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Energy and Life

Energy and Life. Key Concepts : Where do plants get the energy they need to produce food? What is the role of ATP in cellular activities? Vocabulary: Autotroph Heterotroph Adenosine triphosphate (ATP). Energy and Life . Autotrophs: (auto = self)

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Energy and Life

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  1. Energy and Life • Key Concepts: • Where do plants get the energy they need to produce food? • What is the role of ATP in cellular activities? • Vocabulary: • Autotroph • Heterotroph • Adenosine triphosphate (ATP)

  2. Energy and Life • Autotrophs: (auto = self) • Organisms that make their own food (energy). • Heterotrophs: (hetero = other) • Obtain energy from food they consume. troph = "food"

  3. Energy and Life • Chemical Energy and ATP • Energy can be stored in many forms: • Light • Heat • Electricity • Chemical Compounds (BONDS!)

  4. Energy and Life • ATP • Adenosine TriPhosphate • Adenine (N) • 5-Carbon Sugar (Ribose) • 3-phosphate groups • ADP • Adenosine DiPhosphate • Adenine (N) • 5-Carbon Sugar (Ribose) • 2-phosphate groups tri = 3 di = 2

  5. Bonds = Energy

  6. Energy and Life • Energy in ATP is released when it is converted to ADP. • The characteristics of ATP make it an exceptionally useful molecule that is used by all types of cells as their basic energy source.

  7. Energy and Life • ATP: • Efficient in transferring energy • Not very good for storing large amounts of energy long term. • A single molecule of sugar (glucose) stores more than 90 times a molecule of ATP.

  8. How is ATP Used? • Energy stored in ATP is released by breaking the bond between the 2nd and 3rd phosphate atoms. • Powers cellular activities – active transport, protein synthesis, and muscle contraction • Only enough to last a few seconds of activity

  9. Photosynthesis • Key Concepts: • What did the experiments of van Helmont, Priestley, and Ingenhousz reveal about how plants grow? • What is the overall reaction for photosynthesis? • What is the role of light and chlorophyll in photosynthesis? • Vocabulary: • Photosynthesis • Pigment • chlorophyll

  10. Photosynthesis: An Overview • Photosynthesis: • Plants use the energy of sunlight to convert water and carbon dioxide into oxygen and high energy carbohydrates (sugars and starches). H2O + CO2 + Sunlight O2 + Carbohydrates (glucose)

  11. SCIENCE HISTORY… • 3 different scientists helped identify the components of the photosynthesis equation • Van Helmont • Priestley • Ingenhousz

  12. Jan Baptiste Van Helmont 17th century

  13. The Von Helmont Problem QUESTION: Do plants grow by taking material out of the soil? He put a 2.3 kg. (5 lb.) willow tree in 90.8 kg (200 lbs). of soil.  The tree received only rainwater for five years.  After 5 years, Von Helmont found that the soil only weighed 57 g less than when the experiment began.  The willow tree now weighed 76.8 kg (169 lbs. 3 oz.).  

  14. What did Von Helmont conclude was responsible for most of the tree weight gain? -WATER! Is this the only thing responsible? -NO

  15. In 1772 another Englishman, Joseph Priestly (1733-1804), reported the results of an important experiment. He found that a sprig of mint would not die when placed in air that had been “spent” (used) by burning a candle in it. To the contrary, in such air the plant would grow and the air would then, to his astonishment, again support a candle flame. Priestly inferred that the mint produced a substance that was required for burning. • What is that substance?

  16. The Dutch physician, Jan Ingenhousz, published Experiments on Vegetables, which supplied experimental evidence stating that the effect observed by Priestly occurred only in sunlight. He showed that only the green parts of plants, especially the leaves, have this capacity.

  17. Photosynthesis 6H2O + 6CO2 ----------> C6H12O6+ 6O2 light chlorophyll • Photosynthesis uses the energy of sunlight to convert water and carbon dioxide into oxygen and high energy sugars • C6H12O6 = sugar • Plants use the sugars to produce complex carbohydrates such as starches.

  18. Light & Pigment • White light from the Sun is actually a mixture of different wavelengths of light. • Plants gather the sun’s energy with light absorbing molecules called PIGMENTS. • The plant’s principle pigment is chlorophyll and there are 2 main types: “a” and “b.” • Plants also contain red and orange pigments such as carotene which absorbs light in other areas of the spectrum. • Energy absorbed by chlorophyll is transferred directly to electrons in the chlorophyll molecule. These high energy electrons make photosynthesis work.

  19. So why are leaves green? • Look at the wavelengths of light that chlorophyll absorbs & uses in photosynthesis • The colors that are left are reflected back and that is what you see. GREEN!

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