L2 Qs O.pdf Past Paper PDF

Certainly, here are 10 MCQs based on the next lecture (Lec 4), focusing on blood cells and erythropoiesis: 1. Which of the following is NOT a characteristic of mature red blood cells (RBCs)? a) Biconcave shape b) Presence of a nucleus c) Flexibility d) Contain hemoglobin e) Transport oxygen A...

Certainly, here are 10 MCQs based on the next lecture (Lec 4), focusing on blood cells and erythropoiesis: 1. Which of the following is NOT a characteristic of mature red blood cells (RBCs)? a) Biconcave shape b) Presence of a nucleus c) Flexibility d) Contain hemoglobin e) Transport oxygen Answer: b) Presence of a nucleus Explanation: Mature RBCs lose their nucleus during development to maximize space for hemoglobin and oxygen transport. 2. The primary function of carbonic anhydrase in RBCs is to: a) Facilitate oxygen binding to hemoglobin b) Catalyze the conversion of carbon dioxide to bicarbonate c) Maintain the biconcave shape of RBCs d) Regulate intracellular pH e) Transport iron Answer: b) Catalyze the conversion of carbon dioxide to bicarbonate Explanation: Carbonic anhydrase speeds up the reaction between carbon dioxide and water, forming bicarbonate, which is a major way carbon dioxide is transported in the blood. 3. In adults, the primary site of erythropoiesis (red blood cell production) is the: a) Liver b) Spleen c) Red bone marrow d) Yellow bone marrow e) Lymph nodes Answer: c) Red bone marrow Explanation: In adults, red bone marrow, found in flat bones like the sternum and pelvis, is the main site of RBC production. 4. Which of the following conditions would most likely stimulate erythropoietin production? a) High blood oxygen levels b) Low blood oxygen levels c) High blood iron levels d) Low blood iron levels e) High blood glucose levels Answer: b) Low blood oxygen levels (hypoxia) Explanation: Hypoxia triggers the kidneys to release erythropoietin, which stimulates RBC production to increase oxygen-carrying capacity. 5. A deficiency in vitamin B12 or folic acid would most likely result in which type of anemia? a) Iron-deficiency anemia b) Aplastic anemia c) Megaloblastic anemia d) Hemolytic anemia e) Sickle cell anemia Answer: c) Megaloblastic anemia Explanation: Vitamin B12 and folic acid are essential for DNA synthesis. Their deficiency impairs RBC maturation, leading to larger than normal RBCs (macrocytes) characteristic of megaloblastic anemia. 6. Which of the following is the primary storage form of iron in the body? a) Transferrin b) Ferritin c) Hemosiderin d) Hemoglobin e) Myoglobin Answer: b) Ferritin Explanation: Ferritin is a protein-iron complex that stores iron in a safe, non-toxic form, primarily in the liver and reticuloendothelial system. 7. Iron is primarily absorbed in the: a) Stomach b) Duodenum (upper part of the small intestine) c) Jejunum (middle part of the small intestine) d) Ileum (lower part of the small intestine) e) Colon Answer: b) Duodenum (upper part of the small intestine) Explanation: The duodenum is the primary site of iron absorption, where it is taken up by intestinal cells and transported into the bloodstream. 8. Which of the following hormones directly stimulates erythropoiesis? a) Insulin b) Glucagon c) Thyroid hormone d) Erythropoietin e) Cortisol Answer: d) Erythropoietin Explanation: Erythropoietin is the key hormone that stimulates the production and maturation of red blood cells in the bone marrow. 9. The average lifespan of a red blood cell is approximately: a) 10 days b) 30 days c) 60 days d) 120 days e) 240 days Answer: d) 120 days Explanation: RBCs have a lifespan of about 120 days, after which they become senescent and are removed from circulation by the spleen. 10. Which of the following is NOT a function of red blood cells? a) Transport oxygen b) Transport carbon dioxide c) Act as an acid-base buffer d) Contribute to blood viscosity e) Initiate blood clotting Answer: e) Initiate blood clotting Explanation: Platelets, not RBCs, are responsible for initiating blood clotting. RBCs primarily function in gas transport and maintaining blood pH and viscosity. Feel free to request more questions or clarifications on any of these topics!