Biology HESI A2 Practice Test

Correct Answer: B

Rationale: The correct answer is B: Cell wall. Plant cells have a rigid cell wall made of cellulose, which provides structural support and protection. Animal cells lack cell walls and instead have a flexible cell membrane for support. Choices A, C, and D (Cell membrane, Ribosome, Chloroplast) are present in both plant and animal cells. The cell membrane controls what enters and leaves the cell, ribosomes are responsible for protein synthesis, and chloroplasts are the site of photosynthesis in plant cells.

Correct Answer: A

Rationale: Enzymes can catalyze reactions by lowering the activation energy required for the reaction to occur, thus increasing the reaction rate. This is achieved through the formation of enzyme-substrate complexes. Inhibition refers to the process of preventing enzyme activity, which is contrary to the function of enzymes. Stopping reactions is not the role of enzymes. Therefore, the correct answer is A: Catalyze.

Correct Answer: C

Rationale: The correct answer is C: prokaryotic. Prokaryotic cells lack membrane-bound organelles and a defined nucleus. They have a simple structure with genetic material floating freely in the cytoplasm. Eukaryotic cells (choice A) have membrane-bound organelles and a nucleus. Embryonic (choice B) refers to a developmental stage, not a cell classification. Symbiotic (choice D) relates to a mutually beneficial relationship between two organisms, not cell classification. In summary, prokaryotic cells are characterized by their lack of membrane-bound organelles and nucleus, distinguishing them from eukaryotic cells, embryonic stages, and symbiotic relationships.

Correct Answer: C

Rationale: The correct answer is C: Prophase, prometaphase, metaphase, anaphase, and telophase. 1. Prophase: Chromosomes condense and become visible. 2. Prometaphase: Nuclear envelope breaks down, spindle fibers attach to chromosomes. 3. Metaphase: Chromosomes line up at the metaphase plate. 4. Anaphase: Sister chromatids separate and move towards opposite poles. 5. Telophase: Chromatids reach poles, nuclear envelope reforms. Other choices are incorrect because they either include incorrect phases (A, B) or repeat phases (D).

Correct Answer: A

Rationale: The correct answer is A: hypothesis. A hypothesis is a statement that proposes an explanation for a phenomenon based on available evidence. It helps guide scientific inquiry by providing a testable prediction. Observations (B) are simply data collected through senses. Experiments (C) involve testing hypotheses through controlled conditions. Conclusions (D) are interpretations drawn from the data collected. Therefore, a hypothesis is the initial statement or explanation of certain events or happenings in the scientific process.