Nursing Elites

1. Which molecules are soluble in nonpolar solvents but are hydrophobic?

• A. Carbohydrates
• B. Lipids
• C. Proteins
• D. Nucleic acids

Correct answer: B

Rationale: Lipids are hydrophobic molecules that are soluble in nonpolar solvents like oils but insoluble in water. They consist of fats, oils, waxes, and steroids and play essential roles in energy storage, insulation, and cell membrane structure. Carbohydrates, proteins, and nucleic acids are not typically soluble in nonpolar solvents and do not exhibit the same hydrophobic characteristics as lipids. Carbohydrates are usually hydrophilic and soluble in water, proteins have both hydrophilic and hydrophobic regions but are not generally soluble in nonpolar solvents, and nucleic acids are polar molecules that are not known for their solubility in nonpolar solvents.

2. A substance is only considered acidic if it has a pH less than what?

• A. 12
• B. 9
• C. 7
• D. 4

Correct answer: C

Rationale: A substance is considered acidic if its pH is less than 7. pH values below 7 indicate acidity, while pH values above 7 indicate alkalinity or basicity. Substances with a pH less than 7 are categorized as acidic, not above it. Therefore, a substance is classified as acidic if its pH is less than 7, making choice C the correct answer. Choices A, B, and D are incorrect because a pH of 12, 9, and 4, respectively, are all above 7, and therefore not indicative of acidity.

3. What is the process of making copies of DNA called?

• A. Transcription
• B. Translation
• C. Replication
• D. DNA repair

Correct answer: C

Rationale: A) Transcription is the process of synthesizing RNA from a DNA template. It involves the creation of mRNA molecules from a DNA template. B) Translation is the process of synthesizing proteins from mRNA. During translation, the genetic code carried by mRNA is decoded to produce a specific sequence of amino acids, forming a protein. C) Replication is the process of making copies of DNA. This process occurs before cell division and ensures that each daughter cell receives an identical copy of the genetic material. D) DNA repair is a cellular mechanism that corrects errors in DNA that arise due to various factors such as exposure to mutagens or mistakes during DNA replication. It is essential for maintaining the integrity of the genetic material.

4. How does the respiratory system facilitate gas exchange between air and blood?

• A. Diffusion
• B. Exhalation
• C. Inspiration
• D. Ventilation

Correct answer: A

Rationale: The correct answer is 'Diffusion.' Diffusion is the process by which gases are exchanged between air in the alveoli and blood in the capillaries. Oxygen moves from the alveoli into the blood, while carbon dioxide moves from the blood into the alveoli through diffusion. Exhalation is the process of expelling air from the lungs, inspiration is the process of inhaling air into the lungs, and ventilation refers to the overall movement of air in and out of the lungs. While these processes are essential for the respiratory system to function, they are not directly responsible for the gas exchange between air and blood, which is primarily achieved through diffusion.

5. What is the primary function of the liver in the digestive system?

• A. To absorb water
• B. To produce bile
• C. To store glucose
• D. To regulate metabolism

Correct answer: B

Rationale: The liver's main function in the digestive system is to produce bile. Bile helps in the digestion and absorption of fats by emulsifying them, breaking down large fat globules into smaller droplets that can be acted upon by digestive enzymes. Choices A, C, and D are incorrect because the liver's primary role in the digestive system is not to absorb water, store glucose, or regulate metabolism. While the liver does have roles in metabolism and glucose regulation, its key function in digestion is bile production.

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