8: Photosynthesis Flashcards
range of wavelengths of electromagnetic radiation absorbed by a given substance
absorption spectrum
pigment molecule that directly absorbs light and transfers the energy absorbed to other pigment molecules
antenna protein
light-independent reactions of photosynthesis that convert carbon dioxide from the atmosphere into carbohydrates using the energy and reducing power of ATP and NADPH
Calvin cycle
process of converting inorganic CO2 gas into organic compounds
carbon fixation
photosynthetic pigment (yellow-orange-red) that functions to dispose of excess energy
carotenoid
organism that can build organic molecules using energy derived from inorganic chemicals instead of sunlight
chemoautotroph
form of chlorophyll that absorbs violet-blue and red light and consequently has a bluish-green color; the only pigment molecule that performs the photochemistry by getting excited and losing an electron to the electron transport chain
chlorophyll a
accessory pigment that absorbs blue and red-orange light and consequently has a yellowish-green tint
chlorophyll b
organelle in which photosynthesis takes place
chloroplast
group of reversibly oxidizable and reducible proteins that forms part of the electron transport chain between photosystem II and photosystem I
cytochrome complex
range of all possible frequencies of radiation
electromagnetic spectrum
group of proteins between PSII and PSI that pass energized electrons and use the energy released by the electrons to move hydrogen ions against their concentration gradient into the thylakoid lumen
electron transport chain
stack of thylakoids located inside a chloroplast
granum
organism that consumes organic substances
or other organisms for food
heterotroph
complex that passes energy from sunlight to the reaction center in each photosystem; it consists of multiple antenna proteins that contain a mixture of 300 to 400 chlorophyll a and b molecules as well as other pigments like carotenoids
light harvesting complex
first stage of photosynthesis where certain wavelengths of the visible light are absorbed to form two energy-carrying molecules (ATP and NADPH)
light-dependent reaction
second stage of photosynthesis, through which carbon dioxide is used to build carbohydrate molecules using energy from ATP and NADPH
light-independent reaction
middle layer of chlorophyll-rich cells in a leaf
mesophyll
reaction center of photosystem II
P680
reaction center of photosystem I
P700
ejection of an electron from a reaction center
using the energy of an absorbed photon
photoact
organism capable of producing its own
organic compounds from sunlight
photoautotroph
distinct quantity or “packet” of light energy
photon
group of proteins, chlorophyll, and other pigments that are used in the light-dependent reactions of photosynthesis to absorb light energy and convert it into chemical energy
photosystem
integral pigment and protein complex in thylakoid membranes that uses light energy to transport electrons from plastocyanin to NADP+ (which becomes reduced to NADPH in the process)
photosystem I
integral protein and pigment complex in thylakoid membranes that transports electrons from water to the electron transport chain; oxygen is a product of PSII
photosystem II
molecule that is capable of absorbing certain wavelengths of light and reflecting others (which accounts for its color)
pigment
pigment or other organic molecule in the reaction center that accepts an energized electron from the reaction center
primary electron acceptor
complex of chlorophyll molecules and other organic molecules that is assembled around a special pair of chlorophyll molecules and a primary electron acceptor; capable of undergoing oxidation and reduction
reaction center
gain of electron(s) by an atom or molecule
reduction
instrument that can measure
transmitted light and compute the absorption
spectrophotometer
opening that regulates gas exchange and water evaporation between leaves and the environment, typically situated on the underside of leaves
stoma
fluid-filled space surrounding the grana inside a chloroplast where the light-independent reactions of photosynthesis take place
stroma
disc-shaped, membrane-bound structure inside a chloroplast where the light-dependent reactions of photosynthesis take place; stacks of thylakoids are called grana
thylakoid
aqueous space bound by a thylakoid membrane where protons accumulate during light-driven electron transport
thylakoid lumen
distance between consecutive points of equal position (two crests or two troughs) of a wave in a graphic representation; inversely proportional to the energy of the radiation
wavelength
