Enzymes in Digestion

1. Mini-FRQ Enzymes are a huge part of digestion a) Describe structure and function of an enzyme b) How are enzymes tied to digestion?

2. Why do we breathe oxygen?

3. 2008-2009 gills alveoli elephant seals Gas Exchange Respiratory Systems

4.  Need O 2 in ◦ for aerobic cellular respiration ◦ make ATP  Need CO 2 out ◦ waste product from Krebs cycle O 2 food ATP CO 2

5.  O 2 & CO 2 exchange between environment & cells ◦ need moist membrane ◦ need high surface area

6.  Why high surface area? ◦ maximizing rate of gas exchange ◦ CO 2 & O 2 move across cell membrane by diffusion  rate of diffusion proportional to surface area  Why moist membranes? ◦ moisture maintains cell membrane structure ◦ gases diffuse only dissolved in water High surface area? High surface area ! Where have we heard that before?

7. Aquatic organisms external systems with lots of surface area exposed to aquatic environment moist internal respiratory tissues with lots of surface area Terrestrial

8. Exchange tissue: spongy texture, honeycombed with moist epithelium Why is this exchange with the environment RISKY?

9.  Larynx (upper part of respiratory tract)  Vocal cords (sound production)  Trachea (windpipe)  Bronchi (tube to lungs)  Bronchioles  Alveoli (air sacs)  Diaphragm (breathing muscle)

10.  Gas exchange across thin epithelium of millions of alveoli ◦ total surface area in humans ~100 m 2

11.  Breathing due to changing pressures in lungs ◦ air flows from higher pressure to lower pressure ◦ pulling air instead of pushing it

12. 1) Share plan with tablemates to get A or B on all April quizzes 2) Change Sat, April 21 to Sat, April 14 th 3) Come up with a structure is ties to function example

13.  Water carrying gas flows in one direction, blood flows in opposite direction just keep swimming…. Why does it work counter current? Adaptation !

14.  Blood & water flow in opposite directions ◦ maintains diffusion gradient over whole length of gill capillary ◦ maximizing O 2 transfer from water to blood water blood front back blood 100 % 15% 5% 90% 70% 40% 60% 30% 100 % 5% 50% 50% 70% 30% water counter- current concurrent

15.  Advantages of terrestrial life ◦ air has many advantages over water  higher concentration of O 2  O 2 & CO 2 diffuse much faster through air  respiratory surfaces exposed to air do not have to be ventilated as thoroughly as gills  air is much lighter than water & therefore much easier to pump  expend less energy moving air in & out  Disadvantages ◦ keeping large respiratory surface moist causes high water loss  reduce water loss by keeping lungs internal Why don’t land animals use gills?

16.  air tubes branching throughout body  gas exchanged by diffusion across moist cells lining terminal ends, not through open circulatory system Tracheae

17.  Air enters nostrils ◦ filtered by hairs, warmed & humidified ◦ sampled for odors  Pharynx  glottis  larynx (vocal cords)  trachea (windpipe)  bronchi  bronchioles  air sacs (alveoli)  Epithelial lining covered by cilia & thin film of mucus ◦ mucus traps dust, pollen, particulates ◦ beating cilia move mucus upward to pharynx, where it is swallowed

18.  Homeostasis ◦ keeping the internal environment of the body balanced ◦ need to balance O 2 in and CO 2 out ◦ need to balance energy (ATP) production  Exercise ◦ breathe faster  need more ATP  bring in more O 2 & remove more CO 2  Disease ◦ poor lung or heart function = breathe faster  need to work harder to bring in O 2 & remove CO 2 O 2 ATP CO 2

19.  Why use a carrier molecule? ◦ O 2 not soluble enough in H 2 O for animal needs  blood alone could not provide enough O 2 to animal cells  hemocyanin in insects = copper (bluish/greenish)  hemoglobin in vertebrates = iron (reddish)  Reversibly binds O 2 ◦ loading O 2 at lungs or gills & unloading at cells cooperativity heme group

