Nursing Elites

1. Two mice are both heterozygous for two traits: white fur (Ww) and short fur (Ss). Their offspring are most likely to have which of the following genotypes for these traits?

• A. wwss
• B. WWSS
• C. WwSs
• D. WWSs

Correct answer: C

Rationale: When two mice that are heterozygous for white fur (Ww) and short fur (Ss) mate, they can produce offspring with different combinations of the two traits. The Punnett square for this cross shows that the most likely genotype for the offspring is WwSs. In this case, each offspring receives one allele for white fur (W) and one for short fur (S) from each parent, resulting in a heterozygous genotype for both traits. Choice A (wwss) is incorrect as it represents a homozygous recessive genotype for both traits. Choice B (WWSS) is also incorrect as it represents a homozygous dominant genotype for both traits. Choice D (WWSs) is incorrect as it represents a genotype where one trait is homozygous dominant (W) and the other is heterozygous (S), which is not the most likely outcome based on the given parental genotypes.

2. What term refers to the point of contact between a motor neuron and a muscle fiber, where communication occurs to initiate muscle contraction?

• A. Sarcomere
• B. Synapse
• C. Tendon
• D. Myofibril

Correct answer: B

Rationale: The correct answer is B, 'Synapse.' The synapse is the specific term that refers to the point of contact between a motor neuron and a muscle fiber, where communication occurs to initiate muscle contraction. At the synapse, neurotransmitters are released by the motor neuron, triggering the muscle fiber to contract. Choice A, 'Sarcomere,' is incorrect as a sarcomere is the basic unit of muscle contraction, not the point of contact between a motor neuron and a muscle fiber. Choice C, 'Tendon,' is incorrect as tendons are fibrous connective tissues that connect muscle to bone, not involved in neuronal communication. Choice D, 'Myofibril,' is incorrect as a myofibril is a structure within muscle fibers where muscle contractions occur, not the specific point of contact for communication between a motor neuron and a muscle fiber.

3. Which of the following is NOT a function of the liver?

• A. nutrient processing
• B. blood filtration and detoxification
• C. cholesterol and lipoprotein production
• D. insulin production and blood sugar regulation

Correct answer: D

Rationale: The correct answer is D. The liver does not produce insulin; instead, insulin is produced by the pancreas. The liver plays a crucial role in regulating blood sugar levels by storing and releasing glucose but does not directly produce insulin. Choices A, B, and C are functions of the liver. Nutrient processing, blood filtration, detoxification, cholesterol, and lipoprotein production are essential roles performed by the liver to maintain overall metabolic balance and health.

4. What is the main function of calcitonin, a hormone produced by the thyroid gland?

• A. Stimulate metabolism and heat production
• B. Increase calcium absorption from the intestines
• C. Enhance bone growth and development
• D. Lower blood calcium levels

Correct answer: D

Rationale: Calcitonin is a hormone produced by the thyroid gland that primarily functions to lower blood calcium levels. It achieves this by inhibiting bone breakdown and promoting calcium excretion by the kidneys. Therefore, the correct answer is D as it reflects the main role of calcitonin in calcium homeostasis. Choices A, B, and C are incorrect as they do not align with the primary function of calcitonin. Calcitonin does not stimulate metabolism and heat production (Choice A), increase calcium absorption from the intestines (Choice B), or enhance bone growth and development (Choice C).

5. In the reaction 2Na + 2H2O → 2NaOH + H2, what is the limiting reactant when 3 moles of sodium react with 2 moles of water?

• A. Na
• B. H2O
• C. NaOH
• D. H2

Correct answer: A

Rationale: The balanced chemical equation indicates that 2 moles of sodium react with 2 moles of water to yield 2 moles of sodium hydroxide and 1 mole of hydrogen gas. When 3 moles of sodium react with only 2 moles of water, sodium becomes the limiting reactant as it is present in excess compared to the available water molecules. This situation arises because not all sodium atoms can fully react with the limited amount of water, resulting in sodium being the limiting reactant in this specific case. Choice B (H2O), choice C (NaOH), and choice D (H2) are incorrect as they are not the limiting reactant in the given reaction scenario.

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