8.3 The Reactions of Photosynthesis

chloroplast parts

stroma, thylakoid, and granum

thylakoid

converts light energy into chemical energy

granum

a stack of thylakoids

stroma

where the calvin cycle happens

electron carriers

critical to ETS (electron transport chain), most common is NADP+

NADP+

holds 2 high-energy electrons and a hydrogen ion

NADPH

NADP+ holding 2 high-energy electrons and a hydrogen ion

inner thylakoid space

holds higher concentration of H+ ions compared to stroma

photosystem II

light energy is used to split 2 H2O into 4 H+ ions and 1 oxygen atom (byproduct) and 2 charged electrons

plastoquinone

second step of light-dependent, transports charged electrons from PSII to cytochrome

cytochrome

third step of light-dependent, pumps H+ ions from stroma to inner thylakoid space to maintain H+ gradient

plastocyanin

fourth step of light-dependent, takes depleted electrons from cytochrome to PSI

PSI

fifth step of light-dependent, recharges electrons depleted from cytochrome

after PSI

sixth step of light-dependent, NADP+ picks up electrons and H+ ions and becomes NADPH

ATP synthase

final step of light-dependent, H+ ions pass through protein, generates ATP in the process (like a turbine)

photosynthesis purpose

make ATP and NADPH for calvin cycle

calvin cycle purpose

use NADPH and ATP to make glucose

calvin cycle first step

6 co2 enter, combine with six 5-carbon, result is twelve 3-carbon

calvin cycle second step

12 ATP and 12 NADPH turn two 3-carbon molecule to make sugar and other stuff (6-carbon sugar produced), rest is recycled

calvin cycle third step

remaining 10 3-carbon molecules turned back to six 5-carbon molecules using 6 ATP

factors of photosynthesis

light, water, temperature

best color for photosynthesis to happen

blue and red range

where does light-dependent reaction happen

inside thylakoid membranes

where does calvin cycle happen

inside stroma