BIOL 1361 1nd Edition Lecture 7 Outline of Last Lecture I. Unsaturated Fatty AcidII. PhospholipidsIII. ProteinsIV. Function: Selective PermeabilityV. OsmosisVI. Water Balance in Cells (problem)VII. Passive TransportOutline of Current Lecture I. Active TransportII. Bulk TransportIII. Gas ExchangeIV. Characteristics of Respiratory MembranesV. Respiratory SurfacesCurrent Lecture*Exam covers: Chapter 1, ulcer case, Chapter 33, python case, Chapter 5.1-5, Chapter 34.5-7*Format: 16 matching questions, 1 drawing, 30+ multiple choiceI. Active Transporta. Requires ATPb. Cell can pump substances from low to high concentrationc. Result: internal environment is different from external environmentd. Figure 5.14: Sodium Potassium Pumpi. The purple blob is an integral protein aka Na+ -K+ -ATPaseii. Pumps out 3 NA + to maintain lower internal [Na+]iii. Pumps in 2 K+ to maintain higher internal [K+]iv. Creates a Na+ gradient across cell membrane: outside HIGH; inside lowv. Na+ gradient can drive co-transport of other molecules, moving molecules from low to high concentratione. Fig 5.17: Na+ -glucose co-transport i. Na+ entering down concentration gradient can bring along glucose up its concentration gradientii. Mechanism of glucose absorption in vertebrate intestinal epithelial cellsThese notes represent a detailed interpretation of the professor’s lecture. GradeBuddy is best used as a supplement to your own notes, not as a substitute.1. Happens at the apical membraneII. Bulk Transporta. READ Fig. 5.18 and define these termsi. Phagocytosis – the amoeba videoii. Pinocytosis – cell engulfs liquidiii. Receptor-mediated endocytosisiv. Exocytosis – how enzymes are secretedIII. Gas Exchange: Chapter 34, Sections 5-7a. Physical constraints on gas exchangesi. Partial Pressure of gases – pressure exerted by a particular gas in a mix of gases1. 1 atm = 760 mm Hg2. Out atmosphere is 21% O23. PO2 at sea level = 760 mm Hg x 0.21 = 159.6 mm Hgb. Respiratory FluidAIR WATER21% O2 4-8 ml O2/L (0.4-0.8%)Low density O2 solubility decreased by higher temperature and a higher salt concentrationLow viscosity More dense than airEasy to move over a surface and through vesselsMore viscous than airMore work to move over surfacec. Diffusion Ratesi. All O2 and CO2 exchange occurs by diffusionii. Fick’s Law of Diffusion (equation is given)1. Q – quantity2. D – diffusion constant3. A – area4. C2-C1 – concentration gradient5. x – thickness 6. t – timeIV. Characteristics of Respiratory Membranesa. Has a large surface area (A)b. Has a large concentration difference (C2-C1)c. Has to be thin (small x)d. Needs to be moist: it prevents cell membrane from collapsingV. Respiratory Surfaces a. Body surfacei. Ex. Amphibians, earthwormsii. Have such thin skin that gas exchange can occur through the bodyb. Specialized surfacei. Must be ventilated1. Ventilated – moves the respiratory fluid across surface2. This maintains a high concentration gradient (C2-C1)c. Aquatic Animalsi. Gills – projections of body surfaceii. Water flow in bony fish gillsiii. Counter current flow in fish gills1. Prevents equilibrium from occurring2. Maximizes O2 exchange3. Figure 34.184. Blood flow through gills and water flow over gill filament is counter-currentd. Terrestrial Animalsi. Insects1. Tracheal Systema. The branching system of air tubulesb. All body cells within diffusion distance of tracheole endii. Amphibians, Reptiles, Birds, Mammals1. Lungsa. Lungs are a branching system of air tubules, bronchi and bronchiolesb. Bronchioles end in alveoli = air sacs surrounded by capillaries i. Alveoli are sits of gas
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