In what part of the chloroplast do these particular stages occur?
The trapping of light and conversion of light energy to chemical energy occurs in the thylakoid membrane (the discs that make up the granum). This occurs during the light reaction (the chlorophyll that harnesses light energy is only located in photosystems embedded in the thylakoid membrane). The storage of chemical energy in glucose molecules occurs in the Calvin Cycle. The Calvin Cycle takes place in the stroma (fluid part of the chloroplast), not the granum. It is in this stage that carbon dioxide comes into play and becomes fixed (combined) into sugar molecules, using the chemical energy from molecules formed during the light reactions.
Do plants need chlorophyll to make starch?
chlorophyll is needed in the process of photosynthesis. during the photosynthesis oxigen and glucose are produced. when glucose has to be transported from the leaves to the other parts of plants body it is changed into saccharose (sucrose). when it reaches for example roots and other parts it is transformed into starch. so it is obvious that in the soil there is no sunlight and in the roots there is no chlorophyll, but the process takes place. chlorophyll and sunlight are not needed.
Why are light and chlorophyll needed for photosynthesis ?
In the light stages of photosynthesis basically there are two reaction centres which contain chlorophyll and other pigments, called Photosystem I and photosystem II, which receive energy in the form of light and as a result electrons are displaced from the chlorophyll to a higher level and as they fall back to their original level the energy released is used to make ATP and NADPH which are both used in the Calvin Cycle (dark stage) to fix CO2. For a fully detailed explanation of the light stage - see link
Describe what happens when sunlight strikes chlorophyll. ?
1.Plants absorb light primarily using the pigment chlorophyll, which is the reason that most plants have a green color.this process is called photosynthesis. 2.It looses some of its energy as the orbits it has to occupy in each successive carrier molecule are at progressively lower energy levels. 3.http://en.wikipedia.org/wiki/Dioxygen_in... 4/5.http://www.biologie.uni-hamburg.de/b-onl... 6.http://en.wikipedia.org/wiki/Light-indep... http://en.wikipedia.org/wiki/C4_carbon_fixation 7.ATP and NADPH (formed in the light stage) are the source of energy to convert PGA to PGAL.The light energy is converted to chemical energy using the light-dependent reactions. The products of the light dependent reactions are ATP from photophosphorylation and NADPH from photoreduction. Both are then utilized as an energy source for the light-independent reactions. http://www.solarnavigator.net/photosynthesis.htm 8.The delivery of electrons to a final product (NADPH*) is an important energy storage step. Here, electrical energy is transduced to chemical energy Once electrons are used, they have to be replaced. In plants, replacement electrons to continue the process come from water. In this case, chemical energy is transduced to electrical energy. This is a very difficult reaction and evolution of water splitting capacity was a BIG evolutionary event. Besides electrons, oxygen and protons are released when water splits. ATP production (*) is another energy storing step. It uses energy temporarily stored with the protons.
Does photosynthesis take place in the dark? explain?
I agree with most of them: photosynthesis cannot take place in the dark because it needs sunlight to convert CO2 and H2O into glucose. The plant won't die for a few days if kept in the dark because it has nutrients stored throughout the plant, but after a while the plant will die because it will soon run out of food.