Chapter 3 Exchanging Materials with the Environment

1. Chapter 3 Exchanging Materials with the Environment Just like a computer, living things need on input and output 1 2

2. 3 Living Cells and Homeostasis Homeostasis– This means maintaining a relatively constant environment; temperature, chemical concentrations, pH, etc. within the cell(s) of their bodies. • What needs to be controlled? • Water • Oxygen • Ions • Carbon Dioxide • Nutrients • Hormones • Wastes Cytoplasm Membrane 28 E. Coli Bacteria at 12,205x “Ugly bags of mostly water” Humans described by sentient crystals on Velara III (Star Trek, NG, “Home Soil”)

3. Basic Membrane Structure Outside cell Hydrophilic head Hydrophobic tail Cytoplasm (inside cell) (a) Phospholipid bilayer of membrane Figure 4.7A Remember what the tail and head are???

4. Fluid Mosaic Model of Membranes Hydrophilic region of protein Phospholipid bilayer Hydrophobic region of protein Figure 4.7B What does the membrane do?

5. Functions of Membrane Proteins Cytoplasm Fibers of extracellular matrix c Enzymatic activity b Cell signaling a Attachment to cytoskeleton and extracellular matrix e Intercellular joining f Cell-cell recognition d Transport Cytoplasm Cytoskeleton Figure 4.8

6. Passes through freely Small hydrophobic O2 CO2 N2 Small uncharged Water Glycerol Ethanol Needs transport proteins Large, polar Amino Acids Glucose Nucleotides Selectively Permeable Membranes Write down and memorize! • Ions • H+, Na+, K+ • Ca+2, Mg+2 • Cl- 4

7. No E required Movement down concentration gradients (p. 81-82) Diffusion Concentration Gradients are Potential Energy! Gradients of ions are Electrical Potential! 7 5

8. Hypotonic solution Hypertonic solution Isotonic solutions Sugar molecule (solute) Selectively permeable membrane Osmosis (net movement of water) Figure 5.12 Osmosis5 • Diffusion of WATER across a selectively permeable membrane.

9. Cells and Osmoregulation4 Where is the WATER most concentrated? Why do animal cells burst and plant cells not? Turgor Pressure = Water pressure against a cell wall

10. Passive Transport4 No Energy Required May use membrane proteins Down Concentration Gradients Simple Diffusion Facilitated Diffusion 05_17AN Facilitated Diffusion.MOV

11. Active Transport4 Energy/ATP Required Uses membrane proteins Up Concentration Gradients

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13. Endocytosis and Exocytosis Energy/ATP Required Cytosis = Movement of molecules in/out of a cell 08-19a-IntroExoEndocytosis.swf

14. Phagocytosis & Pinocytosis • Phagocytosis (“cellular eating”) • Pinocytosis (“cellular drinking”) Pseudopod of amoeba Food being ingested Figure 5.17

15. Systems for Input and Output…27

16. Gas Exchange in Multicelluar Organisms Diffusion, diffusion, diffusion • No matter what kind of organism, the basic force moving gases into and out of the organism is diffusion • Specialized tissues may make exchange possible by allowing gases to dissolve in liquid near cells

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19. The systems can look different… 4 but the principles are all the same.

20. Oxygen contacts moist membrane near capillaries. • Diffusion of oxygen into the blood. • Transport of oxygen to the cells of the body. • Diffusion of oxygen from the blood into cells. • Carbon dioxide returns following same path backwards. 27

21. Create concentration gradient of O2/CO2 Get the gases to diffuse into/out of the blood through capillaries You useGills. When you live in the water… Goldfish infected with BRANCHOMYCOSIS - Showing destroyed gill filaments12 Water contains about 5-10 mL of Oxygen gas per Liter

22. 13 Krill Gills 8 Note the delicate structures designed to maximize surface area for gas exchange. 14

23. The Structure and Function of Gills • Continuous water flow • Concentration gradient • of O2 across • capillary walls • Diffusion across entire length of gill filament See P. 87 for illustration 5

24. Countercurrent Blood Flow 5 See how the concentration gradient pushes O2 into the capillaries all along the gill lamella! 22_04AN Countercurrent Flow Gills.MOV

25. Gills of the Rainbow Trout Fluorescence micrograph of a trout gill. Leading edge of gill is at the bottom. Water flow is from bottom to top. 15 Look at the capillaries inside each lamella!

26. But if you’re a Land Organism… 17 • Air contains 21% oxygen, more than 20x what is available in water, and • Diffusion works for simple organisms in moist environments (p. 89). • However, gills must be moistto function and require water for support. 16 So, what to do without water? 18

27. Insects use Tracheae27 27 Trachea get very fine and allow O2 and CO2 to diffuse across the cell membranes. Insect body movements help pump air through trachea. See. p. 90 for details

28. Vertebrates use Lungs To keep them moist-- • Protected in the body • Two way flow of air which works but decreases efficiency Frogs also “breathe” through their moist skin! Kind of like earthworms and planaria. 4

29. The Human Respiratory System Air is filtered by hairs and mucous membranes as it passes through to the bronchial tubes. Don’t forget about thediaphragm! 4

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32. Negative Pressure Breathing27

33. Breathing Control Brain • The breathing control centers can increase or decrease breathing rate in response to CO2 levels in the blood Breathing control centers stimulated by CO2 increase in blood Nerve signals trigger contraction of muscles Diaphragm Figure 23.21 Rib muscles

34. 19 Plant Gas Exchange • Water loss minimized by Cuticle on leaves • Gas exchange through Stomates Transverse section of leaf of bearberry (kinnikinnick; Arctostaphylos uva-ursi). Hornwort stomate 20 What will happen if a plant loses too much water to transpiration?

