PHOTOSYNTHESIS

Adenosine Triphosphate (ATP) Principle energy-storing compound in cells Made up of an adenosine compound with 3 phosphate groups attached When the bond that holds the last phosphate group is broken the energy is released The new compound is now called adenosine diphosphate (ADP)

Autotrophs Organisms that make their own food Also known as producers because they produce food for other organisms Ex: plants, bacteria

Heterotrophs Organisms that cannot make their own food Also known as consumers because they consume autotrophs and other heterotrophs Ex: humans, fungi

Pigments Molecules that absorb certain wavelengths of light while reflecting others Chlorophyll: a pigment in plants that absorbs red, blue, and violet light while reflecting green light

Chloroplast Structures in plant cells that contain chlorophyll Photosynthesis occurs in these structures Made up of 3 parts: Thylakoid: series of membranes that contain the photosystems Grana: stacks of thylakoids Stroma: gel-like material between the grana

Photosynthesis (photo=“light” synthesis=“to make”) The process by which autotrophs convert sunlight into energy in the form of glucose The photosynthetic reaction is: sunlight 6H2O + 6CO2 C6H12O6 + 6O2

Photosystems The reactions of the photosystems are called the light-dependent reactions because they require sunlight; they take place in the thylakoid Photosystem II: Uses the light energy from the sun to break water apart into hydrogen, oxygen and electrons; the electrons enter an electron transport chain

Photosystems (cont.) Photosystem I: picks up the electrons from the electron transport chain and uses them and the hydrogen to make ATP and NADPH (an energy carrier)

Calvin Cycle A set of reactions that uses the energy in ATP and NADPH (made in the photosystems) to convert carbon dioxide into glucose These reactions are called the light-independent reactions because they do not require sunlight; they take place in the stroma

Rate of Photosynthesis Rate is affected by: 1. Sunlight 2. Temperature 3. Carbon Dioxide As all of these increase, so does the rate of photosynthesis. They are directly proportional.

Glucose The glucose made during photosynthesis is used by the plant to provide energy for cellular functions Excess glucose is linked together to form starch which can then be stored by the plant