Chapter 8 Photosynthesis Vocabulary Flashcards
The range of a pigment’s ability to absorb various wavelengths of light; also a graph of such range
Absorption Spectrum
A graph that profiles the relative effectiveness of different wavelengths of radiation in driving a particular process
Action Spectrum
An organism that obtains organic food molecules without eating other organisms or substances derived from other organisms. They use energy from the sun or from oxidation of inorganic substances to make organic molecules from inorganic ones.
Autotroph
A plant that uses crassulacean acid metabolism, an adaptation for photosynthesis in arid conditions. In this process, carbon dioxide entering open stomata during the night is converted to organic acids, which release CO2 for the Calvin cycle during the day, when stomata are closed.
CAM Plant
A plant that uses the Calvin cycle for the initial steps that incorporate CO2 into organic material, forming a three-carbon compound as the first stable intermediate.
C3 plant
The second of two major stages in photosynthesis (following the light reactions), involving fixation of the atmosphere CO2. and reduction of the fixed carbon into carbohydrate.
Calvin Cycle
The initial incorporation of carbon from CO2 in to an organic compound by an autotropic organism (a plant, another photo synthetic organism, or a chemoautotropic prokaryote.
carbon fixation
An accesory pigment, either yellow or orange, in the chloroplasts of plants and in some prokaryotes. By absorbing wavelengths of light that chlorophyll cannot, carotenoids broaden the spectrum of colors that can drive photosynthesis.
carotenoid
A green pigment located in membranes within the chloroplasts of plants and algae and in the membranes of certain prokaryotes. Chlorophyll a participates directly in the light reactions, which convert solar energy to chemical energy.
chlorophyll
A pigment that participates directly in the light reactions, which convert solar energy to chemical energy.
chlorophyll a
An accesory photosynthetic pigment that transfers energy to chlorophyll a.
chlorophyll b
A plant in which the Calvin cycle is preceded by reactions that incorporate CO2 into a four-carbon compound, the end product of which supplies CO2, for the Calvin cycle.
C4 plants
A route of electron flow during the light reactions of photosynthesis that involves both photosystems (I and II) and produces ATP, NADPH, and O2. The net electron flow is from H2O to NADP+.
Linear electron flow
An organism that absorbs nutrients from nonliving organic material such as corpses, fallen plant material , and the wastes of living organisms and converts them to inorganic forms; a detritivore.
Decomposer
The entire spectrum of electromagnetic radiation, ranging in wavelength from less than a nanometer to more than a kilometer.
electromagnetic spectrum
A three-carbon carbohydrate that is the direct of the Calvin cycle; it is also an intermediate in glycolysis.
glyceraldehyde-3-phosphate (G3P)
An organism that obtains organic food molecules by eating other organisms or substances derived from them.
heterotroph
The first of two major stages in photosynthesis (preceeding the Calvin cycle). These reactions, which occur on the thylakoid membranes of the certain prokaryotes, convert solar energy to the chemical energy of ATP and NADPH, releasing oxygen in the process.
light reactions
A complex of proteins associated with pigment molecules (including cholorphyll a, cholorphyll b, and carotenoids) that captures light energy and transfers it to reaction-center pigments in a photosystem.
light-harvesting complex
Leaf cells specialized for photosynthesis. In C3 and CAM plants, mesophyll cells are located between the upper and lower epidermis; in C4 plants, they are located between the bundle-sheath cells and the epidermis.
mesophyll
Nicotinamide adenine dinucleotide, a coenzyme that cycles easily between oxidized (NAD+) and reduced (NADH) states, thus acting as an electron carrier.
NADP+
A quantum, or discrete quantity, of light energy that behaves as if it were a particle.
photon
The process of generating ATP from ADP and phosphate by means of chemiosmosis, using a proton-motive force generated across the thylakoid membrane of the chloroplast or the membrane of certain prokaryotes during the light reactions of photosynthesis,
photophosphorylation
A metabolic pathway that consumes oxygen and ATP, releases carbon dioxide, and decreases photosynthetic output. Photorespiration generally occurs on hot, dry, bright days, when stomata close and the O2/CO2 ratio in the leaf increases, favoring the binding of O2, rather than CO2 by rubisco.
photorespiration
The conversion of light energy to chemical energy that is stored in sugars or other organic compounds; occurs in plants, algae, and certain prokaryotes.
photosynthesis
A light-capturing unit located in the thylakoid membrane of the cholorplast or in the membrane o some prokaryotes, consisting of a reaction-center complex surrounded by numerous light-harvesting complexes. There are two types: I & II; they absorb light best at different wavelengths.
photosystem
One of the two light capturing units in a chloroplast’s thylakoid membrane or in the membrane of some prokaryotes; it has two molecules of P700 cholorphyll a at its reaction center.
photosystem I (PS I)
One of the two light-capturing units in a chloroplast’s thylakoid membrane or in the membranes of some prokaryotes; it has two molecules of P680 cholrophyll a at its reaction center.
photosystem II (PS II)
In the thylakoid membrane of a chloroplast or in the membrane of some prokaryotes, a specialized molecule that shares the reaction-center complex with a pair or cholorpyll a molecules and that accepts an electron from them.
primary electron acceptor
An organism that produces organic compounds from CO2 by harnessing light energy (in photosynthesis) or by oxidizing inorganic chemicals (in chemosynthetic reactions carried out by some prokaryotes).
Producer
A complex of proteins associated with a special pair of cholorphyll a molecules and a primary electron acceptor. Located centrally in a photosystem, this complex triggers the light reactions of photosynthesis. Excited by light energy, the pair of chlorophylls donates an electron to the primary electron acceptor, which passes an electron to an electron transport chain.
reaction center complex
Ribulose bisphosphate (RuBP) carboxylase, the enzyme that catalyzes the first step of the Calvin cycle (the addition of CO2 to RuBP).
rubisco
An instrument that measures the proportions of light of different wavelengths absorbed and transmitted by a pigment solution.
spectrophotometer
Plural for stoma
stomata
A microscopic pore surrounded by guard cells in the epidermis of leaves and stems that allows gas exchange between the environment and the interior of the plant.
stroma
A flattened, membranous sac inside a chloroplast. Thylakoids often exist in stacks called grana that are interconnected; their membranes contain molecular “machinery” used to convert light energy to chemical energy.
thylakoid
That portion of the electromagnetic spectrum that can be detected as various colors by the human eye, ranging in wavelength from about 380 nm to about 750 nm.
visible light
The distance between crests of waves, such as those o the electromagnetic spectrum.
wavelength
