Nursing Elites

1. In the hierarchy of biology, cells combine to form which of the following?

• A. Macromolecules
• B. Molecules
• C. Tissues
• D. Organelles

Correct answer: C

Rationale: In the hierarchy of biology, cells combine to form tissues. Tissues are groups of cells that work together to perform specific functions. This is a fundamental level of organization above individual cells but below organs and organ systems. Macromolecules and molecules are smaller components that make up cells, not what cells combine to form. Organelles are structures within cells that perform specific functions and do not result from the combination of cells.

2. In meiosis, the chromosome number is reduced from:

• A. 46 to 23
• B. 46 to 33
• C. 28 to 14
• D. 24 to 12

Correct answer: A

Rationale: The correct answer is A: "46 to 23." In meiosis, the chromosome number is reduced by half to form gametes for sexual reproduction. In humans, where the diploid chromosome number is 46, meiosis results in haploid cells with 23 chromosomes. Choices B, C, and D are incorrect because they do not represent the correct reduction in chromosome number during meiosis.

3. The term pleiotropy is best defined as which of the following?

• A. A situation in which one gene remains unexpressed
• B. One gene influencing multiple, seemingly unrelated phenotypic traits
• C. Two genes affected by a single allele
• D. A condition in which multiple genes are missing

Correct answer: B

Rationale: Pleiotropy is best defined as one gene influencing multiple, seemingly unrelated phenotypic traits. This phenomenon showcases the multifunctionality of genes, where a single gene can have effects on various aspects of an organism's phenotype. Choices A, C, and D do not accurately capture the concept of pleiotropy. Option A refers to gene expression, not pleiotropy. Option C describes genetic interactions but not in the context of pleiotropy. Option D talks about missing genes, which is unrelated to the definition of pleiotropy.

4. A molecule's specific heat is the amount of heat necessary to raise the temperature of 1 gram of that molecule by:

• A. One degree Celsius
• B. Five degrees Celsius
• C. Two degrees Celsius
• D. Four degrees Celsius

Correct answer: A

Rationale: The correct answer is A: 'One degree Celsius.' Specific heat is defined as the amount of heat required to raise the temperature of one gram of a substance by one degree Celsius. This property is specific to each substance and is used in various calculations involving heat and temperature changes. Choices B, C, and D are incorrect because specific heat is always measured per one degree Celsius increase in temperature for one gram of the substance, not five degrees, two degrees, or four degrees.

5. 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.

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