Photosynthesis NB pgs 7-11 odd Pic 8,10

Chemistry Review What is an electron? –Negatively charged particle What is a proton? –Positively charged particle Do P and E carry energy? –Yes- they are charged particles If the concentration of hydrogen protons (H+) is greater inside a cell than outside the cell, which direction will the H+ generally flow? Inside to Outside

What is the difference between: –ADP and ATP –ATP = Adenosine Triphosphate Why is ATP an energy storing compound? –When bonds are broken energy is released. –The phosphate bonds store energy ATP has an extra phosphate ATP What is the difference between: –ADP and ATP –ATP = Adenosine Triphosphate Why is ATP an energy storing compound? –When bonds are broken energy is released. –The phosphate bonds store energy ATP has an extra phosphate

How Much ATP do Human Cells Use? Each cell in the human body is estimated to use between one billion and two billion ATP's per minute! With 100 trillion cells in the human body, how much ATP do we need? – Roughly 1 x molecules. –In the span of twenty-four hours, 100 trillion cells produce about 441 lbs of ATP.

NADPH In addition to ATP being used to release (ATP-ADP) and store (ADP-ATP) energy, a molecule called NADPH is used. NADP –Carrier molecule –Moves H+ ions from one reaction to another (light to dark reaction) –NADP - NADPH

Nicotinamide adenine dinucleotide phosphate

Why is Photosynthesis Important? Heterotrophs obtain their energy from other organisms. Whatever we eat can eventually be traced back to producers. The Sun provides Earth with energy. We cannot eat the sun…plants “eat” the sun harvesting its energy and passing it on to us. Oxygen

Process by which plants change the energy in sunlight to kinds of energy that can be stored for later use. 6CO 2 + 6H 2 O (+ light energy) →C 6 H 12 O 6 + 6O 2 Carbon Dioxide + Water+ (Light) = Glucose + Oxygen Yes….you will need to know this! What is Photosynthesis?

All in the Chloroplast

2 Main Steps Light Reaction -Needs light -Thylakoid membrane -Converts light energy to chemical energy (ATP and NADPH) Dark Reaction (Calvin Cycle) -No light needed (but must have ATP and NADPH) -Stroma -Converts CO2 to sugar Photosynthesis Basics

Light Reactions

Where do the light reactions occur? Thylakoid

Label D E F A B C

A Light absorbed by chlorophyll C E- move through “electron transport chain” like hot potatoes passing from one membrane protein to another Chlorophyll B. Electrons in chlorophyll get excited

D As water enters the cell- a water splitting enzyme splits 2 molecules of water into atmospheric O 2 and H + and e- 2H 2 O → O 2 + 4H + What we breathe Builds a concentration gradient H+ concentration gradient Where do the e- that get excited in chlorophyll come from?

E After e - pass through electron transport chain (ETC), they help attach a H + to NADP + to become NADPH. NADP + + H + → NADPH What is NADPH? Molecule that stores energy. This energy will be used later

Energy from H+ used by membrane protein to catalyze the reaction of ADP → ATP F. As H+ builds inside thylakoid, a gradient builds. H+ ions move down concentration gradient We have created an extra phosphate bond (stored energy) ATP is the second energy storing molecule made.

Let’s Review The light reactions convert energy from the sun to chemical energy Light is absorbed by (green structures) chloroplasts. Electrons become excited and move like hot potatoes through the electron transport chain. At the end of the ETC an energy storing molecule called NADPH is made At the same type a concentration of H+ build up in the thylakoid space. This concentration gradient gives energy to the membrane proteins which catalyze the reaction of ADP to ATP Electrons are replaced when the water is split into O 2 and H+

Dark Reactions

Where do the dark reactions occur? Stroma

Uses energy from the light reactions to change CO 2 from the atmosphere into sugar Energy needed comes from the ATP and NADPH (light reactions) Calvin Cycle

Other C molecules recycle A carbon in the form of CO 2 is attached to a 5C compound to form a 6C compound The 6C compound is unstable and breaks in half. One 3C product is used to make glucose and other compounds.

How many ATP molecules are needed in the Calvin Cycle? 9 ATP How many NADPH molecules are needed in the Calvin Cycle? 6 NADPH