Nursing Elites

1. Which of the following biological macromolecules is non-soluble, composed of hydrocarbons, and acts as an important source of energy storage for the body?

• A. carbohydrates
• B. nucleic acids
• C. lipids
• D. proteins

Correct answer: C

Rationale: Lipids are non-soluble biological macromolecules composed mostly of hydrocarbons such as fatty acids. They act as an essential source of energy storage for the body, providing efficient storage of energy in the form of fats. Carbohydrates are also an energy source for the body, but lipids excel in long-term energy storage. Nucleic acids are not known for energy storage; instead, they are involved in genetic information transmission and protein synthesis. Proteins play diverse roles in the body, such as enzymatic functions, structural support, and immune response, but they are not primarily known as a source of energy storage.

2. What is the function of introns in eukaryotic genes?

• A. They code for protein sequences.
• B. They are involved in gene regulation.
• C. They are removed during mRNA processing.
• D. They are non-functional remnants of ancient DNA.

Correct answer: C

Rationale: A) Introns do not code for protein sequences. Exons are the segments of DNA that code for proteins. B) While introns can indirectly influence gene regulation, their primary function is not directly involved in gene regulation. C) Introns are non-coding regions of DNA that are transcribed into pre-mRNA but are removed during mRNA processing through a process called splicing. This allows only the exons to be included in the mature mRNA that will be translated into proteins. D) While introns were once thought to be non-functional remnants of ancient DNA, research has shown that they can have regulatory functions and play a role in gene expression.

3. Which muscle has involuntary cells that are branched and striated and connected by intercalated discs with gap junctions?

• A. Smooth muscle
• B. Cardiac muscle
• C. Skeletal muscle
• D. Epithelial muscle

Correct answer: B

Rationale: The correct answer is B: Cardiac muscle. Cardiac muscle cells fit the description provided in the question; they are involuntary, striated, and branched, with intercalated discs containing gap junctions that allow for synchronized contractions of the heart. Smooth muscle (choice A) lacks striations and is found in the walls of internal organs. Skeletal muscle (choice C) is voluntary and attaches to bones for movement. 'Epithelial muscle' (choice D) is not a valid muscle type, making it an incorrect choice.

4. What is the independent variable in the botanist's experiment?

• A. Temperature
• B. Root tissue
• C. Light exposure
• D. Root length

Correct answer: A

Rationale: In an experiment, the independent variable is the factor that is deliberately manipulated or changed by the researcher. The botanist is likely altering the temperature to observe its effect on the plants. Therefore, temperature is the independent variable in the botanist's experiment. Choice B, root tissue, is not the independent variable as it is not the factor being intentionally changed in the experiment. Choice C, light exposure, and choice D, root length, are also not the independent variables as they are not the factors being purposely manipulated by the researcher in this scenario.

5. What property of a wave determines the loudness of sound when heard by the human ear?

• A. Frequency
• B. Amplitude
• C. Wavelength
• D. Velocity

Correct answer: B

Rationale: The amplitude of a wave determines the loudness of sound when heard by the human ear. The greater the amplitude of a sound wave, the louder the sound will be perceived. Frequency (Choice A) refers to the number of wave cycles in a given time period. Wavelength (Choice C) is the distance between two corresponding points on a wave. Velocity (Choice D) is the speed at which the wave travels and does not directly affect the loudness of sound perceived by the human ear.

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