35. Homeostasis and Materials Balance 8 21 9 Osmoregulation = Control of water balance in organism

36. Ammonia22 Urea23 Uric Acid24 Removing Nitrogenous Wastes Where does all the nitrogen come from? Did you know? Fish can eliminate wastes through their gills!

37. Planaria Paramecia Ant Earthworm Animal Excretory Systems4

38. The Human Excretory System4 Kidneys function in homeostasis by: • Controlling volume of extracellular fluid • Regulating ionic balance • Maintaining pH and salt concentration • Excreting toxic wastes (eg. Urea, ammonia, uric acid) Kidneys are the primary organ of excretion

39. Kidney Structure The Nephronis the primary unit of blood filtration Each kidney has about 1 million nephrons And produces about 0.75 L of urine a day 4

40. Nephron Structure and Function5 2 1 3 • Glomerulus: Cluster of capillaries for blood filtration • Bowman's Capsule: Blood filtration; part of collecting tubule • Proximal Tubule: Reabsorbs most of the water, salts, glucose, and amino acids (active transport) • Loop of Henle: Countercurrent exchange to maintain the concentration gradient • Distal Tubule: Tubular secretion of H+ and K+ ions in. (active transport) • Collecting Duct: Transports urine to the ureter. 5 4 25

41. Reprise… 26 • Filtration: Fluid from blood passes into nephron • Reabsorption: Molecules returned to capillaries • Secretion: Molecules from blood transported to nephron.

42. Control of Nephron Function ADH: • Anti-Diuretic Hormone produced by pituitary gland • Increases water reabsorption • Responds to dehydration via hypothalamus Aldosterone: • Hormone produced by adrenal gland • Increases sodium reabsorption and hydrogen ion secretion • Controls blood pH See p. 96 for ADH diagram

43. What problems would each animal pictured have to overcome? Think water, oxygen, nutrients, and wastes! Lamprey9 Echidna10 Desert Collared Lizard8 Pacific White Sided Dolphin11

44. Sources Cited 1. Eating Frog: allaboutfrogs.org/info/ doctor/bugs.html 2. Blue Whale Blow: www.pmel.noaa.gov/vents/acoustics/ whales/bioacoustics.html 3. E. Coli: www.denniskunkel.com with permission 4. http://gened.emc.maricopa.edu/Bio/BIO181/BIOBK/BioBookTOC.html; from Purves et al., Life: The Science of Biology, 4th Edition, by Sinauer Associates (www.sinauer.com) and WH Freeman (www.whfreeman.com) 5. Liebaert, Richard. Interactive Study Partner for Bioly, Fifth Edition by Campbell, Reece & Mitchell. 6. Cell Membrane: sun.menloschool.org/~cweaver/ cells/c/cell_membrane/ 7. Diffusion Cartoon: http://www.sciencenet.org.uk/database/Chemistry/StructBond/c00218b.html 8. racphoto.com/Parks/OR/HighDesert/ DesertCollared01.jpg 9. www.dcnr.state.pa.us/ wrcf/mblamppic.htm; Photo Credit Gary Meszaros 10. http://www.mbayaq.org/efc/living_species/default.asp?hOri=1&inhab=225 11. www.mwf.com.au/ littravel2.html 12. users.jagunet.com/~fishvet/ fvsoftware/fvimg43.htm 13. www.cbl.umces.edu/fogarty/usglobec/ gaag/study-area.html 14. http://www.ecoscope.com/gill0001.htm 15. www.science.mcmaster.ca/ Biology/4S03/751.html 16. www.pbs.org/wgbh/nova/seahorse/ superdads.html 17. www.hawaii-forest.com/ evolution.html 18. http://www.americanparknetwork.com/parkinfo/hv/flora/ 19. Hornwort Stomate: http://www.science.siu.edu/landplants/Anthocerophyta/anthocerophyta.html 20. Leaf Cuticle: www.esb.utexas.edu/mauseth/weblab/ webchap10epi/10.2-4.htm 21. www.durr.demon.co.uk/ 22. wine1.sb.fsu.edu/chm1045/notes/ Geometry/VSEPR/Geom02.htm 23. 192.211.16.13/curricular/genchem2001/ hw/hw7/hw7ans.htm 24. http://hmchemdemo.clt.binghamton.edu/zumdahl/docs/realworld/medicine/gout.htm 25. ms.yuba.cc.ca.us/vet02/ bio/notes/B15ch25.htm 26. http://www.mhhe.com/biosci/ap/dynamichuman2/content/urinary/visuals.mhtml 27. Bioshow: for Biology: Concepts and Connections, Second Edition. Campbell, Mitchell, and Reece 28. http://memory-alpha.org/de/images/thumb/7/72/200px-Anorganische_Lebensform_Evolution.jpg Unlabeled Pictures are from the PowerPoint CD for Essential Biology with Physiology. 2006.