Part 1
Respiration & Photosynthesis
Key Question: Why do we need to eat food?
Initial Thoughts:
• Cells need energy to do work.
• For example: moving your muscles, thinking
with your brain, fighting off illnesses, just to
name a few.
• We need Oxygen and sugar (glucose) to get
energy for our cells to do things.
• As a byproduct, CO2 (carbon dioxide) and H2O
(water) are given off.
• We breathe in O2, breath out CO2
• Plants can make their own food using sunlight
as energy.
• What organelle do plants use to do this?
Chloroplast
It’s what makes
plants GREEN
They absorb water through their roots
& CO2 through their leaves.
They use sunlight to power this
transformation into food.
They store their food in the
form of sugars (glucose).
• When you eat potatoes, rice, beans, or wheat
flour, you are eating big molecules of glucose
called starch, made through photosynthesis.
Starches are a type of carbohydrate.
Photosynthesis and Cellular Respiration Activity
• Work with a partner, but each of you must record
your equations & answers in your journal.
• Answer in complete sentences.
• When you have arranged your cards, raise your
hand and I will initial your paper for each
equation.
glucose/sugar
O2 + C6H12O6
Reactants
(what goes in)
ATP
H20 + CO2+ E
Products
(What comes out)
glucose/sugar
H20 + CO2+ E
O2 + C6H12O6
Reactants
(what goes in)
Products
(What comes out)
• As a byproduct, plants give off Oxygen
• We consume/eat plants and need oxygen they
make. We are called CONSUMERS.
• This why plants and all photosynthetic
organisms are called PRODUCERS.
The Cycle
CO 2
Consumers
O2
Producers
1. Explain what gases are involved in
Photosynthesis and Respiration. Which ones are
inputs, and which are by-products?
2. Compare the chemical equations for
photosynthesis and cellular respiration. How are
they similar? How are they different?
3. Do you think plants do cellular respiration?
Explain your reasoning.
In a well developed paragraph:
– What did you think before about how plants &
animal cells use food? (look back at your initial
thoughts)
– What did you learn about how plants & animal cells
use food?
Be specific! (look back at your evidence section).
– What evidence do you have that you learned this?
– Further Thoughts
Make sure this is thoughtful and thorough.
• Create a diagram that shows how the gases
are recycled between producers and
consumers.
• - (make your own big idea)