Key Idea #15

Photosynthesis transforms light energy to
chemical energy which is used to form
the key chemical building blocks of living
organisms.
eoearth.org
The Process of Photosynthesis
Plants (producers)



produce their own
food.
use light energy to
make sugar
molecules (glucose)
from the atoms of
carbon dioxide and
water.
use sugars as the
building block to form
bigger carbohydrates
and fats.
http://extension.oregonstate.edu/mg/botany/images/fig24.gif
Light energy



is necessary for photosynthesis to occur.
can be in the form of sunlight or artificial light.
is used to combine materials from air, water, and soil
to produce carbohydrates, proteins, and fats.
http://www.petpitcher.com/wp-content/uploads/2009/03/4ft_terrarium.jpg
Glucose (C6H12O6) = Sugars (food)
Sugars = Simple Carbohydrates
http://www.annekeckler.com/wp-content/uploads/2008/03/glucose-molecule.gif
Photosynthesis is a Two Step Process
Step 1 (book page 51)
 Captures light energy
– occurs in the chloroplasts of cells
– chlorophyll acts like a solar cell
The main function of green, chlorophyll
containing leaf cells is photosynthesis.
plantcell.org.uk
Step 2 (book page 52)

Uses water, carbon dioxide and energy to make
food (glucose) and oxygen.
– obtains water from the roots, and carbon dioxide through
the stomata
– chemical reaction makes glucose and oxygen
Stomata
Photosynthesis Equation


Carbon dioxide and water are the raw materials
of photosynthesis
Sugars (glucose) and oxygen are the products of
photosynthesis
Plants make, use, and store food



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A seed contains stored food.
As it germinates, the seed
shrivels as the growing
seedling uses its stored food.
Plant parts rich in food value
are nuts, seeds, roots
(carrots and beets), and fruits
Animals get energy and
useful materials by eating
plants or plant parts.
http://www.tomatosphere.org/teacher-resources/teachers-guide/images/transparency/seed-germination.jpg
Plants contain specialized food storage
structures which include:



Roots
Tubers
Bulbs
FYI: Respiration and Photosynthesis
http://msmcgartland.pbworks.com/f/cell%20resp%20and%20photo.jpg
http://www.tomatosphere.org/teacher-resources/teachers-guide/grades-8-10/images/photosynthesis-respiration.jpg
RESPIRATION

The process that cells use to withdraw
energy from glucose in order to
release energy.
oum.ox.ac.uk
Two Stages
 In
the cytoplasm of the cells,
glucose molecules are broken
down into smaller molecules.
 Inside the mitochondria those
chemicals are broken down further
releasing energy for the body to
use.