Nursing Elites

1. What causes Down's syndrome?

• A. Alcohol abuse by the mother at the time of conception.
• B. Sex-linked chromosomal abnormalities.
• C. An extra chromosome on the 21st pair.
• D. Drug abuse by the mother during pregnancy.

Correct answer: C

Rationale: Down's syndrome, also known as trisomy 21, is caused by the presence of an extra chromosome on the 21st pair. Choice A is incorrect as alcohol abuse is not the cause of Down's syndrome. Choice B is incorrect because Down's syndrome is not related to sex-linked chromosomal abnormalities. Choice D is also incorrect as drug abuse by the mother during pregnancy is not the cause of Down's syndrome.

2. After mitosis, the genetic code is identical in new cells unless _________ occur through radiation or other environmental influences.

• A. reductions
• B. expulsions
• C. conceptions
• D. mutations

Correct answer: D

Rationale: After mitosis, the genetic code is typically preserved and remains identical in the new cells. However, mutations can occur due to radiation or environmental influences, leading to changes in the DNA sequence and potentially altering the genetic code. Therefore, the correct answer is 'mutations.' Choices A, B, and C are incorrect because reductions, expulsions, and conceptions do not accurately describe the changes in the genetic code that can result from external factors. Mutations are the only option that reflects the alteration in the genetic code caused by external influences, making it the correct choice in this context.

3. Rico is a man who has enlarged breasts and suffers from mild mental retardation. He has a problem learning languages, and his body produces less of the male sex hormone testosterone than normal males. Rico is most likely suffering from:

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

Correct answer: A

Rationale: Rico's symptoms align with Klinefelter syndrome, which is characterized by an extra X chromosome in males (XXY). Enlarged breasts (gynecomastia), mild mental retardation, learning difficulties, and reduced testosterone production are common features of Klinefelter syndrome. Choice B, Tay-Sachs disease, is a genetic disorder that affects the nervous system and is not associated with the symptoms described. Choice C, Turner syndrome, occurs in females with a missing or partially missing X chromosome and does not fit Rico's profile. Choice D, Down syndrome, is caused by an extra copy of chromosome 21 and typically does not present with the symptoms mentioned for Rico.

4. 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.

5. What is the typical sex chromosome pattern for females?

• A. XX
• B. XYY
• C. XY
• D. XXY

Correct answer: A

Rationale: The typical sex chromosome pattern for females is XX. Females have two X chromosomes, which is represented as XX. Choice B (XYY) is incorrect as it represents the sex chromosome pattern for males with an extra Y chromosome. Choice C (XY) is the sex chromosome pattern for males. Choice D (XXY) represents a genetic disorder known as Klinefelter syndrome, where males have an extra X chromosome.

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