Nursing Elites

1. An individual’s phenotype reflects both genetic and environmental influences.

• A. phenotype
• B. chromosome
• C. allele
• D. genotype

Correct answer: A

Rationale: The correct answer is A: phenotype. A phenotype is the observable characteristics of an individual, which result from the interaction of their genotype with the environment. This interaction between genetics and the environment determines how genes are expressed and how traits are manifested in an individual. Choices B, C, and D are incorrect because chromosomes, alleles, and genotypes are components of an individual's genetic makeup, but they do not directly reflect the observable traits influenced by both genetics and the environment.

2. Does the probability of having a child with Down’s syndrome increase with the age of the parents?

• A. TRUE
• B. FALSE
• C. Sometimes
• D. Never

Correct answer: A

Rationale: The correct answer is A: TRUE. Advanced parental age, particularly maternal age, is associated with an increased risk of Down's syndrome in offspring. As parents get older, the likelihood of having a child with Down's syndrome increases. Choices B, C, and D are incorrect because the risk of Down's syndrome is known to rise with parental age, especially maternal age, due to the increased likelihood of chromosomal abnormalities during egg formation.

3. Polygenic traits are those that are:

• A. developed during adolescence.
• B. transmitted by the mother.
• C. uncommon in humans.
• D. determined by several pairs of genes.

Correct answer: D

Rationale: Polygenic traits, such as height and skin color, are determined by several pairs of genes working together. These traits are influenced by the combined effects of multiple genes across the genome, rather than being controlled by a single gene pair. Choices A, B, and C are incorrect because polygenic traits are not specifically developed during adolescence, transmitted by the mother, or uncommon in humans. Understanding polygenic traits is essential in genetics as they demonstrate the complexity of genetic inheritance and the influence of multiple genes on a single trait.

4. The _____ is the inner layer of the embryo from which the lungs and digestive system develop.

• A. neural tube
• B. mesoderm
• C. endoderm
• D. umbilical cord

Correct answer: C

Rationale: The endoderm is the correct answer. It is the innermost layer of the embryo that gives rise to organs such as the lungs, digestive system, liver, and pancreas. The neural tube (Choice A) forms the brain and spinal cord, not the lungs or digestive system. Mesoderm (Choice B) develops into structures like muscles, bones, and circulatory system, not the lungs or digestive system. The umbilical cord (Choice D) serves as a connection between the embryo and the placenta, providing nutrients and oxygen, but it is not the layer from which lungs and digestive system develop.

5. Twenty-year-old Jack is extremely tall and has very thick facial hair. Most of his male secondary sex characteristics are also more pronounced than men of his age. In this scenario, Jack is most likely:

• A. an XYY male.
• B. diagnosed with Klinefelter syndrome.
• C. an XXY male.
• D. diagnosed with Down syndrome.

Correct answer: A

Rationale: The correct answer is A: an XYY male. Individuals with XYY syndrome often exhibit increased height and more pronounced secondary male characteristics, such as thick facial hair. Choice B, Klinefelter syndrome (XXY), typically presents with less prominent male secondary sex characteristics due to the presence of an extra X chromosome. Choice C, XXY male, refers to Klinefelter syndrome, which does not align with the description of Jack having more pronounced male secondary sex characteristics. Choice D, Down syndrome, is caused by a trisomy of chromosome 21 and is not associated with the physical characteristics described in the scenario.

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