20.  Binding O 2 ◦ binding of O 2 to 1 st subunit causes shape change to other subunits  conformational change ◦ increasing attraction to O 2  Releasing O 2 ◦ when 1 st subunit releases O 2 , causes shape change to other subunits  conformational change ◦ lowers attraction to O 2

21.  Dissolved in blood plasma as bicarbonate ion Tissue cells Plasma CO 2 dissolves in plasma CO 2 combines with Hb CO 2 + H 2 O H 2 CO 3 H+ + HCO 3 – HCO 3 – H 2 CO 3 CO 2 Carbonic anhydrase Cl– carbonic acid CO 2 + H 2 O  H 2 CO 3 bicarbonate H 2 CO 3  H + + HCO 3 – carbonic anhydrase

22.  Lower CO 2 pressure at lungs allows CO 2 to diffuse out of blood into lungs Plasma Lungs: Alveoli CO 2 dissolved in plasma HCO 3 – Cl – CO 2 H 2 CO 3 H 2 CO 3 Hemoglobin + CO 2 CO 2 + H 2 O HCO 3 – + H +

23.  Circulation and Gas Exchange

24.  Animal cells exchange material across their cell membrane ◦ fuels for energy ◦ nutrients ◦ oxygen ◦ waste (urea, CO 2 )  If you are a 1-cell organism that’s easy! ◦ diffusion  If you are many-celled that’s harder

25.  What needs to be transported ◦ nutrients & fuels  from digestive system ◦ respiratory gases  O 2 & CO 2 from & to gas exchange systems: lungs, gills ◦ intracellular waste  waste products from cells  water, salts, nitrogenous wastes (urea) ◦ protective agents  immune defenses  white blood cells & antibodies  blood clotting agents ◦ regulatory molecules  hormones

26.  All animals have: ◦ circulatory fluid = “ blood ” ◦ tubes = blood vessels ◦ muscular pump = heart open closed hemolymph blood

27.  Taxonomy ◦ invertebrates  insects, arthropods, mollusks  Structure ◦ no separation between blood & interstitial fluid  hemolymph

28.  Taxonomy ◦ invertebrates  earthworms, squid, octopuses ◦ vertebrates  Structure ◦ blood confined to vessels & separate from interstitial fluid  1 or more hearts  large vessels to smaller vessels  material diffuses between blood vessels & interstitial fluid closed system = higher pressures

29.  Adaptations in closed system ◦ number of heart chambers differs 4 chamber heart is double pump = separates oxygen-rich & oxygen-poor blood; maintains high pressure What’s the adaptive value of a 4 chamber heart? 2 3 4 low pressure to body low O 2 to body high pressure & high O 2 to body

30.  Fish : 2-chambered heart; single circuit of blood flow  Amphibians : 3-chambered heart; 2 circuits of blood flow- pulmocutaneous (lungs and skin); systemic (some mixing)  Mammals : 4-chambered heart; double circulation ; complete separation between oxygen-rich and oxygen poor blood

31. convergent evolution  Selective forces ◦ increase body size  protection from predation  bigger body = bigger stomach for herbivores ◦ endothermy  can colonize more habitats ◦ flight  decrease predation & increase prey capture  Effect of higher metabolic rate ◦ greater need for energy, fuels, O 2 , waste removal  endothermic animals need 10x energy  need to deliver 10x fuel & O 2 to cells

32.  Chambered heart ◦ atrium = receive blood ◦ ventricle = pump blood out  Blood vessels ◦ arteries = carry blood away from heart  arterioles ◦ veins = return blood to heart  venules ◦ capillaries = thin wall, exchange / diffusion  capillary beds = networks of capillaries

33. Blood vessels arteries arterioles capillaries venules veins artery arterioles venules veins

34.  Arteries ◦ thicker walls  provide strength for high pressure pumping of blood ◦ narrower diameter ◦ elasticity  elastic recoil helps maintain blood pressure even when heart relaxes

