Nursing Elites

1. The adaptive immune system has two main branches: humoral and cell-mediated immunity. Which type of immune cell is primarily responsible for antibody production?

• A. Helper T cells
• B. Cytotoxic T cells
• C. B cells
• D. Natural killer cells

Correct answer: C

Rationale: B cells are primarily responsible for antibody production in the adaptive immune system. When activated, B cells differentiate into plasma cells, which are specialized to produce antibodies. Helper T cells play a crucial role in activating B cells, but they do not directly produce antibodies. Cytotoxic T cells are involved in cell-mediated immunity by killing infected cells, while natural killer cells are part of the innate immune system and target virus-infected and cancerous cells. Therefore, the correct answer is C (B cells) as they are directly involved in the production of antibodies, essential for humoral immunity.

2. According to the Law of Conservation of Energy, what happens to the total amount of energy in a closed system?

• A. Increases over time.
• B. Decreases over time.
• C. Remains constant.
• D. Depends on the temperature of the system.

Correct answer: C

Rationale: According to the Law of Conservation of Energy, the total amount of energy in a closed system remains constant. This principle states that energy cannot be created or destroyed within the system but can only be transformed from one form to another. Therefore, the total energy within the system is conserved and does not change over time. Choice A is incorrect because the total energy in a closed system does not increase over time, as it remains constant. Choice B is incorrect as the total energy does not decrease over time within a closed system. Choice D is incorrect as the conservation of energy is not dependent on the temperature of the system, but rather on the transformation and conservation of energy within the system. Understanding this concept is fundamental for understanding the behavior of energy in various physical systems and processes.

3. What is the product of translation from an RNA template?

• A. DNA
• B. Lipid
• C. Polypeptide
• D. Carbohydrate

Correct answer: C

Rationale: Translation is the process by which the genetic information carried by mRNA is decoded to synthesize a polypeptide chain. This essential process occurs at the ribosomes within the cell. The product of translation from an RNA template is a polypeptide, not DNA, lipid, or carbohydrate. DNA is involved in transcription, lipids are not directly produced in translation, and carbohydrates are not synthesized through translation. Therefore, the correct product resulting from translation from an RNA template is a polypeptide, making choice C, 'Polypeptide,' the correct answer.

4. In a single displacement reaction, one element takes the place of another element in a compound. Which of the following is an example?

• A. 2H2 + O2 -> 2H2O
• B. Zn + 2HCl -> ZnCl2 + H2
• C. CaCO3 -> CaO + CO2
• D. CH4 + 2O2 -> CO2 + 2H2O

Correct answer: B

Rationale: Option B demonstrates a single displacement reaction where zinc (Zn) displaces hydrogen (H) in hydrochloric acid (HCl) to produce zinc chloride (ZnCl2) and hydrogen gas (H2). This reaction exemplifies the concept of one element (Zn) replacing another element (H) in a compound (HCl), which is characteristic of single displacement reactions. Choices A, C, and D do not involve a single element displacing another in a compound, making them incorrect. In choice A, hydrogen and oxygen combine to form water, which is not a single displacement reaction. In choice C, calcium carbonate decomposes into calcium oxide and carbon dioxide, not involving displacement of elements. In choice D, methane reacts with oxygen to form carbon dioxide and water, which is a combustion reaction, not a single displacement reaction.

5. What is the process of breaking down lipids into fatty acids and glycerol called?

• A. Lipolysis
• B. Gluconeogenesis
• C. Krebs cycle
• D. Oxidative phosphorylation

Correct answer: A

Rationale: - Lipolysis is indeed the correct answer. It is the process of breaking down lipids (fats) into fatty acids and glycerol. This process occurs in adipose tissue and is important for releasing stored energy in the form of fatty acids. - Gluconeogenesis is the process of synthesizing glucose from non-carbohydrate sources like amino acids and glycerol, not breaking down lipids. - The Krebs cycle (also known as the citric acid cycle) is a series of chemical reactions that occur in the mitochondria to generate energy through the oxidation of acetyl-CoA derived from carbohydrates, fats, and proteins. - Oxidative phosphorylation is the final stage of cellular respiration where ATP is produced through the transfer of electrons in the electron transport chain. It is not specifically related to the breakdown of lipids into fatty acids and glycerol.

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