Respiration Chapter 6

Cellular Respiration - Basics releases energy from glucose released energy is chemical energy occurs in cell cytoplasm mitochondria works better with oxygen (aerobic) than without oxygen (anaerobic)

Cellular Respiration - Process carbon dioxide glucose + oxygen + water + energy CO2 C6H12O6 H2O O2 ATP +

Aerobic Respiration aerobic = with oxygen C6H12O6 + O2 -----> CO2 + H2O + ATP Three process occur in aerobic respiration 1. Glycolysis glucose 2 pyruvic acid PEP C C C occurs in the cytoplasm oxygen is not required electron acceptor is nicotinamide adenine dinucleotide NAD --> NADH

Aerobic Respiration cont’d 2. Krebs Cycle (citric acid cycle) C C C CO2 acetyl-coenzymeA (2C) (in mitochondron) pyruvic acid (3C) (in cytoplasm) Krebs Cycle C CO2 occurs in: mitochondria electron acceptors are NAD and FADH2 FADH2 ATP CO2 C NADH

Kreb’s Cycle

Aerobic Respiration cont’d 3. Electron transport electrons transferred from NADH, FADH2 to oxygen and water is formed oxidative phosphorylation ATP synthase complex protons pumped across membrane occurs in mitochondria conversion equivalents: NADH = 3 ATP FADH2 = 2 ATP

Aerobic Respiration cont’d Energy from aerobic respiration Glycolysis net gain of 6 ATP pyruvic acid --> acetyl-CoA 2 NADH = 6 ATP Krebs Cycle 2 ATP Electron Transport 6 NADH = 18 ATP 2 FADH2 = 4 ATP oxidative phosphorylation Total = 36 ATP / glucose 39% of energy available 61% of energy is lost as heat

Anaerobic Respiration (without oxygen) 1. ethanol fermentation glucose ---> pyruvic acid ---> ethyl alcohol + CO2 + ATP C6H12O6 ----> 2C2H5OH + 2CO2 + 3ATP 25% of energy of aerobic respiration occurs in some plants and microorganisms including yeasts

Alcohol Fermentation Ancient Eqyptian wall painting: historical record of wine-making ~ 5000 yrs ago, perhaps earlier Grapes were picked, crushed by foot, juice collected in jugs, then fermented producing wine.

Anaerobic Respiration cont’d 2. lactic acid fermentation glucose ---> pyruvic acid ---> lactic acid + ATP C6H12O6 ----> 2C3H6O3 + 2ATP 22% of energy of aerobic respiration mammalian muscle and some microorganisms

Organic Macromolecules four groups Carbohydrates built from monosaccharides Protein built from amino acids Lipids built from glycerol & fatty acids Nucleic acids built from nucleotides

Carbohydrates monosaccharides polysaccharide disaccharides

Lipids

Protein

Biochemical Pathways note catabolic and anabolic pathways note production and use of: proteins lipids besides carbohydrates

What is the connection between respiration and photosynthesis?

A review: Carbon flow: from atmosphere through photosynthesis in autotrophs through cellular respiration in autotrophs and heterotrophs back into atmosphere

Carbon Cycle Carbon atom movement. Numbers are estimates of carbon expressed in billions of metric tons stored in reservoirs (2000 data) CARBON + OXYGEN -> CO2 + heat Carbon released by respiration and combustion now exceeds the amount fixed by photosynthesis, by 3 billion metric tons/year.

Major reservoirs of the carbon cycle

Production of CO2 fossil fuels produces 70% of CO2 emmisions U.S. 24% EU 15% China 15% Russia 6% India 5% Japan 5% per capita CO2 emmissions (tons/capita) U.S. 5.4 EU 2.6 China 0.8 Russia 2.9 India 0.3 Japan 2.5

http://upload. wikimedia http://upload.wikimedia.org/wikipedia/en/b/bf/Carbon_Emission_by_Region.png

http://upload. wikimedia http://upload.wikimedia.org/wikipedia/en/5/56/Global_Carbon_Emission_by_Type.png

Global Response to global warming Kyoto Protocol protocol to the international Framework Convention on Climate Change with the objective of reducing Greenhouse gases that cause climate change agreed on 11 December 1997 at the 3rd Conference of the Parties to the treaty when they met in Kyoto, and entered into force on 16 February 2005. Participation in the Kyoto Protocol, as of December 2011, Brown = Countries that have signed and ratified the treaty               (Annex I & II countries in dark brown) Blue = No intention to ratify at this stage Dark blue = Canada, which withdrew from the Protocol in December 2011
Grey = no position taken or position unknown United States although a signatory to the Kyoto Protocol, has neither ratified nor withdrawn from the Protocol both Clinton and Bush administrations have refused obtain senate ratification reasons: top emitters excluded (China, India) cause U.S. economic strain to meet requirements

