Nursing Elites

1. What macromolecules are proteins that speed up chemical reactions and act as biological catalysts?

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

Correct answer: B

Rationale: Enzymes are proteins that act as biological catalysts, speeding up chemical reactions without being consumed in the process. Lipids, carbohydrates, and nucleic acids do not serve as proteins that function as catalysts; they have different biological roles. Lipids are primarily used for energy storage, structural components, and signaling molecules. Carbohydrates are mainly for energy storage and providing structural support. Nucleic acids are involved in genetic information storage and transfer. Therefore, the correct answer is B: Enzymes.

2. What is the process of combining two or more substances to form a heterogeneous mixture called?

• A. Dissolving
• B. Diluting
• C. Mixing
• D. Reacting

Correct answer: C

Rationale: The correct answer is 'Mixing.' When substances are combined, a heterogeneous mixture is formed where the components are physically distinguishable. 'Dissolving' (Choice A) is the process of a solute becoming uniformly dispersed in a solvent to form a solution, not a heterogeneous mixture. 'Diluting' (Choice B) refers to reducing the concentration of a solute in a solution. 'Reacting' (Choice D) involves a chemical change where substances interact to form new products, rather than just physically mixing to form a heterogeneous mixture.

3. What is the name for the sac-shaped structures in which carbon dioxide and oxygen exchange takes place?

• A. Kidneys
• B. Medulla oblongata
• C. Alveoli
• D. Bronchioles

Correct answer: C

Rationale: The alveoli are the tiny sac-shaped structures in the lungs where gas exchange occurs. Oxygen from the air we breathe diffuses into the bloodstream through the alveoli, while carbon dioxide, a waste product produced by cells, is removed from the blood and exhaled out of the body through the alveoli. Choices A, B, and D are incorrect. Kidneys are organs responsible for filtering waste from the blood, the medulla oblongata is a part of the brain responsible for autonomic functions, and bronchioles are smaller airway passages in the lungs that branch off from the bronchi.

4. After a person eats birthday cake, which of the following enzymes is needed to break down the sucrose in the cake?

• A. Lactase
• B. Maltase
• C. Peptidase
• D. Sucrase

Correct answer: D

Rationale: Sucrase is the correct enzyme needed to break down sucrose into its component sugars, glucose, and fructose. Lactase is responsible for breaking down lactose, maltase for maltose, and peptidase for proteins; therefore, they are not the enzymes required to digest sucrose specifically. In the context of digesting birthday cake, which contains sucrose, sucrase is the enzyme needed for this particular sugar.

5. What type of energy is stored in food?

• A. Mechanical energy
• B. Kinetic energy
• C. Chemical potential energy
• D. Thermal energy

Correct answer: C

Rationale: Food stores energy in the form of chemical potential energy. This energy is released during digestion and metabolism to provide the body with the energy it needs to function. It is derived from the bonds within the molecules of food, such as carbohydrates, fats, and proteins. Choice A, mechanical energy, is incorrect as food does not store energy in the form of mechanical energy. Choice B, kinetic energy, is incorrect as kinetic energy is associated with the motion of objects, not stored in food. Choice D, thermal energy, is incorrect as thermal energy relates to heat energy, which is not the primary form of energy stored in food.

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