Download Cell Respiration--The Kreb`s Cycle

Packet #27
Chapter #9
Introduction I
 The Kreb’s Cycle is known by two different names,
the Tricarboxylic Acid Cycle and the Citric Acid
Cycle, and accounts for about two thirds of the total
oxidation of carbon compounds in most cells.
Introduction II
 The major end products
produced are CO2 and
NADH formed from high
energy electrons.
 NADH is produced via the
oxidation of acetyl groups,
from ACoA, into CO2.
 The eight step/reaction
process begins and ends
with the reproduction of
oxaloacetate.
 Additionally, without the use
of oxygen, ATP is produced.
 Substrate level
phosphorylation.
Steps of the Kreb’s Cycle
 The two carbon acetyl
group combines with
the four carbon
substance oxaloacetate
during step #1.
 During the series of
reactions, two CO2,
three NADH, one FADH
and one ATP are
produced.
 Per pyruvate/ACoA.
The Kreb’s Cycle
Review/End Products of the
Kreb’s Cycle
 Per pyruvate/ACoA
 3 NADH
 1 FADH
 1 GTP

Later changed to ATP
 2 CO2
 Per Glucose
 Remembering that
glucose was split into
two.
 6 NADH
 2 FADH
 2 GTP

Later changed to ATP
 4 CO2
Special Notes
Kreb’s Cycle
 The Kreb’s Cycle provides hydrogen atoms, which
ultimately yield the major part of the energy derived
from the oxidation of a glucose molecule.
 It is a valuable source of intermediates which are
used to manufacture other substances.
 Fatty acids
 Amino acids
 Carotenoids