Ch. 7 - Photosynthesis Flashcards
C4 plants
A plant that prefaces the Calvin cycle with reactions that incorporate CO2 into four-carbon compounds, the end product of which supplies CO2 for the Calvin cycle.
Calvin cycle
The second of two stages of photosynthesis; a cyclic series of chemical reactions that occur in the stroma of a chloroplast, using the carbon in CO2 and the ATP and NADPH produced by the light reactions to make the energy-rich sugar molecule G3P, which is later used to produce glucose.
CAM plants
A plant that uses the following adaptation for photosynthesis in arid conditions: Carbon dioxide entering open stomata during the night is converted to organic compounds, which release CO2 for the Calvin cycle during the day, when stomata are closed.
chlorophyll
A light-absorbing pigment in chloroplasts that plays a central role in converting solar energy to chemical energy.
chlorophyll a
A green pigment in chloroplasts that participates directly in the light reactions.
Chloroplast
An organelle found in plants and photosynthetic protists. Enclosed by two concentric membranes, a chloroplast absorbs sunlight and uses it to power the synthesis of organic food molecules (sugars).
Electromagnetic spectrum
The full range of radiation, from the very short wavelengths of gamma rays to the very long wavelengths of radio signals.
granum
(plural, grana) A stack of hollow disks formed of thylakoid membrane in a chloroplast. Grana are the sites where light energy is trapped by chlorophyll and converted to chemical energy during the light reactions of photosynthesis.
light reactions
The first of two stages in photosynthesis, the steps in which solar energy is absorbed and converted to chemical energy in the form of ATP and NADPH. The light reactions power the sugar-producing Calvin cycle but produce no sugar themselves.
NADPH
An electron carrier (a molecule that carries electrons) involved in photosynthesis. Light drives electrons from chlorophyll to NADP1, forming NADPH, which provides the high-energy electrons for the reduction of carbon dioxide to sugar in the Calvin cycle.
photon
A fixed quantity of light energy. The shorter the wavelength of light, the greater the energy of a photon.
Photosynthesis
The process by which plants, algae, and some bacteria transform light energy to chemical energy stored in the bonds of sugars made from carbon dioxide and water.
primary electron acceptor
A molecule in the reaction center of a photosystem that traps the light-excited electron from the reaction center chlorophyll.
reaction center
In a photosystem in a chloroplast, the chlorophyll a molecule and primary electron acceptor that trigger the light reactions of photosynthesis. The chlorophyll donates an electron excited by light energy to the primary electron acceptor, which passes an electron to an electron transport chain.
stoma
(plural, stomata) A pore surrounded by guard cells in the epidermis of a leaf. When stomata are open, CO2 enters the leaf, and water and O2 exit. A plant conserves water when its stomata are closed.
