HESI A2 Biology Practice Test 2024

Correct Answer: B

Rationale: The slide is typically placed on the stage of a microscope. The stage is the platform where the slide sits for observation. Placing the slide on the stage allows for easy movement and adjustment to focus on different areas of the specimen. The eyepiece is where you look through to view the specimen, the focus knob is used to adjust the focus, and the objective lens magnifies the specimen. The stage is the correct answer because it is where the slide is physically positioned for examination.

Correct Answer: D

Rationale: The primary function of the endoplasmic reticulum (ER) in a cell is the transport of materials. The ER consists of a network of membranes that help in the synthesis, folding, and transport of proteins and lipids. It plays a crucial role in the intracellular transport of materials between different cell compartments. This process ensures that newly synthesized proteins and lipids are properly transported to their respective destinations within the cell. The ER also serves as a site for the modification and packaging of proteins before they are transported to other organelles or secreted outside the cell. Therefore, the correct answer is D. Incorrect choices: A: Energy production - This is not the primary function of the ER. Energy production mainly occurs in mitochondria. B: Protein synthesis - While the ER is involved in protein synthesis, its primary function is the transport of materials. C: Waste removal - Waste removal is primarily carried out by lysosomes and peroxisomes in a cell, not the ER

Correct Answer: B

Rationale: The main function of ribosomes is protein synthesis. Ribosomes are responsible for translating the genetic information encoded in mRNA into proteins. This process involves decoding the mRNA sequence and linking amino acids together to form a protein. Ribosomes do not participate in DNA replication (Choice A), lipid breakdown (Choice C), or cell division (Choice D). DNA replication occurs in the nucleus, lipid breakdown is carried out by enzymes in the cytoplasm, and cell division involves processes such as mitosis and cytokinesis. Therefore, the correct answer is B because ribosomes are directly involved in protein synthesis.

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.

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.