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RESPIRATION
Two Meanings:
1. BREATHING OR EXTERNAL
RESPIRATION
2. CELLULAR RESPIRATION - Process
by which organic compounds are
broken down to yield energy for work
• This energy molecule is _________
Overall Equation
Glucose + Oxygen+ --->
Carbon Dioxide + Water +
Energy
or
C6H12O6 + 6O2 + ---> 6CO2 +
6H2O + (32-36)ATP
Two main reasons
1. ATP is made that allows cells to
carry out all its activities
2. Carbon Dioxide produced is
used by autotrophs for
Photosynthesis
In all Living cells
Prokaryotic cells - in cytoplasm
and inner foldings of plasma
membrane
Eukaryotic cell – cytoplasm
and mitochondria
• Sugar (glucose)
• Oxygen (not always)
• Water
TYPES OF RESPIRATION
• Aerobic - with oxygen,
releases the most ATP per
glucose molecule
• Anaerobic - without oxygen,
releases the least ATP per
glucose molecule
Info About Aerobic Respiration
• Oxygen needed
• Breakdown of pyruvate
• In mitochondria
• Krebs cycle - in the matrix
• Electron transport chain - in the cristae
• 6 carbon dioxide molecules formed
• 36-38 ATP molecules formed
Both Processes start with
Glycolysis
• Glyco stands for Glucose
• Lysis means to Split
• What is Glycolysis?
Glycolysis
(occurs in the cytoplasm
2 ATP
Glucose
2 ADP+P
4 ADP+P
2 PGAL
4 ATP
2 Pyruvate
2 NAD+
2 NADH
What happens Glycolysis?
• Occurs in the cytoplasm of all organisms.
• 6 Carbon Glucose splits into 2 molecules
each containing 3 carbons (called pyruvate)
• Because Glucose is a pretty stable
molecule, energy is needed to start this
reaction (2ATP)
What is Glycolysis?
• This process generates 4 ATP and 2
NADH
• What is the net gain of ATP at the end of
this reaction? 2
Krebs Cycle or Citric Acid Cycle
• Hans Krebs ( Nobel Prize)
• Pyruvate lysed through a series of steps to
release all the carbon as Carbon dioxide.
• How many carbon dioxide molecules are
formed? ______
• What else?
• 2 ATP
• 6 NADH (+2 in the intermediate)=8
• 2 FADH2 (similar molecule to NADH)
Let’s Take Inventory!
So far (from Glycolysis to Krebs Cycle)
We have used 2 ATP
We have made 4 ATP in glycolysis
We have made 2 ATP in Krebs Cycle
Total gain of ATP __4
How many ATP molecules do you need per
minute per cell? Is this enough?
From Wikipedia.org/wik/Electron_transport_chain
Electron Transport Chain
(ETC)
• Occurs on the mitochondrial inner
membrane or cristae
• NADH and FADH2 release their
Hydrogen atoms
• Hydrogen atoms breaks up into eand H+
• Electrons travel through the
membrane proteins
Electron Transport Chain
(ETC)
• Hydrogen accumulate inside the cristae
• Concentrations gradient drives the H+
through the ATP Synthase
• Energy used to make ATP (32 ATP)
• The hydrogen then reacts with the
oxygen molecules to make H+ + O2 -->
H 2O
• Some energy lost as heat – useful to keep
warm
So How many ATPs are made
Glycolysis: Net gain of 2
Krebs Cycle: 2
ETC: 32-34
Note:
Each NADH can make 3 ATP
Each FADH2 can make 2 ATP
TOTAL
= 36 ATP
Anaerobic Respiration
Absence of oxygen
Krebs Cycle and ETC cannot function
Glycolysis can occur
Cell gets 2 ATP per glucose
NADH builds up and will eventually stop
formation of ATP
Survival Tactics??
Anaerobic Respiration
Alcoholic
fermentation
Yeast helps bread
rise
Yeast used to make
alcoholic bevs
Used to make
gasohol
Lactic acid
fermentation
Human muscle contract
in low O2
In Bacteria to make
cheese, yogurt,
sauerkraut
2 ATP made and NADH recycled
Alcoholic fermentation
2 ATP made and NADH recycled
Lactic Acid Fermentation
Glucose
2pyruvate
•No oxygen needed (anaerobic)
•Many enzymes needed
•4 ATPs needed, 2 ATPS made
net gain of 2 ATP
•2NAD
2 NADH