HESI A2 Biology Practice Test 2024

Correct Answer: B

Rationale: The main component of blood plasma is water. Plasma is the liquid component of blood, making up about 55% of total blood volume. It serves as a carrier for various substances such as nutrients, waste products, hormones, and electrolytes. Water helps maintain blood volume, regulates body temperature, and facilitates the transport of essential components throughout the body. Proteins, red blood cells, and platelets are also present in blood plasma but are not the main component. Proteins play a role in clotting and immune function, red blood cells carry oxygen, and platelets aid in blood clotting. Water is the correct answer as it is the primary constituent of blood plasma.

Correct Answer: B

Rationale: The correct answer is B: Microtubules. Microtubules are cylindrical structures made up of tubulin proteins that provide structural support and serve as tracks for cellular movement. They are involved in various cellular processes, including cell motility and intracellular transport. Microfilaments (A) are involved in cell shape and movement but are not primarily responsible for cell propulsion. Flagella (C) and Cilia (D) are cellular appendages that aid in cell movement, but they are composed of microtubules and are not the primary structures responsible for providing the cell with the ability to move and propel.

Correct Answer: B

Rationale: The correct answer is B: Chloroplasts. Chloroplasts are the organelles responsible for photosynthesis in plant cells. They contain chlorophyll, the pigment that captures sunlight for photosynthesis. Mitochondria (A) are involved in cellular respiration, not photosynthesis. Ribosomes (C) are responsible for protein synthesis, not photosynthesis. Endoplasmic Reticulum (D) is involved in protein and lipid synthesis, not photosynthesis. Therefore, the correct answer is B because chloroplasts are specifically designed for photosynthesis in plant cells.

Correct Answer: B

Rationale: The correct answer is B: Eukaryotic. Animal cells are eukaryotic cells because they have a defined nucleus that houses the genetic material. This nucleus is surrounded by a membrane, along with other membrane-bound organelles like mitochondria and endoplasmic reticulum. Prokaryotic cells (Option A) lack a true nucleus and membrane-bound organelles. Plant cells (Option C) have similar characteristics to animal cells but also have additional features like a cell wall and chloroplasts. Bacterial cells (Option D) are prokaryotic cells and differ significantly from animal cells in structure and function.

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.