Nursing Elites

1. What is the balanced chemical equation for the reaction between sodium and chlorine to form sodium chloride?

• A. Na + Cl2 -> NaCl
• B. 2Na + Cl2 -> 2NaCl
• C. Na2 + Cl -> 2NaCl
• D. Na + 2Cl -> NaCl2

Correct answer: B

Rationale: In a balanced chemical equation, the number of atoms of each element must be the same on both sides of the equation. When sodium (Na) reacts with chlorine (Cl2) to form sodium chloride (NaCl), we need to ensure the equation is balanced. There are 2 chlorine atoms in Cl2; hence, we need 2 sodium atoms on the left side to balance it. Therefore, the balanced chemical equation is 2Na + Cl2 -> 2NaCl. Choice A is incorrect because it does not have the correct coefficients to balance the equation. Choice C is incorrect as it incorrectly represents the formula of sodium. Choice D is incorrect as it forms NaCl2, which is not the correct compound formed in this reaction.

2. What are Mendel's laws?

• A. Law of inheritance, law of expression
• B. Law of segregation, law of independent assortment
• C. Law of dominance, law of recessiveness
• D. Law of mutation, law of crossing over

Correct answer: B

Rationale: The correct answer is B. Mendel's laws consist of the law of segregation, which states that each parent passes one allele for each trait, and the law of independent assortment, which explains that genes for different traits are inherited independently. Choice A is incorrect because 'law of expression' is not one of Mendel's laws. Choice C is incorrect because 'law of dominance' and 'law of recessiveness' do not represent the two main laws proposed by Mendel. Choice D is incorrect because 'law of mutation' and 'law of crossing over' are not part of Mendel's original laws.

3. 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.

4. Where does sperm production occur?

• A. Prostate gland
• B. Seminal vesicles
• C. Scrotum
• D. Seminiferous tubules

Correct answer: D

Rationale: Sperm production occurs in the seminiferous tubules within the testes. These tubules are responsible for spermatogenesis, the process of sperm creation. The prostate gland and seminal vesicles contribute to seminal fluid production, while the scrotum houses the testes but does not produce sperm. Therefore, choices A, B, and C are incorrect as they are not sites for sperm production.

5. Blood type is a trait determined by multiple alleles, with IA coding for A blood, IB coding for B blood, and i coding for O blood being recessive. If an individual with A heterozygosity and an O individual have a child, what is the probability that the child will have A blood?

• A. 25%
• B. 50%
• C. 75%
• D. 100%

Correct answer: B

Rationale: When an A heterozygote individual (IAi) and an O individual (ii) have a child, there are four possible combinations of alleles that the child can inherit: IA from the A parent and i from the O parent; IA from the A parent and i from the O parent; i from the A parent and i from the O parent; i from the A parent and i from the O parent. Out of these combinations, 50% of the offspring will inherit the A allele from the A parent, resulting in A blood type. Therefore, the correct answer is 50%. Choice A is incorrect because the probability is not 25%. Choice C is incorrect as it overestimates the likelihood. Choice D is incorrect as it suggests a certainty which is not the case in genetics.

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