Question of the Day What color does chlorophyll reflect? 1-10 What color does chlorophyll reflect? What organisms can make their own energy (there are at least 4 correct answers)?

Review Photosynthesis uses… Photosynthesis produces… 1-10 Organisms that make their own energy = ??? Organisms that have to eat to get their energy = ??? 3 cellular activities that require energy = …

Review Photosynthetic pigments … 1-10 Photosynthetic pigments … What colors does a plant primarily use for photosynthesis? How do you know?

webquest

Question of the Day How are heterotrophs and autotrophs different? 1-11 How are heterotrophs and autotrophs different? webquest

Why is the sky blue? http://science.howstuffworks.com/nature/climate-weather/atmospheric/sky.htm http://spaceplace.nasa.gov/en/kids/misrsky/misr_sky.shtml

Photosynthesis Light is absorbed – excites electrons in pigments = start of photosynthesis Explain why a leaf appears green Because it is absorbing most of the other wavelengths of light and reflecting green

Lets Photosynthesize! It all starts with a….

Lets Photosynthesize! Calvin cycle 1st stage 2nd stage

Lets Photosynthesize!

Lets Photosynthesize! Light reactions = first stage of photosynthesis – light energy is converted to chemical energy (energy from the sun  ATP + NADPH)

The Leaf What organelle in the leaf is responsible for photosynthesis? Chloroplast Parts of a chloroplast Thylakoids - Flattened sacs where photosynthesis occurs – surrounded by a membrane Grana – Stacks of thylakoids Stroma – Solution that surrounds the grana

The Light-Dependent Reactions: Generating ATP and NADPH The light-dependent reactions encompass the steps of photosynthesis that directly involve sunlight. The light-dependent reactions occur in the thylakoids of chloroplasts.

The Light-Dependent Reactions: Generating ATP and NADPH Thylakoids contain clusters of chlorophyll and proteins known as photosystems. Photosystems absorb sunlight and generate high-energy electrons that are then passed to a series of electron carriers embedded in the thylakoid membrane.

Chloroplast 17

Light Reactions Occurs on thylakoid membrane Chlorophyll absorbs light and electrons get excited – flow on electron transport chain Energy in excited electrons is used to create NADPH and ATP  These are temporary energy carrier molecules Water – electron donor – releases O2 ATP + NADPH are then used to create glucose in the Calvin Cycle 18

Chlorophyll absorbs light and electrons are excited Chlorophyll absorbs light and electrons are excited. These electrons flow on electron transport chain along the thylakoid membrane. As the electron is transported it loses some energy and is used create a H+ concentration gradient inside the thylakoid, which is later used to create ATP from ADP +P. The electron finally reaches the final electron acceptor and is combined with NADP+ and a H+ to form NADPH, which is an energy carrier molecule. Water is split to (2 H2O = 4H+ + 4e- + O2) to replace the lost electrons.

Light Reactions 2 H2O = 4H+ + 4e- + O2 One of the most important steps (water molecules split): 2 H2O = 4H+ + 4e- + O2 protons oxygen electrons

REVIEW During the light reactions ___ and ___ are used to make ___, ___, and ___.

DRAW! Also label: thylakoid grana stroma 22

Question of the Day 1-13 During the light reactions ___ and ___ are used to make ___, ___, and ___.

Light Reactions 2 H2O = 4H+ + 4e- + O2 One of the most important steps (water molecules split): 2 H2O = 4H+ + 4e- + O2 protons oxygen electrons

Light Reactions http://www.youtube.com/watch?v=HrMka8vj73U http://www.youtube.com/watch?v=v590JJV96lc http://www.youtube.com/watch?v=TwnJtsL0tfw

Announcement 1-13 Quiz up to and including the light reactions (notes pages 1-7) on Wednesday 1-19

REVIEW How are heterotrophs and autotrophs different? 1-13 How are heterotrophs and autotrophs different? 2. Photosynthetic pigments … 3. What colors does a plant primarily use for photosynthesis? How do you know?

Review 4. Photosynthesis uses… Photosynthesis produces… 1-13 5. Where do the light reactions take place? 6. Why is the splitting of water molecules important for photosynthesis?

Review 7. The light rxns use… To produce… 1-13 8. What’s the electron transport chain?

QUICK TALK Light Reactions Thylakoid Glucose Carbon dioxide Chloroplast Autotroph Chlorophyll Chemosynthetic bacteria Thylakoid Carbon dioxide Photosynthesis Producer Stroma Heterotroph NADPH