Transcript S7-3-1 Leaves

Leaves
S7-3-1
Look! Vascular tissue!
1 main function of a leaf
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Make food
It uses the process photosynthesis to
make food for the plant (more on this
later!)
2 types of leaves
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Simple—blade in
one piece
Ex. maple, oak,
apple trees
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Compound—
blade is divided
into many leaflike parts
Ex. marigold,
sensitive plant
Photosynthesis
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Food is synthesized (made) using
sun’s energy
Sun’s energy is captured by
chlorophyll (green pigment in the
leaf)
Chemical reactions take place—
sugar (AKA glucose AKA C6H12O6)
6H2O + 6CO2 ----------> C6H12O6+ 6O2
Add sunlight
**AKA = Also Known As
C6H12O6
Parts of a leaf
**I apologize for this blurriness of this picture!
It is as if the leaf is cut in half and you are
looking at a side view!
Veins: Phloem & xylem
Cuticle: waxy covering, prevents excess water loss
Epidermis: outer covering
Palisade mesophyll: most
chloroplasts located here
Spongy mesophyll:
gases (CO2 & O2)
are exchanged here
Mesophyll:
inner part
of leaf
Enlarged view:
Stoma: opening for CO2 to
come in & O2 to go out
Guard cells: Surround stoma,
regulate its opening & closing
Transpiration
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Water is evaporated
through the leaves by
the sun
Each time a water
droplet is “picked up,” it
pulls the next droplet
through
This is how the water
gets from the roots to
the leaves
Red arrows show the path of the water
Specialized leaves #1
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Tendrils—Thin leaves that reach out
and “lasso” objects
to help plant extend
itself
Ex. peas, pumpkins
Spines—Thin, pointy leaves; help to reduce
water loss
Ex. Cacti
Specialized leaves #2
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Reproduction— “babies”
drop from the grown leaf
Ex. Spider plant
Kalanchoe
• “Fake petals”—Some leaves are brightly
colored and look like petals (to attract
pollinators)
• Ex. Poinsettias
Specialized leaves #3
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Carnivorous plants—some leaves catch insects to eat
sundew
insects get stuck on sticky drops on leaves
Pitcher plant
Insects land on leaf and slide down
into digestive juice
Venus flytrap
Snap shut when insect lands on leaf
Specialized leaves #4 FOOD!
We EAT the leaves of many plants!
Cabbage
Herbs,
such as
parsley
and
basil
Spinach
Bulbs: Onion and garlic
Cloves
Lettuce
Questions:
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Please answer of separate piece of paper
List the one main function of a leaf.
What category of leaf is shown here:
What 2 substances react with each other during
photosynthesis?
What 2 substances are produced through
photosynthesis?
Can a plant make food in the dark? Explain.
What part of the leaf captures the sun’s energy? In
which section of the leaf are these organelles located?
What is the job of the cuticle?
In which direction does transpiration move water?
Name 3 specialized functions of leaves (besides food).
List your 3 favorite leaf foods.