Transcript Glycolysis - Kreb`s Cycle - Electron Transport Chain

Phosphorylation
When glucose enters
a cell, a phosphate group
(from ATP) gets attached
to C #6.
C6H12O6 + PO4 
glucose-6-phosphate
All glucose inside a cell
must be in the form of
gluc-6-phos in order to
be used.
Non-reversible process
in all except LIVER CELLS.
Glycogenesis
“genesis” = formation
Glucose is stored as
GLYCOGEN (long
chains of gluc-6-phos
molecules)
Glycolysis
“lysis” = breaking apart
Gluc-6-phos + 2ATP
 Pyruvate + 4ATP
Anaerobic process
http://www.science.smith.edu/departments/Biology/Bio231/glycolysis.html
Glucose
H- C = O
|
H - C - OH
|
HO- C - H
|
H - C - OH
|
H - C - OH
|
H - C - OH
H
Pyruvate (Pyruvic acid)
CH3 - C – COOH
||
O
Kreb’s Cycle
• Pyruvic acid (from glycolysis)
goes into the mitochondria
• CO2 + H+ are split off and
leaves a 2 carbon (acetyl)
Group
http://www.science.smith.edu/departments/Biology/Bio231/krebs.html (step 1)
• Acetyl group combines
w/ CoA  acetyl CoA
Coenzyme
Organic compound made by
cells that must combine with
an enzyme in order to work.
Coenzyme may be a hydrogen
“carrier”
Hydrogen carriers
NAD – nicotinamide
adenine
dinucleotide
FAD –
flavin adenine dinucleotide
NAD +
FAD +
+
H
+
H


+
NADH
+
FADH
Coenzyme A
Coenzyme that is NOT a
hydrogen carrier.
Coenzyme A carries a
2-carbon (acetyl) group
ADP
Is also a coenzyme – carries
phosphate groups
First part of Kreb’s cycle
CoA carries acetyl groups
into the Kreb’s cycle
to transfer them to
oxaloacetic acid to
form CITRIC ACID (name
of cycle)
http://www.science.smith.edu/departments/Biology/Bio231/krebs.html (step 2)
Kreb’s cycle
is important in
the metabolism of:
• Carbohydrates
• Proteins
• Lipids
In one “turn” of the
Kreb’s cycle…..
1 molecule acetyl CoA 
• 2 molecules CO2
• 4 molecules H2
(3 NADH + 1FADH)
•1 molecule ATP
And, now for
the Kreb’s
Cycle itself………
From glycolysis
CH3 – C – COOH + CoA
|| Pyruvic acid
O
CH3 – C – CoA
||
Acetyl CoA
O
Step #1
CH3 – C – CoA
||
O acetyl CoA
COOH
|
NADNADH
CH2
|
HO – C – COOH
|
CH2
|
COOH
citric acid
+
COOH
|
C=O
|
CH2
|
COOH
oxaloacetic acid
Animation
http://www.science.smith.edu/department
s/Biology/Bio231/krebs.html (step 2)
COOH
|
CH2
|
HO – C – COOH
|
CH2
|
COOH
citric acid
Step #2
COOH
|
CH2
|
C – COOH
||
CH
|
COOH
cis-aconitic acid
(unstable intermediate)
Step #3
COOH
|
CH2
|
C – COOH
||
CH
|
COOH
cis-aconitic acid
(unstable intermediate)
COOH
|
CH2
|
H - C – COOH
|
HO - CH
|
COOH
isocitric acid
Step #4
COOH
|
CH2
|
H - C – COOH
|
HO - CH
|
COOH
isocitric acid
-2H
COOH
|
CH2
|
H - C – COOH
|
C=O
|
COOH
oxalosuccinic acid
Step #5
COOH
|
CH2
|
H - C – COOH
|
C=O
|
COOH
oxalosuccinic acid
-CO2
COOH
|
CH2
|
CH2
|
C=O
|
COOH
-ketoglutaric acid
Step #6
COOH
|
CH2
-CO2
|
-2H
CH2
NADH+NAD
|
C=O
|
COOH
-ketoglutaric acid
COOH
|
CH2
|
CH2
|
C=O
|
CoA
succinyl CoA
Step #7
COOH
|
CH2
|
CH2
|
C=O
|
CoA
succinyl CoA
+H2O
NADNADH+
COOH
|
CH2
|
CH2
|
COOH
succinic acid
Step #8
COOH
|
CH2
|
CH2
|
COOH
succinic acid
-2H
COOH
|
CH
||
CH
|
COOH
fumaric acid
Step #9
COOH
|
CH
||
CH
|
COOH
fumaric acid
+H2O
COOH
|
HO - CH
|
CH2
|
COOH
malic acid
Step #10
COOH
|
HO - CH
|
CH2
|
COOH
malic acid
-2H
COOH
|
C=O
|
CH2
|
COOH
oxaloacetic acid
(back to where we started!)
Animation Summary
http://www.science.smith.edu/department
s/Biology/Bio231/krebs.html (step 3)
Summary to end of Kreb’s Cycle
In
Out
1 pyruvic acid
1 CO2 (as waste)
1 NAD
1 NADH
CoA
Acetyl CoA
1 acetyl CoA
2 CO2 (as waste)
3 NAD
3 NADH
1 FAD
1 FADH2
1 ADP
1 ATP
What happens to the CO2
produced in the Kreb’s Cycle?
Diffuses from mitochondria 
cytoplasm (cytosol) 
bloodstream
 exhaled (whew!)
Electron Transport Chain
The pairs of hydrogen ions (-2H) from
the Kreb’s Cycle enter the electron
transport chain.
There are a series of HYDROGEN
ACCEPTORS (NAD, FAD & cytochromes)
that, as they pass the hydrogen ions
along, ATP is being produced.
What ultimately happens to
pairs of H?
Oxygen is final acceptor of H 
produces H2O!
From 4 pairs of H 
36-38 ATPs produced in
the electron transport chain!
Glucose ATP count?
Phosphorylation & glycolysis: 8 ATP
Kreb’s cycle &
electron transport: 30 ATP
Total = 38 ATPs
Electron Transport Chain
(Animation)
http://www.science.smith.edu/departments/Biology/Bio231/etc.html
Fat metabolism
1 unit of FAT
3 fatty acids
1 glycerol
18 C each chain
glycolysis
Each 18 C  6 pyruvic acid
So total of 18 pyruvic acids
Kreb’s cycle &
electron transport
18 pyruvic acids  684 ATP
So, 684 + 38 = 722 ATPs!
38 ATP
What about protein?
Single amino acids are used to build
muscle, bones, connective tissue,
and cytoplasm and cell membrane
of cells.
Not typically catabolized (broken down)
for energy – only during starvation.
22 amino acids – 8 are “essential”
Chemistry of Digestion writing
prompt:
The carbohydrates, proteins and lipids
have now been broken down into
single sugars, amino acids or fatty acids
and glycerol. They are now in the liver.
Describe, in detail, the process by
which glucose creates ATP and
then how the other substances
become ATP as well.
Be sure to include structures to
help your explanation.