Nursing Elites

1. How many pairs of chromosomes do all humans have?

• A. 24 pairs
• B. 23 pairs
• C. 22 pairs
• D. 20 pairs

Correct answer: B

Rationale: All humans have 23 pairs of chromosomes, totaling 46 chromosomes. Choice A is incorrect because humans do not have 24 pairs. Choice C is incorrect as humans have 23 pairs, not 22 pairs. Choice D is incorrect as humans have 23 pairs of chromosomes, not 20 pairs.

2. In an example of a male with hemophilia and a female carrier, what ratio of the offspring is predicted to have the disease?

• A. 0 female : 2 males
• B. 1 female : 0 males
• C. 1 female : 2 males
• D. 2 females : 1 male

Correct answer: C

Rationale: In this scenario, the male offspring will inherit the hemophilia trait from their mother due to the sex-linked inheritance pattern. The female offspring will inherit one X chromosome from their mother, becoming carriers of hemophilia. Therefore, the predicted ratio of offspring with the disease would be 1 female as a carrier and 2 males with hemophilia. Choice A is incorrect because there would be male offspring with the disease. Choice B is incorrect as there would be male offspring with hemophilia. Choice D is incorrect as it does not reflect the inheritance pattern of hemophilia.

3. How many phases are there in the process of mitosis?

• A. 2
• B. 3
• C. 4
• D. 5

Correct answer: C

Rationale: The correct answer is C: '4'. Mitosis consists of four phases: prophase, metaphase, anaphase, and telophase. These phases are crucial in the orderly division of the cell's genetic material. Choice A is incorrect because mitosis is a more complex process involving multiple phases. Choice B is incorrect as it is one phase short of the total phases in mitosis. Choice D is incorrect as mitosis does not consist of five phases.

4. In contrast with triglycerides, phospholipids are lacking one of which of the following components?

• A. Monosaccharide
• B. Glycerol
• C. Phosphates
• D. Fatty acid

Correct answer: B

Rationale: Phospholipids are structurally similar to triglycerides but lack one of the fatty acid chains that triglycerides possess. Triglycerides consist of three fatty acid chains attached to a glycerol molecule, while phospholipids have two fatty acid chains and a phosphate group attached to a glycerol backbone. Therefore, phospholipids are lacking the third fatty acid chain found in triglycerides. Choice A (Monosaccharide) is incorrect because neither triglycerides nor phospholipids contain monosaccharides in their structure. Choice C (Phosphates) is incorrect because phospholipids actually contain phosphates, unlike triglycerides. Choice D (Fatty acid) is incorrect as both triglycerides and phospholipids contain fatty acids, but the number of fatty acid chains differs between the two.

5. Duchenne muscular dystrophy is a recessive sex-linked trait carried on the X chromosome. In an example of an unaffected father and a female carrier who have two daughters and two sons, which is the predicted outcome?

• A. Both daughters will carry the disease.
• B. Both sons will carry the disease.
• C. One daughter may have the disease.
• D. One son may have the disease.

Correct answer: C

Rationale: Duchenne muscular dystrophy is a recessive sex-linked trait carried on the X chromosome. Since the father is unaffected and does not carry the disease, he must have a normal X chromosome. The mother is a carrier, which means she has one normal X chromosome and one X chromosome with the disease allele. The daughters will inherit one X chromosome from each parent; one would be normal, and the other has a chance of carrying the disease allele. So, there is a 50% chance that one daughter may have the disease, as she could inherit the X chromosome with the disease allele. The sons will inherit the Y chromosome from the father and the X chromosome from the mother, so they will not be affected by the disease. Therefore, the predicted outcome is that one daughter may have the disease, while the sons will not carry the disease. This rules out choices A, B, and D.

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