Nursing Elites

1. The resolution of an optical instrument, like a microscope, refers to its ability to distinguish between:

• A. Different colors of light
• B. The presence or absence of light
• C. Variations in intensity
• D. Very close, nearly identical objects

Correct answer: D

Rationale: The resolution of an optical instrument, such as a microscope, refers to its ability to distinguish between very close, nearly identical objects. This is crucial in microscopy to clearly visualize and differentiate fine details and structures. Resolving power plays a significant role in determining the quality and effectiveness of an optical instrument. Choices A, B, and C are incorrect because the resolution of an optical instrument does not primarily deal with different colors of light, presence or absence of light, or variations in intensity. Instead, it specifically focuses on the instrument's ability to differentiate between objects that are very close and nearly identical in nature.

2. Which statement is true regarding the process of digestion?

• A. Digestion of starch begins in the mouth.
• B. Amylase is produced by the stomach to help break down food in the upper intestine.
• C. The di- and tri-saccharides produced in early digestion are absorbed through the intestinal wall.
• D. Proteases are responsible for breaking down starches.

Correct answer: A

Rationale: The statement 'Digestion of starch begins in the mouth' is correct. Salivary amylase, an enzyme produced in the salivary glands, initiates the breakdown of starch into simpler sugars like maltose in the mouth before further digestion in the stomach. This initial breakdown of starch is crucial in the digestion of carbohydrates, marking the beginning of the digestive process. Choice B is incorrect because amylase is produced in the salivary glands, not the stomach. Choice C is incorrect because di- and tri-saccharides are further broken down into monosaccharides before absorption. Choice D is incorrect because proteases are enzymes that break down proteins, not starches.

3. Which of the following is not part of the digestive system?

• A. Esophagus
• B. Liver
• C. Stomach
• D. Pancreas

Correct answer: D

Rationale: The correct answer is 'D: Pancreas.' While the pancreas contributes to digestion by secreting enzymes, it is not part of the main digestive tract. The esophagus, liver, and stomach are integral components of the digestive system. The esophagus helps in the transport of food to the stomach, the stomach aids in food breakdown, the liver produces bile for fat digestion, and the pancreas secretes digestive enzymes. Therefore, the pancreas is the correct answer as it is not part of the primary digestive tract but supports digestion through enzyme secretion.

4. Most catalysts found in biological systems are which of the following?

• A. Special lipids called cofactors.
• B. Special proteins called enzymes.
• C. Special lipids called enzymes.
• D. Special proteins called cofactors.

Correct answer: B

Rationale: Enzymes are special proteins that act as catalysts in biological systems. They accelerate chemical reactions by lowering the activation energy required for the reaction to occur. Enzymes play a critical role in the regulation of metabolic pathways and are essential for various biological processes. While some enzymes may require cofactors for activity, the enzymes themselves are the catalysts in biological systems. Therefore, choice B, special proteins called enzymes, is the most suitable answer. Choices A, C, and D are incorrect because enzymes, not lipids, are the primary catalysts in biological systems.

5. Which property of a substance refers to its ability to undergo a chemical change and form new substances?

• A. Density
• B. Mass
• C. Reactivity
• D. Volume

Correct answer: C

Rationale: Reactivity is the property of a substance that describes its ability to undergo a chemical change and form new substances through chemical reactions. Density, mass, and volume are physical properties of a substance and do not directly relate to its ability to undergo chemical changes. Density is the mass of a substance per unit volume, mass is the amount of matter present, and volume is the amount of space occupied by the substance. Reactivity specifically deals with how likely a substance is to engage in chemical reactions. Therefore, the correct answer is C - Reactivity.

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