Photosynthesis Test Vocab List
Terms
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- autotrophs
- organisms that make their own food
- mesophyll
- The ground tissue of a leaf, sandwiched between the upper and lower epidermis and specialized for photosynthesis.
- stomata (stoma)
- under hot and dry environments, this is where plants can lose water. they are pores. located on underside of leaves. major passage way where CO2 enters the plant and O2 leaves. when it is closed CO2 levels fall and )2 levels rise. both a low O2 level and a high CO2 level inhibit carbon fixation by the Calvin cycle. alternative pathways help deal with this problem.
- stroma
- the dense colorless framework of a chloroplast
- thylakoids
- A flattened membrane sac inside the chloroplast, used to convert light energy to chemical energy.
- grana (granum)
- Stacks of thylakoids
- light reactions
- reactions of photosynthesis that use energy from light to produce ATP and NADPH
- Calvin Cycle
- reactions of photosynthesis in which energy from ATP and NADPH is used to build high-energy compounds such as sugars
- Carbon Fixation
- The incorporation of carbon from carbon dioxide into an organic compound by an autotrophic organism.
- electromagnetic energy
- The energy of light and other forms of radiation.
- wavelength
- The distance from the peak of one light wave to the peak of the next
- photon
- A particle of electromagnetic radiation with no mass that carries a quantum of energy.
- reaction center
- Complex of proteins associated with two special 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, one of the chlorophylls donates an electron to the primary electron acceptor, which passes an electron to an electron transport chain.
- photosystem
- in the thylakoid membranes of chloroplasts, a cluster of chlorophyll and other pigment molecules that harvest light energy for the light reactions of photosynthesis
- excited electron
- An electron that is in a higher energy level than its own
- ground state electron
- lowest level of energy an electron can be, so lowest amount of energy an electron can have
- photosystem I
- one of two light-harvesting units of a chloroplast's thylakoid membrane; it uses the P700 reaction-center chlorophyll.
- photosystem II
- one of two light-harvesting units of a chloroplast's thylakoid membrane; it uses the P680 reaction-center chlorophyll.
- P680
- Chlorophyll a molecules that serve as the reaction center of Photosystem II, transferring photoexcited electrons to a primary acceptor
- P700
- Chlorophyll a molecules that serve as the reaction center of Photosystem I, transferring photoexcited electrons to a primary acceptor; named by their absorption peak at 700 nm.
- electron transport chain
- sequence of electron carrier molecules that transfer electrons and release energy during cellular respiration
- 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
- ATP Synthase
- large protein that uses energy from H+ ions to bind ADP and a phosphate group together to produce ATP
- photophosphorylation
- The process of generating ATP from ADP and phosphate by means of a proton-motive force generated by the thylakoid membrane of the chloroplast during the light reactions of photosynthesis.
- concentration gradient
- a difference in the concentration of a substance across a distance