Nursing Elites

1. Water is capable of dissolving many substances that organisms need to carry out life functions. Which of the properties of water listed below is responsible for its ability to dissolve important nutrients like ionic salt compounds?

• A. adhesion
• B. cohesion
• C. high specific heat
• D. high polarity

Correct answer: D

Rationale: The property of water that is responsible for its ability to dissolve important nutrients like ionic salt compounds is its high polarity. Water is a polar molecule with a positive and negative end, which allows it to attract and surround individual ions from salt compounds, causing them to dissociate and dissolve in water. This property makes water an excellent solvent for various substances necessary for life functions. Adhesion refers to the ability of water molecules to stick to other substances, cohesion is the attraction between water molecules themselves, and high specific heat is the amount of heat energy required to raise the temperature of water. While these properties are important characteristics of water, they are not directly responsible for its ability to dissolve ionic salt compounds.

2. What is the difference between isometric and isotonic muscle contractions?

• A. Isometric involves movement, while isotonic does not.
• B. Isotonic involves shortening of muscle, while isometric maintains length.
• C. Isometric uses more energy, while isotonic uses less.
• D. Isotonic involves smooth muscle, while isometric involves skeletal muscle.

Correct answer: B

Rationale: The correct answer is B. Isometric contractions occur when the muscle generates tension without changing its length, while isotonic contractions involve the muscle changing length to move a load. In isotonic contractions, the muscle shortens to move a load, whereas in isometric contractions, the muscle contracts to hold a position without movement. Choice A is incorrect because isometric contractions do not involve movement, while choice C is incorrect as isotonic contractions typically require more energy due to movement. Choice D is incorrect because the type of muscle involved (smooth or skeletal) is not the defining factor between isometric and isotonic contractions.

3. Which orbital can hold a maximum of 8 electrons?

• A. s orbital
• B. p orbital
• C. d orbital
• D. f orbital

Correct answer: B

Rationale: The correct answer is the p orbital. Each p orbital can hold a maximum of 6 electrons (2 electrons in each of the 3 p orbitals), totaling 18 possible electrons when considering all three p orbitals. The s orbital can hold a maximum of 2 electrons, the d orbital can hold a maximum of 10 electrons, and the f orbital can hold a maximum of 14 electrons. Therefore, the p orbital is the orbital that can hold a maximum of 8 electrons, making it the correct choice.

4. What effect does doubling the net force applied to an object have on its acceleration, assuming mass remains constant?

• A. Acceleration doubles
• B. Acceleration is halved
• C. Acceleration remains the same
• D. Acceleration quadruples

Correct answer: A

Rationale: According to Newton's second law of motion, acceleration is directly proportional to the net force applied to an object when mass is constant. Therefore, if the net force is doubled, the acceleration of the object will also double. This relationship is expressed by the formula F=ma, where F is the net force, m is the mass, and a is the acceleration. When mass is constant, doubling the force applied will result in a proportional doubling of acceleration. Choices B, C, and D are incorrect because doubling the net force does not halve, maintain, or quadruple the acceleration; it directly and proportionally increases the acceleration.

5. During which of the following stages does crossing over occur?

• A. Mitosis Prophase
• B. Meiosis Prophase I
• C. Meiosis Prophase II
• D. Interphase

Correct answer: B

Rationale: Crossing over occurs during Prophase I of meiosis. This stage is specifically associated with genetic recombination, where homologous chromosomes exchange genetic material. This process contributes to genetic diversity by creating new combinations of alleles. Choices A, C, and D are incorrect. In mitosis, crossing over does not occur as it involves the separation of replicated chromosomes. Meiosis Prophase II is focused on the reformation of nuclei and does not involve crossing over. Interphase is a stage where the cell prepares for division and is not associated with crossing over.

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