Nursing Elites

1. A car skids on a wet road. What is the main force preventing the car from stopping?

• A. Friction
• B. Gravitational force
• C. Normal force from the road
• D. Air resistance

Correct answer: A

Rationale: The correct answer is A: Friction. Friction is the force that opposes the motion of the car on the wet road surface, making it harder for the car to stop. When the car skids, the friction between the tires and the wet road surface is reduced, leading to a loss of traction and making it challenging for the car to come to a halt. Gravitational force (choice B) is the force that pulls objects toward each other due to gravity and does not directly impact the car's ability to stop on a wet road. The normal force from the road (choice C) is the force exerted by the road surface perpendicular to the car's tires and does not play a significant role in stopping the car. Air resistance (choice D) is the force that opposes the motion of an object through the air, but it is not the main force preventing the car from stopping on a wet road.

2. 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.

3. What is the process of converting simple sugars into complex carbohydrates called?

• A. Glycolysis
• B. Gluconeogenesis
• C. Krebs cycle
• D. Oxidative phosphorylation

Correct answer: B

Rationale: Gluconeogenesis is the correct answer. It is the process of synthesizing glucose from non-carbohydrate sources, such as amino acids or glycerol. A) Glycolysis is the process of breaking down glucose into pyruvate to produce energy. C) The Krebs cycle, also known as the citric acid cycle, generates energy through the oxidation of acetyl-CoA derived from carbohydrates, fats, and proteins. D) Oxidative phosphorylation is the final stage of cellular respiration where ATP is produced using energy derived from the electron transport chain. Therefore, choices A, C, and D are not the processes involved in converting simple sugars into complex carbohydrates.

4. Isotopes are variants of a single element that differ in:

• A. Having the same number of protons but varying numbers of neutrons
• B. Having the same number of neutrons but varying numbers of protons
• C. Having the same mass but different atomic numbers
• D. None of the above

Correct answer: A

Rationale: Isotopes are variants of a single element that have the same number of protons, the defining characteristic of an element. They differ in the number of neutrons they possess, leading to isotopes having different atomic masses while retaining the same chemical properties. Choice B is incorrect because isotopes have the same number of neutrons and differ in the number of protons. Choice C is incorrect because isotopes have different masses due to varying numbers of neutrons, not different atomic numbers. Choice D is incorrect as isotopes do differ in the number of neutrons they possess.

5. What type of intermolecular force is responsible for the high surface tension of water?

• A. Hydrogen bonding
• B. London dispersion forces
• C. Ionic bonding
• D. Metallic bonding

Correct answer: A

Rationale: The high surface tension of water is primarily due to the strong hydrogen bonding between water molecules. Hydrogen bonding is a specific type of intermolecular force that occurs between a hydrogen atom covalently bonded to a highly electronegative atom, like oxygen in water, and another electronegative atom nearby. This unique interaction results in a strong attraction between water molecules at the surface, leading to the cohesive forces responsible for the high surface tension of water. Choices B, C, and D are incorrect because London dispersion forces, ionic bonding, and metallic bonding do not account for the high surface tension observed in water. London dispersion forces are relatively weaker intermolecular forces, while ionic and metallic bonding are types of intramolecular forces that do not directly contribute to the surface tension of water.

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