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Question:. Some plant leaves contain yellow and red pigments as well as chlorophyll. In the fall, those leaves may become red or yellow. Suggest an explanation for those color changes. Explanation for color change….
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Question: Some plant leaves contain yellow and red pigments as well as chlorophyll. In the fall, those leaves may become red or yellow. Suggest an explanation for those color changes.
Explanation for color change… • The chlorophyll may be broken down by the cooling temperatures or the changing light, so the green color disappears. • A leaf then shows the color of its remaining pigment(s).
What wavelengths of light do you think plants use the least in photosynthesis?
How plants harness energy from sunlight… Photosynthetic pigments Chlorophyll a – the “main” photosynthetic pigment Accessory pigments.. Chlorophyll b Carotenoids
Photosystems use some wavelengths of light but reflect others…
Plant Photosynthesis internal leaf structure chloroplasts outer membrane inner membrane thylakoid Photosynthesis Video
Photosynthesis can be described by the following reaction 6CO2+6H2O----C6H12O6 + 6O2 Carbon dioxide and water with sunlightyields (produces) glucose and oxygen gas
Where does photosynthesis take place? Inside the leaves.
Within the chloroplasts of the leaf cells. This whole thing is a chloroplast and inside are the thylakoids stacked up to form granum.
The stages of photosynthesis… Light Dependent Reactions • REQUIRES light • Take place in the Thylakoidmembrane of chloroplast • Splits water – produce O2 gas and H+ ions • Produce ATPand NADPH
Analogy of the way electrons are being passed on from one photosystem to next.
Light-dependent Reactions • Photosystem: light capturing unit, contains chlorophyll, the light capturing pigment • Electron transport system: sequence of electron carrier molecules that shuttle electrons, energy released to make ATP • Electrons in chlorophyll must be replaced so that cycle may continue-these electrons come from water molecules, Oxygen is liberated from the light reactions • Light reactions yield ATP and NADPH used to fuel the reactions of the Calvin cycle (light independent or dark reactions)
The stages of photosynthesis… Light Independent Reactions • Takes place in • the stroma (inside the chloroplast, but outside the thylakoid) • Does not require light • Does require ATP and NADPH • CO2 is transformed into glucose
Factors affecting Photosynthesis • Water availability • Temperature (0-35° C) • Light Intensity
Cellular Respiration occurs in the Mitochondria • Cellular Respiration is the process that releases energy by breaking down glucose and other food molecules in the presence of oxygen. • The Big Picture: In the presence of Oxygen, Glycolysis is followed by the Krebs Cycle and then Electron Transport Chain. • Glycolysis is the process in which one molecule of glucose is broken in half, producing two molecules of pyruvic acid, a 3-carbon compound.
Two More Videos • Cellular Respiration • Respiration
On the back of your notes… • Cellular Respiration Flow Chart