Download What`s in a Leaf - Renton School District

What’s in a Leaf
What’s the relationship between structure and
function in a leaf?
Model 1 – Leaf Sun-Catcher
1) Sun (energy), Water
(liquid), Carbon Dioxide
2) Water (gas), Oxygen,
Sugars
3) Water
4) Central Vein
5) Water has changed from a
liquid to a gas.
Equation for Photosynthesis
6) Using above equation:
a) Reactants? Carbon Dioxide and Water
b) Reactants enter? Carbon Dioxide through stomata (underside of leaf), Water
through roots to stem (xylem) and then central vein of leaf
c) Products? Sugars and Oxygen
d) Products exit? Oxygen through the stomata, Sugars through the veins
7) Matter OR Energy ?
Solar (light) Energy
Chemical Energy
(C-C and C-H bonds)
Model 2 – Cross Section of a Leaf
8) Layers:
Cuticle
Upper epidermis (skin)
Palisade mesophyll (middle)
Spongy mesophyll (middle)
Lower epidermis (skin)
Cuticle
9) Vein position
a) Model 1 - Central vein in
middle with other veins
branching off
b) Model 2 – Between palisade
and spongy mesophyll
Model 2 – Cross Section of a Leaf
10) Veins: get water to all
parts of the plant … the
leaf requires water to
help make sugar
11) Sunlight enters
Water enters (liquid)
Carbon dioxide enters
Sugar exits
Oxygen exits
Water (gas) exits
Xylem (liquid water)
Phloem (sugar)
12)Palisade mesophyll
and guard cells have
chloroplasts
13)Palisade and guard
cells (chloroplasts
conduct photosynthesis)
14)Chlorophyll (green
pigment) are mostly in
Palisade mesophyll
15)Light goes through
cuticle and upper
epidermis
16) Palisade mesophyll have lots of
chloroplasts, arranged vertically, tightly
packed, and larger.
17) More cells = More chloroplasts = More
photosynthesis
18)Most light is absorbed before
reaching the spongy mesophyll
19)If Upper epidermis had
chloroplast it would decrease
light reaching the Palisade
layer
20)Epidermis functions like skin
to protect what’s inside a leaf
21)The cuticle is “water-tight” to
prevent water from escaping.
Water must be used for the
plant to photosynthesize.
22)Lower surface
a) Stoma is between guard cell
b) Stoma is an opening
c) Water can exit through the
stoma when open … good or
bad?
23)Guard cells regulate the
opening and closing of the
stoma just like “gates”
24)Stoma open = access to more
air space
25)Air space = oxygen, carbon
dioxide, water
26)Stomata are closed …
what happens?
Water and Oxygen stay in
the plant. Upside?
Carbon Dioxide cannot
enter. Downside?
26)Cuticle and stomata
work together. How so?
Water regulation!
28 & 29
•Use your sentences tracing the
pathway or reactants entering
the leaf and products exiting the
leaf to draw a picture of the
equation of photosynthesis.
Extension Questions
30) Plants with larger leaves …
advantage or disadvantage?
31) Cacti … what structures give an
advantage or disadvantage?
32) Aquatic plants … adaptations?
33) Knowledge of Plant Cells
a) Water storage?
a)
Large Vacuole
b) Sugar destination?
b)
Go to mitochondria (energy)
c) Cell wall function?
c)
Structure and strength so leaf is
lifted up toward the light