Download Cellular Respiration

Cellular Respiration
Cellular Respiration
=the release of energy stored in food
=the released energy is stored short-term in
molecules of ATP (Adenosine Triphosphate)
Adenine
Ribose
Phosphates
Stored Energy
Energy Released
Energy had been used
Adding Phosphates=phosphorylation
The breakdown of glucose results in the
formation of many ATPs
How do we breakdown glucose?
Cellular Respiration
• Aerobic Cellular Respiration (Eukaryotes)
Cellular Respiration
• Anaerobic Respiration (Prokaryotes)
Glucose
Lactic Acid or Ethyl
Alcohol and CO2
+2ATP
How do you pull apart a glucose
molecule?
Series of Oxidation/Reduction
Reactions
• Oxidation=a molecule loses electrons or H
atoms
• Reduction=a molecule gains electrons or
H atoms
LEO goes GER
What molecules are going to
accept the electrons or H atoms?
• Hydrogen Acceptors:
– NAD+
– FAD
Both are coenzymes
Important Enzymes In Respiration
• Isomerases= converts a molecule into an
isomer
Important Enzymes In Respiration
• Dehydrogenases and Hydrogenase
=Transfer “H”s
Important Enzymes In Respiration
• Kinases and Phosphatases= Transfer
phosphate groups
Anaerobic Respiration Steps
1. Glycolysis (Splitting of glucose)
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Start with one molecule of glucose
Don’t need O2
Process happens in cytoplasm of
eukaryotes and prokaryotes
Need to use 2 ATPs to start reaction
Form 2 NADH
Form 4 ATPs (so net 2 ATPs)
Form 2 Pyruvic Acid Molecules (3 Carbons)
(Activation Energy)
PGAL
Anaerobic Respiration Steps
2. This step only happens in prokaryotes
and eukaryotic muscle cells experiencing
muscle fatigue or oxygen debt and yeast :
FERMENTATION (Primitive)
2Pyruvic Acid
2 ethyl alcohol + 2 CO2 +2NAD (From NADH)
Yeast and Bacteria
2Pyruvic Acid
2 lactic Acids + 2 NAD (From NADH)
Bacteria and Muscle fatigue
Types of Anaerobic Organisms
• Facultative Anaerobes= (Switch hitters)
– If O2 is present, it will do aerobic respiration
– If no O2 then it will do anaerobic respiration
– Ex. Yeast
Types of Anaerobic Organisms
• Obligate or Strict Anaerobes= only do
anaerobic respiration
– They can die in the presence of O2
– Ex. Some types of bacteria
Anaerobic Respiration Stops Here
What do Aerobic Organisms do?
• Aerobic Respiration begins here!
Aerobic Respiration Steps
1. Glycolysis with NO FERMENTATION!!!!!
2. Pyruvic Acid Breakdown
Pyruvic Acid Breakdown
Pyruvic Acid
Decarboxylation
Reaction
In terms of numbers, double everything for each molecule of glucose
End Result of Pyruvic Acid
Breakdown
1 NADH/ Pyruvic Acid=2 NADH/Glucose
Molecule
1 CO2/ Pyruvic Acid=2 CO2/Glucose
Molecule
Aerobic Respiration Steps
3. Krebs Cycle (a.k.a Citric-Acid Cycle)
– Occurs in Matrix Region of Mitochondrion
Cycle goes around once for each Acetyl CoA, So 2 turns/Glucose Molecule
Kreb’s Cycle Bottom Line
3 NADH/Turn= 6 NADH/Glucose Molecule
1 FADH2/Turn=2 FADH2/Glucose Molecule
1 ATP/Turn =2 ATP/ Glucose Molecule
[1 GTP/Turn =2 GTP/Glucose Molecule]
2 CO2/ Turn =4 CO2/Glucose Molecule
So Far Not Too Many ATPs
formed!
But we got all those NADHs and
FADH2s!
What happens to them?
They move to the inner membrane cristae of the
mitochondria
4. Chemiosmosis and the Electron Transport Chain
100 ATP
made/sec
Electron Transport Chain
• The electrons of H+s (of FADH2 and
NADH) are transferred from one
membrane carrier to another membrane
carrier (Cytochromes)
• The electrons lose energy as they are
transferred (like hot potato)
• This energy drives membrane pumps
involved with Chemiosmosis
Electron Transport Chain
• Once the electrons have lost all energy
they combine with O2 and H+ to form H2O
Chemiosmosis
• The creation of a concentration gradient of
H+ ions across the inner membrane. This
involves active pumping of H+s.
• The H+s then diffuse down their
concentration gradient through an ATP
Synthase enzyme that produces ATP
• Process produces about 32 ATP
• Electron Transport Chain Animation
Aerobic Cellular Respiration
C6H12O6 + 6O2
6CO2 + 6H2O + 36 ATP
Fact:
25 ATPs
10
Every day a person uses
Poisons
• Cyanide and Carbon Monoxide
– Block last electron carrier
• Rotenone (Insect Poison)
– Block initial electron carrier
• Oligomycin (Antifungal cream)
– Blocks ATP Synthase function
What if you get low on carbs?
1. Fats (Gives 2X ATP #s compared to
glucose)
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However, need to be twice as active to
“burn” fat
Breakdown into glycerol and fatty acids
Glycerol converted into a glycolysis
intermediary
Fatty acids converted into Acetyl CoA
What if you get low on carbs?
2. Proteins (yields same amount of ATP as
carbs)
NOT the preferred energy source
Amino acids converted into:
• Pyruvic Acid
• Acetyl CoA
• Kreb’s Cycle Intermediary