Lab 5

A. What is the name of the pigment that captures light?
Chlorophyll

B. Why does the pigment appear green?
It absorbs other colors of light such as red and blue, so in a way the green light is reflected out since the pigment does not absorb it.

2. List two variables besides the wavelength (color) of light which might affect the rate of food production in plants.
Light intensity and carbon dioxide

3. Why is chlorophyll important for all biological life?
It is necessary for photosynthesis which creates food for plants which is food for animals.

4. A. In Part I of the procedure, what is the name of the indicator used to identify the presence of CO2? Phenol Red
4. B. What color did the indicator turn after blowing air into the water through the straw? Yellow
5. A. What color did the indicator turn after the tube was placed under a light source for 30 minutes? Light red
5. B. Why did this occur? Because the light, water, and CO2 were creating photosynthesis. 6. List the four common pigments found in plants and their functions.
1. Anthocyanin is red or purple and helps protect the plant from ultraviolet damage.
2. Chlorophyll a absorbs mainly blue violet and red light. It participates directly in the light reactions.
3. Chlorophyll b absorbs mainly blue and orange light. It broadens the range of light that a plant can use by conveying absorbed energy into chlorophyll a which then puts the energy to work in light spectrums.
4. Carotenoids or carotene absorb mainly blue green light. Some pass energy to chlorophyll a others have a protective function. They absorb and dissipate excessive light energy that would otherwise damage chlorophyll.
7. If the Rf factor of a pigment is .8400 and the distance that the solvent traveled is 12 cm, how far did the pigment travel? 10.08cm
8. List the pigments extracted from the spinach leaves and their corresponding Rf values, from lowest to highest Rf value
1. Xanthophyll 0.3500
2. Chlorophyll b 0.5000
3. Chlorophyll a 0.6000
4. Carotene 0.9500

9. Based on the results, which pigment has the highest molecular weight? Chlorophyll b

10. from the chromatography lab, which pigments were soluble in the acetone? Carotene 11. The earth's early atmosphere did not contain oxygen. This changed dramatically once the early cells underwent photosynthesis. Explain why photosynthesis could have occurred in such an atmosphere and how it eventually affected the evolution of other organisms.

Photosynthesis does not require oxygen. It produces it from carbon dioxide. Organisms like blue-green algae fed off atmospheric carbon dioxide and converted much of it into marine sediments consisting of the shells of sea creatures. Oxygen produced did not build up in the atmosphere. Once oxygen had been produced, ultraviolet light split the molecules, producing the ozone UV shield. Only at this point did life move out of the oceans and respiration evolved.

12. A. In reviewing the data from the floating disk experiment, which factor had a greater impact on the rate of photosynthesis (light intensity or concentration of carbon dioxide)?

Light intensity

B. How did the student come to this conclusion?

Because the disks stayed afloat longer in the light.

13. Based on the data presented in the table, which two containers could be correctly used to compare the rate of photosynthesis at two different light intensities?
e. 4 and 5

14. Compare Containers 1 and 2. What independent variable is tested by this comparison? e. Light source
15. Which container had the slowest rate of photosynthesis? e. 5
16. How might the information gained from this lab pertaining to photosynthesis and pigments be useful to the student or how can the student apply this knowledge to everyday life as a non-scientist?

The information gained from this lab pertaining to photosynthesis and pigments really made me stop and think about my carbon footprint and the consequences of our daily actions. Without photosynthesis plants would not have food and if there were no plants then humans would not have food and life as we know it would cease to exist. We also need plants to create the air that we breathe. Most of the energy we use to power our lives comes from fossil fuels, whose energy was harnessed from the sun by photosynthesis. All things living depend on each other in some way or another. Because of the information that I gained I can be more mindful of to not waste energy or take common things like air for granted.