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. Which of the following pairs of bases is present in the rungs of the ladder-like structure of deoxyribonucleic acid (DNA)?

• A. Cytosine with guanine.
• B. Rhodamine with biotin.
• C. Diaminopurine with ribozyme.
• D. Serine with tyrosine.

Correct answer: A

Rationale: The correct answer is A: Cytosine with guanine. In the DNA double helix, cytosine always pairs with guanine forming a base pair, and adenine pairs with thymine. These complementary base pairs form the rungs of the ladder-like structure of DNA. Choice B, Rhodamine with biotin, is incorrect as they are not base pairs found in DNA. Choice D, Serine with tyrosine, is incorrect as they are amino acids, not DNA bases. Choice C, Diaminopurine with ribozyme, is also incorrect as ribozyme is an enzyme, not a base, and diaminopurine is not one of the standard bases found in DNA.

3. In the structure of deoxyribonucleic acid (DNA), which of the following bases combines with thymine?

• A. Cytosine
• B. Adenine
• C. Rhodamine
• D. Serine

Correct answer: B

Rationale: The correct answer is B: Adenine. In the structure of DNA, adenine pairs with thymine through hydrogen bonding, forming one of the complementary base pairs that make up the double helix structure of DNA. Cytosine pairs with guanine, not thymine. Rhodamine and serine are not DNA bases and do not participate in DNA base pairing. Therefore, choices A, C, and D are incorrect.

4. Which of the following conditions is considered a multifactorial problem?

• A. Cystic fibrosis
• B. Down syndrome
• C. Diabetes mellitus
• D. XYY syndrome

Correct answer: C

Rationale: The correct answer is 'Diabetes mellitus' because it is a multifactorial disease, influenced by both genetic predisposition and environmental factors. Cystic fibrosis (choice A) is primarily a genetic disorder caused by mutations in the CFTR gene. Down syndrome (choice B) is due to an extra copy of chromosome 21. XYY syndrome (choice D) is a genetic condition where males have an extra Y chromosome. These conditions are not considered multifactorial as their origins are primarily genetic.

5. Which of the following statements about Rh incompatibility is true?

• A. Rh incompatibility occurs most commonly during a woman’s first pregnancy.
• B. Rh incompatibility is an untreatable condition that leaves a woman infertile for the rest of her life.
• C. Rh incompatibility is an abnormality that is transmitted from generation to generation and carried by a sex chromosome.
• D. Rh incompatibility occurs due to antibodies transmitted to a fetus during subsequent deliveries causing brain damage or death.

Correct answer: D

Rationale: Rh incompatibility occurs when the mother's antibodies attack the fetus's red blood cells, leading to serious complications, usually in subsequent pregnancies. Choice A is incorrect because Rh incompatibility often occurs in subsequent pregnancies, not necessarily the first one. Choice B is incorrect as Rh incompatibility does not render a woman infertile but can lead to complications during pregnancies. Choice C is incorrect as Rh incompatibility is not carried by a sex chromosome but involves the Rh factor on red blood cells.

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