Photosynthesis III

Question 1

What is the purpose of Photosynthesis III lab?

Answer 1

-To study the effect of light quantity on the rate of oxygen production by chlorella

Question 2

What is Chlorella?

Answer 2

• Member of phylum Chlorophyta

- It’s an aquatic photosynthetic unicellular organism

Question 3

What is the Independent variable?

Answer 3

-Light quanity= measured as PFR (photon fluence rate)= units of micromoles of photons per square meter per second

Question 4

What is the Dependent variable?

Answer 4

-Rate of oxygen gas production

Question 5

What is the relationship between oxygen gas production & PFR?

Answer 5

• They’re directly proportional

- The closer the chlorella is to the light, the rate of oxygen production increases

Question 6

How many photons are in a Micromole?

Answer 6

6.023E17 Photons

Question 7

How did we calculate oxygen production rate?

Answer 7

-Difference in voltage over time

Question 8

How tool did we use to measure oxygen production?

Answer 8

-A small probe in the tube

Question 9

What is the relationship between mV and time when it is dark?

Answer 9

-The slope will be negative because oxygen is being used for respiration

Question 10

What is the relationship between mV and time when there’s light energy?

Answer 10

-The slope will be positive because light triggers photosynthesis= water oxidation

Question 11

What role does voltage play in measuring water oxidation?

Answer 11

• It corresponds to specific oxygen concentration

- We got the 8.3 value in the table from stirred water & making it saturated w/ oxygen

Question 12

How did we get the 0 value in the table for Dissolved oxygen concentration?

Answer 12

-By adding the Sodium Sulfite & Cobalt catalyst

Question 13

What was the purpose of adding Sodium Sulfite & Cobalt Chloride to the distilled water in the oxygen chamber?

Answer 13

-Removal of dissolved oxygen from water in oxygen chamber