Transcript Plants

Plants with Seeds
Structure –
Leaves
stem
roots
Leaves
Function of leaves
 Trap light energy for photosynthesis
 Producing sugar from photosynthesis
 Take in water
 Exchange of gases –
oxygen and carbon dioxide
Parts of Leaves
 Stalk:
connects leaves
Compound
to the stem
 Blades: thin flat part that
is the site of
photosynthesis
 Simple leaf: 1 single leaf
 Ex. Maple, Oak, Apple
 Compound: divided into a
# of separate parts
 Ex. Roses, clovers, and
palms
 Simple
Structure
Wide
Helps to catch more light
energy
Thin
Help get carbon dioxide
from bottom to top of
leaf for photosynthesis
Internal Parts of Leaves
 Epidermis: outside
layer of leaf covered
in cuticle
 Stomata: pores where
CO and H O enter
the leaf and O leaves
 Guard Cells: cells on
both sides of stomata
that open and close
2
2
2
Internal Parts of Leaves
 Mesophyll: inner
layer of leaf
 Pallisade: upper
mesophyll where
photosynthesis
happens
 Spongy Layer: filled
with air spaces for
CO ,H O and O
2
2
2
Leaf structure
Most chlorophyll
Greener on top
CO2 gets in
here
Leaf diagram – palisade layer
Most
chlorophyll
CO2
Gas exchange
 Leaves are designed to allow carbon
dioxide to get to the main chlorophyll
layer at the top of the leaf
 They have small holes called stomata on
the under surface
 Each hole is open & closed by 2 guard
cells
Stoma position
Stoma is a small hole
Its size is controlled by 2 guard cells
closed
open
Stoma function is for gas
exchange in the leaf
Guard
cell
oxygen
Provided plant is
photosynthesising
Carbon
dioxide
Stomata open and
close at different
times of the day
When it is light the
plant needs CO2 for
photosynthesis so
the stoma open
At night (darkness)
they close
Gas exchange
PHOTOSYNTHESIS
 The process of photosynthesis is a
chemical reaction.
 It is the most important
chemical reaction on our planet.
PHOTOSYNTHESIS
EQUATION
PHOTOSYNTHESIS
EQUATION
Six molecules of carbon dioxide
react with six molecules of water to
form 1 molecule of glucose and six
molecules of oxygen.
Describe Photosynthesis
 The process of changing light energy to
chemical energy
 Energy stored as sugar
 Plants need light energy, CO2, and H2O
 Takes place in the chloroplasts, using
chlorophyll, the green pigment in plants
What happens during
photosynthesis?
 Carbon dioxide enters the leaf through holes
called stomata
 CO2 combines with the stored energy in the
chloroplasts through a chemical reaction to
make glucose
 The sugar is moved through tubes in the leaf to
the roots, stems and fruits of the plants
 Some of the sugar is used right away by the
plant for energy; some is stored as starch; and
some is built into plant tissue
ROOTS
ROOTS – function and
structure
 Anchor plant in position
 Absorb water and minerals
from the soil
 Specialized cells to increase
surface area for water intake
 Store food
Types of Roots
 Fibrous: several
thin roots that
branch to form a
tangle mass
 Ex. Grass, corn,
most trees
Types of Roots
 Taproots: long
thick main root
and thin
branching roots
 Ex. Carrots,
cacti,dandelions
Parts of a root
 Epidermis:
outermost layer
of the root that
has hairs on it
Parts of a root
 Cortex: layer
just inside the
epidermis
 Stores food
 Carries water
and minerals
into vascular
tissue
Parts of a root
 Root Cap:
protects the root
as it grows
through the soil
Parts of a root
 Growth tissue:
just behind the
root cap, where
new cells form
Human uses for roots
 Food:
 Carrots, beets, yams
 Licorice, horseradish,and sassafras used as
spices
 Medicine
 Dyes
 Insecticides
Parts of
Root
Root hairs
•Fragile parts of
cells that grow
from the main root
•They massively
increase the
surface area for
absorption
STEM: Structure and
Function
 Gets water and
nutrients from the
roots to the leaves
 Holds the leaves up
in the air so it can get
sunlight to make food
STEM: Structure and
Function
 Vary greatly in size
 Trunk
 Branches
 Twigs
Types of Stems
 Herbaceous: have
stems that are
green and soft
 Ex. Sunflowers,
pea, tomatoes,
grass, abd
dandekions
Types of Stems
 Woody: have
stems that are
hard and made of
wood
 Ex. Roses, Firs,
and Maples
Structure of Woody stem
Structure of Woody stem
 Bark: outermost layer
of stem
 Tough
 Waterproof
 Helps protect the
fragile tissue inside
 Inner part of the bark
is the phloem
Phloem
 Transports glucose and starch made
during photosynthesis.
Structure of Woody Stem
 Vascular Cambium:
growth region of the
stem
 This is where xylem
and phloem are
produced
 Pith: Center of the
stem
 Stores water and
food
Stem Rings
 Each ring represents a year’s growth of
xylem
 1 ring = 1 year
 If a tree had 12 rings how old would it
be?
 12 years old