Which of the following is responsible for transporting oxygen in the blood?
- A. White blood cells
- B. Red blood cells
- C. Platelets
- D. Plasma
Correct Answer: B
Rationale: Red blood cells are responsible for transporting oxygen in the blood. Hemoglobin, a protein found in red blood cells, binds to oxygen in the lungs and carries it to tissues throughout the body. White blood cells are involved in the immune system's defense mechanisms against infections, platelets help in blood clotting, and plasma is the liquid component of blood that carries various substances like nutrients, hormones, and waste products.
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What type of joint is found in the shoulder and hip, allowing for a wide range of motion?
- A. Hinge joint
- B. Ball-and-socket joint
- C. Pivot joint
- D. Saddle joint
Correct Answer: B
Rationale: The correct answer is B: Ball-and-socket joint. A ball-and-socket joint, like those in the shoulder and hip, allows for a wide range of motion. In a ball-and-socket joint, the rounded end of one bone fits into the cup-like socket of another bone, enabling movement in multiple directions. Choice A, Hinge joint, is incorrect because hinge joints allow movement only in one plane, like a door hinge. Choice C, Pivot joint, is incorrect as it allows rotational movement around a single axis, not the wide range of motion seen in the shoulder and hip. Choice D, Saddle joint, is also incorrect as it allows movement in multiple directions but to a lesser extent compared to the ball-and-socket joint.
Which of the following structures is responsible for gas exchange in the lungs?
- A. Bronchi
- B. Alveoli
- C. Trachea
- D. Diaphragm
Correct Answer: B
Rationale: The alveoli are tiny air sacs in the lungs where the exchange of oxygen and carbon dioxide takes place. Oxygen from inhaled air diffuses into the blood vessels surrounding the alveoli, while carbon dioxide from the blood is released into the alveoli to be exhaled. The bronchi are air passages that carry air into the lungs but do not participate in gas exchange. The trachea is the windpipe that connects the larynx to the bronchi and serves as an airway for breathing. The diaphragm is a muscle that aids in the breathing process by contracting and relaxing to change the volume of the chest cavity.
Which of the following are the products of anaerobic respiration in humans?
- A. Ethyl alcohol and CO2
- B. Ethyl alcohol only
- C. Lactic acid and CO2
- D. Lactic acid only
Correct Answer: C
Rationale: During anaerobic respiration in humans, lactic acid and CO2 are produced. Choice A, 'Ethyl alcohol and CO2,' is incorrect because ethyl alcohol is not a product of anaerobic respiration in humans. Choice B, 'Ethyl alcohol only,' is incorrect as ethyl alcohol is not a product of anaerobic respiration in humans. Choice D, 'Lactic acid only,' is incorrect because CO2 is also a product of anaerobic respiration in humans.
Which type of muscle is responsible for moving the skeleton?
- A. Cardiac muscle
- B. Skeletal muscle
- C. Smooth muscle
- D. Voluntary muscle
Correct Answer: B
Rationale: Skeletal muscle is the correct answer as it is responsible for moving the skeleton. Skeletal muscles are under voluntary control, meaning they can be consciously controlled by the individual. Cardiac muscle (Choice A) is found in the heart and is responsible for pumping blood, not moving the skeleton. Smooth muscle (Choice C) is found in internal organs and is responsible for involuntary movements like digestion. Voluntary muscle (Choice D) is not a specific type of muscle; it refers to muscles that can be consciously controlled, which includes skeletal muscles.
What are stem cells that can develop into many different cell types, but not a complete organism, known as?
- A. Totipotent stem cells
- B. Multipotent stem cells
- C. Pluripotent stem cells
- D. Hematopoietic stem cells
Correct Answer: C
Rationale: Pluripotent stem cells are capable of developing into many different cell types, but they cannot form a complete organism. Totipotent stem cells have the ability to give rise to all cell types in an organism, including extraembryonic tissues, enabling them to form a complete organism. Multipotent stem cells can differentiate into a limited range of cell types. Hematopoietic stem cells specifically give rise to blood cells.