View
27
Download
0
Category
Preview:
Citation preview
+
Photosynthesis: Converting sunlight into chemical
energy
Students who demonstrate understanding can:
HS-LS1-5: Use a model to illustrate how photosynthesis transforms light energy into stored chemical energy.
+Where does the oxygen (O2) we
breathe come from?
O2 is produced by different
kinds of bacteria, algae, and
plants (including trees)
during photosynthesis.
About 25% of O2 comes from
land plants.
Most of Earth’s O2 comes
from the ocean.
Released from tiny ocean plants
called, phytoplankton.
+Autotrophs and Photosynthesis
Called “self feeders” or
”producers”.
Organisms that can produce their
own food using light, water,
carbon dioxide, or other
chemicals.
Examples of autotrophs: green
plants, some algae, few bacteria.
Most autotrophs use
photosynthesis to make their
food.
+Overview of Photosynthesis
Light energy gets converted into chemical energy.
Chemical energy is stored in the form of glucose (sugar).
Carbon dioxide, water, and sunlight are used to produce carbohydrates and oxygen.
Occurs in two stages:
Light Dependent Reactions
Light Independent Reactions
https://www.youtube.com/wa
tch?v=1XilneV3cJI
+Where Does Photosynthesis Take Place
in the Cell?
+Chloroplast Anatomy:
+Closer Look at Chloroplast
Structures
Chlorophyll:
Allows plants to absorb energy from light
Gives leaves their green color
Membrane Envelope:
Inner and outer membranes
Protects and keep chloroplast structures enclosed.
Thylakoid membrane:
Internal membrane system
Flattened sac-like membrane structures called thylakoids
Serve as the sites of conversion of light energy to chemical energy.
Granum
Dense layered stacks of
thylakoid sacs
Sites of conversion of light
energy to chemical energy.
Stroma
Dense fluid within the chloroplast
Lies inside the envelope but
outside the thylakoid membrane
Site of conversion of carbon
dioxide to carbohydrates
+
Two Processes of Photosynthesis
Location: Thylakoid Membrane
Reactants: Sunlight and water
(H2O)
End Products: ATP, NADPH,
and O2
Also called “Calvin Cycle” or
Dark Reactions
Location: Stroma
Reactants: ATP, NADPH, and
O2
End Products: Glucose
Light Dependent Reactions Light Independent Reactions
Remember:
Cells use ATP for energy
NADPH is a cofactor in reactions that acts as a reducing agent
+How Does It All Work?
+Photosynthetic Equation
Photosynthesis can be represented using a balanced chemical
equation:
+Why is photosynthesis essential to life
on Earth?
Well..
Life can be sustained in plants.
Plants provide oxygen for
humans.
We BREATHE oxygen!
Without oxygen we cannot
survive!
Recommended