HESI A2 Biology Practice Test

Correct Answer: D

Rationale: Failed to generate a rationale after 5 retries.

Correct Answer: D

Rationale: The plasma membrane is a phospholipid bilayer, meaning it consists of two layers of phospholipid molecules. This arrangement forms a barrier that separates the cell from its external environment. The hydrophobic tails of the phospholipids face inward, while the hydrophilic heads face outward. This structure allows the membrane to control the movement of substances in and out of the cell. Choices A and B are incorrect as the membrane is not solely made of proteins. Choice C is incorrect as the membrane consists of a double layer of phospholipids, not a single layer.

Correct Answer: B

Rationale: The correct answer is B because animal cells do not use chloroplasts to gain energy, they use mitochondria for cellular respiration. Lysosomes in animal cells break down old cells (A) and plant cells have a cell wall (C). Choice D is incorrect as B is false.

Correct Answer: A

Rationale: The correct order of the hierarchy in biological classification is Kingdom, Phylum, Class, Order, Family, Genus, and Species. This system is known as the Linnaean taxonomy. Kingdom is the broadest category, followed by Phylum which groups organisms based on major body features. Class further refines this classification, followed by Order, which organizes similar families. Family groups similar genera, and Genus is a group of closely related species. Finally, Species is the most specific category, representing individual organisms. This hierarchical structure allows for easy organization and categorization of living organisms based on shared characteristics. Choices B, C, and D are incorrect because they do not follow the correct order of the biological classification hierarchy.

Correct Answer: D

Rationale: The correct answer is D: Biomes. Biomes are large geographical areas characterized by specific climate, vegetation, and animal life. Tundra, savannas, grasslands, deserts, and rainforests are all examples of biomes. They are classified based on factors like temperature, precipitation, and flora/fauna. Biomasses (A) refer to the total mass of living organisms in a given area. Biospheres (B) are the regions of the Earth where life exists. Biodiversity (C) refers to the variety and variability of life forms in a specific habitat, not the specific types of habitats themselves.