ATP Why do we use it for Energy?

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

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

How does ATP store energy? P O–O– O–O– O –O–O P O–O– O–O– O –O–O P O–O– O–O– O –O–O P O–O– O–O– O –O–O P O–O– O–O– O –O–O P O–O– O–O– O –O–O P O–O– O–O– O –O–O P O–O– O–O– O –O–O Each negative PO 4 more difficult to add Each negative PO 4 more difficult to add a lot of stored energy in each bond a lot of stored energy in each bond most energy stored in 3rd P i = releases energy ∆G = -7.3 kcal/mole 3rd P i is hardest group to keep bonded to molecule Bonding of negative P i groups is unstable Bonding of negative P i groups is unstable spring-loaded spring-loaded P i groups “pop” off easily & release energy P i groups “pop” off easily & release energy Instability of its P bonds makes ATP an excellent energy donor AMP ADPATP

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 ATP / ADP cycle A working muscle recycles over 10 million ATPs per second Whoa! Pass me the glucose (and O 2 )! ATP ADP PiPi kcal/mole cellular respiration

PHOTOSYNTHESIS.

CAPTURING THE ENERGY IN LIGHT The process by which organisms obtain energy directly from sunlight is called photosynthesis. 6CO 2 + 6H 2 O → C 6 H 12 O 6 + 6O 2

ENERGY FOR LIFE PROCESSES Autotrophs: Plants, Algae, and some Bacteria. 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. Products used in cellular respiration. The Basic Biochemical Pathway

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

CHLOROPLASTS

LIGHT AND PIGMENTS

chlorophylls accessory pigments carotenoids

LIGHT REACTIONS 1. ELECTRON TRANSPORT CHAIN: PHOTOSYSTEMS II AND I 2. RESTORING PHOTOSYSTEM II 3. CHEMIOSMOSIS Photosystem I & II

ELECTRON TRANSPORT CHAIN

RESTORING PHOTOSYSTEM II

CHEMIOSMOSIS

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

Photosynthesis Animation mat/metabolism/photosynthesis.swf mat/metabolism/photosynthesis.swf mat/metabolism/photosynthesis.swf mat/metabolism/photosynthesis.swf

LIGHT INDEPENDENT REACTIONS KNOWN AS THE CALVIN CYCLE. KNOWN AS THE CALVIN CYCLE. CO 2 IS FIXED INTO ORGANIC COMPOUNDS: CARBON FIXATION. CO 2 IS FIXED INTO ORGANIC COMPOUNDS: CARBON FIXATION. THREE MAJOR STEPS, WHICH OCCUR WITHIN THE STROMA. Calvin Cycle How do Plants Capture CO2?

RATE OF PHOTOSYNTHESIS