2. How do plants get CO2 in and let O2 out?

3. Stomata & Guard Cells Function of stomata – CO 2 in – O 2 out – H 2 O out gets to leaves for photosynthesis Function of guard cells – open & close stomates guard cell stomata

4. Guard cells & Homeostasis Homeostasis – keeping the internal environment of the plant balanced Stomata open – let CO 2 in needed to make sugars – let H 2 O out needed for photosynthesis – let O 2 out get rid of waste product Stomata close – if too much H 2 O evaporating

5. 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

6. 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

7. 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

8. 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?