Monday, August 16, 2010

Simple Explanation of Photosynthesis(components)

1.Photosynthetic pigments

Photosynthetic pigments include chlorophylls, carotenoids and xanthophylls. These pigments are each sensitive to a particular range of light wavelengths.

2.Chloroplasts

Eukaryotic cells perform photosynthesis in a specialized, double-membraned structure called the chloroplast. The chloroplast contains a stacked series of membranes known as the thykaloid. Stack of thykaloids are called grana with the intermembrane space between thykaloids called the stroma.


3.Light Dependent Reactions

When light strikes photosensitive pigments such as chlorophyll, the electrons enter a high energy state. Through a series of electron transports, the energy from these excited electrons is utilized to create adenosine triphosphate (ATP) and nicotine adenine dinucleotide phosphate (NADPH). This process is known as photophosphorylation and occurs in the grana.


4.Light Independent Reactions

The high energy bonds produced during the light dependent reactions are used to create carbon-carbon bonds from carbon dioxide. This process, sometimes referred to as the Calvin Cycle, involves a multi-step series of enzymatic reactions to create a glucose sugar molecule from the addition of the carbon from a carbon dioxide molecule to a starter molecule called ribulose bisphosphate.

2 comments:

  1. Better theory : Eukaryotic cells is an organism whose cells contain complex structures enclosed within membranes. The defining membrane-bound structure that sets eukaryotic cells apart from prokaryotic cells is the nucleus, or nuclear envelope, within which the genetic material is carried.Most eukaryotic cells also contain other membrane-bound organelles such as mitochondria, chloroplast apparatus. Almost all species of large organisms are eukaryotes, including animals, plants and fungi, although most species of eukaryotic protists are microorganisms.

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  2. Additional information on photosynthesis:
    1.Light energy is absorbed by chlorophyll and the accessory pigments in the plant leaves ,and the energy is transferred to reaction center chlorophylls.
    2.The electrons form reaction center chlorophylls are excited and move to outer orbitals.
    3.Proteins in the electron transport chain pull the electrons form chlorophyll and pass them along the chain of proteins.
    4.Chemiosmosis is used to make ATP.
    5.The electrons are accepted at the end of the chain by the electron carrier NADO+.
    6.As light energy is absorbed by chlorophyll ,some light energy is used to spilt water molecules by photolysis into protons electrons and oxygen gas .
    The electrons are transferred to chlorophyll to replace the electrons lost to the electrons transport chain. The protons are released into the plant cell. The oxygen is released to the cell and then the atmosphere as a waste product of photosynthesis.

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