Biology HESI A2 Practice Test

Correct Answer: A

Rationale: The correct answer is A because the apical side of an epithelial cell is the top surface that is exposed to fluid or air. This surface is specialized for absorption, secretion, and protection. Choice B is incorrect because the apical side is actually the top side of the cell, not the bottom. Choice C is incorrect because the apical side allows substances to pass through via various transport mechanisms such as active transport, facilitated diffusion, or simple diffusion. Choice D is incorrect because the apical side of an epithelial cell is indeed exposed to fluid or air, making it the correct answer.

Correct Answer: B

Rationale: The correct answer is B: mitochondria. Heart muscle cells require a significant amount of energy to constantly contract and pump blood, making mitochondria crucial for energy production through aerobic respiration. Mitochondria are abundant in heart muscle cells to meet their high energy demands. Lysosomes (A) are involved in cellular waste disposal, mRNA (C) carries genetic information, and ribosomes (D) are involved in protein synthesis, but they are not expected to be unusually high in heart muscle cells.

Correct Answer: A

Rationale: The correct answer is A: Ribosome. Ribosomes are the organelles responsible for protein synthesis in the cell. They can be found in the cytoplasm or attached to the endoplasmic reticulum. Ribosomes read the mRNA and assemble amino acids into proteins through a process called translation. Summary of other choices: B: Chloroplast - responsible for photosynthesis in plant cells. C: Lysosome - contains enzymes for digesting waste materials. D: Mitochondrion - produces ATP through cellular respiration. These organelles are not directly involved in protein synthesis, making them incorrect choices for this question.

Correct Answer: B

Rationale: The correct answer is B: Tendons, ligaments. Tendons connect muscles to bones, enabling movement. Ligaments connect bones to each other, providing stability. Muscles and ligaments are not directly involved in connecting muscles to bones. Therefore, option B is the most appropriate choice.

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.