Chapter 5: Cellular Processes 5.12 Pg. 82 ATP: Energy Currency of Cell Objective: I can explain how ATP is used as energy for the cell, in comparison to other energy molecules like glucose or lipids.

ATP = Adenosine Triphosphate Easiest molecule to get energy from Like cash (currency) (glucose = check, lipids = stocks) All energy-providing molecules eventually broken down to make ATP (NOT broken down into ATP) ATP can be “used up” to make other molecules

Structure of ATP 3 parts Adenine (a nitrogen base) Ribose (sugar) 3 phosphate groups High-energy bonds ALMOST looks like a… nucleotide is it a nucleic acid? Adenine + Ribose = Adenosine

ATP-ADP Cycle When break off 1 phosphate, release energy Turns into ADP (Adenosine Diphosphate) P i = inorganic phosphate group Can add energy to reattach 1 phosphate Turn back into ATP(becomes a cycle) ATP  ADP + P i + energy Matter cycled (ATP  ADP) But energy flowed ADP can  AMP… but…

Reaction Names Breaking down ATP into ADP + P i is called hydrolysis (need H2O) Adding phosphate to another compound = phosphorylation (ADP phosphorylated to ATP) (ATP phosphorylates another molecule)

What is the point? ATP  ADP is exergonic or endergonic ADP  ATP is exergonic or endergonic Energy Coupling When ATP  ADP, energy released can power endergonic reaction (or provide activation energy for exothermic reaction) Heat energy is (always) lost in transfer ATP often breaks down to build something else up…

Specific Cases – Will learn these in great detail soon… Photosynthesis Chloroplasts can use sun energy to make ATP (from ADP) directly ATP is broken down to ADP to turn carbon dioxide into glucose (store nrg) Cellular Respiration Glucose is broken down for energy Energy used to turned ADP into ATP ATP is broken down to ADP to run various cellular activities