Why do we use it for Energy? ATP Why do we use it for Energy?

ATP: Adenosine Triphosphate Consists of Adenosine + 3 Phosphates Highly unstable molecule 3 phosphates each highly negative repel each other (like the wrong end of a magnet) each phosphate is surrounded by very negative oxygen atoms. Hence a phosphate group is removed through hydrolysis energy is released (-7.3 kcal/mole) and breaks down into the more stable molecule ADP. 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

I think he’s a bit unstable… don’t you? ATP: Pictures Where does the Negativity come from? Oxygen I think he’s a bit unstable… don’t you? Oxygen

ATP / ADP cycle Can’t store ATP ATP good energy donor, not good energy storage too reactive transfers Pi too easily only short term energy storage carbohydrates & fats are long term energy storage ATP cellular respiration 7.3 kcal/mole ADP Pi + A working muscle recycles over 10 million ATPs per second Whoa! Pass me the glucose (and O2)! 4

PHOTOSYNTHESIS . Chemosynthesis

Plants take H2O, Sun, and CO2 to make Glucose the sugar that they use for food and O2 too!

CAPTURING THE ENERGY IN LIGHT The process by which organisms obtain energy directly from sunlight is called photosynthesis. 6CO2 + 6H2O → C6H12O6 + 6O2

ENERGY FOR LIFE PROCESSES Autotrophs: Plants, Algae, and some Bacteria. Autotrophs store energy in various organic compounds, primarily carbohydrates.

Photosynthesis involves a complex series of chemical reactions: Biochemical Pathway Products used in cellular respiration. How it was Discovered

Photosynthesis

LIGHT ABSORPTION IN CHLOROPLASTS Light Reactions or Light Dependent Reactions They begin with the absorption of light in chloroplasts.

LIGHT AND PIGMENTS

chlorophylls accessory pigments carotenoids Chromatography

CHLOROPLASTS

RESTORING PHOTOSYSTEM II

Light Dependent Reaction

CHEMIOSMOSIS

PUTTING IT ALL TOGETHER Review of the Light Reaction With All Details!

LIGHT INDEPENDENT REACTIONS KNOWN AS THE CALVIN CYCLE. CO2 IS FIXED INTO ORGANIC COMPOUNDS: CARBON FIXATION. THREE MAJOR STEPS, WHICH OCCUR WITHIN THE STROMA. How do Plants Capture CO2? Calvin Cycle

RATE OF PHOTOSYNTHESIS