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Cellular Respiration
KEY WORDS:OxidationReductionNAD/ NADHFAD/ FADH2
Cellular respirationGlycolysisKreb’s cycleElectron transport chainATP synthase
Food is used to energize ATP
Electrons transfer energy toEnergize ATP
REDOX REACTIONS
Oxidation = Losing electrons
Reduction = Gaining electrons
TIP: OIL RIG
Gradual transfer of electrons provides most energy (ATP) from food
Main Players: Making ATPFood used to make ATP and NADH & FADH2
Electrons provide energy to pump H+ across inner mitochondrial membrane
NAD+/H carry electrons FAD/H2 carry electrons
H+ provide energy for synthesis of ATP
O2 final electron acceptor in ETC
Cytosol location of glycolysis Mitochondria location of Kreb’s cycle & ETC
ATP Synthase brings together ADP and P to make ATP
Obtaining Energy from Food
C6H12O6 + 6O2 6CO2 + 6H2O + Energy
• Organisms extract energy from food over several steps in small “bite sized” pieces
C6H12O6+ 6O2
Energy Energy Energy
6CO2+6H2O
ATP
CellularRespiration
Occurs in 3 stages:
1.Glycolysis2.Kreb’s cycle3.ETC
1. Glycolysis•Takes place in the cytoplasm
NAD+
What’s Happened so far?Glycolysis
O2
Used?
Glucose C now Product:
ATP
#
NADH
#
Glycolysis
glucose
Electron carriers
Some energy captured as electrons
•Energy in food in form of high energy electrons•Electrons captured when food is broken down
•Held by electron carriers•NAD, FAD
NAD+ as an electron shuttle
After Glycolysis•Pyruvic Acid shipped into mitochondria•One carbon is removed as CO2
•Attach Coenzyme-A Acetyl-Co-A
•Make one NADH for each pyruvic acid
Pyruvate as a key juncture in catabolism
2. Krebs Cycle
•Remaining two carbons removed as CO2
•For each Acetyl-Co-A:
Make •1 ATP•3 NADH•1 FADH2
This is what you need to know
What’s Happened so far?Krebs Cycle
Original C of glucose are
now
ATP NADH FADH2
Glycolysis 2 pyruvate 2 2
Acetyl CoA formation
2 CO2
& 2 acetyl CoA
2
Krebs Cycle
Total
glucose
3. Electron Transport Chain (ETC)
•Electrons give up energy as passed along
•Electrons are passed between several molecules
What is oxygen for?
Receives electrons at the end of the ETC
With H+, forms water
ATP synthase
•Works like hydro-electric dam
•Large concentration gradient of H+ builds up across the mitochondrial membrane
*H+ is pumped against its gradient into the mitochondrial matrix.*Energy for active transport comes from electrons
Harnessing energy in small steps allows the cell to get more energy that can be used to do work
Free energy of electrons decreases as they are
passed through the ETC
Chemiosmosis couples the electron transport chain to ATP synthesis
ATP synthase, a molecular mill
1. Enzymes2. ATP3. NAD+
4. vitamins5. proteins
You need energy to think, to keep your heart beating, to play a sport, and to study this book. This energy is directly supplied by _____, which is (are) produced in the process of cellular respiration.
1. transported ... becoming more energetic2. digested ... becoming more energetic3. reduced ... losing electrons to it4. oxidized ... losing electrons to it5. oxidized ... gaining electrons from it
Energy transfer in living things works through redox reactions, in which one substance is _____ by another substance, thereby _____.
1. glycolysis ... the Krebs cycle ... yield of electrons transported to the ETC
2. glycolysis ... the ETC ... yield of electrons transported to the cytosol
3. Redox reactions ... fatty acid breakdown ... yield of calories
4. The Krebs cycle ... the ETC ... numerous redox reactions
5. The Krebs cycle ... the ETC ... fatty-acid breakdown
_____ and _____ are important not so much for the ATP produced in them, but for their _____.
1. 22. 83. 244. 365. 75
At most, how many molecules of ATP can be produced per glucose molecule in cellular respiration?
1. both atmospheric nitrogen and the oxygen for energy transformation
2. oxygen to donate electrons to3. nitrogen to donate phosphate groups to oxygen4. oxygen to act as the final acceptor of electrons in the
ETC5. oxygen to donate phosphate groups to ADP, making it
ATP
We need to breathe because we need
Anaerobic Respiration
Fermentation•live off glycolysis alone
Alcoholic Fermentation
Pyruvate + NADH
Ethanol + CO2 + NAD+
Vinegar
Lactic Acid Fermentation
Pyruvate + NADH
Lactic Acid + NAD+
Fermentation allows the cycle of glycolysis to continue by regenerating NAD+
Fermentation
An overview of cellular respiration (Layer 1)
An overview of cellular respiration (Layer 2)
Substrate-level phosphorylation
An overview of cellular respiration (Layer 3)
Max of 36 ATP per Glucose
What is all of the ATP used for?