chapter 6 bio

accessory pigment

pigment that absorbs light energy and transfers energy to cholorphyll a in photosynthesis

adenosine diphosphate (ADP)

substance involved in energy metabolism formed by breakdown of adenosine triphosphate

atp synthase

enzyme that catalyzes the synthesis of ATP from ADP and phosphate

biochemical pathway

series of chemical reations in which the product of one reactions is consumed in next reaction

carotenoid

light absorbing compound that functions as an accessory pigment in photosynthesis

chemiosmosis

process in chloroplasts and mitochondria in which movement of protons down concentrations gradient across a membrane is coupled to the synthesis of ATP

chlorophyll

class of light absorbing pigments used in photosynthesis

electron transport chain

molecules in the thylakoid membrane or linner mitochondria membrane that uses some of the energy in electrons to pump protons across the membrane

granum

stack of thylakoids in chloroplast

light reactions

initial reactions in photosynthesis, including the absorbtion of light by photosystems I and II, passage of electrons along electron transport chain, and the production of HADPH and oxygen 2, synthesis of ATP through chemiosmosis

NADP+ (nicotinamide udenine dinucleotide phosphate)

organis molecule that accepts electrons during redox reactions

photosynthesis

conversion of light energy into chemical energy stored in organic compounds

photosystem

in plants: a unit of several hundred chlorophyll molecules and carotenoid pigment molecules in the thylakoid membrane

photosystem I

light energy forces electrons to enter higher energy level in the 2 chlorophyll a molecules

photosystem II

excited electrons have enough energy to leave chlorophyll a

pigment

in plants, a compound that absorbs light and imparts color

primary electron acceptor

moleecule in thylakoid membrane that accepts electrons that chlorophyll a loses in light reactions

stroma

in plants, the solution that surrounds thylakoid's in chloroplast

visible spectrum

portion of sunlight percieved by human eye as various colors

wavelength

difference between crests in a wave

C3 plant

plant species that fix carbon exclusively

C4 pathway

alternative pathway that enables plants to fix co2 into four carbon compounds

calvin cycle

biochemical pathway of photosynthesis in which co2 is converted into carbohydrate

CAM (crassulacean acid metabolism)

biochemical pathway in certain plants in which co2 is incorporated into organic acids at night and released for fixation in calvin cycle during the day

carbon fixation

incorporation of carbon dioxide into compounds

PGA (phophogly cerate)

three-carbon molecule formed in 1st step of calvin cycle

PGAL ( glyceraldhyde phosphate)

3-carbon molecule formed in 2nd step of calvin cycle that can leave cycle and be used to make other organic compounds

RuBP (ribulose biphosphate)

5-carbon carbohydrate that combines with co2 to form 2 molecules of PGA in 1st step of calvin cycle

stoma

one of many small pores usually located on underside of a leaf; aids in gas exchange