Name: _________________________________________________ Date: __________________ Class: ______________ 8-­‐3 The Reactions of Photosynthesis (25 pts) 1. Please label the diagram of the Chloroplast below with the following words AND their explanations using figure 8-­‐6 on page 208 (6 pts): Stroma, Thylakoid, Granum Stroma Thylakoid Granum Inside a Chloroplast page 208 (6 pts) One part of photosynthesis happens during the time it is light—these are called Light Dependent Reactions and cannot happen without depending on light. Some can happen with or without light (independent of light). We sometimes call these the dark reactions, but mostly refer to them as the Calvin Cycle. Explain: 1. Where these two processes take place in the chloroplast 2. Which ones take in which substrates 3. What the products are for each one 1._The light dependent reactions take place in the thylakoids and granum(stacks of thylakoids). The Calvin cycle takes place in the stroma, or the area inside the chloroplast that surrounds the granum & thylakoids. Name: _________________________________________________ Date: __________________ Class: ______________ 2.The reactants, or the things that go into the reaction, are different for both reactions. Light and water are what is needed for light dependent reactions, while carbon dioxide is used in the Calvin cycle. 3. The products, or the things that come out of the reaction, are different for both reactions. Oxygen is produced by light dependent reactions, while sugar is produced by the Calvin cycle. NADPH page 209 (4 pts) Please explain: 1. How NADP+ becomes NADPH when electrons get involved. 2. Also describe how this is similar to putting a hot coal from a fire into a bucket and carrying it to another place. 1.NADP+ becomes NADPH when two high-­‐energy electrons and hydrogen are added to it. Because electrons are negative, the + goes away, and because the hydrogen is added, it gets an H in its name. 2.If we had to take a hot coal from a fire and move it to another place, we would need to use a bucket or pan to transport it because it’s so hot. The high-­‐energy electrons are so high energy they need something to carry them, so NADP+ is like a bucket used to carry the electrons. Light Dependent Reactions pages 210-­‐211 (5 pts) The first confusing thing to understand is that Photosystem II is actually the 1st thing that happens. It’s only called II because it was discovered second. Photosystem I was discovered first, but it actually takes place 2nd in the light dependent reactions. Think of it like a count down. “Photosystem II, Photosystem I, BLASTOFF!” That’s not the only thing that can be confusing about the L.D.P.’s. Create a timeline of the processes steps using the bars and spaces below. Be sure to put everything in order, oh, and one more thing: you may not copy straight from the book. PUT IT IN YOUR OWN WORDS J !! Name: _________________________________________________ Date: __________________ Class: ______________ 1. Photosystem II absorbs light, And gives energy to electrons. Then the electrons are passed on to the next step. (Electron Transport Chain) Also H2O splits up into O2 and H+ and 2 electrons. 5. ADP gets 1 phosphate group added to it and becomes ATP so the cell can use it for energy. 4TH 2ND 3. Photosystem I uses more light energy to replenish electrons. Then energy and NADPH is made by adding electrons & H+ to NADP. 1ST 2. The energy from electrons is used by molecules to transport H+ to the thylakoid 3RD 5TH 4. Because the inside of the thylakoid is filling up with H+ it becomes positively charged and the outside becomes negatively charged. Name: _________________________________________________ Date: __________________ Class: ______________ The Calvin Cycle pages 212-­‐213 (4 pts) Formerly known as “the dark reactions,” the Calvin Cycle explains the part of photosynthesis that doesn’t need light to happen. These reactions are also called “light independent” because they are independent of light, or don’t need the sun to take place. However, the Calvin Cycle does use ATP and NADPH from the light dependent reactions to produce high-­‐energy sugars. So it needs the energy captured in the light reactions to actually carry out it’s own job. Please add the steps of the Calvin Cycle to the diagram below by filling in the boxes. Oh, but one more thing: you may not copy straight from the book. PUT IT IN YOUR OWN WORDS J !! 2. Energy from ATP and high energy 1.Carbon dioxide comes into the Calvin cycle and electrons (provided by the light combines with six 5-­‐carbon molecules to make 12 3-­‐
reactions) are used to convert the 12 3-­‐
carbon molecules. carbon molecules into higher energy forms. 4. The rest of the 10 3-­‐carbon molecules are converted back into six 5-­‐carbon molecules, and they go back to step 1 to start the process all over again. 3. Sugar is made! Two of the 3-­‐
carbon molecules combine to make one 6 carbon sugar.