Learning
Goal: Explain how the sun
supplies living things with the energy
they need. Explain photosynthesis.
Warm
up: Why do plants need light?
Homework:
Packet pages 21, 22, 23


Photosynthesis

Photosynthesis: the process by which a cell captures
energy in sunlight and uses it to make food
o Photo– means “light”, synthesis– means “putting together”

Nearly all living things obtain energy either directly or
indirectly from the energy of sunlight captured during
photosynthesis

Autotroph
o an organism that makes their own food
o What are some examples?

Heterotroph
o an organism that cannot make their own food
o What are some examples?

Fungi– absorb their food from other organisms
1.
Capturing the sun’s energy
2.
Producing sugars

Both stages must occur in the correct order

Energy capturing process occurs mostly in leaves

The green color comes from pigments– colored chemical
compounds that absorb light

The MAIN photosynthetic pigment in chloroplasts is called
CHLOROPHYLL
Chlorophyll captures light energy and
uses it to power the second stage
of photosynthesis…


Cell uses captured energy to produce sugars

The cell needs two raw materials
1.
2.
water – enters plant through roots and move upward to the leaf
carbon dioxide– enters through openings called stomata
Once in the leaves the water and
carbon dioxide move into the
chloroplasts….


Inside the chloroplasts undergo a series of chemical
reactions

Chemicals are the products of the reactions (2)
o Six-carbon sugar (use this energy to carry out cell functions)
o Oxygen (exits leaf through stomata)

Fun Fact: Almost all oxygen in Earth’s atmosphere was
produced by living things through the
process of photosynthesis
Raw Materials

The arrow stands for YIELDS
Products

Plants use it for food

Some sugar is made into other compounds, such as
cellulose

Some sugar is stored in the plant’s cells for later use