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The Krebs Cycle
Jun 4, 2024
The Krebs Cycle
Overview
The Krebs cycle further breaks down acetyl-CoA from the link reaction.
These acetyl-CoA molecules are derivatives of the original glucose molecule used at the beginning of respiration.
By completing the Krebs cycle, glucose is fully oxidized and converted to carbon dioxide.
Key Steps
Formation of Citric Acid
Acetyl-CoA
reacts with a 4-carbon molecule,
oxaloacetate
, to form
citric acid
(6-carbon).
The Krebs cycle is also known as the Citric Acid Cycle due to this key molecule.
Oxidation Reactions
Citric acid is
oxidized
, transferring electrons and hydrogens to NAD+ to form
NADH
.
This reaction releases
CO2
.
Result: 5-carbon molecule.
The 5-carbon molecule undergoes further
oxidation
.
Produces another NADH and CO2.
Result: 4-carbon molecule.
This 4-carbon molecule undergoes another chemical transformation, yielding
ATP
and converting to a different 4-carbon molecule.
Further Oxidation
The new 4-carbon molecule is
oxidized
again, transferring electrons and hydrogens to
FAD
, forming
FADH2
.
FADH2, like NADH, carries electrons to the electron transport chain.
The resulting molecule is
oxidized
once more to produce another NADH and reform
oxaloacetate
.
This completes the cycle, regenerating oxaloacetate to react with another acetyl-CoA.
Products Formed
NADH
and
FADH2
: Electron carriers for the electron transport chain.
ATP
: Usable energy for the cell.
CO2
: Released as a waste product during exhaling.
Importance of the Krebs Cycle
Illustrates a cyclical process in cellular respiration.
Generates key molecules necessary for the electron transport chain and energy production.
Recommended Activity
For further learning, complete the respiration interactive activity at BioMan Biology.
Tip: Refer to the description of the activity for its length and details.
Additional Resources
Like, subscribe, and explore other educational content such as games, quizzes, and interactive activities at BioMan Biology.
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