Nursing Elites

1. Which of the following structures is not directly involved in translation?

• A. tRNA
• B. mRNA
• C. ribosome
• D. DNA

Correct answer: D

Rationale: The correct answer is 'D: DNA.' DNA is not directly involved in translation, which is the process of synthesizing proteins from mRNA. tRNA carries amino acids to the ribosome, mRNA provides the template for protein synthesis, and ribosomes are the cellular machinery where translation occurs. DNA's main role is in transcription, where it serves as the template for mRNA synthesis, not in translation.

2. Which of the following are found both in open and closed circulatory systems?

• A. Arteries
• B. Red blood cells
• C. Capillaries
• D. Immune cells

Correct answer: C

Rationale: The correct answer is C, Capillaries. Capillaries are found in both open and closed circulatory systems. Capillaries are small blood vessels that connect arteries and veins, allowing for the exchange of nutrients and wastes between the blood and tissues. They are essential components of circulatory systems regardless of whether they are open or closed. Arteries (Choice A) are not found in open circulatory systems, as these systems lack distinct arteries and veins. Red blood cells (Choice B) are present in the blood but are not exclusive to either open or closed circulatory systems. Immune cells (Choice D) are not specific components of circulatory systems, as they are part of the immune system.

3. 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.

4. Which of the following organelles are responsible for producing cell energy?

• A. Mitochondrion and chloroplast
• B. Mitochondrion and nucleus
• C. Chloroplast and nucleus
• D. Chloroplast and lysosome

Correct answer: A

Rationale: The correct answer is A: Mitochondrion and chloroplast. Mitochondria and chloroplasts are the organelles responsible for producing cell energy through cellular respiration and photosynthesis, respectively. Choice B is incorrect because the nucleus is not involved in energy production. Choice C is incorrect as the nucleus is not an organelle that produces energy. Choice D is incorrect as lysosomes function in digesting waste materials, not in energy production.

5. In order, from lower to upper, the layers of the atmosphere are:

• A. Exosphere, thermosphere, mesosphere, stratosphere, troposphere
• B. Troposphere, stratosphere, mesosphere, thermosphere, exosphere
• C. Mesosphere, troposphere, stratosphere, thermosphere, exosphere
• D. Thermosphere, troposphere, stratosphere, mesosphere, exosphere

Correct answer: B

Rationale: The correct order of the layers of the atmosphere, from lower to upper, is troposphere, stratosphere, mesosphere, thermosphere, exosphere. The troposphere is the lowest layer where weather phenomena occur. The stratosphere contains the ozone layer, which absorbs and scatters the solar ultraviolet radiation. The mesosphere is where most meteorites burn up upon entering the Earth's atmosphere. The thermosphere is characterized by high temperatures due to the absorption of solar radiation. The exosphere is the outermost layer where the atmosphere transitions into space. Therefore, option B is the correct sequence, as it reflects the ascending order of the Earth's atmospheric layers.

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