HESI A2 Biology Practice Test 2024

Correct Answer: B

Rationale: The correct answer is B: Cell. Cells are the fundamental unit of life because they are the basic building blocks of all living organisms. Cells carry out essential functions such as metabolism, growth, and reproduction. Tissues (C) are made up of cells, organs (D) are made up of tissues, and atoms (A) are the smallest unit of matter and are not considered the fundamental unit of life. Therefore, the correct choice is B as it represents the starting point of all living organisms.

Correct Answer: B

Rationale: Passive transport is the term for the movement of ions and other molecular substances across cell membranes without the need for energy. This process relies on the concentration gradient to drive molecules from an area of high concentration to an area of low concentration. Unlike active transport (choice A), which requires energy, passive transport does not involve energy consumption. Diffusion (choice C) is a type of passive transport where molecules move freely across the membrane. Osmosis (choice D) is a specific type of passive transport involving the movement of water molecules across a selectively permeable membrane.

Correct Answer: B

Rationale: The correct answer is B: Communication. The cell membrane serves as a barrier that regulates the passage of materials in and out of the cell. It also plays a crucial role in cell communication by allowing the exchange of signals and molecules with the external environment and other cells. This communication is essential for coordinating various cellular processes and maintaining homeostasis. Other choices are incorrect: A: Energy production - This function is primarily carried out by organelles such as mitochondria and chloroplasts, not the cell membrane. C: Protein synthesis - Protein synthesis occurs in the ribosomes within the cell, not the cell membrane. D: Waste removal - While the cell membrane does play a role in waste removal by allowing certain materials to exit the cell, it is not its main function.

Correct Answer: B

Rationale: The correct answer is B: Mitochondria. Mitochondria are known as the powerhouse of the cell as they produce energy through the process of respiration. They contain enzymes responsible for converting nutrients into ATP, the energy currency of the cell. The nucleus (A) is responsible for storing genetic material, Golgi Apparatus (C) is involved in protein processing and packaging, and Chloroplasts (D) are responsible for photosynthesis in plant cells, not respiration.

Correct Answer: C

Rationale: The correct answer is C: Peroxisomes. Peroxisomes are responsible for detoxifying harmful substances in the cell by using enzymes to break down toxic molecules like hydrogen peroxide. This organelle contains catalase, an enzyme that converts hydrogen peroxide into water and oxygen. Endoplasmic Reticulum (choice A) is involved in protein synthesis and lipid metabolism. Lysosomes (choice B) are responsible for breaking down cellular waste and recycling materials. Golgi Apparatus (choice D) is involved in processing and packaging proteins for secretion. Therefore, Peroxisomes specifically handle detoxification, making it the correct choice.