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Ch. 4 Autotrophy

Ch. 4 Autotrophy. 1. Collecting energy from the nonliving environment. Every living thing is a sort of imperialist, seeking to transform as much as possible of its environment into itself... -- Bertrand Russell 2. What are Autotrophs?. 12. 9. 10. 11. 13. Lots of Autotrophs.

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Ch. 4 Autotrophy

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  1. Ch. 4 Autotrophy 1 Collecting energy from the nonliving environment Every living thing is a sort of imperialist, seeking to transform as much as possible of its environment into itself...-- Bertrand Russell2

  2. What are Autotrophs? 12 9 10 11 13

  3. Lots of Autotrophs (c) Euglena (d) Cyanobacteria (b) Kelp (a) Mosses, ferns, and flowering plants Figure 7.2

  4. 5 Photosynthesis – Making Sugar from SunlightA Play in Two Acts 3 Directed by: The Sun Produced by: Cells, enzymes, and proteins Starring: Supporting Roles: The Leaf and RuBisCo 4 The Chloroplast 6

  5. The Plot Overview Act 1: The Light Reactions Light to Chemical E The "Photo" part of Photosynthesis2 Act 2: The Calvin Cycle Reactions Chemical E to SugarsThe "synthesis" part of Photosynthesis.2 Light + Water --> ATP + NADPH + Oxygen ATP + NADPH + Carbon Dioxide --> Sugar

  6. 3 CO2 + 3 H2O  C3H6O3 + 3 O2 25 Act 1: The Light Reactions Act 2: The Calvin Cycle Reactions

  7. 8 The Setting and Characters 3 Gas Exchange See P. 104 7

  8. Increasing energy Gamma rays Micro- waves X-rays UV Infrared Radio waves Visible light Wavelength (nm) 600 nm Figure 7.5 The Nature of Light

  9. Plant Pigments Absorb Light Energy14 Other pigments such as carotenoids also help absorb energy.

  10. Different Pigments Use Different Colors of Light If a pigment ABSORBS a color of light, it doesn’t look that color! What colors of light should chlorophyll work best with? 14

  11. How Chloroplasts capture E • Photosystem: an organized group of chlorophyll and other molecules • Light-gathering antenna Chloroplast Cluster of pigment molecules embedded in membrane Photon Primary electron acceptor Granum (stack of thylakoids) Electron transfer Reaction center Reaction- center chlorophyll a Antenna pigment molecules Thylakoid membrane Transfer of energy Photosystem Figure 7.9

  12. Oxidation Is Losing Reduction Is Gaining Focus on Redox See P. 64 An electron DONOR is being Oxidized. An electron ACCEPTOR is being Reduced. Oxidation Number = Measure of Charge (# e-) 15

  13. Act I: The Light Reactions • Red and Blue light is absorbed by pigments in Photosystem II (PSII). (See p. 109) Excited electrons leave the photosystem to be replaced by electrons from water. • Electrons gradually lose E as they move from molecule to molecule of the Electron Transport System (ETS), pumping H+ into the thylakoid space as they do. • Electrons reach PSI, get an E boost from more light, and reduced NADP+ to form NADPH. • The concentration of H+ is potential energy which ATP Synthetase uses to make ATP from ADP.

  14. What’s NADP+ and NADPH? It carries energy and electrons to the Calvin Cycle and can be used and recharged, just like ATP. 16

  15. Act I: Light Energy to Chemical Energy – The “Photo” Part Stroma Inside the Thylakoid (Thylakoid Space)

  16. Act II: The Calvin Cycle Reactions • RuBisCo (Ribulose bisphosphate carboxylase oxygenase) fixesCO2by combining it with RuBP (ribulose bisphosphate; 5 carbons) to form a 6 carbon molecule. The enzyme needs light. • The unstable 6 carbon molecule splits into 3 carbon molecules (PGA; phosphoglyceric acid). • Using NADPH, ATP and enzymes, PGA is turned into the 3 carbon sugar PGAL (phosphoglyceraldehyde) – used for cell energy and reactions (see p. 112) or to restart the Calvin Cycle. • More enzyme reactions turn most of the PGAL back into RuBP to feed the cycle.

