(aq) + 2H2O(l)
• C. 2H+(aq) + Ba2+(aq) → Ba2+(aq) + 2H+(aq)
• D. Ba(OH)2(aq) + HCl(aq) → BaCl2(aq) + 2H2O(l)

Correct answer: a

Rationale: The net ionic equation includes only the species that undergo a change during the reaction.

3. What is the role of RNA in the regulation of gene expression?

• A. Provides energy for the process
• B. Controls the timing and location of protein synthesis
• C. Translates the genetic code into amino acids
• D. Stores genetic information

Correct answer: B

Rationale: Rationale: A) RNA does not provide energy for the process of gene expression. Energy is typically provided by molecules like ATP. B) RNA plays a crucial role in controlling the timing and location of protein synthesis through processes like transcriptional regulation, RNA splicing, and post-transcriptional modifications. It helps determine when and where specific proteins are produced in the cell. C) While mRNA translates the genetic code into amino acids during the process of translation, this is not the primary role of RNA in the regulation of gene expression. D) RNA does not store genetic information in the same way that DNA does. DNA is the molecule responsible for storing genetic information in the form of genes. Therefore, option B is the most appropriate choice as it accurately describes the role of RNA in regulating gene expression.

4. Which of the following is NOT a type of chemical bond?

• A. Ionic bond
• B. Covalent bond
• C. Metallic bond
• D. Gravitational bond

Correct answer: D

Rationale: Although gravity exists, it's not considered a chemical bond responsible for holding atoms together within molecules.

5. The muscular tube connecting the mouth to the stomach is lined with a mucous membrane. What is the main function of this mucous membrane?

• A. Secretion of digestive enzymes
• B. Absorption of nutrients
• C. Lubrication and protection
• D. Storage of bile

Correct answer: C

Rationale: The correct answer is C: Lubrication and protection. The mucous membrane lining the esophagus serves to provide lubrication for food as it travels from the mouth to the stomach, making it easier to swallow. Additionally, the mucous membrane protects the esophageal tissue from damage caused by the passage of food and liquids. This function is crucial in preventing irritation and inflammation of the esophagus, ensuring smooth and efficient digestion process. The mucous membrane does not secrete digestive enzymes (A), absorb nutrients (B), or store bile (D), as those functions are carried out by other digestive organs.

6. When a blockage forms in a coronary artery, reducing blood flow to the heart muscle, this condition is called:

• A. Atherosclerosis
• B. Myocardial infarction
• C. Angina pectoris
• D. Heart murmur

Correct answer: C

Rationale: The correct answer is C: "Angina pectoris." Angina pectoris is the condition that occurs when there is a blockage in a coronary artery, leading to reduced blood flow to the heart muscle. This decreased blood flow can cause chest pain or discomfort, typically during physical exertion or stress. Atherosclerosis (option A) is the buildup of plaque in the artery walls, which can lead to blockages. Myocardial infarction (option B) refers to a heart attack, which occurs when there is a complete blockage in a coronary artery resulting in damage to the heart muscle. A heart murmur (option D) is an abnormal sound heard during the heartbeat, not directly related to a blockage in a coronary artery. Therefore, the correct term for a blockage in a coronary artery that reduces blood flow to the heart muscle is angina pectoris.

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