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 glucoseoxygen+waterenergy carbon dioxide ++ CO 2 C 6 H 12 O 6 H2OH2OO2O2 ATP+++

Aerobic Respiration aerobic = with oxygen C 6 H 12 O 6 + O > CO 2 + H 2 O + ATP Three process occur in aerobic respiration 1. Glycolysis occurs in the cytoplasm oxygen is not required electron acceptor is nicotinamide adenine dinucleotide NAD --> NADH glucose 2 pyruvic acid C C C C C C C C C C C C PEP

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

Kreb’s Cycle

Aerobic Respiration cont’d 3. Electron transport electrons transferred from NADH, FADH 2 to oxygen and water is formed oxidative phosphorylation ATP synthase complex protons pumped across membrane occurs in mitochondria conversion equivalents: NADH = 3 ATP FADH 2 = 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 FADH 2 = 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 + CO 2 + ATP C 6 H 12 O > 2C 2 H 5 OH + 2CO 2 + 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 C 6 H 12 O > 2C 3 H 6 O 3 + 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 disaccharides polysaccharide

Lipids

Protein

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

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

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

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

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

What is the connection between respiration and photosynthesis?

Is atmospheric CO 2 in “equilibrium”? Absorption by plants and the oceans Accumulating in the atmosphere as carbon dioxide CO2 emission into the atmosphere by fossil fuel combustion dramatically changed “equilibrium” CARBON (oil, coal, natural gas, etc) + OXYGEN + COMBUSTION -> CO 2 + heat Carbon Cycle Numbers = approximate carbon exchange (Gt/year)

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 Conclusion: carbon released from the burning of fossil fuels has increased exponentially over the last century!

Global Warming Contributors

Consequences of CO 2 increase CO 2 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

CO 2 in atmosphere key component of nature ’ s thermostat If carbon cycle removes excessive CO 2 earth cools If carbon cycle generates excessive CO 2 earth warms

Carbon Flow: Living Systems Life is carbon based All organisms use carbon compounds for Energy: Glucose primarily, is converted to ATP in cells Structural components: Cell membrane & wall; cellulose, proteins, Regulatory components: DNA,enzymes, hormones, neurotransmitters, etc. Thus: energy flow is tied to carbon life is tied to carbon

Carbon Flow: Living Systems Goals for you as student: Trace carbon from atmosphere through photosynthesis in autotrophs through cellular respiration in autotrophs and heterotrophs back into atmosphere