  17. Calvin Cycle S t r u c t u r a l P i c t u r e s : h t t p : / / w w w . m s u . e d u / ~ n g s z e l i n / c a l v i n _ c y c l e _ p l a y e r s . h t m Act II: Chemical E to Sugar – The “Synthesis” Part 3 CO2 needed for each PGAL (G3P) Produced “3 turns of the cycle” 10-16-CalvinCycle.swf

  18. Rate of Photosynthesis • What effect do you think raising the light intensity would have on photosynthesis rate? • RuBisCo requires CO2 to work--- What do you think increasing CO2 concentration would do to photosynthesis rate? • What about temperature? Remember what you know about enzymes. Don’t forget – A Rate is something happening per unit time It is how FAST something is happening, not just how much! Eg. Speed = miles per hour Tempo = beats per minute

  19. Principle of Limiting Factors • Whatever is in shortest supply dictates how much/how fast something happens. • What do we need to make sandwiches? • Bread • Meat • Lettuce • Mayonnaise • Etc… 19

  20. Photosynthesis and Light Photoinhibition – Too much light is too much E too fast. Extra E turns water into hydrogen peroxide or OH- which can damage cells.

  21. Light and Carbon Dioxide 0.10% CO2 0.03% CO2 Rate of Photosynthesis Light Intensity 17

  22. Light and Temperature 18

  23. 8 Photorespiration • RuBisCo can also bind O2 if the concentration of CO2 is too low (remember the full name…). O2 + RuBP  PGA + Glycolate  CO2 • We’re trying to FIX CO2, not produce it! • Photorespiration can reduce the rate of photosynthesis by 40-50% • Problem for plants in hot, dry climates – opening the stomates for gas exchange results in water loss

  24. Stomates: Open and Closed

  25. (a) Sugarcane (b) Pineapple 1 Night CO2 incor- porated into four-carbon compounds Cell type #1 4-C compound 4-C compound Day 2 Four- carbon compounds release CO2 to Calvin cycle Cell type #2 Calvin cycle Calvin cycle Sugar Sugar C4 CAM C4 and CAM25 • Avoids photorespiration • Prevents water loss • Fixes to a 4C compound first – then makes 3C sugar • C4 very efficient • CAM not very efficient Figure 7.14

  26. Oxaloacetate is transported to the bundle sheath cells where the Calvin Cycle takes place. CO2 first fixed to a 4 carbon (C4) molecule in the mesophyll cells. The C4 Pathway 21 14

  27. Photosynthesis and the Atmosphere The biggest chemical operation on Earth! 100s of billions of metric tons of input and output! Think about the issues that increased CO2 in the atmosphere and the greenhouse effect (rising temperatures) would have on plants… 23

  28. Chemoautotrophy • In some areas where there is no light and often high temperatures, chemoautotrophs are the only producers! • Ask yourself • What is the source of E? • What is the source of C? • What is the source of e- for reducing carbon? 23 East Pacific Rise Hydrothermal Vent Look at p. 123 – Chemoautotrophs use all kinds of things as e- sources including elemental sulfur, hydrogen gas, iron, nitrogen, and copper!

