Nursing Elites

1. 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.

2. What propels the cell forward?

• A. Microfilaments
• B. Propulsion
• C. Cilia
• D. Flagella

Correct answer: B

Rationale: Propulsion, not microfilaments, cilia, or flagella, is what drives the cell forward. Propulsion is the force or process that propels the cell forward and allows it to move within its environment. Microfilaments are involved in cell structure, cilia are small hair-like structures for movement, and flagella are tail-like structures used for cell propulsion in some organisms.

3. The fur color in a population of dogs is controlled by two alleles: black (B) and tan (b). The black allele exhibits complete dominance. If the phenotype of the dog is tan fur, what is its genotype?

• A. BB
• B. Bb
• C. bb
• D. Not enough information

Correct answer: C

Rationale: The correct answer is C: "bb." Since tan fur is the recessive trait controlled by the allele 'b,' the only possible genotype for a dog with tan fur is 'bb.' If a dog had the genotype 'BB' or 'Bb,' the dominant trait (black fur) would be expressed, not tan fur. Choice D, 'Not enough information,' is incorrect because based on the information provided, we can deduce the genotype of a dog with tan fur.

4. A cell from heart muscle would more than likely contain an unusually high proportion of which of the following?

• A. lysosomes
• B. mitochondria
• C. mRNA
• D. ribosomes

Correct answer: B

Rationale: A cell from heart muscle would more than likely contain an unusually high proportion of mitochondria because the heart muscle requires a significant amount of energy to function properly. Mitochondria are the powerhouse of the cell and are responsible for producing energy in the form of ATP through cellular respiration. Therefore, to meet the high energy demands of the heart muscle, it would need a higher concentration of mitochondria compared to other cell types. Choices A, C, and D are incorrect because while lysosomes, mRNA, and ribosomes are essential components of a cell, they do not play as direct a role in meeting the high energy demands of heart muscle as mitochondria do.

5. What is the term for the breakdown of glycogen into glucose subunits?

• A. Hydrolysis
• B. Reduction
• C. Metabolism
• D. Transpiration

Correct answer: A

Rationale: Hydrolysis is the term used to describe the breakdown of large molecules into smaller units by adding water. In the case of glycogen being broken down into glucose subunits, this process involves the addition of water molecules to break the glycosidic bonds between glucose molecules, resulting in the release of individual glucose subunits. This process is crucial for providing cells with a source of energy when needed. Choice B, Reduction, refers to a chemical reaction involving a gain of electrons or a decrease in oxidation state, not the breakdown of glycogen into glucose subunits. Choice C, Metabolism, is a broad term encompassing all biochemical processes in an organism, including anabolism and catabolism, but does not specifically describe the breakdown of glycogen into glucose subunits. Choice D, Transpiration, is the process of water movement through a plant and is not related to the breakdown of glycogen into glucose subunits.

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