Nursing Elites

1. In a strand of DNA, you would expect to see adenine paired with ___________.

• A. cytosine
• B. uracil
• C. thymine
• D. guanine

Correct answer: C

Rationale: In a strand of DNA, adenine always pairs with thymine through two hydrogen bonds. This pairing is a fundamental aspect of DNA structure, where adenine and thymine complement each other in the double helix. Choice A (cytosine) is incorrect because adenine does not pair with cytosine in DNA. Choice B (uracil) is incorrect as uracil is found in RNA, not DNA. Choice D (guanine) is incorrect as guanine pairs with cytosine, not adenine, in DNA.

2. Two organisms live in a relationship from which both benefit. What is this called?

• A. Mutualism
• B. Parasitism
• C. Commensalism
• D. Competition

Correct answer: A

Rationale: Mutualism is a type of symbiotic relationship between two organisms in which both parties benefit from the association. It is a mutually beneficial interaction where both organisms gain something valuable, such as food, protection, or some other resource. This contrasts with parasitism, where one organism benefits at the expense of the other, commensalism, where one organism benefits while the other is unaffected, and competition, where both organisms are negatively affected by their interaction.

3. What is another name for the light-independent reaction in plants?

• A. Photosynthesis
• B. Calvin cycle
• C. Germination
• D. Phosphorus cycle

Correct answer: B

Rationale: The light-independent reaction in plants is also known as the Calvin cycle. This biochemical pathway, named after Melvin Calvin who discovered it, takes place in the stroma of chloroplasts and is responsible for converting carbon dioxide into glucose using ATP and NADPH generated during the light-dependent reactions of photosynthesis. The Calvin cycle does not directly require light to function, hence the alternative name as the light-independent reaction. Choices A, C, and D are incorrect. Photosynthesis is the overall process of converting light energy into chemical energy, which includes both light-dependent and light-independent reactions. Germination is the process where a seed sprouts into a new plant. The phosphorus cycle is the biogeochemical cycle that describes the movement of phosphorus through the lithosphere, hydrosphere, and biosphere.

4. Which of the following statements about the respiratory system is true?

• A. The respiratory system consists of all the organs involved in breathing
• B. Organs included in the respiratory system are the nose, pharynx, larynx, trachea, bronchi, and lungs
• C. The respiratory system conveys oxygen into our bodies and removes carbon dioxide from our bodies
• D. All of the Above

Correct answer: D

Rationale: The correct answer is D. The respiratory system consists of all the organs involved in breathing, including the nose, pharynx, larynx, trachea, bronchi, and lungs. Additionally, the respiratory system is responsible for conveying oxygen into our bodies and removing carbon dioxide from our bodies. Therefore, all the statements provided are true, making option D the correct choice. Options A, B, and C are all accurate statements about the respiratory system, reinforcing the correctness of choosing option D.

5. 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.

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