Chap. 6Chap. 6

LecLec

(Photo=light & (Photo=light & SynthesisSynthesis = put = put together) together)

I.I. Energy Formation:Energy Formation:

A. Autotroph v. Heterotroph

1. examples:

B. Photosynthesis is a process of capturing & transforming light energy into chemical energy in the form of carbohydrates.

1. main pathway for carbon & energy

2. Energy stored in ATP molecules.

light energy

12 H2O + 6CO2 6O2 + C6H12O6 + 6H2O

II. Photosynthesis Part 1

A. Light dependent reaction

1.Photons: packets of energy

travel in wavelengths

2. Wavelengths: distance traveled

a. short : high energy (violet)

b. long: low energy (red)

B. Electromagnetic Spectrum: represents full range of light energies & wavelengths.

ROYGBIV

1. sunlight: mixture of all visible wavelengths. All colors reflected evenly.

Electromagnetic Spectrum:

2. Reflection v. Absorption

a. photons not absorbed are reflected.

example:

Black object:

absorbs: ROYGBIV

reflects: none

White object:

absorbs: none

reflects: ROYGBIV

Absorption Spectrum for chlorophyll a and b

C. Photosynthetic Pigments:

1. Pigment: photosynthetic substance that absorbs photons.

a. chlorophyllchlorophyll=main pigment

appears green

2. Pigment types:

main

a. Chlorophyll a: green

absorbs mainly red & violet

accessory pigments

b. Chlorophyll b: green-yellow

c. Carotenes: brown-orange-yellow

d. Xanthophylls: yellow-brown-purple-blue

e. Phycobilins: red-blue-green

f. Anthocyanin: red-purple

III. Photosynthesis in the Chloroplast:

A. Significance of plants/Photosynthesis

1. Basis of food chain

2. Clothing/Cosmetics/Industrial

3. Prevention of CO2 from entering atmosphere.

4. Lead to evolution of larger

organisms.

5. Biodiversity