Mee#ng
7
Aerobic
and
anaerobic
forms
of
metabolism
Key
points
for
today
•  ATP
molecule:
cri#cal
energy
carrier!
•  How
animals
get
ATP
from
food
•  Compare
the
different
mechanisms
of
ATP
produc#on
•  Interplay
of
aerobic
and
anaerobic
metabolism
when
animals
are
ac#ve
Cri#cal
facts
about
ATP
•  ATP
is
an
energy
carrier
in
cells
ADP
+
Pi
+
energy
from
food
ATP
ATP
ADP
+
Pi
+
energy
usable
by
cells
•  Does
each
cell
have
to
make
its
own
ATP?
•  Is
ATP
substan#ally
stored
in
cells?
Cri#cal
facts
about
ATP
•  ATP
is
an
energy
carrier
in
cells
ADP
+
Pi
+
energy
from
food
ATP
ATP
ADP
+
Pi
+
energy
usable
by
cells
•  Does
each
cell
have
to
make
its
own
ATP?
Yes!
•  Is
ATP
substan#ally
stored
in
cells?
No!
How
do
animals
release
energy
from
food
molecules
using
O2?
•  Glycolysis
reac#ons
•  Krebs
cycle
reac#ons
•  Electron
transport
chain
/
Oxida#ve
phosphoryla#on
reac#ons
Glycolysis
Glucose
+
2
NAD
2
Pyruvic
acid
+
2
NADH2
+
2
ATP
Krebs
Cycle
2
Pyruvic
acid
+
8
NAD
+2
FAD
6
CO2
+
8
NADH2
+
2
FADH2
+
2
ATP
Electron
transport
+
Oxida#ve
phosphoryla#on
(slick!)
10
NADH2
+
5
O2
10
H2O
+
10
NAD
+
30
ATP
2
FADH2
+
1
O2
2
H2O
+
2
FAD
+
4
ATP
Key
thing
here:
need
O2
to
get
lots
of
ATP!
Summary
of
aerobic
catabolism
(for
carbohydrates)
C6H12O6
+
6
O2
6
CO2
+
6
H2O
+
38
ATP!
Glycolysis:
2
ATP
Krebs
Cycle:
2
ATP
Electron
transport/oxida#ve
phosphoryla#on:
34
ATP
• 
need
O2
to
get
lots
of
ATP
from
a
glucose
molecule
• 
w/o
NAD
and
FAD
(from
electron
trans/oxida#ve
phos),
glycolysis
and
Krebs
cycle
shut
down
• 
O2
is
cri#cal
for
ge\ng
lots
of
energy
from
food!
Anaerobic
glycolysis:
backup
system
• 
low
efficiency
(2
measly
ATP
per
glucose)
• 
does
not
work
in
all
#ssues
(not
in
brain!)
• 
needs
glucose
and
lactate
dehydrogenase
• 
ni^y
recycling
of
NAD
• 
causes
buildup
of
lac#c
acid
• 
important
source
of
ATP
(when?)
4
mechanisms
of
ATP
produc#on
•
•
•
•
Aerobic
catabolism
using
O2
from
environment
Anaerobic
glycolysis
(Trick
1)
Phosphagen
use
(Trick
2)
Aerobic
catabolism
using
internal
stores
of
O2
such
as
in
myoglobin
(Trick
3)
Compara#ve
proper#es
of
the
4
mechanisms
of
ATP
produc#on
Metabolic
transi#ons
at
start
and
end
of
ac#vity
Oxygen
deficit
Excess
postexercise
oxygen
consump#on
Mee#ng
ATP
costs
of
compe##ve
running