Nursing Elites

1. Which statement is true of enzymes?

• A. They are made from lipids.
• B. They are made from proteins.
• C. They form double chains of DNA.
• D. They bind with catalysts.

Correct answer: B

Rationale: The correct answer is B: Enzymes are made from proteins. Enzymes are biological molecules that act as catalysts to speed up chemical reactions in living organisms. While the majority of enzymes are proteins, a few are made from RNA. The statement that enzymes are made from lipids (choice A) is incorrect. Enzymes do not form double chains of DNA (choice C) as their primary function is not related to DNA structure. Additionally, enzymes themselves do not bind with catalysts (choice D); instead, they act as catalysts to facilitate reactions.

2. 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.

3. The phases of mitosis include:

• A. Prophase, interphase, metaphase, anaphase, and telophase
• B. Prophase, prophase, metaphase, anaphase, and cytokinesis
• C. Prophase, prometaphase, metaphase, anaphase, and telophase
• D. Prophase, interphase, prophase, anaphase, and telophase

Correct answer: C

Rationale: The correct phases of mitosis are prophase, prometaphase, metaphase, anaphase, and telophase. Prophase is the first phase where chromatin condenses into chromosomes, the nuclear envelope breaks down, and the mitotic spindle forms. Prometaphase follows prophase, involving the full disintegration of the nuclear envelope and the attachment of spindle fibers to the kinetochores of the chromosomes. Metaphase is where chromosomes align along the metaphase plate. Anaphase is the phase where sister chromatids separate and move towards opposite poles. Telophase marks the final stage of mitosis, involving the decondensation of chromosomes and the reformation of the nuclear envelope. Choice A is incorrect because it includes interphase, which is not a phase of mitosis. Choice B is incorrect as it repeats prophase, which is the initial phase. Choice D is incorrect because it includes interphase and repeats prophase.

4. 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.

5. Which form of fermentation is used to produce beer?

• A. Lactic acid fermentation
• B. Acetic acid fermentation
• C. Propionic acid fermentation
• D. Ethyl alcohol fermentation

Correct answer: D

Rationale: The correct answer is D, Ethyl alcohol fermentation. During beer production, yeast metabolizes sugars in the wort to produce ethanol (ethyl alcohol) and carbon dioxide, which are responsible for the alcohol content and carbonation in beer. Choices A, B, and C are incorrect because lactic acid fermentation produces lactic acid, acetic acid fermentation produces acetic acid, and propionic acid fermentation produces propionic acid, none of which are used in the production of beer.

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