BIOL371 ANIMAL THEME 4 EXAM QUESTIONS AND ANSWERS WITH COMPLETE SOLUTIONS GRADED

BIOL371 ANIMAL THEME 4 EXAM QUESTIONS AND ANSWERS WITH COMPLETE SOLUTIONS GRADED Homeostasis (4) 1. negative feedback to retain setpoint 2. a steady internal condition maintained 3. biochemical reactions are sensitive to changes in tempt, pH, [solute], water, pressure 4. broadens geographic range External cells must face the environment, sometimes dead Internal externalized cells (4) 1. must be alive 2. rapid turnover: replicate quickly 3. lethal environment to microbes: low pH in digestive system 4. secretions: to isolate them from the environment Internal cells (2) 1. internalized to be protected through homeostasis 2. bathed in fluids: protected from drying out Extracellular fluid (2) 1. interstitial fluid (surrounding cells) and plasma (fluid portion of blood) 2. connects all cells to external environment: cells can exchange with interstitial fluid Factors that are heomeostatically regulated (7) 1. temperature 2. [H2O] [NaCl] 3. volume and pressure of blood vessels 4. [waste chemicals] 5. [O2] [CO2] 6. pH 7. [nutrient] Homeostasis topics (4) 1. osmoregulation 2. circulation 3. gas exchange 4. pH regulation Osmoregulation regulation of the internal osmotic (water/salt/waste) environment Bulk flow (3) 1. hydrostatic (water) pressure 2. fluids flow from high to low [ ] 3. can move fluid over long distances Diffusion (4) 1. movements of solutes dissolved in fluids 2. net movement from high to low [solute] 3. uses Fick's Law 4. usually only over short distances Fick's Law Diffusion rate = DA (dC/dX) D = diffusion coefficient A = SA across which things are moving dC = delta [ ] dX = delta distance Osmotic potential potential of H2O moving from hypotonic (more water less solute) to hypertonic (less water more solute) Osmotic pressure applied to a pure solvent to prevent it from passing into a given solution from osmosis Water potential includes (4) 1. osmotic potential 2. hydrostatic 3. gravity 4. humidity Hyperosmotic high [solute] compared to something else Hyposmotic low [solute] compared to something else Isosmotic same [solute] in both compartments Significance of isosmotic (2)