Nursing Elites

1. According to a survey by Adhikari and Liu in the year 2013, at birth, women have:

• A. close to 100,000 ova.
• B. around 300,000 to 400,000 ova.
• C. around 100 to 200 ova.
• D. only 500 ova.

Correct answer: B

Rationale: Women are born with approximately 300,000 to 400,000 ova, which gradually decrease in number as they age. Choice A ('close to 100,000 ova.') is incorrect as the actual number is much higher. Choice C ('around 100 to 200 ova.') is incorrect as it underestimates the quantity significantly. Choice D ('only 500 ova.') is incorrect as it greatly underestimates the number of ova present at birth.

2. 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.

3. Rh incompatibility occurs when an Rh-negative woman is carrying an Rh-positive fetus.

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

Correct answer: B

Rationale: Rh incompatibility occurs when an Rh-negative woman is carrying an Rh-positive fetus, not the other way around. Therefore, the statement that an Rh-positive woman is carrying an Rh-negative fetus is incorrect. Rh incompatibility can lead to hemolytic disease of the newborn, where maternal antibodies attack the fetal red blood cells. Choice A is incorrect because the statement is false. Choice C is incorrect as Rh incompatibility has a clear cause and effect relationship. Choice D is incorrect as Rh incompatibility can occur, but it depends on the Rh status of the mother and fetus.

4. What is the central layer of the embryo from which the bones and muscles develop?

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

Correct answer: B

Rationale: The correct answer is mesoderm. The mesoderm is the middle layer of the embryo that gives rise to the bones, muscles, and other connective tissues. The neural tube (choice A) develops into the nervous system, not bones and muscles. The ectoderm (choice C) forms the skin and nervous system, not bones and muscles. The umbilical cord (choice D) is a structure that connects the developing fetus to the placenta; it is not a layer of the embryo that gives rise to bones and muscles.

5. After meiosis, each new cell nucleus contains _____ chromosomes.

• A. 46
• B. 35
• C. 23
• D. 12

Correct answer: C

Rationale: After meiosis, each resulting cell contains 23 chromosomes. Meiosis is a process that involves two sequential divisions resulting in four daughter cells, each with half the number of chromosomes as the parent cell. In humans, the parent cell has 46 chromosomes (diploid), and after meiosis, the resulting cells (sperm or ova) have 23 chromosomes (haploid). Choice A (46 chromosomes) is incorrect because this is the number of chromosomes in a human diploid cell before meiosis. Choices B (35 chromosomes) and D (12 chromosomes) are incorrect as they do not represent the correct number of chromosomes after meiosis in human cells.

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