ATP
BOOM!
WHAT DO YOU DO?
WORK!
Mechanical
Chemical
Transport
WHAT DO YOU LOOK LIKE?
Adenine
3 Phosphate groups
Ribose
ATP!!!!!!
Bonds between P groups of ATP’s can be
broken by hydrolysis (ADP)
ATP + H2O  ADP + P
What do you think ΔG is? – or +???
-7.3 kcal/mol
BONDS
Which molecule do you think is more stable
(A or B)?
MORE STABLE!
A
B
Are P bonds strong or weak? How do you
know?
BONDS– OPOO!
Phosphates are negative. Being negative means:
REPULSION  MORE UNSTABLE REGION
PHOSPHORYLATION
When the P leaves the ATP where does it go?
Which molecule is PHOSPHORYLATED (A or B)?
Why does the P attach to another molecule?
ADP + P  ATP
Where do we get the E to “recharge” ADP?
E released from catabolic reactions
ATP
Energy from
Catabolism
(sunlight or food)
Release of energy
during the hydrolysis
of ATP comes from
the chemical change
to a state of lower
free energy!
Energy for
cellular work and
for chemical
synthesis
ADP + P
REVIEW
Describe the forms of energy found
in an apple as it grows on a tree,
then falls and is digested by
someone who eats it?
ANSWER
The apple has potential E in its
position hanging on the tree. The
sugars it contains have chemical
E. The apple has kinetic E as it
falls from the tree to the ground.
When the apple is digested and
the molecules are broken down,
some of the chemical E is used
to do work.
REVIEW
At nighttime celebrations, revelers
can sometimes be seen wearing glow
in the dark necklaces. The necklaces
start glowing once they are
“activated” (snapping the necklace in
a way that allows 2 chemicals to react
and emit light in the form of
chemiluminescence). Is the reaction
exergonic or endergonic? Explain.
ANSWER
Exergonic. It releases energy in
the form of light.
REVIEW
In most cases, how does ATP
transfer E from exergonic to
endergonic reactions in the cell?
ANSWER
ATP transfers E to endergonic
processess by phosphorylating
other molecules.
**Exergonic processes
phosphorylate ADP to
regenerate ATP**