Date: December 10, 2015 Aim #34: How do plants carry out the process of photosynthesis? HW: 1)Article- Changing Colors of Leaves 2)Bring in headphones/ear buds for computer lab please 3) Missing work?? Please get in ASAP 4)Plant Packet (follow calendar of suggested deadlines!!) Do Now: Warm-Up Notebook DateTitle of Activity Page # 12/10Light! Pigments! Action!60

Aim #34: How do plants carry out the process of photosynthesis?

1) What is the formula of Aerobic Cell Respiration? Light + 6H 2 O + 6CO > C 6 H 12 O 6 + 6O 2 2) What is the formula of Photosynthesis? C 6 H 12 O 6 + 6O 2  6CO 2 + 6H 2 O + 38ATP Cell Respiration- there is a “fall” of electrons from glucose to O 2 (ETC) that releases energy to form ATP. Photosynthesis- energy from sunlight is used to boost electrons from water “uphill” to produce glucose. 3) What is the difference between the two?

4) Where in the cell does photosynthesis take place? Stroma Inner Membrane Outer Membrane Thylakoid Grana Chloroplast

5) Two Main Stages of Photosynthesis: a)Light Reactions- convert the energy in sunlight to chemical energy. It takes place in the membrane of the thylakoids. b)Calvin Cycle- makes glucose from the atoms of CO 2, plus the H atoms and high energy electrons of NADPH & ATP produced during the light reactions. Takes place in the stroma.

Photosynthesis (3 minutes)

6) Details of the Light Reactions: Light + 6H 2 O + 6CO > C 6 H 12 O 6 + 6O 2 + H 2 O O 2 released into atmosphere H atoms & electrons Light splits water into oxygen, H atoms, and electrons This is called photolysis

Light Reactions: H atoms & electrons + NADP + NADPH ETC ATP

7) What is Chlorophyll? Are the pigments (chemical compounds that give a substance its color) found in the chloroplasts. There are different types of pigments in the chloroplasts. Ex: Chlorophyll a, Chlorophyll b, Carotenoids

8) What is the role of the chlorophyll pigments in the light reactions? Within the thylakoid membrane, chlorophyll and other molecules are arranged in clusters called photosystems The clusters of pigment molecules act like a light gathering panel (solar collector)

What is the role of Chlorophyll? Ground State Energy Excited StateGround State Each time a pigment molecule absorbs light energy, its electrons gain energy and become “excited”. Almost immediately, the excited electron falls back to the ground state & transfers the energy to its neighboring molecule

What is the role of Chlorophyll? This transfer of energy to neighboring pigment molecules sets off a chain reaction. The chain reaction will continue until it reaches the reaction center of the photosystem. Here the electron is captured by the primary electron acceptor.

What does the primary electron acceptor do with the electrons? The electrons are sent down an electron transport chain which helps produce some ATP. Next, the electrons are passed on to a second photosystem. This photosystem passes the light-excited electrons to NADP + and combine with the H+ from H 2 O forming NADPH.

Let’s take a look at this:

Primary Electron Acceptor ETC

Photosystem e-e- H2OH2O Electron Acceptor (protein) O2O2 H+H+

Electron Transport Chain e-e- Electron Acceptor (protein) Electron Acceptor Electron Acceptor

9) Details of the Calvin Cycle (Dark Reaction or Carbon Fixation): 2)Calvin Cycle- makes glucose from the atoms of CO 2, plus the H atoms and high energy electrons of NADPH & ATP produced during the light reactions. Takes place in the stroma. CO 2 + NADPH + ATP  G3P  Glucose Comes from atmosphere Comes from Light Reactions

Light Reactions & Calvin Cycle:

Calvin Cycle

Photosynthesis Summary EnergySunlight  Chemical bonds in glucose Materials usedcarbon dioxide, and water Materials produced Glucose, water, and oxygen Time frameDaylight hours Locationchloroplasts ImportanceStores energy from sun… made available to other organisms

Water Light Energy Carbon Dioxide Oxygen Glucose

A more detailed summary: Light dependent reaction Light independent reaction AKALight reactionDark reaction, Calvin Cycle or carbon fixation LocationGranaStroma What’s going on… Water is split (photolysis) Oxygen is released into atmosphere NADPH and ATP are made to be used in Light Independent reaction Enzyme Rubisco converts inorganic CO2 into organic glucose by combining two PGAL molecules (a 3 C molecule)

Amoeba Sisters (~8 minutes)

Light-dependent reaction 1.In thylakoid spaces of the grana in the chloroplast. 2.Sunlight strikes the chlorophyll contained within the thylakoid spaces which causes electrons to become excited and infused with energy. 3.Electrons are transferred down an electron transport chain. 4.The energy in the electrons is used to set up a proton gradient across the membrane of the thylakoid spaces. 5.Protons flowing back across the thylakoid membrane according to the concentration gradient are harnessed to produce ATP and NADPH (the reduced form of NADP).

photolysis 6.As a by-product of this process, molecules of water are split into molecular hydrogen and oxygen (photolysis). 7.The plant needs the hydrogen to produce ATP. 8.The oxygen you’re breathing right now is some of that waste product. 9.The purpose of the light reaction is to make the usable energy necessary to run the light- independent reaction.

Light-independent reaction 1.AKA the Calvin cycle, or carbon fixation or dark reaction 2.The reaction takes place in the stroma of the chloroplast 3.In the dark reaction, the carbon from carbon dioxide is added to the five-carbon sugar ribulose bisphosphate (RuBP) to produce a six- carbon compound. 4.This unstable six-carbon sugar is immediately split into two three-carbon molecules, which in a chain reaction using the ATP and NADPH from the light reaction are modified to form glyceraldehyde 3-phosphate.

5.The glyceraldehyde 3-phosphate can be synthesized into carbohydrates such as glucose. 6.One of the glyceraldehyde 3-phosphate molecules is made into carbohydrates, while the other molecules remain in the Calvin cycle to serve as raw materials for the next round of production.