Nursing Elites

1. Prophase is the first stage of mitosis. Which of the following best describes chromosomes during this stage?

• A. They are gathered on either side of the separating cell
• B. They are all aligned along the metaphase plate
• C. They are attached to the spindle
• D. They are visibly separate

Correct answer: D

Rationale: The correct answer is D. During prophase, the chromosomes condense and become visible as distinct structures under a microscope. Choice A is incorrect as chromosomes are not gathered on either side of the separating cell during prophase. Choice B is incorrect because chromosomes align along the metaphase plate during the subsequent stage, metaphase. Choice C is incorrect as chromosomes become attached to the spindle fibers during prometaphase, the stage following prophase.

2. A water molecule contains two types of atoms that are covalently bonded. Which of the following makes up a water molecule?

• A. One hydrogen atom and one oxygen atom
• B. One hydrogen atom and two oxygen atoms
• C. Two hydrogen atoms and two oxygen atoms
• D. Two hydrogen atoms and one oxygen atom

Correct answer: D

Rationale: The correct answer is D: Two hydrogen atoms and one oxygen atom. A water molecule consists of two hydrogen atoms covalently bonded to one oxygen atom. This forms a stable structure known as H2O. Choice A is incorrect as water molecule contains two hydrogen atoms. Choices B and C are incorrect as they do not reflect the correct composition of a water molecule.

3. In DNA, the nucleotide base adenine always binds with which of the following?

• A. Guanine
• B. Uracil
• C. Thymine
• D. Cytosine

Correct answer: C

Rationale: The correct answer is C: Thymine. In DNA, adenine always pairs with thymine, forming a base pair held together by hydrogen bonds. Guanine pairs with cytosine. Uracil is found in RNA, not DNA. Cytosine pairs with guanine. Therefore, option C is the correct pairing for adenine in DNA.

4. The Punnett square shows that one parent carries the recessive gene for a cleft chin (c) while the other parent does not. What percentage of the parents' offspring is predicted to have a cleft chin?

• A. 25%
• B. 50%
• C. 0%
• D. 75%

Correct answer: C

Rationale: The correct answer is 0%. If one parent carries the recessive gene for a cleft chin while the other parent does not, none of the offspring will express the recessive phenotype. This is because in order for a child to have a cleft chin, they would need to inherit the recessive gene from both parents. Therefore, although the offspring could be carriers of the gene, none are predicted to have a cleft chin. Choices A, B, and D are incorrect because the presence of the recessive gene in one parent and its absence in the other would not result in any offspring showing the cleft chin trait.

5. In meiosis, the chromosome number is reduced from:

• A. 46 to 23
• B. 46 to 33
• C. 28 to 14
• D. 24 to 12

Correct answer: A

Rationale: The correct answer is A: "46 to 23." In meiosis, the chromosome number is reduced by half to form gametes for sexual reproduction. In humans, where the diploid chromosome number is 46, meiosis results in haploid cells with 23 chromosomes. Choices B, C, and D are incorrect because they do not represent the correct reduction in chromosome number during meiosis.

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