Teacher Information Sheet
1. What does photosynthesis mean? You may be able to figure it out just by looking at
the prefix photo and the root word synthesis.
When looking at the word photosynthesis, I can see photo and synthesis. When you think
of photo, what do you think of? Photo means light. When you think of synthesis, what
do you think of? Do you think synthesis means putting something together, or pulling it
apart? Synthesis means putting together. So, if we combine or synthesize photo and
synthesis, what does photosynthesis mean? Yes, photosynthesis means putting together
light.
2. What are the major players in photosynthesis? In other words, photosynthesis
consists of what major components?
If photosynthesis depends on light, what is our planet’s major source of light? Yes,
sunlight from the sun. So the sun is one of the major players in photosynthesis.
Additional major players in photosynthesis are trees and green plants.
3. How important is the sun in photosynthesis and what role does it play?
Did you know that the sun is a star? It is essentially a huge ball of hot gas (hydrogen
and helium) that undergoes nuclear reactions. It is located at the center of our solar
system and provides energy in the form of sunlight and heat to our planet. Without
the sun, plants and animals could not exist.
4. How important are trees and green plants in photosynthesis and what role do they
play? Did you know that trees are often referred to as the lungs of the planet? Why do
you think that is? Basically, trees and green plants absorb carbon dioxide (a greenhouse
gas) and produce oxygen upon which all animals depend on for survival. Rainforests
play a huge and critical role in the amount of oxygen in Earth’s atmosphere. Even
though they cover less than 2 percent of Earth’s surface, rainforests house more than 50
percent of the plants and animals on Earth! Note: This incredible diversity of life
(biodiversity) will be discussed in Lesson 3.
5. Can you describe the process of photosynthesis? What happens first, second, third,
etc? (Sketch each step on the board as you discuss each one)
First: Trees and plants absorb: (a) water from the ground through their roots; (b) carbon
dioxide from the air through tiny openings on the underside of leaves called stomata; and
(c) sunlight from the sun by tiny organelles on the surface of leaves called chloroplasts.
Second: These chloroplasts contain chlorophyll (a green pigment). When
sunlight shines on the surface of a leaf, the light energy is trapped by the
chlorophyll. This energy is used to drive chemical reactions.
Third: This chemical reaction consists of carbon dioxide (absorbed through
stomata) and water. [Note: When the stomata open to absorb carbon dioxide, they also
lose water (transpiration, Lesson 1).] However, water absorbed from tree and/or plant
roots and carbon dioxide undergo a chemical reaction and are converted (synthesized)
into sugar and oxygen. Both oxygen and water are released into Earth’s atmosphere and
the sugar remains inside the tree and/or plant leaves. Trees and plants use sugar as
energy and store the rest.
6. How and why is photosynthesis important to our planet?
Like the water cycle (Lesson 1), photosynthesis is one of the driving forces of life on
our planet. Since rainforests are located along the equator (show map or globe) they
receive approximately 12 hours of sunlight each day all year round. So, we can
surmise that perhaps rainforests have a higher rate of photosynthesis, which means
they absorb more carbon dioxide and emit more oxygen and water into Earth’s
atmosphere. Planet earth would not be able to sustain life without oxygen and water.
Plants are dependent on photosynthesis in addition to all animals.
7. How and why is photosynthesis important to animals?
All animals depend on both sugar (glucose) and oxygen for their survival.
Without glucose and oxygen, the brain simply cannot survive. And without a
brain, an animal cannot survive.
8. Could we live without photosynthesis? Why? Explain your answer.
No, we could not live without photosynthesis because all life is dependent on
the sun. Without the sun, the process of photosynthesis could not occur.
Without photosynthesis, there would be no plants. Without plants, there would be no
animals (that includes humans).
9. What would happen if the process of photosynthesis became disrupted, i.e., loss of
trees due to deforestation (cutting down forests), too much carbon dioxide due to
burning non-renewable sources of energy (oil, gasoline, coal) and wood?)
The quality of life for all animals would suffer significantly. There would be less
oxygen in Earth’s atmosphere and more carbon dioxide from the loss of trees and
burning of fossil fuels. The air pollution would become unbearable. More people
would most likely develop respiratory problems (asthma) and other illnesses. In
addition to air pollution, water pollution would occur as well. Basically the water
would become more acidic which is harmful, if not deadly, to aquatic plants and
animals.
10. Is there anything human beings can due to decrease the amount of carbon
dioxide released into Earth’s atmosphere? Why is this important?
We must use our brains to invent creative solutions using renewable forms of energy
(solar, wind, geothermal, etc) rather than the old, archaic, traditional forms we are
still using today (oil, gasoline, coal, nuclear, burning wood, etc.) There are solutions.
We just need to work together and think ‘outside the box’ to find them.
References:
Rainforests by Rhett Butler copyright 2011
http://www.biology4kids.com/files/plants_photosynthesis.html
http://meridianacademy.org/parents_&_students/hw_portal/mst/documents/Photosynthesis.pdf