Cellular Respiration

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Cellular Respiration
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Energy and Life8-1Page 201
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To live and perform life functions all organisms
need
The sun is the original source of energy for all
living things.
ENERGY!
Autotrophs Able to make their own food using the
suns energy.
Heterotrophs Get their energy from feeding on
autotrophs or other heterotrophs.
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The food eaten must be turned into a chemical
form to be used for life processes.
Adenosine Triphosphate (ATP) the main chemical
compound that cells use to store and release
energy
ATP
ATP
ATP
ATP
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• Energy from ATP powers
• - active transport across cell membranes
• - synthesis of proteins nucleic acids
• - responses to chemicals at the cell surface
• - can even be used to produce light

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• ATP is made up 3 parts
• adenine
• 5-carbon sugar called ribose
• three phosphate groups

adenine
ribose
phosphate groups
P
P
P
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• Phosphate groups are the key to ATPs ability to
  store and release energy.
• Energy is stored in the bond between the 2nd
  and 3rd phosphate.

adenine
ribose
P
P
P
phosphate groups
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When the 3rd phosphate breaks off it is called
ADP (adenosine diphosphate)
adenine
ribose
P
P
P
phosphate groups
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• Breaking the chemical bond between the 2nd 3rd
  phosphate RELEASES energy.

adenine
ribose
ENERGY!
P
P
P
phosphate groups
ATP
ADP
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• Breaking the chemical bond between the 2nd 3rd
  phosphate RELEASES energy.

P
adenine
ribose
ENERGY!
P
P
phosphate groups
ADP
ATP

• Adding the chemical bond between the 2nd and 3rd
  phosphate STORES energy.

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• Most cells have only a small amount of ATP,
  enough to last them for a few seconds of
  activity.
• ATPs ability to recharge is very important
  to its usefulness.

ADP
ATP
Energy
Energy
Adenosine diphosphate (ADP) Phosphate
Adenosine triphosphate (ATP)
Partially charged battery
Fully charged battery
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• ATP is great for transferring energy, not good
  for long term energy storage.
• A single molecule of glucose stores 90 times the
  chemical energy of one molecule of ATP.
• Cells regenerate ATP from ADP as needed.

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Cellular Respiration
Mitochondrion
Electrons carried in NADH
Electrons carried in NADH and FADH2
Figure 92 Cellular Respiration An Overview
Figure 92 Cellular Respiration An Overview
Pyruvic acid
Glucose
Electron Transport Chain
Krebs Cycle
Glycolysis
Mitochondrion
Cytoplasm
Total ATP molecules formed during cellular
respiration 36 ATP
Net gain of 2 ATP
Net gain of 34 ATP
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CELLULAR RESPIRATION

• 6O2 C6H12O6 ? 6CO2 6H2O Energy
• Oxygen Glucose ? Carbon Water Energy
  (ATP) Dioxide

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Where did that glucose come from?

• ?

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CELLULAR RESPIRATION

• After glycolosis, there are two possible
  pathways depending on the presence or absence of
  O2

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Chemical Pathways of Cellular Respiration
Glucose
Krebs cycle
Electrontransport
Glycolysis
Fermentation (without oxygen)
Alcohol or lactic acid
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CELLULAR RESPIRATION

• If oxygen is present aerobic respiration will
  begin
• If oxygen is not present anaerobic respiration
  will occur

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After Glycolysis cont.

• If oxygen is not present one of two types of
  anaerobic respiration or Fermentation takes
  place
• Alcoholic Fermentation
• Lactic Acid Fermentation
• Requires NADH to convert pyruvic acid into lactic
  acid

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The Krebs Cycle

• If oxygen is present aerobic respiration begins
• The Krebs Cycle begins when the two molecules of
  pyruvic acid produced in glycolysis enter the
  Mitochondria and with the help of enzymes form
  Citric Acid. As a result the Krebs cycle is also
  referred to as the Citric Acid

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The Krebs Cycle cont.

• Energy Extraction
• The citric acid is broken down into carbon
  compounds and the following are released
• 2 ATP
• 6 molecules of CO2
• Electron carriers (NADH and FADH2 )

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The Krebs Cycle cont.
Citric Acid Production
Mitochondrion
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Electron Transport Chain

• The electron transport chain uses the
  high-energy electrons (donated electron carriers
  NADH and FADH2) from the Krebs cycle to convert
  ADP into ATP.
• High-energy electrons from NADH and FADH2 are
  passed along the electron transport chain
  (carrier proteins).
• An enzyme at the end of the electron transport
  chain combines electrons with hydrogen ions and
  oxygen to form water.
• Oxygen is the final electron acceptor.
• Releases 6H2O and 32 molecules of ATP

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Cellular Respiration
Total ATP produced 36