Nursing Elites

1. Enzymes can _ reactions.

• A. Catalyze
• B. Inhibit
• C. Stop
• D. None of the above

Correct answer: A

Rationale: Enzymes function as catalysts that promote and accelerate chemical reactions in biological systems. They do this by lowering the activation energy required for the reactions to occur, thereby speeding up the process without being consumed in the reaction. Enzymes facilitate reactions rather than inhibiting or stopping them. Therefore, the correct answer is 'Catalyze.' 'Inhibit' and 'Stop' are incorrect because enzymes do not hinder or halt reactions but rather enhance them.

2. Which animal has an open transport system?

• A. Grasshopper
• B. Earthworm
• C. Dolphin
• D. Chicken

Correct answer: B

Rationale: The correct answer is B: Earthworm. Earthworms have an open circulatory system, meaning their blood and interstitial fluid are not enclosed in blood vessels. Instead, the blood flows freely within the body cavity, allowing for direct exchange of nutrients and waste products with surrounding tissues. This lack of a closed transport system is a characteristic feature of earthworms. Choices A, C, and D are incorrect because grasshoppers, dolphins, and chickens have closed circulatory systems where the blood is enclosed within blood vessels, unlike earthworms.

3. How many phases are there in the process of mitosis?

• A. 2
• B. 3
• C. 4
• D. 5

Correct answer: C

Rationale: The correct answer is C: '4'. Mitosis consists of four phases: prophase, metaphase, anaphase, and telophase. These phases are crucial in the orderly division of the cell's genetic material. Choice A is incorrect because mitosis is a more complex process involving multiple phases. Choice B is incorrect as it is one phase short of the total phases in mitosis. Choice D is incorrect as mitosis does not consist of five phases.

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. Beeswax is an example of what kind of molecule?

• A. Lipid
• B. Carbohydrate
• C. Protein
• D. Nucleic acid

Correct answer: A

Rationale: Beeswax is primarily composed of esters of long-chain aliphatic alcohols and fatty acids, making it a type of lipid. Lipids are a diverse group of molecules that are hydrophobic in nature and have important functions in energy storage, signaling, and forming cellular membranes. Beeswax's chemical composition and properties categorize it as a lipid rather than a carbohydrate, protein, or nucleic acid. Carbohydrates are composed of sugars, proteins are made up of amino acids, and nucleic acids consist of nucleotides; none of which match the chemical composition of beeswax.

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