+
Related Flashcards
Related Topics
Cards In This Set
| Front | Back |
|
How is water oxidized?
|
When photosystem 2 absorbs light energy its able (with the help of manganese atoms and proteins) to remove electrons from water
|
|
What does the oxidation of water yield?
|
Protons and Oxygen gas
H2O-> 4e-+ 4H+ +O2 |
|
What do the electrons liberatted from water do?
|
They are energized by light and eventually are used to reduce CO2 to produce energy-rich molecules, like glucose
|
|
What role does oxygen play in photosynthesis?
|
None, but is vital in cellular respiration
|
|
What role do the protons from the oxidized water play in photosynthesis?
|
They play an improtant part in the production of ATP by chloroplasts
|
|
ATP is used in what?
|
ATP is used in the Clavin-Benson cycle to help make glucose
|
|
In this lab, what are we meausuring?
|
The effect of light quanitity on the rate of oxygen production by an alga called chlorella
|
|
What is chlorellla
|
Its an unicellular aquatic photosynthetic organism from the phylum chlorophyta
|
|
What is the independent variable?
|
Light quantity measures as PFR (Photon Fluence Rate) (micromoles of photons/(m2 /s)
placing chlorellla culture at various predetermined distances from a light source mole_photons=6.023e23 photons (avagadros #) micromole_photons=6.023e17 photons |
|
What measures PFR?
|
A quantum sensor,
the device produces a voltage that is proportional to the dissolved oxygen concentration. The difference in voltage/time=oxygen production rate |
|
What is the dependent variable?
|
The rate at which chlorella produces oxygen
|
|
The first calibration point represents what?
|
Water that contains no dissolved oxygen (deoxidize water with sodium sulfite and a cobalt catalyst)
reaction takes about 100s Na2SO3+O2-> NA2SO4 |
|
What does the second calibration point represent?
|
Water that is saturated with atmospheric oxygen
stir atmospheric oxygen with water for 20min, take not of voltage which is equivilant to a dissolved oxygen concentration of 8.3mg/L Assumes atmospheric pressure is 760 torr and temp in 25C |
|
How do we calculate the relationship between the volatage ang the amount of oxygen dissolved in the water?
|
Since we know that the dissolved oxygen concentration is with the atmospheric oxygen dissolved in it (8.3 mg?L) we use the oxygen probe to measure the voltage (which we got as 104mV), so that tells us that 1mV=(8.3mg/L)/(104)=.08mg/L of dissolved oxygen in the test tube.
also wait 100 s for it to stabalize when reading it |
|
When callibrating what should the gain control be set at?
|
One position beyond mid
|
