Photosynthesis

conversion of light energy to chemical energy stored in glucose

Photoautotrophs

organisms that use light energy to produce glucose

Redox reaction

reaction where water is oxidized and carbon dioxide is reduced

Water oxidation

water loses electrons and hydrogen to form oxygen

Carbon dioxide reduction

carbon dioxide gains electrons and hydrogen to form glucose

Visible light spectrum

range of 380 nm to 750 nm used for photosynthesis

Wavelength energy rule

shorter wavelengths have more energy and longer wavelengths have less energy

Pigments

molecules that absorb some wavelengths of light and reflect others

White pigments

pigments that reflect all wavelengths and absorb none

Black pigments

pigments that absorb all wavelengths and reflect none

Chlorophylls

primary green pigments that reflect green and absorb red and blue

Carotenoids

accessory pigments that reflect red orange and yellow and absorb green and blue

Mesophyll cells

photosynthetic cells in the middle of a leaf

Palisade layer

upper compact layer of mesophyll cells

Spongy layer

lower loosely packed mesophyll layer

Stomata

pores in the lower epidermis that allow CO2 in and O2 out

Guard cells

cells that regulate the opening and closing of stomata

Epidermis

single cell layer covering the top and bottom of a leaf

Cuticle

waxy layer that prevents water loss

Chloroplast envelope

double membrane covering of the chloroplast

Thylakoid disks

pigment covered disks where light reactions occur

Granum

stack of thylakoid disks

Stroma

energy rich fluid of the chloroplast

Light reactions

first stage of photosynthesis requiring light

Photosystem

group of pigment molecules that trap specific wavelengths of light

Photosystem II

photosystem with reaction center P680 that splits water

P680

reaction center of Photosystem II absorbing 680 nm light

Photolysis

splitting of water into oxygen hydrogen ions and electrons

Electron transport chain

series of proteins that de energize electrons to make ATP

ATP synthase

enzyme that produces ATP using hydrogen ion flow

Photosystem I

photosystem with reaction center P700 that re energizes electrons

P700

reaction center of Photosystem I absorbing 700 nm light

NADPH

electron carrier produced at the end of Photosystem I

Dark reactions

second stage of photosynthesis that does not require light

Calvin Cycle

cycle in the stroma that uses CO2 ATP and NADPH to make glucose

Carbon fixation

attachment of CO2 to RuBP by rubisco

RuBP

five carbon molecule that binds CO2 in the Calvin Cycle

Rubisco

enzyme that attaches CO2 to RuBP

3PGA

three carbon molecules formed after CO2 fixation

G3P

three carbon sugar produced in the Calvin Cycle

Regeneration phase

stage where G3P is used to regenerate RuBP

Glucose formation

two G3P molecules combine to form glucose