Making energy!
ATP
The Point is to Make ATP!
AP Biology
3/24/2016
Energy needs of life
 Organisms are endergonic systems

What do we need energy for?
 synthesis (biomolecules)
 reproduction
 active transport
 movement
 temperature regulation
AP Biology
3/24/2016
Transformations between kinetic
and potential energy
More potential energy.
Kinetic Energy Converted to
Potential Energy
AP Biology
Potential energy converted
to kinetic energy.
Less potential energy
Where do we get the energy from?
 Work of life is done by energy coupling

use exergonic (catabolic) reactions to
fuel endergonic (anabolic) reactions
+
+
AP Biology
+
+
energy
energy
3/24/2016
The two laws of thermodynamics
Heat
+
H2O
Chemical
energy
(a)
First law of
thermodynamics: Energy
can be transferred or
transformed but
neither created nor
destroyed.
AP Biology
co2
(b)
Second law of thermodynamics: Every energy transfer or
transformation increases the disorder (entropy) of the universe.
How Food Becomes Energy
H2 + 1/2 O2
2H
/2 O2
1
+
(from food via NADH)
Explosive
release of
heat and light
energy
ATP
Free energy, G
Free energy, G
2 H+ + 2 e–
Controlled
release of
energy for
synthesis of
ATP
ATP
ATP
2 e–
/2 O2
1
2 H+
H2O
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(a) Uncontrolled reaction
H2O
(b) Cellular respiration
Where do we get the energy from?
 Work of life is done by energy coupling

use exergonic (catabolic) reactions to
fuel endergonic (anabolic) reactions
digestion
+
synthesis
+
AP Biology
+
energy
+
energy
Living economy
 Fueling the economy



eat high energy organic molecules (food)
break them down = catabolism (digest)
capture energy in form cell can use
 Need an energy currency

a way to pass energy around
Whoa!
Hot stuff!
AP Biology
ATP
3/24/2016
ATP
 Adenosine Triphosphate

modified nucleotide
 adenine + ribose + Pi  AMP
 AMP + Pi  ADP
 ADP + Pi  ATP
How efficient!
Build once,
use many ways
AP Biology
an RNA
nucleotide
3/24/2016
Why does ATP store energy?
O– O– O – O– O–
–O P –O
O– P –O
O––P
OO
P––O
O– P O–
O O O O O
I think he’s
a bit
unstable…
don’t you?
 Each Pi group more difficult to add

a lot of stored energy in each bond
 most stored in 3rd Pi
 ∆G = -7.3 kcal/mole
 Close packing of
negative Pi groups

spring-loaded
AP Biology
instability
of its P bonds makes ATP an excellent energy donor
3/24/2016
How does ATP transfer energy?
O– O– O –
–O P –O
O– P –O
O– P O–
O O O
O–
–O P O – +
O
 Phosphorylation

when ATP does work, it transfers
its 3rd Pi to other molecules
 ATP  ADP
 releases energy
 ∆G = -7.3 kcal/mole
 it destabilizes the other molecule
AP Biology
energy
Why is 3rd
phosphate
like a baaad
boyfriend?
3/24/2016
An example of Phosphorylation…
 Building polymers from monomers

need ATP for energy & to take the water out
H
C
OH
H
C
it’s never
that simple!OH
H
C
AP Biology
+
H
C
OH
+4.2 kcal/mol
“kinase”
+ ATP
+
P
H
C
OH
enzyme
-7.3 kcal/mol
-3.1 kcal/mol
H H
C C
O
H
C
+
+
H2O
ADP
P
H H
C C
O
+
3/24/2016
Pi
Another example of Phosphorylation…
 The first steps of cellular respiration

beginning the breakdown of glucose  ATP
glucose
C-C-C-C-C-C
2 ATP
2 ADP
enzyme 1
those
phosphates
sure make it
uncomfortable
around here
enzyme 2
fructose-6P
P-C-C-C-C-C-C-P
enzyme 3
enzyme 5
DHAP
P-C-C-C
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enzyme 4
PGAL
C-C-C-P
enzyme 6
3/24/2016
ATP / ADP cycle
Can’t store ATP
 too reactive
 transfers Pi too
easily
 only short term
energy storage
 carbs & fats are
long term energy
storage
Whoa!
Pass me the
glucose & oxygen!
AP Biology
A working muscle recycles over
10 million ATPs per second
3/24/2016
What’s the point?
 Cells spend a lot of time making ATP!
“The point is to make ATP!”
Make ATP!
That’s all I
do all day.
And no one
even notices!
AP Biology
I didn’t
HEAR you!
3/24/2016
Any Questions??
AP Biology
3/24/2016