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Concepts of Biology

Key Terms

Concepts of BiologyKey Terms
absorption spectrum
the specific pattern of absorption for a substance that absorbs electromagnetic radiation
autotroph
an organism capable of producing its own food
Calvin cycle
the reactions of photosynthesis that use the energy stored by the light-dependent reactions to form glucose and other carbohydrate molecules
carbon fixation
the process of converting inorganic CO2 gas into organic compounds
chlorophyll
the green pigment that captures the light energy that drives the reactions of photosynthesis
chlorophyll a
the form of chlorophyll that absorbs violet-blue and red light
chlorophyll b
the form of chlorophyll that absorbs blue and red-orange light
chloroplast
the organelle where photosynthesis takes place
electromagnetic spectrum
the range of all possible frequencies of radiation
granum
a stack of thylakoids located inside a chloroplast
heterotroph
an organism that consumes other organisms for food
light-dependent reaction
the first stage of photosynthesis where visible light is absorbed to form two energy-carrying molecules (ATP and NADPH)
mesophyll
the middle layer of cells in a leaf
photoautotroph
an organism capable of synthesizing its own food molecules (storing energy), using the energy of light
photon
a distinct quantity or “packet” of light energy
photosystem
a 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
pigment
a molecule that is capable of absorbing light energy
stoma
the opening that regulates gas exchange and water regulation between leaves and the environment; plural: stomata
stroma
the fluid-filled space surrounding the grana inside a chloroplast where the Calvin cycle reactions of photosynthesis take place
thylakoid
a disc-shaped membranous structure inside a chloroplast where the light-dependent reactions of photosynthesis take place using chlorophyll embedded in the membranes
wavelength
the distance between consecutive points of a wave
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