Making energy! ATP The point is to make ATP! 2008-2009
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 digestion + + energy synthesis + + energy
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 Whoa! ot stuff!
ATP Adenosine TriPhosphate modified nucleotide nucleotide = adenine + ribose + P i AMP AMP + P i ADP ADP + P i ATP adding phosphates is endergonic ow efficient! Build once, use many ways high energy bonds
ow does ATP store energy? I think he s a bit unstable don t you? AMP ADP ATP O O O O O O P O P O PO O P O P O O O O O O Each negative PO 4 more difficult to add a lot of stored energy in each bond most energy stored in 3rd P i 3rd P i is hardest group to keep bonded to molecule Bonding of negative P i groups is unstable spring-loaded P i groups pop off easily & release energy Instability of its P bonds makes ATP an excellent energy donor
ow does ATP transfer energy? ADP ATP O O O O P O P O P O O O O O O P O O + 7.3 energy ATP ADP releases energy G = -7.3 kcal/mole Fuel other reactions Phosphorylation released P i 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! C O + + 2 O C O It s never that simple! C O synthesis +4.2 kcal/mol C C O kinase + enzyme ATP C + ADP -7.3 kcal/mol P C OO C enzyme C P + C C C O -3.1 kcal/mol O + P i
Another example of Phosphorylation The first steps of cellular respiration beginning the breakdown of glucose to make ATP Those phosphates sure make it uncomfortable around here! glucose C-C-C-C-C-C hexokinase phosphofructokinase fructose-1,6bp P-C-C-C-C-C-C-P 2 2 ATP ADP P C C C P DAP P-C-C-C G3P C-C-C-P activation energy
ATP / ADP cycle Can t store ATP good energy donor, not good energy storage too reactive transfers P i too easily only short term energy storage carbohydrates & fats are long term energy storage cellular respiration ATP ADP A working muscle recycles over 10 million ATPs per second + P i 7.3 kcal/mole Whoa! Pass me the glucose (and O 2 )!
Cells spend a lot of time making ATP! The point is to make ATP! What s the point?
ATP synthase Enzyme channel in mitochondrial membrane permeable to + + + + + + + + + rotor + flow down concentration gradient rod flow like water over water wheel flowing + cause change in shape of ATP synthase enzyme ADP + P catalytic head powers bonding of P i to ADP: ADP + P i ATP ATP + But ow is the proton ( + ) gradient formed?
That s the rest of my story! Any Questions? 2008-2009
Bioenergetics Video Link https://www.youtube.com/watch?v=ndcxipii 7-Y
Free Energy Gibb s Gibb s free energy is the energy that is available in a system to do work. Energy that is available to make ATP. ATP is used for the signal transduction pathway, moving materials around within the cell, moving materials across the membrane, and anabolic/catabolic reactions. The change is the free energy, determined by using the formula on the next slide, will be positive or negative, depending on the type of reaction.
Gibbs Free Energy Δ G = Δ TΔ S G- Gibbs free energy Enthalpy (Total usable energy in the system) T Temperature in Kelvin (273 + C⁰) S- Entropy (Disorder created by something being broken down) Δ Change in a variable over time ****Overall, the change in free energy is the final energy minus the initial energy in the system.****