Download How Plants Make Food

How Plants Make Food
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Photosynthesis = the process by which plants make food
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Takes place mainly in the leaves
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Photo = light
Synthesis = putting together
Cells in the leaf have most of the chloroplasts that contain chlorophyll
Chlorophyll takes in light energy from the sun and changes it into chemical energy
Xylem and phloem tubes (veins) carry water from the roots to the
chloroplasts AND carry food from the chloroplasts back to the stem and
roots.
Veins help a plant keep its shape and keep it from wilting
The adaptation of a leaf being thin and flat helps the leaf take in as much
sunlight as possible
Epidermis = the upper layer of a leaf that protects the inner cells like skin
on a person .
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Sunlight can pass easily through the epidermis
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The upper epidermis helps the leaf not lose water through the
surface
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Palisade Layer = layer of cells below the epidermis made of long,
thin, packed tight cells.
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Lots of chloroplasts in these cells
Most photosynthesis takes place here
Spongy layer is next
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Sometimes there is a waxy covering called a cuticle on the leaf that also
helps the leaf not lose water
Loosely packed cells with lots of air spaces
Air spaces allow carbon dioxide to pass through to get to the chloroplasts
Have chloroplasts in the spongy layer but not as much as the palisade
layer
Lower epidermis is the underside of the leaf
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Stomata are in this layer surrounded by guard cells
Guard cells can change shape to allow the stomata to open and close
Stomata open = carbon dioxide can enter the leaf and oxygen can leave
Stomata closed = not much water and no photosynthesis takes place
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Photosynthesis begins when the sun hits a leaf
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Light is taken in by chlorophyll in the chloroplasts and is
changed from light energy to chemical energy
2 reactions take place in the chemical energy
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2.
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Water is split into hydrogen and oxygen
Hydrogen combines with carbon dioxide to make glucose
and oxygen
Glucose is used by the plant for food and some is
stored as starch
Oxygen is released into the air
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Most of the food that a plant produces is used by that plant for it to growth,
repair, and reproduce
Cellular Respiration = plants releasing the energy in food to carry on the
life process
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Plants store food to use when they can’t make food (cloudy days or dry
periods)
Stored food is starch. When the plant needs food, it can turn this starch
back into glucose
Plants use 90% of their food. They give 10% to animals who eat it
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Animals use most of food they eat to survive (90%)
Energy stored in the food is released by cellular respiration
Energy from the sun passes to the plant and then to the animal
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Oxygen combines with glucose to form carbon dioxide and water and produce energy
10% of the food an animal eats is stored in their body
When an animal eats another animal, it gets stored energy from that animal.
All energy can be traced by to the SUN!!