Correlation Between Historic CO2 Levels and Historic Temperatures: Ice core data Most important, we can look at isotopes of oxygen. In cold years, water molecules with slightly-lighter oxygen atoms evaporate more easily than water slightly-heavier isotopes. Consequently, by looking at the proportions of heavier and lighter oxygen atoms (isotopes), climatologists can reconstruct temperatures over time, and map temperature changes against CO2 concentrations and other atmospheric components. The first very long The longest ice record was from the ever collected is the Vostok ice core , which reached 3,100 m into the Antarctic ice, and gives us a record of both global temperatures and atmospheric CO2 over the past 420,000 years (fig. 9.8). A team of Russian scientists worked for 37 years at the Vostok a site, about 1,000 km from the South Pole to extract this ice core. A similar core , nearly as long as the Vostok, has been drilled from the Greenland ice sheet. More recently the European Project for Ice Coring in Antarctica (EPICA) has produced a record reaching back over 800,000 years. Other glaciers throughout the world have also now been cored. All these cores show that climate has varied dramatically over time, but that there is a close correlation between atmospheric temperatures and CO2 concentrations. 31 31

http://cdiac.esd.ornl.gov/ Carbon Dioxide Information Analysis Center Air samples at Mauna Loa, Hawaii are collected continuously from air intakes at the top of four 7-m towers and one 27-m tower. Four air samples are collected each hour for the purpose of determining the CO2 concentration Carbon Dioxide Information Analysis Center http://cdiac.esd.ornl.gov/

Global Temperature Change

How well does CO2 predict global temperature?

What Causes Natural Climatic Swings? Modest climate changes correspond to an 11-year cycle in the Sun’s intensity Milankovitch Cycles are caused by changes in the Earth’s orbit (100,000 yr), rotation (40,000 yr) and the wobble of its axis (26,000 yr) Ice core records also show that there have been repeated climate changes over time. What causes these periodic (repeated) changes? Modest changes correspond to an 11-year cycle in the sun's intensity. About every 11 years there is a peak in incoming solar energy. More dramatic changes are associated with periodic shifts in the earth’s orbit and tilt (fig. 9.9). These are known as the Milankovitch cycles, after the Serbian scientist Milutin Milankovitch, who first described them in the 1920s. There are three of these cycles: (1) The earth’s elliptical orbit stretches and shortens in a 100,000- year cycle. (2) , while the earth's axis of rotation changes its angle of tilt in a 40,000- year cycle. (3) Furthermore, over a 26,000-year period, the axis wobbles like an out- of-balance spinning top. 9-35 35

temperature/precipitation changes from the 20th Century The impacts of global change are not likely to be distributed evenly throughout the world. For instance, the following graph of the world shows that estimates of temperature and precipitation changes very in different parts of the world.

Possible Implications of and Debate Surrounding Global Warming More heat waves More extreme storm activity Changes in rainfall, snowfall patterns Ecosystem effects Higher sea levels More disease Winners: Siberia, Scandinavia Losers: most of U.S. (particularly SE; Washington may be nicer), island states The potential impacts of global warming are numerous, and it is difficult to discount much of anything important. Depending on the location and current weather conditions, future climates could be hotter or cooler, show more or less precipitation, show more extreme storm activity, flooding of coastal areas, and potentially result in the increased spread and incidence of disease. One of the major impacts of climate change could be the migration or extinction of species not adapted to the future climate. In particular, where mountains range from east vs. west instead of north vs. south, extinctions are likely since the species dependent on previous conditions could not move north or south to adjust their environments.

Shoreline with 1 m sea-level rise Fig. 09.13 Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. New Orleans Shoreline with 1 m sea-level rise Remaining land Miami Current shoreline 100 km 50 km

Consequences of Global Warming uncertainty why? testing the predictions Probable environmental alterations from GW: changing climate and weather patterns intensity of weather increased rising sea levels - 3’ higher all around the world in 100 years shifting climate zones causing ecosystem devastation and species losses

Consequences of CO2 increase CO2 as a Greenhouse Gas third most abundant gas in atmosphere absorbs heat energy reflected by earth acts as a blanket around earth produces the greenhouse effect This is normal, and good! Excessive greenhouse gas accumulation? increase GH gas; increase heat absorption increased heat of earth Global Warming

CO2 in atmosphere key component of nature’s thermostat If carbon cycle removes too much CO2 If carbon cycle generates too much CO2 earth cools earth warms

350.org Because the World Needs to Know

1. Cellular Respiration reactions are anabolic? True False

2. The ultimate energy molecule produced in cellular respiration is A. oxygen B. ATP C. glucose D. ethanol

3. The final electron acceptor in cellular respiration is A. NADP+ B. oxygen C. ATP D. glucose

4. Without oxygen, which process in cellular respiration would NOT occur? glycolysis Kreb’s cycle electron transport all of the above

5. Where does glycolysis occur? cytoplasm inner mitochondrial membrane chloroplast thylakoid

6. Where does Kreb’s cycle and electron transport occur? cytoplasm mitochondria chloroplast thylakoid

7. In cellular respiration all glucose is metabolized into ATP. True False

organic compound building block(s) 8. Name the four groups of organic compounds and their respective building block(s): organic compound building block(s) 1. 2. 3. 4.

9. Carbon reservoirs on earth include atmosphere ocean plants all of the above

What is the most abundant atmospheric gas? nitrogen oxygen carbon dioxide ozone

What is the second most abundant atmospheric gas? nitrogen oxygen carbon dioxide ozone

What is the third most abundant atmospheric gas? nitrogen oxygen carbon dioxide ozone

How abundant is CO2 in the atmosphere? 1000ppm 500ppm 390ppm 350ppm