PNB Predicted Questions and Correct Answers 2024

Which statement is true? a. Heme is commonly found within seawater b. Heme-based proteins played a key role in the metabolism of carbon dioxide into forms less toxic to cells. c. Heme-based proteins likely developed as a means by which Fe was transported safely. d. Oxygen binding to heme is insensitive to the presence of acid in mammals. e. Early anaerobic life used heme-based proteins to minimize oxygen toxicity. - (e) Early anaerobic life used heme-based proteins to minimize oxygen toxicity. Why was the evolution of vascular valves so important? (E1) a. Vascular valves increase the efficiency of blood flow by limiting the direction in which it can move. b. Vascular valves are the precursors of a chambered heart. c. Vascular valves are only found in animals with peristaltic pumps. d. Vascular valves prevent high blood pressures from damaging pump walls e. All of the above are reasons why the evolution of vascular valves is so important. - (a) Vascular valves increase the efficiency of blood flow by limiting the direction in which it can move. Support for the evolution of terrestrial animals from aquatic animals is provided by...(E1) a. some aquatic animals ability to use the swim bladder and digestive tract to absorb oxygen from gulped air. b. present day examples of transient aquatic hypoxia in warm, shallow waters c. African lungfish. d. Dolphins. e. all of the above answers - e. all of the above answers Heart rate is ________ increasing body size. (E1) a. positively correlated with b. independent of c. inversely correlated with d. exponentially correlated with e. related by the square root - c. inversely correlated with What is an advantage of a closed circulatory system? (E1) a. Blood can flow in any direction within a blood vessel. b. It requires less blood volume than an open circulatory system. c. It is usually a low...pressure (15 to 50 mm Hg) system. d. It is anatomically more complex. e. It is not dependent on a heart to generate pressure. - b. It requires less blood volume than an open circulatory system. In animals, circulatory systems ...(E1) a. overcome the limitation of diffusion in providing oxygen to tissues far away from respiratory membranes b. provide a mechanism for transport of solutes c. accelerate the loss of carbon dioxide from the body. d. can vary the distribution of blood to tissues with the greatest need for oxygen e. can do all of the above. - e. can do all of the above. An advantage of a four chamber heart is ...(E1) a. that an animal can have less blood volume (on a % basis) than an animal with a two...chambered heart b. an animal can also use peristalsis to move blood around the body. c. the ability to have two blood circuits within the body. d. the ability to pump different volumes of blood from the two ventricles. - c. the ability to have two blood circuits within the body. An open circulation system ...(E1)