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Name __________________________________________________ Date ____________________ Tab __________________________ Photosynthesis and Cellular Respiration Reading The purpose of photosynthesis is to capture the energy in sunlight and store it in the bonds of a glucose molecule. Cells use sunlight energy to combine 6 molecules of H2O and 6 molecules of CO2 to produced 1 molecule of C6H12O6 and 6 molecules of O2. This process occurs in Eukaryotic Plant cells, autotrophs, which can produce their own sugars. Photosynthesis takes place in the chloroplasts in Eukaryotic Plant Cells. The ingredients for photosynthesis are 6 molecules of CO2, 6 molecules of H2O, and sun light energy. The CO2 and H2O are able to enter plants cells by diffusing through the membrane. These molecules move from where they are more concentrated outside the cell to the less concentrated area inside the cell. The sun energy is absorbed by the pigment chlorophyll, which is found in the chloroplasts. The products of photosynthesis are 1 molecule of C6H12O6 and 6 molecules of O2. The O2 is waste and exits the cell through the membrane by diffusion. The C6H12O6 is kept and stored by the cell for later energy use. The purpose of cellular respiration is to break the bonds of glucose to release stored energy. Cells use 6 molecules of O2 to break apart the bonds of 1 molecule of C6H12O6 to create energy, 6 molecules of CO2, and 6 molecules of H2O. This process happens in all Eukaryotic cells, both plant cells (autotrophic) and animal cells (heterotrophic). It takes place in the cytoplasm and in the mitochondria. The ingredients for cellular respiration are 1 molecule of C6H12O6 and 6 molecules of O2. Cells get the C6H12O6 from eating other organisms (heterotrophs, animal cells) or from photosynthesis (autotrophs, plant cells). The O2 enters the cell by diffusing across the membrane. It moves from where it is more highly concentrated outside of the cell to the inside of the cell where it is less concentrated. The products of cellular respiration are energy, 6 molecules of CO2, and 6 molecules of H2O. The energy is kept by the cell and used to bind the third phosphate to ADP molecules to create ATP molcules. The CO2 and H2O are waste products and they diffuse out of the cell following the concentration gradient. Photosynthesis: Stage 1 Purpose: Capturing the sun’s energy Stage 1 Location: Chloroplast Stage 1 How it happens: The chlorophyll in the chloroplasts absorbs the sun’s energy much like a solar panel on a house. Stage 2 Purpose: Store the energy in a glucose molecule Stage 2 Location: Chloroplast Stage 2 How it happens: The cell uses the energy captured by the chlorophyll to combine 6 molecules of water (H2O) and 6 molecules of carbon dioxide (CO2) to produce 1 molecule of Glucose (C6H12O6) and 6 molecules of Oxygen (O2) Cellular Respiration: Stage 1 Purpose: Break down glucose into smaller parts to release a small amount of energy Stage 1 Location: Cytoplasm Stage 1 How it happens: Glucose molecules are broken down into smaller parts, which releases a very small amount of energy Stage 2 Purpose: Completely break down glucose to release a lot of energy Stage 2 Location: Mitochondria Stage 2 How it happens: The cells uses 6 molecules of Oxygen (O2) to break apart the bonds of 1 Glucose (C6H12O6) molecule to release energy, 6 molecules of water (H2O), and 6 molecules of carbon dioxide (CO2). The energy released is then use to bind a third phosphate to ADP molecules to create ATP molecules. Passive Transport, Photosynthesis, and Cellular Respiration The waste products of carbon dioxide and water from cellular respiration are the ingredients for photosynthesis are. Similarly, the waste product of oxygen from photosynthesis is one of the ingredients for cellular respiration. What do all of these molecules have in common? Look at the image to the right and see if you can take a guess. That’s right! CO2, H2O, and O2 are all small, uncharged molecules, which means they can always pass through the membrane by diffusion or osmosis! Cells use this to their advantage, because they do not have to expend energy obtaining the ingredients or getting rid of the waste from Cellular Respiration and Photosynthesis. They don’t have to spend energy to make energy, which makes these processes much more efficient. While Glucose is a large molecule, it is able to get into the cell through facilitated diffusion, so no energy spent there either. BIG PICTURE: cells do not have to expend energy obtaining ingredients or getting rid of waste from Cellular Respiration or Photosynthesis, because these molecules can pass back and forth across the membrane with the use of diffusion (CO2 and O2), osmosis (H2O), or facilitated diffusion (C6H12O6), which are all types of passive transport. Surface Area, Photosynthesis, and Cellular Respiration Take a look at the images below of chloroplasts and mitochondria. How do these two organelles increase their surface area? That’s right! Folds and wrinkles in the membrane increase the surface area of chloroplasts and mitochondria. Why might increased surface area be helpful for photosynthesis and cellular respiration? More room! Think of it this way: Folds/wrinkles = more membrane space More membrane space = more room for passive transport More passive transport = more ingredients into the cell More ingredients into the cell = Photosynthesis and Cellular Respiration can happen faster More Photosynthesis and Cellular Respiration = more products More products = MORE NRG stored (Photosynthesis) or released (Cellular Respiration) However, more Photosynthesis and Cellular Respiration = more waste More waste is OK, because the large surface area enables waste to pass out of the cell quickly BIG PICTURE: Surface area makes the processes of Cellular Respiration and Photosynthesis happen more efficiently, because it provides more room for ingredients to get in and waste products to get out of the cell.