3/14

Agenda

*Plant of the day

*Discuss pigment lab

*Finish photosynthesis (go over UP 81-85)

*Factors influencing photosynthesis UP 73-76

Homework

*UP 93-76

*Quiz tomorrow on photosynthesis

*National Park presentation due 8am on 3/23

Our homework for UP 73-76 is a lab but you don't need to have been in class to do it. The idea is that there is a lamp and a plant soaking in water. You put the lamp either close to the plant, or far away. Then, you look at the bubbles coming from the water that the plant is in and if there are more bubbles, more photosynthesis is being done. If there are less bubbles, less photosynthesis is being done. We know this because oxygen is a product of photosynthesis. You are supposed to compare and contrast the amount of photosynthesis/bubbles there are when the lamp is close to the plant or far away form the plant. On page 74, the chart is: Trial 1: 50 bubbles, 27 bubbles, and 78 bubbles. Trial 2: 62 bubbles, 24 bubbles, and 84 bubbles. Mrs. Stein gave us the answers to that chart because we are not actually doing the lab. Now, you just need to find the averages and do the rest of the pages.

 

We got back our Pigment lab and UP 81-85.

Pigment lab

We discussed the pigment lab in class. We decided that just because it looks like chlorophyll is the only pigment, doesn't mean that it is. There are many other pigments in leaves that are just not visible because chlorophyll over powers them. When the weather changes, chlorophyll breaks down and the other pigments (which were always there - you just couldn't see them) begin to show through.

UP 81-85 answers:

1. The light-dependent reactions take place within the thykloid membranes.

2. The light-independent reactions are also known as the Calvin Cycle

3. The energy carriers NADPH and ATP are produced during the light-dependent reactions.

4. In the light-dependent reactions, the gas oxygen is produced.

5. High-energy sugars are produced during the light independent reactions.

6. The light independent reactions take place in the stroma.

8. If there is no light coming into the chloroplasts, how will this affect the Calvin cycle? The Calvin cycle will NOT be affected because it is light independent, it doesn't need the light.

9. What effect does weather have on the process of photosynthesis? Photosynthesis will be slowed down if there is no sun or the temperature is too cold.

10. If you place a plant in a clear, sealed box, how could you use a measurement of the gases in the boxed air to measure the rate of photosynthesis? What gas would you measure? You would measure oxygen and/or carbon dioxide because oxygen is a product of photosynthesis and carbon dioxide is used in photosynthesis. So, if there was a lot of oxygen and a little carbon dioxide, you would be able to measure the rate of photosynthesis.

**NOTES**

Plant of the Day:

Sensitive Plant (Mimosa pudica)

We learned that the plant is sensitive to touch and when you touch it, the leaves cu

rl inwards. Scientists are not sure exactly why the plant does this. It might be a defense mechanism.

Electron Carriers

*Light energy "excites" electrons in chloroplasts

Light Reaction

*Chlorophyll absorbs light, and electrons become energized

*Water splits to produce H+ and O2

*Electron lose energy to form ATP

*ATP then goes to the Calvin Cycle

*H+ and NADP form NADPH

*these carry energy to Calvin Cycle

Calvin Cycle

*CO2 is added to a 5 carbon sugar

*Energy from NADPH and ATP are used to carry out reactions

*Produces glucose

It is REALLY important to know and understand this diagram of photosynthesis! Remember:

*This diagram takes place in the chloroplast.

*The light reaction takes place in the thykloid.

*A stack of thykloids is called a granum.

*The empty space in the chloroplast is called the stroma.

The next scribe is Steven.