Nursing Elites

1. Which of the following illnesses causes degeneration of the central nervous system?

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

Correct answer: A

Rationale: Tay-Sachs disease is a genetic disorder that causes a progressive degeneration of the central nervous system, particularly in infants. Choice B, Cystic fibrosis, is a genetic disorder that primarily affects the lungs and digestive system, not the central nervous system. Choices C and D, Turner syndrome and Klinefelter syndrome, are chromosomal disorders that do not directly involve degeneration of the central nervous system.

2. 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.

3. Does a blastocyst gain mass only when it receives nourishment from outside?

• A. TRUE
• B. FALSE
• C. Sometimes
• D. Always

Correct answer: A

Rationale: A blastocyst does indeed require external nourishment from the mother's body to continue developing and gaining mass. Without this external nourishment, the blastocyst would not be able to grow and develop properly. Therefore, the statement that a blastocyst gains mass only when it receives nourishment from outside is true. Choices B, C, and D are incorrect because they do not accurately reflect the dependency of a blastocyst on external nourishment for its development and growth.

4. 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.

5. Which of the following statements is true of Down’s syndrome?

• A. Down’s syndrome is usually caused by an extra copy of chromosome 21 in an individual.
• B. The symptoms of Down’s syndrome are similar to those of sickle-cell anemia.
• C. Down’s syndrome is caused by a sexually transmitted infection (STI) during conception.
• D. The probability of having a child with Down’s syndrome increases with the age of the parents.

Correct answer: D

Rationale: The correct answer is D. The likelihood of having a child with Down’s syndrome increases as the age of the parents increases, particularly the mother's age. Choice A is incorrect because Down’s syndrome is caused by an extra copy of chromosome 21, not a defect in the sex chromosomes. Choice B is incorrect as the symptoms of Down’s syndrome and sickle-cell anemia are different. Choice C is also incorrect as Down’s syndrome is not caused by a sexually transmitted infection during conception.

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