Making energy! ATP 2007-2008

The energy needs of life Organisms are energy absorbing systems What do we need energy for? synthesis building biomolecules reproduction movement active transport temperature regulation Which is to say… if you don’t eat, you die… because you run out of energy. The 2nd Law of Thermodynamics takes over!

The first law of thermodynamics states that energy can be transformed, i.e. converted from one form to another, but cannot be created or destroyed. Light energy to chemical energy Chemical energy to mechanical energy The second law of thermodynamics states that this conversion of energy cannot occur without some loss of energy.

Where do we get the energy from? Work of life is done by energy coupling use catabolic (breaking) reactions to fuel anabolic (building) reactions energy + + energy + +

ATP Living economy Fueling the body’s economy eat high energy organic molecules food = carbohydrates, lipids, proteins, nucleic acids break them down catabolism = digest capture released energy in a form all processes in the organism can use Need a universal energy currency a way to pass energy around need a short term energy storage molecule ATP

Build once, use many ways ATP Adenosine Triphosphate modified nucleotide nucleotide = adenine + ribose + Pi  AMP AMP + Pi  ADP (uncharged battery) ADP + Pi  ATP (charged battery) Marvel at the efficiency of biological systems! Build once = re-use over and over again. Start with a nucleotide and add phosphates to it to make this high energy molecule that drives the work of life. Let’s look at this molecule closer. Think about putting that Pi on the adenosine-ribose ==> EXERGONIC or ENDERGONIC? How efficient! Build once, use many ways high energy bonds

How does ATP store energy? I think he’s a bit unstable… don’t you? How does ATP store energy? P O– O –O P O– O –O P O– O –O P O– O –O P O– O –O ADP AMP ATP Each negative PO4 becomes 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 Not a happy molecule Add 1st Pi  Kerplunk! Big negatively charged functional group Add 2nd Pi  EASY or DIFFICULT to add? DIFFICULT takes energy to add = same charges repel  Is it STABLE or UNSTABLE? UNSTABLE = 2 negatively charged functional groups not strongly bonded to each other So if it releases Pi  releases ENERGY Add 3rd Pi  MORE or LESS UNSTABLE? MORE = like an unstable currency • Hot stuff! • Doesn’t stick around • Can’t store it up • Dangerous to store = wants to give its Pi to anything Instability of its P bonds makes ATP an excellent energy donor

How does ATP transfer energy? + ATP ADP ATP helps all reactions occur in two ways: ATP  ADP releases energy & can fuel other reactions Phosphorylation released Pi can transfer to other molecules destabilizing the other molecules or changing the shape, allowing the reaction to occur How does ATP transfer energy? By phosphorylating Think of the 3rd Pi as the bad boyfriend ATP tries to dump off on someone else = phosphorylating How does phosphorylating provide energy? Pi is very electronegative. Got lots of OXYGEN!! OXYGEN is very electronegative. Steals e’s from other atoms in the molecule it is bonded to. As e’s fall to electronegative atom, they release energy. Makes the other molecule “unhappy” = unstable. Starts looking for a better partner to bond to. Pi is again the bad boyfriend you want to dump. You’ve got to find someone else to give him away to. You give him away and then bond with someone new that makes you happier (monomers get together). Eventually the bad boyfriend gets dumped and goes off alone into the cytoplasm as a free agent = free Pi.

An example of Phosphorylation… Building polymers from monomers need to destabilize the monomers phosphorylate! H OH C H HO C enzyme C H OH HO O + H2O + ADP C H OH enzyme C H P Monomers  polymers Not that simple! H2O doesn’t just come off on its own You have to pull it off by phosphorylating monomers. Polymerization reactions (dehydration synthesis) involve a phosphorylation step! Where does the Pi come from? ATP + ATP C H P H HO C + C H O + Pi

Another example of Phosphorylation… The first steps of cellular respiration beginning the breakdown of glucose to make ATP glucose C-C-C-C-C-C C H P ATP 2 Enzyme 1 ADP 2 Enzyme 2 These are the very first steps in respiration — making ATP from glucose. Fructose-1,6-bisphosphate (F1,6bP) Dihydroxyacetone phosphate (DHAP) Glyceraldehyde-3-phosphate (G3P) 1st ATP used is like a match to light a fire… initiation energy / activation energy. The Pi makes destabilizes the glucose & gets it ready to split. fructose-1,6bP P-C-C-C-C-C-C-P DHAP P-C-C-C G3P C-C-C-P

A working muscle recycles over 10 million ATPs per second ATP / ADP cycle Can’t store ATP too reactive transfers Pi too easily only short term energy storage carbohydrates & fats are long term energy storage ATP respiration 7.3 kcal/mole ADP P + A working muscle recycles over 10 million ATPs per second

Going back some months…. What is the ultimate source of energy for all living organisms? What is the name of organisms that can capture the energy from that source? What are the critical products they make that all other life depends upon? Can you name 5 structures on that type of organism that help it do the job?

Check for Understanding 1. What do the first two laws of thermodynamics say about energy. 2. List five processes of life that require energy. 3. I eat a slice of greasy, yummy pizza. My stomach takes it and anabolizes/catabolizes it. 4. How does ATP become ADP? What is released when that happens? 5. Does your body use a form of sugar or ATP to store energy?

Parts of a plant Four basic parts leaves stems roots flowers

Internal Stem Structure phloem- vascular tissue, carries manufactured foods down. Xylem- vascular tissue, carries water and minerals up.

Roots Usually underground functions: anchor plant and hold upright absorb water and minerals form soil and conduct to stem store food, & propagation

Leaves the food factory of the plant produce the food used by the plant or stored for later use Move to expose maximum surface area to perpendicular angle with sunlight http://www.youtube.com/watch?v=wjZ1UYwrO8A

Shape and size of leaves Each species leaf is distinctive from all others. Location usually dictates size of leaves due to resource availability.

Internal leaf structure epidermis skin of the leaf single layer of cells protects leaf from loss of too much moisture (cuticle = wax layer)

Guard Cells & Stomata open and close the small pore on the underside of the leaf

Stomates allow the plant to breathe and transpire

Chloroplasts contain chlorophyll

PHOTOSYNTHESIS

Photosynthesis is TWO Steps Light Dependent Reactions Light splits water at the Thylakoid to produce ELECTRONS AND ATP Light Independent Reactions (Dark Rxns) The Calvin cycle uses the electrons and ATP to turn Carbon Dioxide into SUGARS