Question

conduct a experimental design on the question that how does the amount of carbon dioxide impact the rate of photosynthe

Answer 1

Photosynthesis is the process by which autotrophs synthesize sugars from carbon dioxide and water. Chlorophyll pigments present in most photosynthetic organisms harvest light energy from the sun. This energy is used to excite electrons to carry out photosynthesis. Photosynthesis involves light reactions and the Calvin cycle. Effect of carbon dioxide concentration on rate of photosynthesis can be measured in an organism by calculating amount of substrate utilized or amount of product formed. Sunken leaf disk will float to the surface when oxygen is produced after photosynthesis. Depending on the amount of oxygen produced, the time taken by the disk to float will vary.

Hypothesis: Rate of photosynthesis will increase as the concentration of carbon dioxide increases.

Experimental design:

Requirement:

Sodium bicarbonate

Distilled water

Beakers

Spinach leaves

Hole Puncher

Syringes

B) Preparation of Carbon Dioxide Solutions:

1. 0%, 0.5%, 1.0%, 2.0% and 3% CO2 solution are prepared in water in beakers. (You could use other concentrations too). Sodium bicarbonate can be used as it form carbon dioxide in water.

0% = 100 ml distilled water

0.5%= 05 gm of sodium bicarbonate in 100 ml distilled water

1%= 1 gm of sodium bicarbonate in 100 ml distilled water

2%= 2 gm of sodium bicarbonate in 100 ml distilled water

3%= 3 gm of sodium bicarbonate in 100 ml distilled water

B) Floating Disk Method:

1. Holes are punched in spinach leaf by a hole puncher. Extra air in these disks are removed from the disks by using a syringe to create a vacuum. In each beaker with the sodium bicarbonate solution, a drop of dish soap is added and covered. The dish soap will act as a surfactant and allow the solution to be drawn on surface of the leaf disks, which is hydrophobic.

              

2. Equal number of leaf disks are placed in the beaker. The beaker is covered with aluminum foil and place in front of light source. This will prevent photosynthesis from occurring after the leaf disk before the lamp is set. The light source used is a lamp.

3. Each aluminum-covered beaker is placed at an equal distance from the lamp, so that each beaker get equal amount of light intensity. The aluminum foil is removed and the timer set. Number of disk that are floating are recorded after every minute, till all disks are found floating.

4. The data is collected, analyzed, and conclusions formulated.

Expected results: As the concentration of the carbon dioxide, it is expected that the disks should float faster. At the highest concentration of 3%, all the disks should float fastest (maybe within 1 min). At 0% concentration, no disks should float.

Possible errors:

1. Tapping of disks that are stuck on side of tube can lead to error.

2. There was a gap between opening of the aluminum foil and the start of measurement.