The simple story of photosynthesis and food - Amanda Ooten
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0:14 - 0:15Ever wonder where most of the food
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0:15 - 0:18you eat every day comes from?
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0:18 - 0:20Well, about 60% of the food you eat
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0:20 - 0:22is carbohydrates.
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0:22 - 0:24As you can probably tell from its name,
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0:24 - 0:25carbohydrates contain carbon,
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0:25 - 0:26hydrogen,
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0:26 - 0:27and oxygen.
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0:27 - 0:29But where do these atoms originally come from
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0:29 - 0:31and how do they join together
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0:31 - 0:34to make delicious foods like fruits and pasta?
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0:34 - 0:36It actually all starts with the air
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0:36 - 0:38you are exhaling this very minute,
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0:38 - 0:41specifically the carbon dioxide molecules.
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0:41 - 0:43Plants are going to breath in
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0:43 - 0:44this very same carbon dioxide
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0:44 - 0:47through pores in their skin, called stomata.
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0:47 - 0:49Plants drink in water from their roots
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0:49 - 0:52to get the needed oxygen and hydrogen atoms,
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0:52 - 0:53and their electrons,
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0:53 - 0:55in order to build carbohydrates.
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0:55 - 0:57What is that thing?
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0:57 - 0:59Well, that's a special plant organelle
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0:59 - 1:00inside the leaves of plants
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1:00 - 1:02called a chloroplast.
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1:02 - 1:04It's green beceause of a special light-absorbing pigment
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1:04 - 1:06called chlorophyll.
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1:06 - 1:09Each leaf has about 44,000 cells
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1:09 - 1:11and every cell can have anywhere
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1:11 - 1:14between 20 to 100 chloroplasts.
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1:14 - 1:18That's up to 4,400,000 chloroplasts!
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1:18 - 1:19By now, you've probably guessed
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1:19 - 1:22that we're talking about the process of photosynthesis
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1:22 - 1:23and you might be wondering
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1:23 - 1:26when the sun is going to make its entrance.
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1:26 - 1:28Let's go back to that original molecule of water.
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1:28 - 1:31The plant has to split this molecule of water
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1:31 - 1:33so it can get electrons from it.
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1:33 - 1:36But, the plant can't pull that water apart by itself.
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1:36 - 1:39It needs help from the high-energy rays of the sun.
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1:39 - 1:42So now that the chloroplast has all the building blocks
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1:42 - 1:45- carbon, hydrogen, oxygen, and electrons -
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1:45 - 1:46it can use them to go through
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1:46 - 1:48the rest of the steps of photosynthesis
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1:48 - 1:51to transform that original carbon dioxide gas
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1:51 - 1:54into a simple carbohydrate called glucose,
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1:54 - 1:57C-6-H-12-O-6.
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1:57 - 1:59That little glucose molecule then helps to build
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1:59 - 2:01bigger and better carbohydrates
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2:01 - 2:03like cellulose.
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2:03 - 2:05Cellulose is a type of carbohydrate found in plants
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2:05 - 2:07that our body cannot break down.
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2:07 - 2:09We call it fiber
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2:09 - 2:10and we eat it in vegetables like lettuce,
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2:10 - 2:11broccoli,
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2:11 - 2:12and celery.
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2:12 - 2:15Plants use cellulose to keep themselves strong.
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2:15 - 2:18The plant could also turn that glucose into starch,
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2:18 - 2:20a large molecule that stores energy for the plant.
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2:20 - 2:22We love eating starch from plants like potatoes,
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2:22 - 2:23corn,
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2:23 - 2:24and rice.
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2:24 - 2:26So you see, when you eat plants,
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2:26 - 2:29we're actually benefiting from photosynthesis.
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2:29 - 2:31The plant makes things like starch,
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2:31 - 2:31which we eat
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2:31 - 2:34and then break back down into glucose,
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2:34 - 2:36the first form the plant made.
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2:36 - 2:38Then, the mitochondria in our cells,
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2:38 - 2:40powered by the oxygen we breath,
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2:40 - 2:43can turn glucose into pure energy molecules
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2:43 - 2:45called ATP.
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2:45 - 2:47ATP powers all work done
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2:47 - 2:49by each and every one of your cells,
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2:49 - 2:50things like communication,
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2:50 - 2:51movement,
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2:51 - 2:53and transport.
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2:53 - 2:56But why do we have to turn that glucose into ATP?
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2:56 - 2:58Well, think of it like this.
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2:58 - 3:00You're excited to start your summer job
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3:00 - 3:02at the local ice cream stand,
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3:02 - 3:03but your boss has just told you
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3:03 - 3:07that she is going to pay you in ice cream cones.
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3:07 - 3:09What are you going to be able to do
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3:09 - 3:11with those ice cream cones?
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3:11 - 3:12Nothing,
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3:12 - 3:15which is why you kindly asked to be paid in dollars.
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3:15 - 3:17ATP is just like dollars.
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3:17 - 3:20It is the currency that all cells of life use
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3:20 - 3:22while glucose is,
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3:22 - 3:24well, kind of like ice cream.
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3:24 - 3:27Even plants have mitochondria in their cells
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3:27 - 3:30to break down the glucose they make into ATP.
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3:30 - 3:32So as you can see,
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3:32 - 3:34humans and plants are intricately connected.
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3:34 - 3:35The air we breath out
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3:35 - 3:37is used by plants to make the carbohydrates
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3:37 - 3:39we enjoy so much.
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3:39 - 3:41And, in the process,
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3:41 - 3:43they are releasing the very same oxygen molecules
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3:43 - 3:44we need to breath in
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3:44 - 3:47in order that our mitochondria can break down
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3:47 - 3:49our delicous carbohydrate meal.
- Title:
- The simple story of photosynthesis and food - Amanda Ooten
- Description:
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View full lesson: http://ed.ted.com/lessons/the-simple-but-fascinating-story-of-photosynthesis-and-food-amanda-ooten
Photosynthesis is an essential part of the exchange between humans and plants. Amanda Ooten walks us through the process of photosynthesis, also discussing the relationship between photosynthesis and carbohydrates, starch, and fiber -- and how the air we breathe is related to the food we ingest.
Lesson by Amanda Ooten, animation by Bouncepad Collective.
- Video Language:
- English
- Team:
- closed TED
- Project:
- TED-Ed
- Duration:
- 04:01
Bedirhan Cinar approved English subtitles for The simple story of photosynthesis and food - Amanda Ooten | ||
Bedirhan Cinar accepted English subtitles for The simple story of photosynthesis and food - Amanda Ooten | ||
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Andrea McDonough added a translation |