2- transport Flashcards
Q: Why do unicellular organisms not need transport systems?
A: They have a large surface area to volume ratio, allowing diffusion, osmosis, and active transport across their membrane to meet their needs.
Q: Why do multicellular organisms require transport systems?
A: Diffusion alone is too slow due to the longer distance between surface and internal cells; they need circulatory (animals) or vascular (plants) systems.
Q: What is the function of the xylem?
A: To transport water and mineral ions from the roots to the rest of the plant.
Q: What is the structure of xylem vessels?
A: Hollow tubes made of dead cells with lignin reinforcement for water transport via transpiration.
Q: What is the function of the phloem?
A: To transport sucrose and amino acids from the leaves to the rest of the plant.
Q: What is the structure of phloem vessels?
A: Living cells arranged in tubes with small holes allowing movement of substances.
Q: What are the four components of blood
?
A: Red blood cells, white blood cells, platelets, and plasma.
Q: What is plasma and what does it transport?
A: Straw-colored fluid transporting CO₂, urea, digested food, hormones, and heat energy.
Q: How are red blood cells adapted to their function?
A: Biconcave shape, no nucleus, filled with haemoglobin to maximize oxygen transport.
Q: What are the two main types of white blood cells?
A: Phagocytes and lymphocytes.
Q: What do phagocytes do?
A: Engulf and digest pathogens—non-specific response.
Q: What do lymphocytes do?
A: Produce antibodies specific to antigens—specific immune response.
Q: Define immunity.
A: The body’s ability to resist a particular infection through memory of antibodies.
Q: What is the difference between an antigen and an antibody?
A: Antigens are found on pathogen surfaces; antibodies are proteins made by lymphocytes that bind to antigens
Q: Why is the heart a double pump?
A: It pumps deoxygenated blood to the lungs (right side) and oxygenated blood to the body (left side).
Q: Why is the left ventricle thicker than the right?
A: It pumps blood at higher pressure to the entire body.
Q: What are the main valves of the heart and their roles?
A: Tricuspid (right side) and bicuspid (left side) valves prevent backflow; semilunar valves prevent backflow from arteries.
Q: Route of blood through the heart?
A: Vena cava → Right atrium → Tricuspid valve → Right ventricle → Pulmonary artery → Lungs → Pulmonary vein → Left atrium → Bicuspid valve → Left ventricle → Aorta
Q: What controls the natural heart rate?
A: Pacemaker cells in the right atrium send electrical impulses.
Q: How does exercise affect heart rate?
A: Increases due to demand for more oxygen and glucose; also affected by adrenaline.
Q: Why does the heart rate remain high after exercise?
A: To break down lactic acid from anaerobic respiration using oxygen.
Q: Compare arteries, veins, and capillaries.
A:
Arteries: Thick walls, high pressure, carry blood away from the heart.
Veins: Thin walls, valves, low pressure, carry blood to the heart.
Capillaries: One-cell thick walls, allow diffusion.
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Q: What is the general pathway of blood circulation?
A: Heart → Arteries → Arterioles → Capillaries → Venules → Veins → Heart
Q: What helps veins transport blood under low pressure?
A: Large lumen and presence of valves to prevent backflow.
Q: What does the lymphatic system do?
A: Collects excess tissue fluid and returns it to the circulatory system.
Q: Main vessels associated with organs?
A:
Heart: Vena cava & pulmonary vein (to), aorta & pulmonary artery (from)
Lungs: Pulmonary artery (to), pulmonary vein (from)
Kidneys: Renal artery (to), renal vein (from
