Monday, November 30, 2009

Photosynthesis_Chapter 10


1.Explain a possible reason why photorespiration still exists.

A metabolic pathway that consumes oxygen and atp. Releases co2, and decreases photosynthetic output. It generally occurs on hot, dry, bright days, when stomata close and the oxygen concentration in the leaf exceeds that of co2. It occurs in the light and consumes o2, while producing co2. C3 plants do.

2. The two reactions of photosynthesis.

Light reaction : It is an noncyclic reaction, and also anabolic reaction. It requires light energy, and used in both photosynthesis 1 and 2. It converts solar energy into chemical energy. The light energy comes to the grana of the chloroplast and the energy is transferred from light to chemicals. The water is broken down into H2 and O2

Location : grana of the chloroplast

Reactants : Light, water, ADP and Pi and NADP+

Products : Oxygen, ATP and NADPH, and H+ pumps out of the membrane to create a concentration gradients.

Dark reaction : Food production. (sugar)Happens in the stroma of the chloroplast. The enzyme Rubisco !! the most important enzyme in the earth.without it, no photosynthesis, no plants, no oxygen.phosphoglycerate is another enzyme.

Products ; sugar and ADP and NADP+

Requierements : CO2 ATP NADPH

3. What are the accessory pigments?

Accessory pigments ; absorb light ebergy and transfer it to sholorophyll. Carotene the orange color, xanthopyll is the yellow color.Green light doesn’t work because the green pigments on the plant reflect the green light.!

Video on photosynthesis:

http://www.youtube.com/watch?v=hj_WKgnL6MI&feature=related

5 main facts about photosynthesis.

. Photosynthesis equation is 6 CO2(g) + 6 H2O(l) + photonsC6H12O6(aq) + 6 O2(g)

. Photosynthesis can be affected and changed by light intensity, carbon dioxide concentration, the temperature, the measure of water etc..

. Photosynthesis is a redox reaction like cellular respiration. Hydrogens are added to carbons.

. Chlorophyll is a ps pigment which locates in the chloroplast. A typical plant cell contains 10 to 100 chloroplasts.

. Rubisco is the enzyme that captures CO2 in the light and the dark reaction, it's located in the bundle sheath.

From this chapter, we learnt the main equation of ps, light and dark reactions, alternate ps forms like c3, c4, and cam plants do.