Nursing Elites

1. Which of the following is a constant?

• A. The number of protons in an oxygen atom
• B. The temperature at which iron ore will melt
• C. The human population size
• D. The time the sun rises each day

Correct answer: A

Rationale: The number of protons in an oxygen atom is a constant. This value is determined by the atomic number of the element and does not change regardless of the isotope of oxygen. The number of protons defines the element and remains consistent under normal conditions. Choices B, C, and D are not constants. The temperature at which iron ore will melt can vary depending on factors like pressure, the human population size is constantly changing, and the time the sun rises each day varies with the seasons and location.

2. Which of these is NOT a function of the large intestine?

• A. Absorbing water and electrolytes
• B. Producing vitamins
• C. Breaking down fiber
• D. Eliminating waste products

Correct answer: B

Rationale: A) Absorbing water and electrolytes: The large intestine plays a crucial role in absorbing water and electrolytes from the indigestible food matter that passes through it. This helps in maintaining the body's fluid balance and preventing dehydration. B) Producing vitamins: While the large intestine contains bacteria that can produce some vitamins like vitamin K and certain B vitamins, the primary site for vitamin production is the small intestine and other organs like the liver. Therefore, producing vitamins is not a primary function of the large intestine. C) Breaking down fiber: The large intestine is responsible for breaking down fiber that was not digested in the small intestine. The bacteria in the large intestine ferment fiber, producing short-chain fatty acids that can be used as an energy source by the body. D) Eliminating waste products: One of the main functions of the large intestine is to eliminate waste products, including indigestible food matter, dead cells, and bacteria, from the body in the form of feces. Therefore, the correct answer is B, as producing vitamins is not a primary function of the large intestine.

3. The critical angle is defined as the minimum angle of incidence in a denser medium for which light undergoes:

• A. Total internal reflection
• B. Continued refraction
• C. Specular reflection
• D. Increased dispersion

Correct answer: A

Rationale: The critical angle is the minimum angle of incidence in a denser medium at which light undergoes total internal reflection instead of refraction. This phenomenon occurs when light travels from a denser medium to a less dense medium, and the angle of incidence is greater than the critical angle. Total internal reflection is a crucial concept in optics and is utilized in various applications such as fiber optics and prisms. Choice B, 'Continued refraction,' is incorrect as the critical angle specifically marks the point at which total internal reflection occurs, not continued refraction. Choice C, 'Specular reflection,' does not accurately describe the phenomenon associated with the critical angle. Choice D, 'Increased dispersion,' is unrelated to the concept of the critical angle and does not describe the behavior of light at this specific point.

4. Which of the following enzymes is responsible for adding a nucleotide to a growing DNA chain?

• A. Helicase
• B. Ligase
• C. Nuclease
• D. Polymerase

Correct answer: D

Rationale: The correct answer is Polymerase. Polymerase is the enzyme responsible for adding nucleotides to a growing DNA chain during DNA replication. Helicase unwinds the DNA double helix to separate the DNA strands for replication, Ligase joins DNA fragments together by catalyzing the formation of phosphodiester bonds between them, and Nuclease cuts or degrades DNA strands. Therefore, choices A, B, and C are incorrect in the context of adding nucleotides to a growing DNA chain.

5. Passive transport does not require energy input from the cell. Which of the following is an example of passive transport?

• A. Active transport of ions across a membrane
• B. Diffusion of small molecules across a concentration gradient
• C. Movement of large molecules using vesicles
• D. Endocytosis of particles into the cell

Correct answer: B

Rationale: Passive transport refers to the movement of molecules across a cell membrane without the input of energy. Diffusion of small molecules across a concentration gradient is a classic example of passive transport, as it occurs spontaneously from an area of high concentration to an area of low concentration. Active transport (option A) requires energy input in the form of ATP to move substances against their concentration gradient. Movement of large molecules using vesicles (option C) involves processes like endocytosis and exocytosis that require energy in the form of ATP. Endocytosis of particles into the cell (option D) is an active process that requires energy expenditure by the cell to engulf and internalize extracellular substances.

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