1.
Absorption Spectrum: A graph plotting a pigment's light absorption (the fraction not transmitted or reflected) versus wavelength.
2.
Action Spectrum: Profiles the relative performance of the different wavelengths.
3.
Autotrophs: They sustain themselves without eating other organisms or substances derived from other organisms. They obtain CO2 and other inorganic materials from the environment. AKA producers.
4.
Bundle-Sheath Cell: A type of photsynthetic cell arranged into tightly packed sheaths around the veins of a leaf.
5.
C3 Plant: A plant that uses the initial steps that incorporate CO2 into organice material, forming a three-carbon compoud as the first stable intermediate.
6.
C4 Plant: A plant that prefaces the Calvin cycle with reactions that incorporate CO2 into four-carbon compouds, the end product of which supplies CO2 for the Calvin cycle.
7.
Calvin Cycle: The second of two major sages in photosynthesis (following the light reactions), involving atmospheric CO2 fixation and reduction of the fixed carbon into carbohydrate.
8.
CAM Plant: A plant that uses crassulacean acid metabolism, an adaption for photosynthesis in arid conditions, first discovered in the family Crassulacae. Carbon dioxide entering open stomata during the night is converted into organic acids which release CO2 for the Calvin cycle during the day, when stomata are closed.
9.
Carbon Fixation: The Calvin cycle begins by incorporating CO2 from the air into organic molecules already present in the chloroplast.
10.
Carotenoids: An accessory pigment, either yellow or orange, in the chloroplasts of plants. By absorbing wavelenghs of light that chlorophyll cannot, carotenoids broaden the spectrum of colors that can drive photosynthesis.
11.
Chlorophyll: The green pigment within chloroplasts. Light energy absorbed by this drives the synthesis of food molecules within the chloroplast.
12.
Chlorophyll a: A type of blue-green photosynthetic pigment that participates directly in the light reactions.
13.
Chlorophyll b: A type of yellow-green accessory photosynthetic pigment that tranfers energy to chlorophyll a.
14.
Crassulacean Acid Metabolism (CAM): A type of metabolism in which carbon dioxide is taken in at night and incorporated into a variety of organic acids.
15.
Cyclic Electron Flow: A route of electron flow during the light reactions of photosyntheis that involves only photosystem I and that produces ATP but not NADPH or oxygen.
16.
Cyclic Photophosphorylation: The generation of ATP by cyclic electron flow.
17.
Electromagnetic Spectrum.: The entire range of radiation from gamma rays to radio waves.
18.
Glyceraldehyde-3-Phosphate (G3P): The carbohydrate produced directly from the Calvin cycle.
19.
Heterotrophs: Obtain their organic material by the second major mode of nutrition. Consumers.
20.
Light Reactions: The steps in photosynthesis that occur on the thylakoid membranes of the chloroplast and that convert solar energy to the chemical energy of ATP and NADPH, evolving oxygen in the process.
21.
Mesophyll: The tissue in the interior of the leaf.
22.
Mesophyll Cell: A loosely arranged photosynthetic cell located between the bundle sheat and the leaf surface.
23.
NADP+: An acceptor that temporarily stores the energized electrons in the light reaction.
24.
Noncyclic Electron Flow: A route of electron flow during the light reactions of photosynthesis that involves both photosystems and produces ATP, NADPH, and oyxygen. The net electron flow is from water to NADP+.
25.
Noncyclic Photophosphorylation: The production of ATP by noncyclic electron flow.
26.
PEP Carboxylase: An enzyme that adds carbon dioxide to phosphoenolpyruvate (PEP) to for oxaloacetate.
27.
Photons: A quantum, or discrete amount, of light energy.
28.
Photophosphorylation: A process where light reactions generate ATP by powering the addition of a phosphate group to ADP.
29.
Photorespiration: A metabolic pathway that consumes oxygen, releases carbon dioxide, generates no ATP, and decreases photosynthetic output; generally occurs on hot, dry, bright days, when stomata close and the oxygen concentration in the leaf exceeds that of carbon dioxide.
30.
Photosynthesis: The conversion of light energy to chemical energy that is stored in glucose or other organic compounds; occurs in plants, algae, and certain prokaryotes.
31.
Photosystem I: One of two light-harvestin units of a chloroplasts' thylakoid membrane, it uses the P700 reaction-center chlorophyll.
32.
Photosystem II: Light-harvesting unit of a chloroplast's thylakoid membrane; it uses the P680 reaction-center chlorophyll.
33.
Photosystems: The light-harvesting unit in photosynthesis, located on the thylakoid membrane of the chloroplast and consisting of the antenna complex, the reaction-center chlorophyll a, and the primary electron acceptor. There are two types of photosystems, I and II; they absorb light best at different wavelengths.
34.
Primary Electron Acceptor: A specialized molecule sharing the reaction center with the chlorophyll a molecule; it accepts an electron from the chlorophyll a molecule.
35.
Reaction Center: The chlorophyll a molecule and the primary electron acceptor in a photsystem; they trigger the light reactions of photosynthesis. The chloroplyll donates an electron, excited by light energy, to the primary electron acceptor, which passes an electron to an electron transport chain.
36.
Rubisco: Ribulose carboxylase, the enzyme that catalyzes the first step of the Calvin cycle (the addition of CO2 to RuBP, or ribulose bisphosphate).
37.
Spectrophotometer: A machine that directs beams of light of different wavelengths through a solution of the pigment and measures the fraction of the light transmitted at each wavelenth. Measures the ability of a pigment to absorb various wavelengths of light.
38.
Stomata: Microscopic pores that carbon dioxide enters the leaf through and oxygen exits.
39.
Visible Light: The segment most important to life that ranges from 380 to 750 nm in wavelength.
40.
Wavelength: The distance between the crests of electromagnetic waves.