35.  Veins ◦ thinner-walled ◦ wider diameter  blood travels back to heart at low velocity & pressure  lower pressure  distant from heart  blood must flow by skeletal muscle contractions when we move  squeeze blood through veins ◦ valves  in larger veins one-way valves allow blood to flow only toward heart Open valve Blood flows toward heart Closed valve

36.  Capillaries ◦ very thin walls  lack 2 outer wall layers  only endothelium  enhances exchange across capillary ◦ diffusion  exchange between blood & cells

37.  Blood flow in capillaries controlled by pre-capillary sphincters  supply varies as blood is needed  after a meal , blood supply to digestive tract increases  during strenuous exercise , blood is diverted from digestive tract to skeletal muscles ◦ capillaries in brain , heart , kidneys & liver usually filled to capacity sphincters open sphincters closed

38. Arteriole Blood flow Venule Lymphatic capillary Interstitial fluid Fluid & solutes flows out of capillaries to tissues due to blood pressure  “bulk flow” Interstitial fluid flows back into capillaries due to osmosis  plasma proteins  osmotic pressure in capillary BP > OP BP < OP 15% fluid returns via lymph 85% fluid returns to capillaries What about edema ? Capillary

39.  Plasma: liquid matrix of blood in which cells are suspended (90% water)  Erythrocytes (RBCs): transport O 2 via hemoglobin  Leukocytes (WBCs): defense and immunity  Platelets : clotting  Stem cells: pluripotent cells in the red marrow of bones  Blood clotting: fibrinogen (inactive)/ fibrin (active); hemophilia; thrombus (clot)

40.  Parallel circulatory system ◦ transports white blood cells  defending against infection ◦ collects interstitial fluid & returns to blood  maintains volume & protein concentration of blood  drains into circulatory system near junction of vena cava & right atrium

41. Production & transport of WBCs Traps foreign invaders lymph node lymph vessels (intertwined amongst blood vessels)

42. Coronary arteries to neck & head & arms

43. What do blue vs. red areas represent? What do blue vs. red areas represent? pulmonary systemic systemic

44. bypass surgery

45.  http://www.smm.org/heart/heart/pumping.h tm

46. AV SL AV  4 valves in the heart ◦ flaps of connective tissue ◦ prevent backflow  Atrioventricular (AV) valve ◦ between atrium & ventricle ◦ keeps blood from flowing back into atria when ventricles contract  “lub”  Semilunar valves ◦ between ventricle & arteries ◦ prevent backflow from arteries into ventricles while they are relaxing  “dub”

47. AV SL AV  Heart sounds ◦ closing of valves ◦ “Lub”  recoil of blood against closed AV valves ◦ “Dub”  recoil of blood against semilunar valves  Heart murmur ◦ defect in valves causes hissing sound when stream of blood squirts backward through valve

48. systolic ________ diastolic pump (peak pressure) _________________ fill (minimum pressure)  1 complete sequence of pumping ◦ heart contracts & pumps ◦ heart relaxes & chambers fill ◦ contraction phase  systole  ventricles pumps blood out ◦ relaxation phase  diastole  atria refill with blood 110 ____ 70

49.  High Blood Pressure (hypertension) ◦ if top number ( systolic pumping) > 150 ◦ if bottom number ( diastolic filling) > 90

50.  Cardiovascular disease (>50% of all deaths)  Heart attack - death of cardiac tissue due to coronary blockage  Stroke - death of nervous tissue in brain due to arterial blockage  Atherosclerosis : arterial plaques deposits  Arteriosclerosis : plaque hardening by calcium deposits  Hypertension : high blood pressure  Hypercholesterolemia : LDL, HDL

51.  Demonstrate the path of an O2 molecule from the air to a knee cell as it travels through the respiration system and the circulatory system (travelling on a red blood cell). Make sure to include arteries, capillaries and/or veins.  Demonstrate the path of an CO2 molecule from a knee cell to the air as it travels through the respiration system and the circulatory system (travelling on a red blood cell). Make sure to include arteries, capillaries and/or veins. Demonstrations Demonstrations

52.  All members verbally involved  8 or more different props  Creativity  Accurate description  Kinesthetic Scoring guide Scoring guide