CH6:photosynthesis

photosynthesis

metabolic pathway using light to get carbon from CO2 and water

photoautotrophs

get energy from the sun/ photosynthesis

chemoautotrophs

get their energy from other inorganic compounds (not photosynthesis)

light dependent reactions

photosynthesis reaction that needs light to run. produces NADPH

light independent reactions

Calvin Cycle. runs on ATP and NADPH. photosynthesis reaction

chloroplast

a plastid that contains chlorophyll and in which photosynthesis takes place

thylakoids

carry out light dependent reactions, membranous disks inside chloroplasts

stroma

carry out light independent actions; fluid inside chloroplast, suspends thylakoids

endosymbiotic theory

chloroplasts come from ancient cyanobacteria

cytoplasm

where light independent reactions are carried out in prokaryotes

Theodor Engelman

discovered sunlight is the driver of photosynthesis. hypothesized light color affects photosynthesis.

Engelman's results

blue and red are best for driving photosynthesis

photon

particle of light

pigment

organic molecule that selectively absorbs light of specific wavelength

photosystem

A large complex of molecules - pigments, proteins, and cofactors embedded in thylakoid membrane

reaction center

The core of the photosystem

special pair

a pair of chlorophylls in the reaction center

photosystem I

p700

photosystem II

p680

Light Harvesting Complexes

Circular array of chlorophylls, accessory pigments, lipids, and proteins; most energy absorbed by photosystems happens here

cyclic light dependent reactions

only uses photosystem I. cyclic photophosphorylation. only produces ATP

ATP synthase

transport protein/ enzyme

electron transfer phosphorylation

any process where flow of electrons through electron transfer chain drives ATP formation

photolysis

breaking apart of molecules by light energy

reducing agent

electron donor

noncyclic light dependent reactions

main pathway in modern photosynthetic organisms. noncyclic electron transfer phosphorylation. produces ATP, NADPH, and Oxygen

strong oxidizer

can pull electrons from other molecules

free radicals

unstable atoms that can destroy cells

light independent reactions

take place in the stroma.

carbon fixation

taking carbon atoms from inorganic molecules (CO₂) to attach them to organic molecules (sugar)

sucrose

main sugar in plants

vascular tissues

veins of the plant

cuticle

thin waterproof layer covering plant. keeps plant from losing water. also keeps gases from moving in or out of the plant

stomata

controls gas exchange . tiny closable pores on a plant

rubisco

most abundant protein on earth

photorespiration

CO₂ needs rubisco for Calvin Cycle but O₂ also likes rubisco and wants to steal it from CO₂

C3 plants

fix carbon by the calvin cycle. 85% of modern plants. produces CO2 and ammonia during photorespiration

C4 plants

fix carbon twice. 3% of modern plants. minimizes photorespiration

malate

enzyme that does not use oxygen. fixes carbon

CAM Plants

fix carbon twice. stomata open at night, conserve water, desert plants. 12% of modern plants