Definitions for Photosynthesis:
Autotroph: An organism that can capture energy from sunlight or chemicals and use
it to produce its own food from inorganic compounds; also called a producer. an
organism that produces its own nutrients from inorganic substances or
from the environment instead of consuming other organisms
Heterotrophs: An organism that obtains energy from the foods it consumes; also
called a consumer. Organism that obtains organic food molecules by
eating other organisms or their byproducts and that cannot synthesize
organic compounds from inorganic materials
Photosynthesis: A process by which plants and some other organisms use light
energy to convert water and carbon dioxide into oxygen and high-energy
carbohydrates such as sugars and starches.
Chloroplast: An organelle found in cells of plants and some other organisms that
captures the energy from sunlight and converts it into chemical energy
Chlorophyll: green pigment in plants that absorbs light energy used to carry out
photosynthesis
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. The initial reactions in
photosynthesis, which are triggered by the absorption of light by
photosystems I and II and include the passage of electrons along the
electron transport chains, the production of NADPH and oxygen gas,
and the synthesis of ATP through chemiosmosis
Calvin Cycle: a biochemical pathway of photosynthesis in which carbon
dioxide is converted into glucose using ATP. The Calvin Cycle is the second
of two major stages in photosynthesis (following the light reactions), involving
atmospheric CO2 fixation and reduction of the fixed carbon into carbohydrate.
NADP+: Nicotinamide adenine dinucleotide phosphate, an acceptor that temporarily
stores energized electrons produced during the light reactions.
Carbon Fixation: The incorporation of carbon from carbon dioxide into an organic
compound by an autotrophic organism. The synthesis of organic compounds
from carbon dioxide, such as in photosynthesis
Wavelength: The distance between crests of waves, such as those of the
electromagnetic spectrum.
Electromagnetic Spectrum: all of the frequencies or wavelengths of
electromagnetic radiation, the entire frequency range of electromagnetic waves.
Visible Light: That portion of the electromagnetic spectrum detected as various
colors by the human eye, ranging in wavelength from about 380 nm to about 750
nm.
Photons: A quantum, or discrete amount, of light energy.
Spectrometer: Instrument that measures index of light reflection.
Chlorophyll a: A blue-black plant pigment having a blue-green alcohol solution
Chlorophyll b: A dark-green plant pigment having a brilliant green alcohol solution
Carotenoid: Yellow and orange plant pigments that aid in photosynthesis.
Primary Electron Acceptor: A specialized molecule sharing the reaction center with
the pair of reaction-center chlorophyll a molecules; it accepts an electron from one
of these two chlorophylls
Photosystem: a cluster of chlorophyll and other molecules in a thylakoid that help to
harvest light energy during photosynthesis
Photosystem I: The photosystem that makes use of light to transfer electron 3
particularly from plastocyanin to ferredoxin, and whose reaction center chlorophyll
is P700.
Photosystem II : The photosystem that absorbs light for use to drive the oxidation of
water and the reduction of plastoquinone, and whose reaction center chlorophyll is
P680.
Thylakoid: A flattened membrane sac inside the chloroplast, used to convert light
energy into chemical energy.
Grana: A stack of thylakoids inside the chloroplast.
Stroma: The fluid of the chloroplast surrounding the thylakoid membrane; involved
in the synthesis of organic molecules from carbon dioxide and water
Pigment: a colored chemical compound that absorbs light, producing color
Electron Transport Chain: A sequence of electron carrier molecules (membrane
proteins) that shuttle electrons during the redox reactions that release energy used
to make ATP.
Chemiosmosis: in chloroplasts and mitochondria, a process in which the movement
of protons down their concentration gradient across a membrane is coupled to the
synthesis of ATP
Biochemical Pathway: a series of chemical reactions that convert one
biological material into another
Stoma: A series of chemical reactions in which the product of one reaction is
consumed in the next reaction
Phototropism: a plant growth movement that occurs in response to the
direction of a source of light
Thigmotropism: a response of an organism or part of an organism to
touch, such as the coiling of a vine around an object