Anatomy HESI A2 Practice Test

Correct Answer: B

Rationale: The correct answer is B: To speed up chemical reactions. Enzymes act as biological catalysts that accelerate chemical reactions by lowering the activation energy required for the reactions to occur. They do not produce energy (choice A), transport molecules (choice C), or repair tissues (choice D). Enzymes specifically facilitate reactions without being consumed in the process, making them crucial for various metabolic pathways in the body.

Correct Answer: A

Rationale: The correct answer is A: To filter blood and remove old red blood cells. The spleen is an important organ in the lymphatic system responsible for filtering blood, removing old or damaged red blood cells, and storing platelets. It also plays a role in immune function by producing antibodies and storing lymphocytes. Choices B, C, and D are incorrect as the spleen's main functions are related to blood filtration and immune response, not lymphocyte production, vitamin storage, or temperature regulation.

Correct Answer: A

Rationale: The correct answer is A: Vitamin A. Vitamin A is essential for vision as it plays a crucial role in the function of the retina and helps maintain a healthy cornea. It is also important for skin health by promoting skin cell growth and repair. Vitamin C (B) is important for immune function and collagen synthesis, not specifically for vision or skin health. Vitamin D (C) is crucial for bone health and immune function. Vitamin E (D) is an antioxidant that helps protect cells from damage, but it is not specifically essential for vision or skin health.

Correct Answer: B

Rationale: The correct answer is B: To transport oxygen. Hemoglobin is a protein in red blood cells that binds to oxygen in the lungs and carries it to tissues throughout the body. This process is essential for cellular respiration and energy production. Choice A is incorrect because fighting infections is the role of the immune system, not hemoglobin. Choice C is incorrect as hemoglobin primarily carries oxygen, not carbon dioxide. Choice D is incorrect as hemoglobin binds and releases oxygen to tissues, rather than storing it.

Correct Answer: D

Rationale: The correct answer is D because the liver is responsible for producing enzymes essential for metabolism. Enzymes are biological catalysts that facilitate chemical reactions involved in breaking down nutrients and creating energy. Storing glucose (A) is mainly done by the liver and muscles, secreting bile (B) is the primary function of the gallbladder, and detoxifying harmful substances (C) is also a crucial role of the liver but not directly related to metabolism.