Transcript The Fate of Glucose

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
glucose
+ oxygen
C6H12O6
+
O2
carbon
dioxide
CO2
+ water + energy
+
H2O
+ ATP
Aerobic Respiration
aerobic = with oxygen
C6H12O6 + O2 -----> CO2 + H2O + ATP
Three process occur in aerobic respiration
1. Glycolysis
glucose
C
C C
C C
C
PEP
2 pyruvic acid
C
C
C
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
C
pyruvic acid
(3C)
(in cytoplasm)
C
C
CO2
acetyl-coenzymeA
(2C)
(in mitochondron)
occurs in:
mitochondria
FADH2
electron acceptors are
NAD and FADH2
CO2
Krebs
Cycle
ATP
CO2
C
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
•Total = 36 ATP / glucose
• 6 NADH = 18 ATP
•39% of energy available
• 2 FADH2 = 4 ATP
• oxidative phosphorylation •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.
EU
China
Russia
India
Japan
24%
15%
15%
6%
5%
5%
• per capita CO2
emmissions
(tons/capita)
•
•
•
•
•
•
U.S.
EU
China
Russia
India
Japan
5.4
2.6
0.8
2.9
0.3
2.5
http://upload.wikimedia.org/wikipedia/en/b/bf/Carbon_Emission_by_Region.png
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
31
400
atmospheric CO2 concentration (ppm)
380
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
R² = 0.9877
360
340
320
300
280
1950
1960
1970
1980
1990
Carbon Dioxide Information Analysis Center
2000
2010
http://cdiac.esd.ornl.gov/
2020
Global Temperature Change
Temperature departure from 1950-1980 average (°C)
80
60
R² = 0.76
40
20
0
-20
-40
1860
1880
1900
1920
1940
1960
1980
2000
2020
How well does CO2 predict global temperature?
CO2 vs temp
60
R² = 0.7512
50
40
30
temp (°C)
20
10
0
-10
-20
-30
-40
280
290
300
310
320
330
CO2(ppm)
340
350
360
370
380
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)
9-35
temperature/precipitation
changes from the 20th Century
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
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
Current shoreline
100 km
50 km
Miami
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
earth
cools
If carbon cycle generates
too much CO2
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?
A.
B.
C.
D.
glycolysis
Kreb’s cycle
electron transport
all of the above
5. Where does glycolysis occur?
A. cytoplasm
B. inner mitochondrial
membrane
C. chloroplast
D. thylakoid
6. Where does Kreb’s cycle and electron
transport occur?
A.
B.
C.
D.
cytoplasm
mitochondria
chloroplast
thylakoid
7. In cellular respiration all glucose is
metabolized into ATP.
True
False
8. Name the four groups of organic
compounds and their respective building
block(s):
organic compound
1.
2.
3.
4.
building block(s)
9. Carbon reservoirs on earth include
A.
B.
C.
D.
atmosphere
ocean
plants
all of the above
What is the most abundant atmospheric
gas?
A.
B.
C.
D.
nitrogen
oxygen
carbon dioxide
ozone
What is the second most abundant
atmospheric gas?
A.
B.
C.
D.
nitrogen
oxygen
carbon dioxide
ozone
What is the third most abundant
atmospheric gas?
A.
B.
C.
D.
nitrogen
oxygen
carbon dioxide
ozone
How abundant is CO2 in the atmosphere?
A.
B.
C.
D.
1000ppm
500ppm
390ppm
350ppm