  29. Sources Cited • Leaf: www.theflowerpotmen.com/; Chloroplast: http://www.hybridmedicalanimation.com/pages/chloroplast.html • Overall “Theater” layout from: http://www.biology.iupui.edu/biocourses/N100H/psynth.html • Sun: w3.arizona.edu/~ws/ • www.nbif.org/products/ clipart/clipart.php • RuBisCo:http://www.msu.edu/~ngszelin/calvin_cycle_players.htm • Leaf: www.inkindex.com/ • “The Working Cell: Energy from Sunlight.” From Biology: Exploring Life. Campbell, Williamson, & Heyden. Pearson Education. 2002. • www.denniskunkel.com, with permission. • Coconut Tree: www.stluciatravel.com.lc/ eastwinds.htm • http://www.grassrootsnursery.com/acatalog/Grass_Roots_Nursery_Underwater_Plants_10.html • Sulfur Bacteria: http://life.bio.sunysb.edu/marinebio/hotvent.html • http://www.mbio.ncsu.edu/JWB/MB409/lab/purple_nonsulfurs/purples.html • www.thepubliccause.net/ LoudSONARs.html • http://www.emc.maricopa.edu/faculty/farabee/BIOBK/BioBookPS.html • Redox: http://www.lifesci.utexas.edu/faculty/sjasper/bio301L/chemistry.html • NADP: www.bio.davidson.edu/courses/ Bio111/NADPH.html • http://www.bbc.co.uk/schools/gcsebitesize/biology/plants/photosynthesishrev4.shtml • www.ldeo.columbia.edu/dees/ees/ climate/lectures/exchange/ • www.northpointgourmet.com/ • Cool Online Lab :http://www.explorelearning.com/gizmos/science/Photosynthesis.htm • http://www.blc.arizona.edu/courses/181gh/rick/photosynthesis/graphics2/c4_path.gif • http://www.bio.umass.edu/biology/conn.river/photosyn.html • www.iusd.k12.ca.us/uhs/ cs2/carbon_cycle.htm • http://www.arches.uga.edu/~jmdavid/ • Bioshow: for Biology: Concepts and Connections, Second Edition. Campbell, Mitchell, and Reece Uncited pictures from instructor CD for Essential Biology with Physiology, 2005

  30. Chemoautotrophs are bacteria... • That oxidize inorganic minerals like iron or sulfur to obtain energy • That do not compete well with other organisms • Found in environments where other organisms cannot survive

  31. http://www.msi.ucsb.edu/ResHi/text/extreme/extreme.htm

  32. Chemoautotrophs are bacteria... • That use the Calvin cycle to fix carbon dioxide • That can sometimes switch electron sources or live heterotrophically if food is plentiful

  33. Some sources of energy and electrons include... • Hydrogen, H2 • Hydrogen sulfide, H2S • Sulfur, S • Ammonia, NH4+ • Ferrous-iron ion, Fe+2

  34. Deinococcus radiodurans • http://www.sciencenews.org/sn_arc98/12_12_98/Bob1.htm • image credit: Uniformed Services University of the Health Sciences. This bacteria is highly resistant to heat, drought, and radiation damage to its DNA. Scientists are trying to use this bacteria to detoxify nuclear wastes.

  35. Iron bogs of Norse settlement in L'Anse aux Meadows, Newfoundland Image from: Talking Dog Productions, Hurstwic. 2000-2001 http://www.hurstwic.org/history/articles/manufacturing/text/bog_iron.htm

  36. Symbiotic metal oxidizing bacteria and tube worms Image from: Charles R. Fisher, Autotrophic Symbiosis. http://www.bio.psu.edu/People/Faculty/Fisher/fisher.htm

  37. Tube worms and bacterial symbionts are... • Found near "black smokers”, so named because the liquid coming out of the vents is black due to rapid precipitation of black polymetal sulfides at 350°C • Dependent upon the energy provided by reduced minerals • Mainly sulfur oxidizing bacteria, which are the primary producers in the deep sea food chain.

  38. Tube worm/bacteria symbiosis • The bacteria lives inside the tube worm Riftia pachytila. • The worm provides a home, space to grow and both hydrogen sulfide and oxygen. • Gases are delivered to the bacteria via the worm’s circulatory system. • In return the bacteria provides a portion of its products from the Calvin cycle to the tube worm.

  39. Chemoautotroph electron transport system 2. Electron Transport and H+ Pumping 1. Electron Donor 3. Chemiosmotic ATP Synthesis Image from: Timothy Paustian, Lithotrophic Bacteria - Rock Eaters. University of Wisconsin-Madison, Sep 21, 2000. http://www.bact.wisc.edu/microtextbook/Metabolism/lithotrophs.html

  40. Nitrogen Oxidizing Bacteria Look at the Oxidation! BioCD. From Biology, Fifth Edition. Campbell, Reece, Mitchell. Addison, Wesley, Longman. 1999.

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