HESI A2 Biology Practice Test 2024

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 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: Krebs Cycle. This cycle, also known as the citric acid cycle, occurs in the mitochondria of cells and plays a crucial role in generating energy through the oxidation of acetyl-CoA derived from carbohydrates, fats, and proteins. It produces ATP, NADH, and FADH2, which are essential for cellular energy production. The Calvin Cycle (A) and Photosynthesis (C) are involved in the process of converting light energy into chemical energy in plants, not in generating energy during cellular respiration. Fermentation (D) is an anaerobic process that generates energy in the absence of oxygen, but it is not as efficient as aerobic respiration in producing ATP.

Correct Answer: A

Rationale: Mitosis is the correct answer as it is the process by which cells divide to form two identical daughter cells for growth, repair, and maintenance. It involves a series of stages such as prophase, metaphase, anaphase, and telophase, ensuring the distribution of genetic material equally. Meiosis is incorrect as it is a process for producing gametes with genetic variation. Binary fission is incorrect as it is a form of asexual reproduction in prokaryotes. Cellular division is too broad and vague, not specifically describing the process of cell division into two identical daughter cells.

Correct Answer: B

Rationale: The correct answer is B: DNA. DNA, or deoxyribonucleic acid, is the molecule that stores the genetic code for each person. It is located in the cell nucleus and organized into structures called chromosomes. DNA contains the instructions for building and maintaining an organism, including traits and characteristics. RNA (choice A) is involved in protein synthesis but does not store the complete genetic information. The nucleus (choice C) is the cellular organelle where DNA is located, not the genetic code itself. Chromosomes (choice D) are made up of DNA and proteins and contain the genetic material in a condensed form. Therefore, the correct choice is DNA as it is the primary storage location for the genetic code.