Transcript Cellular Respiration

Cellular Respiration
Cellular Respiration
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A quick review…
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When we eat, we get ______ from glucose
and other sugars
Food energy is c_______ into usable
energy
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Energy used to bond phosphate
groups to ADP to make _____ .
Cellular Respiration
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What is cell respiration???
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Respiration: the process of breaking down
food molecules into usable energy
THE GOAL:
Create ATP for cells to use
 Free up electrons—have high energy
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C6H12O6 + 6 O2 → 6 CO2 + 6 H2O + Energy (ATP + heat)
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Cellular Respiration
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Types of cell respiration
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Aerobic Processes:
REQUIRE oxygen to take place
 A lot of energy available (efficient)
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Anaerobic Processes:
DO NOT require oxygen to take place
 Get energy quickly (inefficient)
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Cellular Respiration
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Glycolysis
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Involves breaking down 6-carbon sugars
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Break sugars into pyruvic acid molecules
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This process is ANAEROBIC
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3-Carbon molecules
No oxygen necessary
Occurs in the cytoplasm of cells
Glycolysis
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You will need to know this…
Glycolysis
Just Kidding… 
Glycolysis
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Glycolysis also creates hydrogen ions
and free electrons
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H + ions bond with NAD+ to form
NADH + H +
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The whole point of respiration = high energy
NADH carries electrons and H + ions
This process uses 2 ATP but
creates 4 ATP molecules
Glycolysis
Glycolysis
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TOTAL ATP PRODUCTION:
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Glycolysis Step 1 uses 2 ATP molecules
Glycolysis Step 2 converts 4 ADP molecules
into 4 ATP molecules
Net ATP production = 2 ATP for every
glucose molecule
Glycolysis
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Oxygen is our
friend…
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When oxygen is
present,
aerobic respiration
occurs
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Happens in the
mitochondria
Glycolysis
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Breaking down Pyruvic Acid…
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Occurs in the mitochondria
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Pyruvic Acid = 3-carbon compound
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Broken down into…
2-Carbon compound—acetic acid
 Carbon Dioxide
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Glycolysis
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Intermediate Step in Glycolysis
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2-Carbon Compound—Acetic Acid
Combined with coenzyme A (CoA)
 Forms compound called acetyl-CoA
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This is only an intermediate step—have to
move pyruvic acid into Krebs Cycle
Glycolysis
Glycolysis =
2 ATP
Cellular Respiration
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Citric Acid (Krebs) Cycle
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Produces more ATP and releases more
electrons
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Electrons picked up by NAD + and FAD
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Organic carrier molecules
Occurs inside mitochondria
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Mitochondrial Matrix
Citric Acid (Krebs) Cycle
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Acetyl CoA combines with a 4-carbon molecule
to form a 6-carbon molecule
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Citric Acid
NAD becomes NADH
FADH becomes FADH2
CO2 released
ATP is created
The cycle starts again
Citric Acid (Krebs) Cycle
Citric Acid (Krebs) Cycle
Citric Acid Cycle =
2 ATP
Cellular Respiration
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Electron Transport Chain
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What is the ETC???
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A series of molecules along which electrons
are transferred, releasing energy
Occurs in the mitochondria—
mitochondrial matrix
Aerobic process
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Oxygen is involved
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Acts as the electron acceptor
Electron Transport Chain
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As the electrons are passed between
carrier proteins, energy is released
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ATP is created
Carbon is given off as carbon dioxide
Electron Transport Chain
ETC =
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Electron Transport Chain
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A problem exists if there is no oxygen
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When oxygen is used up, electrons cannot
be removed
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Anaerobic process
Traffic jam in the mitochondria
KEY POINT —Electron Transport Chain
cannot run without oxygen
Anaerobic Respiration
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If no oxygen present after glycolysis,
pyruvic acid can still be broken down
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This is Fermentation
Only 2 ATP made during fermentation
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Uses electrons carried by NADH + H +
so that NAD+ can regenerate for
glycolysis
Anaerobic Respiration
Anaerobic Respiration
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**Two types of fermentation
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Lactic Acid Fermentation
Glucose
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2 Pyruvic
Acid
2 Lactic
Acid
Alcoholic Fermentation (Yeast)
Glucose
2 Pyruvic
Acid
2 Ethanol
+ 2 CO2
Anaerobic Respiration
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Lactic Acid Fermentation
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Muscle fatigue
When your muscle cells require more energy
than can be produced
 Lack of oxygen
 Lactic acid build up = muscle fatigue
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When oxygen is present, lactic acid breaks down
Anaerobic Respiration
Anaerobic Respiration
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Alcohol Fermentation
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Occurs in bacteria, plants and most animals
Can you think of a bacteria that is used for
fermentation???
Pyruvic Acid is converted into ethanol and
carbon dioxide
Anaerobic Respiration
Cellular Respiration
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Cellular Respiration
General Formula
C6H12O6 + 6 O2
6 CO2 + 6 H2O
Often, in attempts to simplify, false paradigms are
created.
Some textbooks do this when introducing
biochemical reactions.
Photosynthesis
H 2O  light  CO 2  H 2O  C 6 H 12O 6  O 2
WEG  WEG
light  O 2  C 6 H 12O 6  CO 2
Respiration
H 2O  C 6 H 12O 6  O 2  H 2O  ATP  CO 2
C 6 H 12O 6  O 2  ATP  CO 2