3.21 Discussion: Factors Affecting Transpiration

In this threaded discussion, you will draw on the data from your lab. You will post answers and comments to the following questions:

1 Describe how you conducted your experiment, and explain how you reached your conclusion.

2 Evaluate your investigation, and describe some ways that you could modify your investigation.

3 Respond to your classmates' experimental designs and conclusions. Do they support their conclusions with evidence?

4 How do the results of these experiments support the claim that feedback mechanisms maintain homeostasis?

Answer these questions in the introduction of your Lab Report:

1. What is starch?

2. What are chemical indicators and what are they used for?

3. Which indicator is used to test for starch?

4. How can you use it to test for starch?

5. What was the purpose of your experiment?

6. Answer these questions in the discussion and conclusion of your Lab Report:

7. Which food samples contained starch and what evidence supports your claim?

8. What did you use for controls in your experiment?

9. What are some sources of error in your experiment?

10. How could you modify this experiment?

Describe the Meselson-Stahl experiment. Include their hypotheses, experimental design, results, and conclusions.

Answer these questions in the introduction of your Lab Report:

1. What is surface area?

2. What is volume?

3. How does the surface area-to-volume ratio of a small cell compare to that of a large cell?

4. Why is the relationship between surface area and volume central to many cellular processes?

5. What was the purpose of your experiment?

6. Answer these questions in the discussion and conclusion of your Lab Report:

7. What do the results of the agar blocks indicate about the relationship between cell size and diffusion rate?

8. What do the results of the agar blocks indicate about the relationship between cell size and time for materials to reach the center of the cell?

9. How does being small help cells survive?

10. Include an explanation of how the surface area-to-volume ratio, diffusion rate, and time for substances to reach the center are related. Support your explanation with data.

11. How does being made of many cells help large organisms maintain homeostasis?

12. Explain how you designed your cell, citing observations from your experiment. Be sure to include a description of how you considered the surface area-to-volume ratio.