Does any body have all the answers to Ward's AP Biology Lab # 4 Plant Pigment and photosynthesis?

1. which pigment migrated the farthest? why?





2.During summer, leaves are generally bright green. What would you hypothesize that this indicates about the role of green light wavelengths, chlorophyll, and the photosynthetic process





3.Design an experiment to test your hypothesis from the question above. Describe your experiment or draw a picture of your experimental setup.





4.Why do leaves change color during autumn?





5.What is the function of the chlorophylls in photosynthesis?





6.What are the accessory pigments and what are their functions?





7. Research another form of chromatography and describe it.





8.What does Rf value represent? If you were to perform your experiment on chromatography strip twice t he length, would your are Rf be the same?





10. What is the absorption spectrum?





11.In what way is the spectrophotometer used to measure the rate of photosynthesis?

Does any body have all the answers to Ward's AP Biology Lab # 4 Plant Pigment and photosynthesis?
All during spring and summer the leaves have served as factories where most of the food necessary for the trees’ growth are manufactured. This food-making process takes place in the leaf in numerous cells containing the pigment chlorophyll, which gives the leaf its green color. This chlorophyll absorbs energy from sunlight and uses in in transforming carbon dioxide and water to carbohydrates, such as sugars and starch. Along with the green pigment leaves also contain yellow or orange arytenoids--which, for example, give the carrot its familiar color. Most of the year these yellowish colors are masked by the greater amount of green coloring. But in the fall, partly because of changes in the period of daylight and changes in temperature, the leaves stop their food-making process. The chlorophyll breaks down, the green color disappears, and the yellowish colors become visible and give the leaves part of their fall splendor.





At the same time other chemical changes may occur and cause the formation of additional pigments that vary from yellow to red to blue. Some of them give rise to reddish and purplish fall colors of leaves of trees such as dogwoods and sumacs. Others give the sugar maple its brilliant orange or fiery red and yellow. The autumn foliage of some trees, such as quaking aspen , birch and hickory, shows only yellow colors. Many oaks and others are mostly brownish, while beech turns golden bronze. These colors are due to the mixing of varying amounts of the chlorophyll and other pigments in the leaf during the fall season.





Fall weather conditions favoring formation of brilliant red autumn color are warm sunny days followed by cool nights with temperatures below 45 degrees F. Much sugar is made in the leaves during the daytime, but cool nights prevent movement of the sugar from the leaves. From the sugars trapped in the leaves the red pigment called anthocyanin is formed. Familiar trees with red or scarlet leaves in autumn are red maple, silver maple, flowering dogwood, sweetgum, black tupelo or blackgum, Northern red oak, scarlet oak, and sassafras.





The degree of color may vary from tree to tree. For example, leaves directly exposed to the sun may turn red, while those on the shady side of the same tree or on other trees in the shade may be yellow. The foliage of some tree species just turns dull brown from death and decay and never shows bright colors.





Also, the colors on the same tree may vary from year to year, depending on the combination of weather conditions. Where there is much warm, cloudy, rainy weather in the fall, the leaves may have less red coloration. The smaller amount of sugar made in the reduced sunlight moves out of the leaves during the warm nights. Thus, no excess sugar remains in the leaves to form the pigments.

plant tables