Nursing Elites

1. How does an enzyme work on a chemical reaction that occurs in a substrate?

• A. An enzyme slows down the chemical reaction.
• B. An enzyme speeds up the chemical reaction.
• C. An enzyme has no effect on the chemical reaction.
• D. An enzyme stops most chemical reactions.

Correct answer: B

Rationale: Enzymes are biological catalysts that facilitate chemical reactions by lowering the activation energy required for the reaction to occur. This allows the reaction to proceed more quickly and efficiently. Enzymes do not change the overall outcome of the reaction, but they significantly increase the rate at which it takes place. Therefore, choice B, 'An enzyme speeds up the chemical reaction,' is the correct answer. Choices A, C, and D are incorrect because enzymes do not slow down, have no effect, or stop chemical reactions; instead, they accelerate the process by lowering the activation energy.

2. Why do cells need to use exocytosis?

• A. To obtain energy
• B. To defend against invaders
• C. To remove waste products
• D. To undergo division

Correct answer: C

Rationale: Cells need to use exocytosis to remove waste products from the cell. Exocytosis is a process where cells release molecules or substances outside the cell by fusing vesicles with the cell membrane. This process is crucial for maintaining cellular homeostasis by efficiently eliminating waste materials. Choices A, B, and D are incorrect because exocytosis is specifically involved in the expulsion of molecules, not for obtaining energy, defending against invaders, or cell division.

3. Which of the following is not a function of the skeletal system?

• A. Providing the shape and form of our bodies
• B. Supporting and protecting the body
• C. Producing blood
• D. Storing vitamins

Correct answer: C

Rationale: Producing blood is not a function of the skeletal system. Blood production primarily occurs in the bone marrow, which is found within the bones. The skeletal system provides the shape and form of our bodies, supports and protects the body, and stores minerals like calcium and phosphorus for various functions. Storing vitamins is not a primary function of the skeletal system, although some vitamins may play a role in bone health.

4. Which of the following structures is not directly involved in translation?

• A. tRNA
• B. mRNA
• C. ribosome
• D. DNA

Correct answer: D

Rationale: The correct answer is 'D: DNA.' DNA is not directly involved in translation, which is the process of synthesizing proteins from mRNA. tRNA carries amino acids to the ribosome, mRNA provides the template for protein synthesis, and ribosomes are the cellular machinery where translation occurs. DNA's main role is in transcription, where it serves as the template for mRNA synthesis, not in translation.

5. Which part of the plant produces pollen?

• A. Anther
• B. Style
• C. Stigma
• D. Pistil

Correct answer: A

Rationale: The anther is the part of the flower that produces pollen. It is located at the tip of the stamen, the male reproductive organ of a flower. The anther contains pollen sacs where pollen grains are produced. The style is the part of the pistil that connects the stigma to the ovary, playing a role in pollen tube growth. The stigma is the part of the pistil that receives pollen during fertilization. The pistil is the female reproductive organ of a flower, consisting of the stigma, style, and ovary, and does not produce pollen.

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