PHOTOSYNTHESIS

PHOTOSYNTHESIS

GLUCOSE is converted into OTHER SUBSTANCES
1. GLUCOSE is transported around the plant as SOLUBLE SUGER
2. Soluble sugars can DISSOLVE IN WATER, which makes it easy to TRANSPORT them to other places in the plants
3. Here's how plants USE the glucose the make:
  1. For RESPIRATION
    1. Plants use some of the GLUCOSE for RESPIRATION
    2. This releases ENERGY so the rest of the glucose can be CONVERTED into useful substances
  2. Making CELL WALLS
    1. GLUCOSE is converted into CELLULOSE for making CELL WALL
  3. Stored in SEEDS
    1. GLUCOSE is turned into FATS and OILS for STORING in SEEDS
  4. Stored in STARCH
    1. Some GLUCOSE is turned into STARCH and STORED
    2. Starch is INSOLUBLE-it DOESN'T DISSOLVE IN WATER
    3. Starch is CONVERTED back into glucose when supplies of the sugar are low
  5. Making PROTEINS
    1. GLUCOSE is combined with other things to make PROTEINS
    2. Proteins are used for GROWTH and REPAIR
There have been DIFFEENT IDEAS about HOW PLANTS GAIN MASS
1. When plants grow, they GET HEAVIER -they GAIN MASS
2. ANCIENT GREEK SCIENTIST thought that plants gaind mass from SOIL MINERALS
3. But a scentist called van Helmont later discovered that plants also gain mass from OTHER SOURCES
  1. He dried some SOIL, weighted it, and put it in a pot
  2. He weighted a SMALL WILLOW TREE and planted it in the soil
  3. He added RAINWATER to the pot whenever it was dry
  4. 5 YEARS LATER, the TREE had grown and was much HEAVIER than at the start
  5. The mass of the SIOL had HARDLY CHANGED at all
4. Because the soil still weighted the same, van Helmont thought that the TREE must have GAINED MASS from something other then SIOL MINERALS
5. The ONLY thing he'd added top the pot was RAINWATER-so he concluded the tree must have gained mass by taking in WATER
PRIESTLY'S EXPERIMENT showed that PLANTS PRODUCE OXYGEN
1. Many years after van Helmont, a scientist called PRIESTLY did this experiment
  1. He placed a BURNING CANDLE in a SEALED CONTAINER
  2. The FLAME WENT OUT and COULDN'T be RE-LIT
  3. He then placed a LIVING PLANT in the container
  4. After a FEW WEEKS the candle COULD BE RE-LIT
2. He also did this experiment
  1. He also put a MOUSE in a sealed container full of BREATHED-OUT AIR. The mouse DIED after FEW SECONDS
  2. He filled another container with BREATHED-OUT AIR
  3. He put a LIVING PLANT in the container and waited for a FEY DAYS
  4. He then put a MOUSE in the container- this it survived for A FEW MINUTES
3. He thought that the CANDLE FLAME WENT OUT and that the MOUSE DIED because BURNING and BREATHING had TAKEN SOMETHING OUT OF THE AIR
4. From these experiments, Priestly decided that PLANTS somehow RETURN THIS SUBSTANCE TO THE AIR
5. Today we know that this substance is OXYGEN- a product of photosythesis

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	Criado por Emily Armstrong quase 10 anos atrás