Chapter 8 Notes

Photosynthesis

 

Photosynthesis: The energy from sunlight is used to convert water and carbon dioxide into high-energy carbohydrates (sugars and starches) and produce oxygen as a waste product.

                                      energy

Equation: 6CO2 + 6H2O C6H12O6 + 6O2

 

Reactants: Carbon Dioxide, Water, and Sunlight

 

Products: Glucose and Oxygen

 

Photosynthetic Organisms = Autotrophs Plants, some protists such as algae and euglena, and some bacteria.

 

      Plants gather the suns energy with light absorbing pigments called chlorophyll.

      Chlorophyll absorbs red and blue light but reflects green light.  This is why plants appear green.

      Chlorophyll is located inside the chloroplast of the cell. 

      Chloroplast is an organelle only in plant cells.

There are 2 basic reactions that occur in photosynthesis:

 

1.            The light-dependent reaction.

2.            The light-independent reaction called the Calvin Cycle.

 

Light-dependent reaction:

 

      The chlorophyll in the chloroplast absorbs the suns energy and converts ADP to ATP.

       Water splits to produces oxygen gas as waste and converts NADP+ into the  hydrogen carrier NADPH.

 

Light-independent reaction (Calvin Cycle):

 

      Light is not required.

    Uses the ATP and NADPH produced from the light-dependent reactions and carbon dioxide from the air to produce high energy sugars (glucose).

      Plants use the sugars made during the Calvin Cycle to meet its energy needs and to build more complex macromolecules such as cellulose that it needs for growth and development. 

 

      When heterotrophs eat plants they can also use the energy stored in these carbohydrates.

 

Draw a picture: