Respiration Chapter 6. Cellular Respiration - Basics releases energy from glucose released energy is...
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Transcript of Respiration Chapter 6. Cellular Respiration - Basics releases energy from glucose released energy is...
Respiration
Chapter 6
Cellular Respiration - Basics
• releases energy from glucose• released energy is chemical energy• occurs in cell
cytoplasmmitochondria
• works better with oxygen (aerobic) than without oxygen (anaerobic)
Cellular Respiration - Process
glucose oxygen +water energycarbon dioxide ++
CO2C6H12O6 H2OO2 ATP+ + +
Aerobic Respiration
aerobic = with oxygenC6H12O6 + O2 -----> CO2 + H2O + ATP
Three process occur in aerobic respiration1. Glycolysis
occurs in the cytoplasm
oxygen is not requiredelectron acceptor is nicotinamide adenine
dinucleotideNAD --> NADH
glucose 2 pyruvic acid
CCC
CCC
CCC C
CC
PEP
CO2
Aerobic Respiration cont’d
2. Krebs Cycle (citric acid cycle)
pyruvic acid(3C)
(in cytoplasm)
acetyl-coenzymeA(2C)
(in mitochondron)
Krebs Cycle
CO2
CO2
ATP
NADH
FADH2
occurs in:
mitochondria
electron acceptors are
NAD and FADH2
CCC
CC
C
C
C
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 ATPFADH2 = 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 groupsCarbohydrates
built from monosaccharidesProtein
built from amino acidsLipids
built from glycerol & fatty acidsNucleic acids
built from nucleotides
Carbohydratesmonosaccharides
disaccharides
polysaccharide
Lipids
Protein
Biochemical Pathways
• note catabolic and anabolic pathways
• note production and use of:• proteins• lipidsbesides carbohydrates
Biochemical Pathways
• note catabolic and anabolic pathways
• note production and use of:• proteins• lipidsbesides carbohydrates
Biochemical Pathways
• note catabolic and anabolic pathways
• note production and use of:• proteins• lipidsbesides carbohydrates
Biochemical Pathways
• note catabolic and anabolic pathways
• note production and use of:• proteins• lipidsbesides carbohydrates
Biochemical Pathways
• note catabolic and anabolic pathways
• note production and use of:• proteins• lipidsbesides carbohydrates
What is the connection between respiration and photosynthesis?
• Is atmospheric CO2 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 -> CO2 + 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 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 excessive
CO2
earth cools
If carbon cycle generates excessive
CO2
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