Nursing Elites

1. Most victims of _____ die of respiratory infections in their 20s.

• A. Tay-Sachs disease
• B. cystic fibrosis
• C. Turner syndrome
• D. Klinefelter syndrome

Correct answer: B

Rationale: Individuals with cystic fibrosis have a genetic disorder that causes mucus to be thick and sticky, leading to blockages in the lungs and digestive system. This mucus buildup makes them more susceptible to severe respiratory infections, which can ultimately result in premature death in their 20s. Tay-Sachs disease (Choice A) is a genetic disorder that affects the nervous system, not typically causing respiratory infections. Turner syndrome (Choice C) and Klinefelter syndrome (Choice D) are chromosomal disorders that do not directly lead to the respiratory issues observed in cystic fibrosis.

2. Twins that derive from a single zygote that has split into two are called:

• A. monozygotic (MZ) twins.
• B. fraternal twins.
• C. non-identical twins.
• D. dizygotic (DZ) twins.

Correct answer: A

Rationale: The correct answer is A: monozygotic (MZ) twins. Monozygotic twins, also known as identical twins, occur when a single zygote splits into two embryos, leading to two genetically identical individuals. Choice B, fraternal twins, are twins that develop from two separate eggs fertilized by two different sperm cells, resulting in non-identical siblings. Choice C, non-identical twins, is not a common term used to describe this type of twinning. Choice D, dizygotic (DZ) twins, refer to twins that develop from two separate eggs fertilized by two different sperm cells, leading to non-identical twins.

3. If an individual receives a recessive gene for eye color from both parents, the:

• A. gender of the child will not determine the expression of that trait.
• B. recessive trait will be expressed in the child.
• C. recessive trait will be expressed in all the offspring.
• D. recessive trait will be suppressed, and the dominant trait will not be expressed.

Correct answer: B

Rationale: When an individual inherits a recessive gene for eye color from both parents, the recessive trait will be expressed in the child. This is because having two copies of the recessive gene overrides the presence of any dominant gene. Choice A is incorrect because the expression of the trait is determined by the genetic makeup, not the gender of the child. Choice C is incorrect as the expression of the recessive trait is certain when both parents pass on the recessive gene, but it does not mean that all offspring will express the trait. Choice D is incorrect because if both parents provide a recessive gene, the dominant trait will not be expressed in the child, but it does not mean it will be suppressed; rather, the recessive trait will be expressed.

4. Daisy was always unusually short for her age. She was unable to conceive a child after marriage, and upon visiting a doctor, she was prescribed estrogen replacement therapy. Daisy is most likely suffering from:

• A. Phenylketonuria (PKU).
• B. Cystic fibrosis.
• C. Turner syndrome.
• D. Huntington’s disease (HD).

Correct answer: C

Rationale: Daisy's symptoms of short stature and infertility, along with the prescription of estrogen replacement therapy, are indicative of Turner syndrome. Turner syndrome is a genetic condition in which a female is partially or completely missing one X chromosome. This results in short stature, infertility, and other physical characteristics. Phenylketonuria (PKU) is a metabolic disorder caused by a mutation in the gene responsible for the breakdown of the amino acid phenylalanine. Cystic fibrosis is a genetic disorder affecting the respiratory and digestive systems. Huntington's disease (HD) is a neurodegenerative disorder that affects muscle coordination and leads to cognitive decline.

5. Which field of biology studies heredity?

• A. Etiology.
• B. Ecology.
• C. Genetics.
• D. Eugenics.

Correct answer: C

Rationale: Genetics is the branch of biology that focuses on the study of heredity and variation in organisms. Etiology (choice A) deals with the causes of diseases, not heredity. Ecology (choice B) is concerned with the relationships between organisms and their environment, not specifically heredity. Eugenics (choice D) is a controversial field that involves improving the genetic quality of the human population through selective breeding, which is different from the study of heredity itself.

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