Nursing Elites

1. What is the role of RNA interference in silencing genes?

• A. Increases protein production
• B. Promotes gene mutation
• C. Inhibits the expression of specific genes
• D. Repairs damaged DNA

Correct answer: C

Rationale: Rationale: RNA interference (RNAi) is a biological process that involves the silencing of gene expression by inhibiting the translation of mRNA or by degrading mRNA molecules. This mechanism plays a crucial role in regulating gene expression and can be used to selectively silence specific genes. By interfering with the expression of specific genes, RNAi can downregulate protein production from those genes. Therefore, option C, "Inhibits the expression of specific genes," is the correct role of RNA interference in silencing genes.

2. The pH scale is used to indicate the concentration of:

• A. Oxygen
• B. Hydrogen ions
• C. Salts
• D. Sugar molecules

Correct answer: A

Rationale: The pH scale measures the concentration of hydrogen ions in a solution, indicating acidity or basicity.

3. How does RNA polymerase differ from DNA polymerase?

• A. Both enzymes are identical in function and structure.
• B. RNA polymerase does not require a primer to initiate RNA synthesis.
• C. RNA polymerase can synthesize both RNA and DNA.
• D. RNA polymerase can only synthesize RNA, unlike DNA polymerase.

Correct answer: B

Rationale: Rationale: A) This statement is incorrect. RNA polymerase and DNA polymerase are not identical in function and structure. They have different roles in the cell. B) This statement is correct. Unlike DNA polymerase, RNA polymerase does not require a primer to initiate RNA synthesis. RNA polymerase can start the synthesis of RNA de novo. C) This statement is incorrect. RNA polymerase is specialized for synthesizing RNA, not DNA. DNA polymerase is responsible for synthesizing DNA. D) This statement is correct. RNA polymerase can only synthesize RNA, while DNA polymerase is responsible for synthesizing DNA.

4. Which of the following structures is responsible for preventing the backflow of blood from the left ventricle into the left atrium?

• A. Aortic valve
• B. Pulmonary valve
• C. Tricuspid valve
• D. Mitral valve

Correct answer: D

Rationale: The correct answer is D, the mitral valve. The mitral valve, also known as the bicuspid valve, is located between the left atrium and the left ventricle. Its main function is to prevent the backflow of blood from the left ventricle into the left atrium during ventricular contraction. The aortic valve (A) is responsible for preventing the backflow of blood from the aorta into the left ventricle, the pulmonary valve (B) prevents backflow from the pulmonary artery into the right ventricle, and the tricuspid valve (C) prevents backflow from the right ventricle into the right atrium. Therefore, the mitral valve is specifically responsible for preventing backflow in the left side of the heart, making it the correct answer in this case.

5. Parkinson's disease is a neurodegenerative disorder affecting which neurotransmitter?

• A. Dopamine
• B. Acetylcholine
• C. Serotonin
• D. Glutamate

Correct answer: A

Rationale: The correct answer is A: Dopamine. Parkinson's disease is characterized by a progressive loss of dopamine-producing neurons in the brain. Dopamine is a neurotransmitter responsible for transmitting signals in the brain that control movement and coordination. A decrease in dopamine levels leads to the typical motor symptoms of Parkinson's, such as tremors, rigidity, and bradykinesia. Acetylcholine (option B) is involved in muscle movement but is not primarily affected in Parkinson's disease. Serotonin (option C) and glutamate (option D) are neurotransmitters that play different roles in the brain and are not primarily associated with Parkinson's disease. Therefore, the correct neurotransmitter affected in Parkinson's disease is dopamine.

6. Which term describes the quantity of matter in an object and is measured in kilograms or grams?

• A. Weight
• B. Mass
• C. Volume
• D. Density

Correct answer: B

Rationale: Mass is the term that describes the quantity of matter in an object. It is typically measured in kilograms or grams. Weight, on the other hand, is the force of gravity acting on an object and is measured in newtons. Volume is the amount of space an object occupies, typically measured in cubic units such as cubic meters or cubic centimeters. Density is the mass of an object per unit volume and is measured in units such as kilograms per cubic meter.

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