HESI A2 Biology Practice Test 2024

Correct Answer: B

Rationale: The correct answer is B: Ribosomes. Ribosomes are the organelles responsible for protein synthesis. They are either free-floating in the cytoplasm or attached to the endoplasmic reticulum. Ribosomes read the mRNA and assemble amino acids into proteins during the process of translation. The other choices (A: Endoplasmic Reticulum, C: Lysosomes, D: Vacuoles) are incorrect because the endoplasmic reticulum is involved in protein processing and transport, lysosomes are involved in digestion and waste removal, and vacuoles are involved in storage and maintaining cell structure, not protein synthesis.

Correct Answer: B

Rationale: The correct answer is B: Propulsion. This is because propulsion refers to the act of driving or moving something forward, which is exactly what propels the cell forward. Microfilaments (choice A) are involved in providing structural support and movement within the cell, but they do not directly propel the cell forward. Cilia (choice C) and flagella (choice D) are external structures that can help with cell movement, but they do not serve as the primary driving force behind the cell's forward movement. Therefore, choice B is the correct answer as it directly relates to the action of moving the cell forward.

Correct Answer: C

Rationale: The correct answer is C: 4. Mitosis consists of four phases: prophase, metaphase, anaphase, and telophase. In prophase, chromosomes condense. In metaphase, chromosomes align at the cell equator. In anaphase, sister chromatids separate and move to opposite poles. In telophase, the nuclear envelope reforms. Choices A, B, and D are incorrect because mitosis is a complex process that involves more than 2 or 3 phases.

Correct Answer: B

Rationale: The correct answer is B: Cell Membrane. The cell membrane is the most important component contributing to protection, communication, and the passage of substances. It acts as a barrier, protecting the cell from external threats. It also regulates the passage of substances in and out of the cell through selective permeability. Additionally, the cell membrane contains receptors and proteins that facilitate cell communication. A: Cytoplasm is important for various cellular functions but does not directly contribute to protection, communication, or substance passage. C: Cytoskeleton provides structural support but does not primarily contribute to protection, communication, or substance passage. D: Vacuole plays a role in storage and waste management but is not as critical for protection, communication, or substance passage as the cell membrane.

Correct Answer: C

Rationale: The correct answer is C: Cytoskeleton. The cytoskeleton provides structural support to the cell, helps maintain its shape, and allows it to adapt to external stimuli. It is composed of microfilaments, intermediate filaments, and microtubules. Microfilaments (choice A) play a role in cell movement but are not primarily responsible for maintaining cell shape. Cytoplasm (choice B) is the gel-like substance within the cell where organelles are suspended, but it does not directly contribute to maintaining cell shape. Centrioles (choice D) are involved in cell division and organization of microtubules, but they do not primarily help the cell maintain its shape and adapt.