ATP

Title :

ATP

Author :

Kim Foglia & Kelly Reidell

Number of slides:

13

Slideshow :

Content transcript :

The energy needs of life
* Organisms are endergonic systems
* What do we need energy for?
* synthesis
* building biomolecules
* reproduction
* movement
* active transport
* temperature regulation
Where do we get the energy from?
* Work of life is done by energy coupling
* use exergonic (catabolic) reactions to fuel endergonic (anabolic) reactions
Living economy
* Fueling the body’s economy
* eat high energy organic molecules
* food = carbohydrates, lipids, proteins, nucleic acids
* break them down
* digest = catabolism
* capture released energy in a form the cell can use
* Need an energy currency
* a way to pass energy around
* need a short term energy
storage molecule
ATP
* Adenosine TriPhosphate
* modified nucleotide
* nucleotide =
adenine + ribose + Pi ? AMP
* AMP + Pi ? ADP
* ADP + Pi ? ATP
* adding phosphates is endergonic
How does ATP store energy?
* Each negative PO4 more difficult to add
* a lot of stored energy in each bond
* most energy stored in 3rd Pi
* 3rd Pi is hardest group to keep bonded to molecule
* Bonding of negative Pi groups is unstable
* spring-loaded
* Pi groups “pop” off easily & release energy
How does ATP transfer energy?
* ATP ? ADP
* releases energy
* ?G = -7.3 kcal/mole
* Fuel other reactions
* Phosphorylation
* released Pi can transfer to other molecules
* destabilizing the other molecules
* enzyme that phosphorylates = “kinase”
An example of Phosphorylation…
* Building polymers from monomers
* need to destabilize the monomers
* phosphorylate!
Another example of Phosphorylation…
* The first steps of cellular respiration
* beginning the breakdown of glucose to make ATP
ATP / ADP cycle
Cells spend a lot of time making ATP!
ATP synthase
* Enzyme channel in mitochondrial membrane
* permeable to H+
* H+ flow down
concentration gradient
* flow like water over
water wheel
* flowing H+ cause
change in shape of
ATP synthase enzyme
* powers bonding of
Pi to ADP:
ADP + Pi ? ATP