Nursing Elites

1. Which of the following substances is an example of an acidic gas?

• A. Nitrogen (Nâ‚‚)
• B. Carbon dioxide (COâ‚‚)
• C. Sulfur dioxide (SOâ‚‚)
• D. Oxygen (Oâ‚‚)

Correct answer: C

Rationale: The correct answer is C, Sulfur dioxide (SOâ‚‚). Sulfur dioxide is an acidic gas because when dissolved in water, it forms sulfurous acid, which imparts acidic properties. Nitrogen (Nâ‚‚), carbon dioxide (COâ‚‚), and oxygen (Oâ‚‚) are not considered acidic gases. Nitrogen is a neutral gas, carbon dioxide forms a weakly acidic solution when dissolved in water, and oxygen is a neutral gas.

2. How does the structure of centromeres contribute to chromosome movement during mitosis?

• A. The centromere provides a binding site for spindle fibers, allowing chromosomes to be attached and manipulated.
• B. The centromere serves as a dividing point between sister chromatids, ensuring their separation during anaphase.
• C. The centromere maintains chromosome stability by preventing chromosomal breaks and rearrangements.
• D. The centromere plays a role in DNA replication, ensuring accurate copying of the genetic material.

Correct answer: A

Rationale: A) The centromere provides a binding site for spindle fibers, which are microtubules that help move chromosomes during cell division. This attachment allows the chromosomes to be pulled towards opposite poles of the cell during mitosis. Therefore, the structure of centromeres directly contributes to chromosome movement during mitosis by facilitating the attachment and manipulation of chromosomes by the spindle fibers. B) While the centromere does serve as a dividing point between sister chromatids, ensuring their separation during anaphase, this function is more related to the segregation of chromosomes rather than their movement. C) The centromere does play a role in maintaining chromosome stability by ensuring proper chromosome segregation, but it is not primarily responsible for preventing chromosomal breaks and rearrangements. D) The centromere is not directly involved in DNA replication. Its main function is

3. Which component of the nervous system is responsible for controlling voluntary movements, such as the contraction of skeletal muscles?

• A. Autonomic nervous system
• B. Peripheral nervous system
• C. Somatic nervous system
• D. Sympathetic nervous system

Correct answer: C

Rationale: The correct answer is C: Somatic nervous system. The somatic nervous system is responsible for controlling voluntary movements, such as the contraction of skeletal muscles. This system consists of motor neurons that send signals from the central nervous system to the skeletal muscles, allowing for conscious control over movement. The autonomic nervous system (A) controls involuntary functions like heart rate and digestion, the peripheral nervous system (B) includes all nerves outside the central nervous system, and the sympathetic nervous system (D) is a division of the autonomic nervous system responsible for the fight-or-flight response. Therefore, choices A, B, and D are incorrect as they do not specifically regulate voluntary movements of skeletal muscles, which is a function of the somatic nervous system.

4. In the context of cholesterol levels, LDL cholesterol is often referred to as:

• A. HDL or "good" cholesterol.
• B. LDL or "bad" cholesterol.
• C. Total cholesterol, encompassing both LDL and HDL.
• D. VLDL, a type of triglyceride transported in the bloodstream.

Correct answer: B

Rationale: LDL cholesterol is often referred to as "bad" cholesterol because high levels of LDL can lead to plaque buildup in the arteries, increasing the risk of heart disease and stroke. LDL cholesterol is considered harmful as it contributes to the formation of plaque in blood vessels, whereas HDL cholesterol helps remove LDL from the arteries. Choice A is incorrect because HDL is known as "good" cholesterol, which helps remove LDL cholesterol from the bloodstream. Choice C is incorrect as it refers to total cholesterol, which includes LDL, HDL, and other lipids. Choice D is incorrect as VLDL is a different type of lipoprotein that carries triglycerides and is not specifically related to LDL cholesterol.

5. What is the diastole cycle in the heart?

• A. Relaxation of the heart
• B. Contraction of the heart
• C. Pulse rate of the heart
• D. Blood circulation

Correct answer: A

Rationale: The diastole cycle in the heart refers to the relaxation phase, where the heart chambers relax and fill with blood. This phase is crucial for the heart to refill and prepare for the next contraction (systole), which pumps blood out of the heart. Therefore, the correct answer is choice A, 'Relaxation of the heart.' Choices B, C, and D are incorrect in the context of cardiac physiology. Choice B, 'Contraction of the heart,' refers to systole, the phase of heart contraction. Choice C, 'Pulse rate of the heart,' is related to the number of heartbeats per minute, not the diastole cycle specifically. Choice D, 'Blood circulation,' is a broader term that encompasses the entire circulatory system rather than focusing on the heart's specific relaxation phase.

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