Nursing Elites

1. How does the body maintain a relatively constant blood pH level, even with changes in blood carbon dioxide concentration?

• A. Cellular respiration
• B. Gas exchange
• C. Buffering system
• D. Deoxygenation

Correct answer: C

Rationale: The correct answer is C: Buffering system. The buffering system is responsible for maintaining a relatively constant blood pH level by minimizing changes in pH when acids or bases are added to the blood. This system consists of chemical compounds that can donate or accept protons to help stabilize the pH. Choice A, Cellular respiration, and Choice B, Gas exchange, are processes involved in gas exchange within the body, not specifically related to maintaining blood pH. Choice D, Deoxygenation, refers to the removal of oxygen from a substance and is not directly related to the regulation of blood pH.

2. Muscle tissue is responsible for movement. Which type of muscle tissue is found in the heart?

• A. Skeletal muscle
• B. Smooth muscle
• C. Cardiac muscle
• D. All of the above

Correct answer: C

Rationale: Cardiac muscle is the type of muscle tissue found in the heart. Unlike skeletal muscle and smooth muscle, cardiac muscle is striated and involuntary, meaning it contracts without conscious control. It forms the majority of the heart's structure and is essential for its rhythmic contraction to pump blood throughout the body. Skeletal muscle is attached to bones and responsible for voluntary movements, while smooth muscle is found in organs and blood vessels, controlling various involuntary functions like digestion and blood flow. Therefore, choices A (Skeletal muscle) and B (Smooth muscle) are incorrect as they are not the types of muscle tissue found in the heart.

3. 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

4. Four different groups of the same species of peas are grown and exposed to differing levels of sunlight, water, and fertilizer as documented in the table below. The data in the water and fertilizer columns indicate how many times the peas are watered or fertilized per week, respectively. Group 2 is the only group that withered. What is a reasonable explanation for this occurrence? Group Sunlight Water Fertilizer 1 partial sun 4 mL/hr 1 2 full sun 7 mL/hr 1 3 no sun 14 mL/hr 2 4 partial sun 3 mL/hr 2

• A. Insects gnawed away at the stem of the plant.
• B. The roots rotted due to poor drainage.
• C. The soil type had nutritional deficiencies.
• D. This species of peas does not thrive in full sunlight.

Correct answer: D

Rationale: Group 2, the only group that withered, was exposed to full sun. This suggests that the species of peas being studied does not thrive in full sunlight, leading to its deterioration compared to the other groups with different light exposures. Choices A, B, and C are not the correct explanations for the withering of Group 2. There is no mention of insects in the stem, poor drainage, or soil nutritional deficiencies in the scenario provided. The key factor that sets Group 2 apart from the others is the full sunlight exposure, indicating that the species of peas is not suited for such conditions.

5. What is the independent variable in this experiment?

• A. Time
• B. Dog weight
• C. Dog species
• D. Dog food type

Correct answer: D

Rationale: The independent variable is the factor that is manipulated by the researcher to observe its effects on the dependent variable. In this experiment, the researcher is likely changing the type of dog food, and this manipulation is what impacts the outcome being measured. Therefore, 'Dog food type' is the independent variable. Choices A, B, and C do not represent the variable being intentionally changed by the researcher, making them dependent variables or other factors not directly controlled or manipulated in this experiment.

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