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Warm-Up #9 12/4/12. 1) What are the 3 external plant layers? 2) Why are the top two layers clear? 3) What is the purpose of a stomata? 4) What controls the opening of stomata? 5) What layer are the stomata located?. Leaf Structure. Unit 5 Metabolism. Essential Question:
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Warm-Up #9 12/4/12 1) What are the 3 external plant layers? 2) Why are the top two layers clear? 3) What is the purpose of a stomata? 4) What controls the opening of stomata? 5) What layer are the stomata located?
Leaf Structure Unit 5 Metabolism
Essential Question: What happens when leaves change color and fall to the ground? Objective Diagram the structure of a leaf Today is About…
Photosynthesis • Occurs in the chloroplast of the leaves • Leaf is thin • Very large surface area (ideal for diffusion/absorption). The larger the surface area the more sunlight can be absorbed. • Mesophyll cells are closer to the surface \ • reducing diffusion distance of CO2 from surrounding mesophyll cells
External Features • Waxy Cuticle • Top of leaf • Transparent • Allows light to enter for photosynthesis • Upper epidermal cells • Transparent • Allow light in to reach the chloroplast • Lower epidermis • Has stomata, which allows gas exchange (intake of CO2 and release of O2)
Stomata • Openings in the leaf • Controlled by doors called guard cells • Permit exchange of moisture and carbon dioxide between leaf and atmosphere
Internal Features • Vascular Tissue- found in leaf vein • Xylem • Top of leaf • Transports water to leaf cells and then it diffuses into chloroplast. • Phloem • Bottom of leaf • Transports food from mesophyll to rest of plant
Internal Features Cont. • Mesophyll- two main types • Palisade • Contain the most chloroplast • Found at top of leaf • Closely packed with small spaces in between to allow gas exchange • Spongy • Less chloroplast • Larger open spaces • Store carbohydrates made by photosynthesis
Internal Features Cont. • Chloroplast • Contain chlorophyll (WHERE PHOTOSYNTHESIS TAKES PLACE) • Double membrane that is selectively permeable • Allows H2O and CO2 to diffuse into it and O2 to diffuse out • Parenchyma • Rich in chloroplast • Primary site of photosynthesis in the leaf
http://academic.kellogg.edu/herbrandsonc/bio111/animations/0021.swfhttp://academic.kellogg.edu/herbrandsonc/bio111/animations/0021.swf Internal Features Cont… • Guard Cells • Controls the opening and closing of the stomata
Warm- Up #8 12/3/12 • What part of the plant are most chloroplast found in? • How is energy stored during photosynthesis • How is energy released during photosynthesis? • What is the product of the light dependent reaction? • What is the product of the light independent reaction?