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: 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. Options A, B, and D are incorrect because RNA interference does not increase protein production, promote gene mutation, or repair damaged DNA; its primary function is to inhibit gene expression by degrading or interfering with mRNA.

2. What is the main function of dietary fiber in the digestive system?

• A. To provide energy
• B. To break down fats
• C. To promote gut bacteria growth
• D. To aid in absorption of nutrients

Correct answer: C

Rationale: Dietary fiber refers to the indigestible portion of plant foods that passes relatively intact through the digestive system. While fiber does not directly provide energy to the body, it plays a crucial role in promoting the growth of beneficial gut bacteria. These bacteria help in the fermentation of fiber, producing short-chain fatty acids that can be used as an energy source by the body. Additionally, fiber aids in regulating bowel movements, maintaining gut health, and supporting overall digestive function. The functions described in the incorrect choices do not align with the primary role of dietary fiber in the digestive system. Choice A is incorrect because fiber itself is not a direct energy source. Choice B is incorrect as fiber does not break down fats. Choice D is incorrect because while fiber affects nutrient absorption indirectly by supporting gut health, its primary role is not to aid in the absorption of nutrients.

3. In a balanced chemical equation, the coefficients represent the:

• A. Number of elements
• B. Ratio of reactants and products
• C. Physical state of the substances
• D. Rate of the reaction

Correct answer: A

Rationale: The correct answer is A: 'Number of elements.' In a balanced chemical equation, coefficients represent the ratio of moles of each species involved in the reaction. They indicate the relative number of molecules or formula units of each compound taking part in the reaction. Choice B, 'Ratio of reactants and products,' is incorrect because the coefficients in a balanced equation do not represent the ratio of reactants and products directly, but rather the stoichiometry of the reaction. Choice C, 'Physical state of the substances,' is incorrect because the physical states (solid, liquid, gas, or aqueous) are denoted with symbols next to the chemical formula, not the coefficients. Choice D, 'Rate of the reaction,' is incorrect as coefficients in a balanced equation do not provide information about the rate of the reaction, which is determined by factors like temperature, concentration, and catalysts.

4. Which of the following is an example of an unsaturated fatty acid?

• A. Stearic acid
• B. Palmitic acid
• C. Oleic acid
• D. Butyric acid

Correct answer: C

Rationale: Oleic acid is an example of an unsaturated fatty acid because it contains one or more double bonds in its hydrocarbon chain, leading to kinks in the chain structure. This unsaturation gives it a lower melting point compared to saturated fatty acids. Stearic acid (A), Palmitic acid (B), and Butyric acid (D) are examples of saturated fatty acids as they do not contain any double bonds in their hydrocarbon chains, leading to a straight structure and higher melting points.

5. Which hormone primarily triggers ovulation in the female menstrual cycle?

• A. Estrogen
• B. Progesterone
• C. Luteinizing hormone (LH)
• D. Follicle-stimulating hormone (FSH)

Correct answer: C

Rationale: Luteinizing hormone (LH) is the hormone primarily responsible for triggering ovulation in the female menstrual cycle. LH surge occurs around the middle of the menstrual cycle, causing the mature follicle to release an egg from the ovary. Estrogen and progesterone play crucial roles in regulating the menstrual cycle and preparing the endometrium for potential implantation of a fertilized egg, but they do not trigger ovulation directly. Follicle-stimulating hormone (FSH) is essential for the development of ovarian follicles but is not the primary hormone responsible for ovulation. Therefore, the correct answer is Luteinizing hormone (LH) as it directly initiates the release of the egg during ovulation.

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