I. Photosynthesis - autotrophs (vocabulary) that can synthesize organic nutrients from inorganic materials with the use of sunlight (phototrophs)

A. Van Helmut - in 1600's, water is needed for plant survival
B. Priestley - in 1700's, plants convert Carbon Dioxide to Oxygen
C. Lavoisier - living things need oxygen to survive
D. Mayer - plants convert light energy to chemical energy

II. Photosynthetic Pigments- 'Chloroplasts' the organelle responsible for photosynthesis

A. Pigment - a substance that absorbs light of a particular wavelength

B. Chlorophyll - green pigment, absorbs blue region and red region and reflects the green-yellow range of the absorption spectrum

1. Chlorophyll a
2. Chlorophyll b

a. Accessory Pigments, capture light energy which is transferred to chloropyll a. carotenes, xanthophylls, & chlorophylls are embedded in the thylakoid membranes.

1. Carotenes - orange pigments
2. Xanthophylls - yellow pigment

III. Photosynthetic Membranes - chloroplasts

A. grana - membranes are folded and stacked of thylakoids

IV. Chemistry of Photosynthesis

A. Exact opposite of respiration

6 CO2 + 6 H2O + energy ------> C6H12O6 + 6 O2 + 6 H2O

B. Photosynthesis occurs in two stages

1. Light Reaction- light is absorbed by chlorophyll (in the thylakoid stacks)

a) oxidation of water
b) formation of ATP
c) reduction of NADP (H carrier) - to NADPH2
d) production of Oxygen occurs in this phase of photosynthesis

2. Dark Reaction or Carbon Fixation or Calvin Cycle - does not require light (occurs in the stroma)

a) CO2 is converted to carbohydrates
b) need the ATP and NADPH2 produced by light reaction
c) CO2 from the environment is reacted with ATP and NADPH2 from the light reactions to produce the 3-carbon compound PGAL. Glucose, as well as other nutrients, can be synthesized from PGAL.
d) Earth's biosphere receives most of its energy through photosynthesis. Some botonists estimate 150 billion tons of sugar are produced yearly by plants. Botanical Gardens

3. Factors affecting the rate of photosynthesis

a) Temperature - up to a certain point, photosynthesis increases with temperature increase
b) Light intensity - similar to increasing temperature
c)CO2 level - 0.03 % in air, similar to increasing temperature
d) H2O - a decrease in water decreases photosynthesis
e) Minerals - Mg, N2 - important in formation of chlorophyll

VI. Heterotrophic Plant - in addition to photosynthesis

A. Mistletoe- parasitic on oaks, siphons sap from vascular tissue of host tree
B. Dodder plant- does not photosynthesize, also parasitic, grows on roots of trees

VII. Insect-eating Plants - supplements their nutrition from photosynthesis

A. Pitcher Plants
B. Venus Flytrap
C. Sundew- is common in the northeast. Its leaves are covered with hairlike tentacles which contains a drop of sticky fluid containing digestive enzymes. Insects attracted to the fluid are caught in it and are digested.

VIII. Bacterial Photosynthesis

A. Lack chloroplasts but has chlorophyll throughout the cell
B. Bacteteriochlorophyll
C. H2S is the source of H, not H2O as in green plants

6 CO2 + 12 H2S yields C6H12O6 + 12 S

IX. Chemosynthesis- is the form of autotrophic organism in which energy comes from the oxidation of inorganic substances & not from sunlight

A. Chemotrophs- bacteria that use chemosynthesis

1. live in dark places (caves, bottom of oceans)

B. Help recycle materials in the environment

X. Both Respiration and Photosynthesis occur in plants. Don't forget this fact!!!

	Photosynthesis	Respiration
Function	energy storage	energy release
Location	chloroplasts	mitochondria
Reactants	CO2 , H2O	C6H12O6
Products	C6H12O6	CO2 , H2O
Equation	6 CO2 + 6 H2O + light energy ------> C6H12O6 + 6 O2 + 6 H2O	C6H12O6 + 6 O2 + 6H2O ------> 6 CO2 + 6 H2O + chemical energy