Photosynthesis
Why is Photosynthesis
important?
Makes organic molecules
out of inorganic materials.
It begins all food chains &
webs.
All life is supported by this
process.
It also makes oxygen gas!
Photosynthesis- THE start to food webs!
Photo-synthesis= “making things with light."
Plants use sunlight to
turn water and carbon
dioxide into glucose.
Plants use glucose as
food
Autotrophs make
glucose and
heterotrophs are
consumers of it.
Photosynthesis
Carbon dioxide + water sunlight
glucose + oxygen
absorbed by chlorophyll
6CO2 + 6H2O + energy  C6H12O6 + 6O2
Quick Read
 Turn to page 103 in your text
 Read through pages 103-105
 Take some notes on what you read
 Pay attention to the graphics
1
chloroplast
6H
2O
granum (stack of thy
2
6O2
thylakoid energ
stroma (fluid
y
6CO2
1 six-carb
thylakoids)
sugar
CH O
3
4
6
12
chloroplast
 Chlorophyll is a
molecule that
absorbs light
energy.
• In plants, chlorophyll is
found in organelles called
chloroplasts.
leaf cell
leaf
Photosynthesis in plants occurs
in chloroplasts.
 Photosynthesis
takes place in two
parts of
chloroplasts.
 grana
(thylakoids)
 stroma
grana (thylakoids)
chloroplast
stroma
 The light-dependent reactions capture
energy from sunlight.
–
–
–
–
take place in thylakoids
water and sunlight are needed
chlorophyll absorbs energy
energy is transferred along thylakoid membrane
then to light-independent reactions
– oxygen is released
 The light-independent reactions
make sugars.
– take place in stroma
– needs carbon dioxide from atmosphere
– use energy to build a sugar in a cycle of chemical
reactions
 The equation for the overall process is:
6CO2 + 6H2O  C6H12O6 + 6O2
granum (stack of thylakoids)
1
chloroplast
6H2O
thylakoid
6CO2
6O2
2
energy
stroma (fluid outside the thylakoids)
1 six-carbon sugar
C6H12O6
3
4
Chloroplast Structure
Draw and
label the
thylakoid,
granum,
stroma, &
outer
membrane
Step 1 Light Dependent
Reaction
•
•
•
•
What two things
enter step 1?
Where does step 1
occur?
What two things
leave step 1?
Why is it called
the light
dependent
reaction?
Step 2 Light independent
reaction
• What two things
enter step 2?
• Where does step 2
occur?
• What two things
leave step 2?
Elodea using
photosynthesis
What gas do
you think is in
the bubbles
that the plant
made?
Plants
in
Action
Glucose
Two Steps of Photosynthesis
 Light Dependent Reactions (thylakoid)
 Sunlight is absorbed and converted to chemical
energy
 Water is taken in and broken down into oxygen
 Chemical energy is temporarily stored in plants as
ATP
 Light Independent Reactions (stroma)
 CO2, ATP, make organic compounds
6CO2 + 6H2O
C6H12O6 + 6O2
Studying Photosynthesis
 Know what goes into each step and comes out of each step
 Know the different structures of the chloroplast
 Be able to label the diagram on the following slide
 Watch the following videos:
 Bozeman Science
https://www.youtube.com/watch?v=g78utcLQrJ4
 Animation with Explanation
https://www.youtube.com/watch?v=wJDlxp17rY4
 Crash Course
https://www.youtube.com/watch?v=sQK3Yr4Sc_k