Transcript How do plants get CO2 in and let O2 out?

How do plants get CO2 in and let
O2 out?
Stomata & Guard Cells
• Function of stomata
– CO2 in
– O2 out
– H2O out
• gets to leaves for photosynthesis
• Function of guard cells
– open & close stomates
guard cell
stomata
Guard cells & Homeostasis
• Homeostasis
– keeping the internal environment
of the
plant balanced
• Stomata open
– let CO2 in
• needed to make sugars
– let H2O out
• needed for photosynthesis
– let O2 out
• get rid of waste product
• Stomata close
– if too much H2O evaporating
Photosynthesis Lab
• In this lab we will be determining the affect
light has on the rate of photosynthesis.
• Before we start the lab, we are going to go
through the procedures so we understand
why we do each step
Step One
• I made a solution of baking soda, water, and
soap
– Baking soda is also known as sodium bicarbonate
– Baking soda has a chemical equation of NaHCO3
– With your elbow partner, hypothesize why we
need to make this solution. What things does this
give the plant?
– HINT: Think about the chemical equation of baking
soda
Step 2
• You will get 20 leaf disks from spinach and
place them in a syringe
• Using some of the baking soda solution you
will create a vacuum
• This forces the sodium bicarbonate into the
cells of the leaf
Step 3
• You will put 10 leaf disks in one cup, and 10 in the
other
• One cup will go directly under a light source
• One cup will be covered with black paper
• You will then count how many disks float to the
top each minute and record your data
• What does it mean if a leaf disk floats to the top?