4.6 Respiration Steps
Aerobic and Anaerobic
What is the difference between
cellular respiration and breathing?
•
What is the difference between
cellular respiration and breathing?
• Breathing is using your respiratory
tract to pull air into your lungs and
push air out of your lungs.
• Cellular respiration is using the oxygen in the
air to burn glucose and recharge ATP inside all
of your cells.
What is the overall goal of respiration?
What is the overall goal of respiration?
C6H12O6 + 6H2O 
6CO2 + 6H2O +E to recharge 36 ADP
to ATP
Makes 36 ATP: a lot potential chemical energy for
any cell reaction.
Collect H• to run ATP synthase.
Step 1 Glycolysis in Cytoplasm
Glucose + 2ADP + 2Pi  2 Pyruvic Acid + 2ATP
and
NAD  NADH (start collecting H)
Another Diagram Version:
Know the Areas: Crista Membrane and
Matrix
Step 2: Pyruvic Acid enters the
Mitochondrion’s Matrix
• Goes from 3 C to a 2 C molecule, giving off CO2
• (2 C molecule is called Acetyl Coenzyme A)
Step 3: Krebs Cycle
• The 2 carbon pieces of glucose (Acetyl
Coenzyme A) enter the Krebs Cycle.
• During the Krebs Cycle, electrons and
hydrogen atoms are collected by the NAD and
FAD carrier molecules.
• The left over parts make up CO2 which diffuses
out of the mitochondria and out of the cell, it
is ultimately exhaled.
Step 4: Electron Transport Chain
• The Hydrogen ions carried by NAD and FAD
are released so they can be pumped out into
the intermembrane space
• Electrons carried by NAD and FAD run the
hydrogen ion pumps.
• To keep the circuit going, oxygen picks up the
hydrogens and electrons to make water.
• Water is exhaled.
Step 5: Make ATP
• H+ can run down its concentration gradient
through the ATP synthase membrane protein,
ADP + Pi  ATP
• Lots of ATP now accumulates inside the matrix
of the mitochondria.
Step 6: ATP leaves the Mitochondrion
• It is pumped out through a membrane
protein.
• It is free to supply energy for any cell process.
Mitochondrion vs. Chloroplast?
Mitochondrion vs Chloroplast
Big Ideas: Aerobic/Cellular Respiration
• Harnessing glucose energy – don’t let it burn
all at once.
• The energy you are using and giving off as
heat is the same energy that hit the earth
from the sun some days ago:
• v
E  ATPGLUATP  heat/work E
Fermentation or Anaerobic Respiration
• What if you need ATP but cannot get enough
oxygen? Done without oxygen, done without
mitochondria.
• Use the first glycolysis step in the cell
cytoplasm and just get 2 ATP
• 2 Kinds: Lactic Acid and Alcoholic
Fermentation
Lactic Acid Fermentation
Step 1: Glycolysis (muscles and bacteria)
Glucose + 2ADP + 2Pi  2 Pyruvic Acid + 2ATP
and
NAD  NADH (start collecting H•)
Lactic Acid Fermentation Step 2: Make
Pyruvate into Lactic acid
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To capture H and electrons from NAD
Starts over again
Bypass mitochondria
Pro: Fast source of ATP
Con: Yields 2 ATP,
not 36.
• Con: Acid buildup
hurts.
Ethyl Alcohol Fermentation
Step 1: Glycolysis (yeast)
Glucose + 2ADP + 2Pi 2 Pyruvic Acid +2ATP +CO2
and
NAD  NADH (start collecting H•)
Ethyl Alcohol Fermentation Step 2:
Make Pyruvate into Ethyl Alcohol
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To capture H and electrons from NAD
Starts over again
Bypass mitochondria
Pro: Fast source of ATP
Yeast prefer this to
aerobic respiration
Uses for Fermentation:
• Lactic Acid Fermentation:
Bacteria ferment milk to
create yogurt, now
marketed as “probiotics.”
(Lactobacillus species)
• Ethyl Alcohol Fermentation:
Yeast for baking, brewing,
ethyl alcohol fuel production,
genetics studies. (Saccharomyces species)
• Soy sauce uses both types of fermentation