Nursing Elites

1. What is the role of DNA in heredity?

• A. Provides energy for the cell
• B. Determines the structure and function of proteins
• C. Stores and transmits genetic information
• D. Controls cell division

Correct answer: C

Rationale: DNA (deoxyribonucleic acid) is a molecule that carries the genetic instructions used in the growth, development, functioning, and reproduction of all living organisms. It stores genetic information in the form of a code made up of four chemical bases: adenine (A), thymine (T), cytosine (C), and guanine (G). This genetic information is passed down from parents to offspring and is responsible for determining an organism's traits and characteristics. DNA's primary role is to store and transmit genetic information, making option C the correct answer. DNA does not provide energy for the cell (option A), determine the structure and function of proteins (option B), or control cell division (option D).

2. In an SN2 reaction, what affects the rate of the reaction?

• A. Only the concentration of the nucleophile
• B. Only the concentration of the electrophile
• C. Neither the concentration of the nucleophile nor the electrophile
• D. Both the concentration of the nucleophile and the electrophile

Correct answer: D

Rationale: In an SN2 reaction, the rate of the reaction is affected by both the concentration of the nucleophile and the electrophile. The rate-determining step involves the nucleophile attacking the electrophile, so the concentrations of both species will impact the reaction rate. Increasing the concentration of the nucleophile increases the frequency of nucleophilic attacks, while increasing the concentration of the electrophile provides more opportunities for the nucleophile to react. Therefore, the correct answer is that both the concentration of the nucleophile and the electrophile affect the rate of the SN2 reaction. Choices A, B, and C are incorrect as they do not consider the interplay between the nucleophile and the electrophile in determining the overall reaction rate in an SN2 mechanism.

3. What is the breakdown product of ATP (adenosine triphosphate) that provides energy for muscle contraction?

• A. Glucose
• B. Creatine phosphate
• C. ADP (adenosine diphosphate)
• D. Lactic acid

Correct answer: C

Rationale: ADP (adenosine diphosphate) is the correct breakdown product of ATP that provides energy for muscle contraction. When ATP is hydrolyzed to ADP, energy is released and utilized by the muscles for various cellular processes, including muscle contraction. Glucose serves as an energy source but is not the direct breakdown product of ATP for muscle contraction. Creatine phosphate plays a role in energy storage and transfer, but it is not the immediate breakdown product of ATP. Lactic acid is produced during anaerobic metabolism and is not the direct provider of energy for muscle contraction.

4. What is the primary function of the kidneys?

• A. To digest food
• B. To filter blood and produce urine
• C. To absorb nutrients
• D. To transport oxygen

Correct answer: B

Rationale: The primary function of the kidneys is to filter blood and remove waste products from the body, producing urine in the process. This function helps in maintaining the body's internal environment stable, a process known as homeostasis. Option A, 'To digest food,' is incorrect as digestion primarily occurs in the gastrointestinal system, not in the kidneys. Option C, 'To absorb nutrients,' is also incorrect because nutrient absorption mainly takes place in the intestines. Option D, 'To transport oxygen,' is incorrect as the lungs and circulatory system are responsible for oxygen transport, not the kidneys.

5. In a balanced chemical equation, the coefficients represent the:

• A. Number of elements
• B. Ratio of reactants and products
• C. Physical state of the substances
• D. Rate of the reaction

Correct answer: A

Rationale: The correct answer is A: 'Number of elements.' In a balanced chemical equation, coefficients represent the ratio of moles of each species involved in the reaction. They indicate the relative number of molecules or formula units of each compound taking part in the reaction. Choice B, 'Ratio of reactants and products,' is incorrect because the coefficients in a balanced equation do not represent the ratio of reactants and products directly, but rather the stoichiometry of the reaction. Choice C, 'Physical state of the substances,' is incorrect because the physical states (solid, liquid, gas, or aqueous) are denoted with symbols next to the chemical formula, not the coefficients. Choice D, 'Rate of the reaction,' is incorrect as coefficients in a balanced equation do not provide information about the rate of the reaction, which is determined by factors like temperature, concentration, and catalysts.

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