Plants Perform Work
Even when you are stationary, you still are expending energy maintaining your body: blood is being pumped, oxygen, carbon dioxide, and nutrients are being delivered and removed from cells. As soon as you stop doing this, your cells start to die and break down. We can show the importance of cellular respiration in plants by stopping the input of sugars to certain leaves. By stopping photosynthesis in a leaf, you basically stop its ability to use those sugars for cellular respiration and the leaf will start to break down other parts of the cells for fuel, and they will stop making chlorophyll A.
Procedure
Cut 20, 1/2-by-1-inch (1.25-by-2.5-cm) strips from a sheet of black construction paper (or aluminum foil). At sunset on the night before you begin the experiment, fold each strip in half, wrap it around a blade of grass, and secure it with a small paper clip (or piece of tape). Use the weather report in your local newspaper or on TV to determine how many hours of daylight are predicted for the next day.
On the first day of the experiment, after the grass has received half of the light predicted for that day, remove one black strip from one blade of grass. Cut the blade of grass off at the base and tape it to a sheet of white paper. Label the paper Day 1 (Half Day) and photograph the page. At sunset on the first day, remove a second black strip from a second blade of grass. Again cut off the blade of grass and tape it to a sheet of white paper. Label the paper Day 1 (Full Day) and photograph the page. Repeat this procedure every day for 10 days. You will have to document this experiment before you completely finish it, but you should have some results by that time, so just show what you currently have. Display the photographs to represent the results.
On the first day of the experiment, after the grass has received half of the light predicted for that day, remove one black strip from one blade of grass. Cut the blade of grass off at the base and tape it to a sheet of white paper. Label the paper Day 1 (Half Day) and photograph the page. At sunset on the first day, remove a second black strip from a second blade of grass. Again cut off the blade of grass and tape it to a sheet of white paper. Label the paper Day 1 (Full Day) and photograph the page. Repeat this procedure every day for 10 days. You will have to document this experiment before you completely finish it, but you should have some results by that time, so just show what you currently have. Display the photographs to represent the results.
Questions to Think About...
- What would happen if we couldn’t store energy?
- When you burned different foods in lab one, you saw what happens when the energy in a food item is essentially all released at once. What would happen if this were true of the food we ate (not the burning part), but the very quick release of energy?