Leaf chromatography lab independent variable

Compose answers to the questions below and save the file as a backup copy in the event that a technical problem is encountered while attempting to submit the assignment. Make sure to run a spell check.

You will be submitting your answers to the lab assignment in two parts. The first part of the lab assignment consists of the laboratory exercise questions. The second part of the lab assignment is the application question. The first textbox on the submission page corresponds to the first part of the lab. Be sure to paste the laboratory exercise questions, with your answers, into this textbox. The second textbox on the submission page will be for your response to the application question.

LABORATORY EXERCISE QUESTIONS

~~1.

a. What is the name of the pigment that captures light directly in photosynthesis? (2 points)

b. Why does the pigment appear green? (2 points)

~~2. List two variables besides the wavelength (color) of light which might affect the rate of food production in plants. (4 points)

a.

b.

~~3. Why is chlorophyll important for all biological life? (5 points)

~~4.

a. In Part I of the procedure, what is the name of the indicator used to identify the presence of CO2? (2 points)

b. What color did the indicator turn after blowing air into the water through the straw? (2 points)

~~5.

a. What color did the indicator turn after the tube was placed under a light source for 30 minutes? (2 points)

b. Why did this occur? (3 points)

~~6. List the functions of these four common pigments found in plants. (4 points)

a. Chlorophyll a

b. Chlorophyll b

c. Xanthophyll

d. Carotene

~~7. If the Rf factor of a pigment is .3750 and the distance that the solvent traveled is 8 cm, how far did the pigment travel? (5 points)

~~8. List the Rf values for each of the pigments extracted from the spinach leaves, as seen in the chromatography procedure (4 points).

a. Carotene

b. Xanthophyll

c. Chlorophyll a

d. Chlorophyll b

~~9. Based on the results, which pigment has the highest molecular weight? (5 points)

~~10. From the chromatography lab, which pigments were soluble in the acetone? (5 points)

~~11. The earth's early atmosphere did not contain oxygen. This changed dramatically once the early cells underwent photosynthesis.

a. Explain how photosynthesis was able to occur in earth’s early atmosphere. (5 points)

b. How did photosynthesis eventually affect the evolution of other organisms? (5 points)

~~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)? (5 points)

b. Explain how you came to this conclusion? (5 points)

**INFORMATION NEEDED TO COMPLETE THE FOLLOWING PROBLEMS**

Independent Variable: This is the cause.

Dependent Variable: This is the response or effect.

One hundred samples of several different plants were placed in each of six sealed containers with water in them. At the end of two days the amount of oxygen produced was measured. Results are shown in the table below.

Container

Plant

Height of Plant

Light Intensity

Source of Light

Distance from Light

mL O2 Produced

1

Iris

4"

High

Artificial

6"

16

2

Iris

4"

High

Natural

6"

13

3

Iris

6"

Low

Artificial

5"

12

4

Carnation

6"

High

Natural

4"

13

5

Carnation

6"

Low

Natural

4"

9

6

Carnation

4"

Low

Artificial

5"

14

~~13. Multiple Choice: 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? (5 points)

a. 1 and 2

b. 2 and 3

c. 1 and 5

d. 5 and 6

e. 4 and 5

~~14. Multiple Choice: Compare Containers 1 and 2. What independent variable is tested by this comparison? (5 points)

a. Kind of plant

b. Height of plant

c. Light intensity

d. Distance from light source

e. Light source

~~15. Multiple Choice: Which container had the slowest rate of photosynthesis? (5 points)

a. 1

b. 2

c. 3

d. 4

e. 5

f. 6

APPLICATION QUESTION

~~16. (Application) How might the information gained from this lab pertaining to photosynthesis and pigments be useful to you, or how can you apply this knowledge to your everyday life as a non-scientist? The application will be graded according to the rubric below. (20 points)