Nursing Elites

1. When testing how quickly a rat dies based on the amount of poison it eats, which of the following is the independent variable and which is the dependent variable?

• A. How quickly the rat dies is the independent variable; the amount of poison is the dependent variable.
• B. The amount of poison is the independent variable; how quickly the rat dies is the dependent variable.
• C. Whether the rat eats the poison is the independent variable; how quickly the rat dies is the dependent variable.
• D. The cage the rat is kept in is the independent variable; the amount of poison is the dependent variable.

Correct answer: B

Rationale: The correct answer is B. In this experiment, the independent variable is the amount of poison because it is what is being manipulated by the researcher. The dependent variable is how quickly the rat dies, as it is the outcome that is being measured based on the different amounts of poison administered. Choice A is incorrect because the independent variable should be what is being manipulated or changed, which is the amount of poison in this case. Choice C is incorrect because whether the rat eats the poison is not being varied or controlled by the researcher. Choice D is incorrect because the cage the rat is kept in is not relevant to the relationship being studied between the amount of poison and the rat's survival time.

2. Which element is a critical component of DNA and RNA, essential for storing and transmitting genetic information?

• A. Oxygen
• B. Carbon
• C. Nitrogen
• D. Hydrogen

Correct answer: B

Rationale: Carbon is the correct answer as it is a critical element in DNA and RNA, forming the backbone of these molecules. Its ability to form diverse bonds allows for efficient storage and transmission of genetic information. Oxygen, nitrogen, and hydrogen are also present in DNA and RNA but do not serve as the primary backbone element for these molecules. Oxygen is involved in the structure but not as the backbone element. Nitrogen is present in the bases of nucleotides, and hydrogen bonds help stabilize the structure.

3. In the reaction 2H2 + O2 → 2H2O, how many moles of oxygen are required to react completely with 4 moles of hydrogen?

• A. 1
• B. 2
• C. 3
• D. 4

Correct answer: B

Rationale: The balanced chemical equation indicates that 2 moles of H2 react with 1 mole of O2 to produce 2 moles of H2O. To determine how many moles of O2 are required to react with 4 moles of H2, you can use the mole ratio from the balanced equation: 2 moles of H2 react with 1 mole of O2. Therefore, to react completely with 4 moles of H2, you would need 2 moles of O2 (4 moles H2 ÷ 2 moles H2 per 1 mole O2). Hence, 2 moles of oxygen are required to react completely with 4 moles of hydrogen. Choices A, C, and D are incorrect because they do not reflect the correct stoichiometry as defined by the balanced chemical equation.

4. Antibodies, crucial for immune defense, are produced by:

• A. Neutrophils
• B. Lymphocytes
• C. Monocytes
• D. Basophils

Correct answer: B

Rationale: Antibodies are produced by a specific type of lymphocyte known as B cells. B cells are a critical component of the adaptive immune system and are responsible for producing antibodies in response to pathogens. Neutrophils, monocytes, and basophils are types of white blood cells that are part of the innate immune response and do not have the function of producing antibodies. Neutrophils are primarily involved in phagocytosis, monocytes differentiate into macrophages and dendritic cells for antigen presentation, while basophils are involved in allergic reactions and parasitic infections.

5. Which of the following describes the difference between prokaryotic and eukaryotic cells?

• A. Prokaryotic cells have a nucleus, while eukaryotic cells don't.
• B. Eukaryotic cells are simpler in structure than prokaryotic cells.
• C. Prokaryotic cells have membrane-bound organelles, while eukaryotic cells don't.
• D. Eukaryotic cells have a true nucleus and membrane-bound organelles, while prokaryotic cells lack these.

Correct answer: D

Rationale: Eukaryotic cells have a true nucleus that contains the genetic material, while prokaryotic cells lack a true nucleus. Eukaryotic cells also have membrane-bound organelles such as mitochondria, endoplasmic reticulum, and Golgi apparatus, which are absent in prokaryotic cells.

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