Nursing Elites

1. What are the differences between RNA and DNA?

• A. Both have the same structure and function.
• B. RNA is single-stranded, while DNA is double-stranded.
• C. RNA contains ribose sugar, while DNA contains deoxyribose sugar.
• D. RNA has adenine and guanine, while DNA has thymine and cytosine.

Correct answer: B

Rationale: A) This statement is incorrect. RNA and DNA have different structures and functions. RNA is involved in protein synthesis and other cellular processes, while DNA stores genetic information. B) This statement is correct. RNA is typically single-stranded, while DNA is double-stranded, forming a double helix structure. C) This statement is correct. RNA contains ribose sugar in its backbone, while DNA contains deoxyribose sugar. D) This statement is incorrect. RNA contains adenine, guanine, cytosine, and uracil, while DNA contains adenine, guanine, cytosine, and thymine. Choice B is the correct answer as it accurately describes one of the key differences between RNA and DNA, emphasizing their structural disparity in terms of single-strandedness for RNA and double-strandedness for DNA. Choices A, C, and D contain inaccuracies regarding the structural and compositional distinctions between RNA and DNA, making them incorrect choices.

2. The Gram stain is a differential staining technique used to classify bacteria based on their cell wall composition. Gram-positive bacteria appear

• A. Pink
• B. Blue
• C. Red
• D. Purple

Correct answer: D

Rationale: The Gram stain is a differential staining technique that categorizes bacteria into two groups based on their cell wall composition: Gram-positive and Gram-negative. Gram-positive bacteria have a thick layer of peptidoglycan in their cell walls, which retains the crystal violet stain used in the Gram staining procedure. Consequently, Gram-positive bacteria appear purple under the microscope after staining. On the other hand, Gram-negative bacteria possess a thinner peptidoglycan layer and an outer membrane that can be penetrated by the counterstain safranin, leading them to appear pink or red. Blue is not typically used to describe the color of bacteria in a Gram stain, making it an incorrect choice.

3. What are the three types of capillaries?

• A. Continuous, fenestrated, sinusoidal
• B. Continuous, discontinuous, fenestrated
• C. Sinusoidal, alveolar, continuous
• D. Continuous, fenestrated, vascular

Correct answer: A

Rationale: The correct answer is A: Continuous, fenestrated, sinusoidal. Capillaries are classified into three types based on their permeability: continuous (least permeable), fenestrated (moderately permeable), and sinusoidal (most permeable). Choices B, C, and D are incorrect because they do not represent the three main types of capillaries. Choice B includes 'discontinuous' which is not a recognized type. Choice C includes 'alveolar' which is not a type of capillary, and Choice D includes 'vascular' which is too broad and not specific to capillary classification.

4. Which of the following is an example of a salt?

• A. Sodium hydroxide (NaOH)
• B. Hydrochloric acid (HCl)
• C. Sodium chloride (NaCl)
• D. Sulfuric acid (H₂SO₄)

Correct answer: C

Rationale: Sodium chloride (NaCl) is an example of a salt. Salts are ionic compounds formed by the reaction of an acid with a base. In this case, sodium chloride is formed by the reaction of sodium hydroxide (a base) with hydrochloric acid (an acid). Sodium hydroxide (NaOH), hydrochloric acid (HCl), and sulfuric acid (H₂SO₄) are not salts because they are not formed by the neutralization reaction of an acid and a base, which is a characteristic of salts.

5. What functional group is present in esters?

• A. Hydroxyl
• B. Carbonyl
• C. Ester
• D. Amine

Correct answer: C

Rationale: The functional group present in esters is -COO-, which represents a carbonyl group bonded to an oxygen atom. This group is responsible for the characteristic fruity aroma of esters. Choice A, 'Hydroxyl,' refers to -OH, which is a characteristic group of alcohols, not esters. Choice B, 'Carbonyl,' is a broad term that includes various compounds with a C=O group, but specifically in esters, it is a carbonyl group bonded to an oxygen atom. Choice D, 'Amine,' refers to compounds containing a nitrogen atom bonded to hydrogen atoms or alkyl groups, which is not present in esters. Therefore, the correct answer is 'C: Ester.'

Similar Questions