A group of students wants to study the rate of photosynthesis under various conditions. They use a blender to mechanically disrupt the thylakoid membranes of chloroplasts from an algae sample The liquid mixture is added to test-tubes, and 5 drops of DPIP solution is added to each tube. One set of tubes is placed in direct sunlight, another is placed in indirect sunlight, and a third is placed under an infrared heat
lamp. One test-tube contains only water and 5 drops of DPIP (control). The students check the color of the liquid in the tubes every 15 minutes for a period of 1 hour. They record their observations in a table
Table of Observations
Time (min) Direct Sunlight
Indirect Sunlight
0
Dark Blue
Dark Blue
15
Lighter
Slightly Lighter
30
Lighter
Lighter
45
Nearly colorless
Lighter
60
Clear colorless
Nearly colorless
Which of the statements is the BEST explanation for their results?
Infrared Lamp
Dark Blue
No Change
Slightly Lighter
Slightly Lighter
Slightly Lighter
Control
Dark Blue
Dark Blue
Dark Blue
Dark Blue
Dark Blue
А
The rate of photosynthesis under indirect sunlight is slower than in infrared light
B
The rate of photosynthesis is greatest for direct sunlight and least for the infrared light.
С
The rate of photosynthesis cannot be determined because the infrared lamp degraded the DPIP
D
The rate of photosynthesis cannot be determined because exposure to direct sunlight degraded the DPIP