Photosynthesis
Michael Slemp
BELL WORK


Explain the difference between light dependent
reactions to light independent reactions.
Use complete sentences and be descriptive.
Review



All cells need energy in form of ATP
Most animal cells need to eat energy-rich
molecules like sugars to get their energy
Some organisms, like plants, are able to
produce their own energy via photosynthesis
or chemosynthesis. They are called
producers.
Sunlight
energy
Photosynthesis
Energy rich
molecule (glucose)
Plants, animals and humans use glucose as source of energy
Types of Energy

Light Energy



Plants are able to convert light
energy into chemical energy
during the process of
photosynthesis
Energy from the sun
Human use: solar calculators, solar heaters
Chemical Energy


Energy hidden in the bonds of chemical molecules
(like sugar/glucose. ATP)
This energy is released when bonds are broken
Pair Share
1.
2.
3.
4.
Describe the difference between light and chemical
energy.
Can humans convert light energy into chemical
energy?
What organisms can convert light energy into
chemical energy?
What is this process called?
Pair Share
1.
2.
3.
4.
Describe the difference between light and chemical energy.
Light energy is the energy from sunlight and chemical
energy is hidden in bonds of chemical molecules.
Can humans convert light energy into chemical energy? No
What organisms can convert light energy into chemical
energy? Plants
What is this process called? Photosynthesis
Photosynthesis
What organisms?
What organelle?
Lets look
closely at
the
structure of
chloroplast
Plants
Chloroplast
Draw and
label
picture in
your
notebook
Outer
membrane
Inner
membrane
Chloroplast
Stroma (fluid
outside thylakoids)
Thylakoid
(coin-shaped,
membrane
enclosed
compartment)
Granum
(pl. grana)
stack of
thylakoids
Add to your notes
CHLOROPHYLL
Pigment molecule responsible for sunlight absorption
Chlorophyll is found on the thylakoid membranes of chloroplasts
The main types are: chlorophyll a and
chlorophyll b
Together they absorbs mostly red and blue
wavelenghts (think of a rainbow)
Green wavelengths are being reflected
(that’s why plants look green)
Name all parts
of chloroplast
and answer
question.
Pair Share
3
4)
1
2
5
What is the name of pigment molecule and where is it found?
Name all parts
of chloroplast
and answer
question.
Pair Share
Stroma (fluid
outside thylakoids)
Outer
membrane
Inner
membrane
Thylakoid
(coin-shaped,
membrane
enclosed
compartment)
Granum
(pl. grana)
stack of
thylakoids
What is the name of pigment molecule and where is it found?
Chlorophyll and it’s located on thylakoid membranes.
Process of PHOTOSYNTHESIS
Photosynthesis is complicated process involving variety of molecules and enzymes
It can be summarized as:
6 CO2 + 6 H2O + sunlight energy
Carbon dioxide + water + sunlight energy
C6H12O6 + 6 O2
glucose + oxygen
2 steps:
1. Light-dependent reactions (happens in thylakoids)
2. Light-independent reactions (happens in stroma)
Light-dependent
Where?
What is
needed?
• Sunlight energy
• Water
• Chlorophyll
Thylakoids
At the end of the light-dependent reactions
we have energy-rich carriers (ATP) and
released free oxygen.
Steps:
• Chlorophyll absorbs sunlight
energy
• Water molecule is broken down
• Oxygen is released
• Energy carried along thylakoid
membrane is transferred to
molecules that carry energy (ATP)
Light-independent
Where?
What is
needed?
• Chemical energy
from light dependent
reaction (ATP)
• Carbon dioxide
Stroma
At the end of the light-independent
reactions we have glucose molecule which
serves as a storage of chemical energy.
Steps:
• In order to build larger carbon
molecules, carbon dioxide
molecules are added together in a
cycle of chemical reactions.
• Energy from light dependent
reaction is used.
• Molecule of simple sugar
(glucose) is formed.
Compare
GLUCOSE
Water
Stores chemical energy
Light dependent
Light-independent
(need chlorophyll)
Oxygen
Molecules
that carry
energy (ATP)
(can happen at night)
Carbon dioxide
Pair share
1
2
Fill in the
blanks
8
9
3
10
7
6
4
5
Pair share
9 - Stroma
10 - thylakoids
Water
Light dependent
Stores chemical energy
Light-independent
(need chlorophyll)
Oxygen
GLUCOSE
Molecules
that carry
energy (ATP)
(can happen at night)
Carbon dioxide