Download U11.3P1 StructureLeaf

Leaves
Leaves are like small factories that produce food for the
plant. Different parts of the leaf have different jobs. The
veins in a leaf are bundles of tiny tubes that carry water and
minerals to the leaf and return food from the leaf to the rest
of the plant. Veins also help to support the leaf.
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Leaves
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Photosynthesis
Leaves are green because they contain small
bodies in the cells called chloroplasts. The
chloroplasts contain a green pigment called
chlorophyll. This green material gives the leaf its
colour.
With the help of chlorophyll and energy from the
sun, a leaf can change lifeless substances into food.
This process is called photosynthesis. Plants need
water (H2O) and carbon dioxide (CO2) to make food
through the process of photosynthesis. The water is
gathered by the plant's roots. Carbon dioxide is
gathered from the air through the stomata.
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Photosynthesis (continued)
The leaf uses chlorophyll and sunlight to change
the water and carbon dioxide into oxygen and
glucose (sugar). This sugar is mixed with water
and sent to other parts of the plant to be used by
the plant as food. The oxygen is released into the
air through the stomata. This is usually written as:
Carbon + water
Light
Chlorophyll
Glucose + oxygen
This is usually read as carbon dioxide plus water
in the presence of light and chlorophyll produces
oxygen and sugar glucose.
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Photosynthesis summary
Chloroplast
They
contain
a green
pigment
These
are small
structures
called
chlorophyll.
that vary
in number
and size.
LIGHT
Chlorophyll
The
Photosynthesis
chlorophyll traps
is thesunlight
name of the
Therefore,
Chloroplasts
arethe
where
and
chemical
uses this
reaction
energy
that
to produces
drive
the
a plant
makes
its own food.
process
ofplant’s
photosynthesis.
food.
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Photosynthesis
We know that plants make their own food from sunlight.
They are the producers in the food chain. This is done in
the green parts of the plant, e.g. upper surface of the
leaves. The reaction for this is:
CARBON
DIOXIDE
+
Taken in through
holes in the
leaves
WATER
Taken in
through
the roots
With light and
FOOD
(GLUCOSE)
Made
byphotosynthe
sis and stored
as starch in
leaves, roots,
stems, etc.
+
OXYGEN
waste
product
exhaled
+ ENERGY
USEFUL!
chlorophyll
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