Chapter 8 Vocab Flashcards
The range of a pigment’s ability to absorb various wavelengths of light; also a graph of such a 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.
Autotroph
in C4 plants, a type of photosynthetic cell arranged into tightly packed sheaths around the veins of A leaf.
Bundle sheath cells
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
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 plant
The second of two major stages in photosynthesis (following the light reactions), involving fixation of atmospheric CO2 and reduction of the fixed carbon into carbohydrate.
Calvin cycle
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
The initial incorporation of carbon from CO2 into an organic compound by an autotrophic organism (a plant, another photosynthetic organism, or a chemoautotrophic prokaryote).
Carbon fixation
An accessory 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 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 photosynthetic pigment that participates directly in the light reactions, which convert solar energy to chemical energy.
Chlorophyll a
An accessory photosynthetic pigment that transfers energy to chlorophyll a.
Chlorophyll b
In this process, a plant takes up CO2 and incorporates it into a variety of organic acids at night; during the day, CO2 is released from organic acids for use in the Calvin cycle.
Crassulacean acid metabolism
A route of electron flow during the light reactions of photosynthesis that involves only photosystem I and that produces ATP but not NADPH or O2.
Cyclic electron flow
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 product of the Calvin cycle; it is also an intermediate in glycolysis.
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 (preceding the Calvin cycle). These reactions, which occur on the thylakoid membranes of the chloroplast or on membranes of 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 chlorophyll a, chlorophyll b, and carotenoids) that captures light energy and transfers it to reaction-center pigments in a photosystem.
Light harvesting complex
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
The ground tissue of a leaf, sandwiched between the upper and lower epidermis and specialized for photosynthesis.
Mesophyll
In C4 plants, a type of loosely arranged photosynthetic cell located between the bundle sheath and the leaf surface.
Mesophyll cell
Nicotinamide adenine dinucleotide phosphate, An electron acceptor that, as NADPH, temporarily stores energized electrons produced during the light reactions.
NADP+
An enzyme that adds CO2 to phosphoenolpyruvate (PEP) to form oxaloacetate in C4 plants. It acts prior to photosynthesis.
PEP carboxylase
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 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 oxygen concentration in the leaf exceeds that of carbon dioxide.
Photorespiration
One of two light-capturing units in a chloroplast’s thylakoid membrane or in the membrane of some prokaryotes; it has two molecules of P700 chlorophyll a at its reaction center.
Photosystem I
One of two light-capturing units in a chloroplast’s thylakoid membrane or in the membrane of some prokaryotes; it has two molecules of P680 chlorophyll a at its reaction center.
Photosystem 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 of chlorophyll a molecules and that accepts an electron from them.
Primary electron acceptor
A complex of proteins associated with a special pair of chlorophyll 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
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
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.
Stomata
Within the chloroplast, the dense fluid of the chloroplast surrounding the thylakoid membrane; involved in the synthesis of organic molecules from carbon dioxide and water.
Stroma
A flattened membranous sac inside a chloroplast
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 of the electromagnetic spectrum.
Wavelength
