Nursing Elites

1. What is the composition of the cellular membrane?

• A. A bilayer of phospholipid molecules
• B. A single layer of phospholipid molecules
• C. Proteins that act as transport highways
• D. Carbohydrates

Correct answer: A

Rationale: The cellular membrane is primarily composed of a phospholipid bilayer, which consists of two layers of phospholipid molecules. These molecules have a hydrophilic (water-attracting) head and hydrophobic (water-repelling) tail, creating a barrier that separates the internal cellular environment from the external surroundings. While proteins are embedded within this bilayer and act as transport channels, receptors, and structural support, carbohydrates are found on the outer surface of the membrane for cell recognition and signaling purposes. Therefore, the correct answer is a bilayer of phospholipid molecules.

2. Which organelle is responsible for the synthesis of lipids and steroid hormones?

• A. Rough endoplasmic reticulum
• B. Smooth endoplasmic reticulum
• C. Golgi apparatus
• D. Ribosomes

Correct answer: B

Rationale: The smooth endoplasmic reticulum is the correct organelle responsible for the synthesis of lipids, including phospholipids, cholesterol, and steroid hormones. The rough endoplasmic reticulum is primarily involved in protein synthesis and processing, making choice A incorrect. The Golgi apparatus is responsible for modifying, sorting, and packaging proteins and lipids for transportation, so it is not directly involved in lipid and steroid hormone synthesis, making choice C incorrect. Ribosomes are responsible for protein synthesis and are not involved in lipid or steroid hormone synthesis, making choice D incorrect.

3. Which of the following correctly identifies the two types of cells?

• A. Mitosis and meiosis
• B. Mitochondrion and chloroplast
• C. Genotype and phenotype
• D. Prokaryotic and eukaryotic

Correct answer: D

Rationale: The correct answer is D: Prokaryotic and eukaryotic. Cells are classified into two major types: prokaryotic, which lack a nucleus, and eukaryotic, which have a defined nucleus and other membrane-bound organelles. Choice A, mitosis and meiosis, refers to cell division processes. Choice B, mitochondrion and chloroplast, are cell organelles involved in energy production and photosynthesis, respectively. Choice C, genotype and phenotype, relate to genetic characteristics and physical traits, not cell types.

4. What is the main objective of the translation stage of protein synthesis?

• A. To produce amino acids
• B. To produce nucleotides
• C. To produce fatty acids
• D. To produce proteins

Correct answer: D

Rationale: The main objective of the translation stage of protein synthesis is to produce proteins. During translation, ribosomes decode mRNA sequences to synthesize proteins by linking amino acids together. Choice A, 'To produce amino acids,' is incorrect as amino acids are the building blocks of proteins and are not produced during translation. Choices B and C, 'To produce nucleotides' and 'To produce fatty acids,' are also incorrect as these molecules are not the direct products of the translation stage of protein synthesis.

5. What is the difference between DNA and RNA?

• A. RNA has an extra Phosphate group
• B. DNA has one less oxygen than RNA
• C. RNA has one less oxygen than DNA
• D. DNA has an extra sugar molecule

Correct answer: B

Rationale: The correct answer is B. DNA has one less oxygen atom in its sugar molecule (deoxyribose) compared to RNA, which has a ribose sugar. Choice A is incorrect because RNA does not have an extra phosphate group. Choice C is incorrect as RNA actually has one more oxygen atom than DNA. Choice D is incorrect as DNA and RNA have different sugar molecules, with DNA having deoxyribose and RNA having ribose.

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