Exam 3: Photosynthesis Flashcards
photosynthesis
the process by which light energy is converted into chemical energy
mesophyll
the chlorplastic parenchyma tissue where photosynthesis occurs; located between the two outer tissues of the leaf
bundle-sheath cell
photosynthetic cells packed into tight sheaths that protect leaf veins
mesophyll cell
photosynthetic cells associated with bundle sheath cells;
stoma
a pore formed by two guard cells in the epidermis of a plant that allows for gas exchange
thylakoid
a membrane-bound compartment where the light-dependent reactions of photosynthesis take place; form stacks called grana
stroma
the colorless liquid found within a chloroplast that surrounds the grana
chlorophyll
a green pigment found in plant cells that allows plants to collect light energy for use in photosynthesis
carotenoid
a yellow-orange pigment found in plant cells that absorb blue light for use in photosynthesis
electromagnetic spectrum
the range of frequencies of electromagnetic radiation, starting with short gamma waves and ending with long radio waves
wavelength
the distance between each repeat of the wave’s shape
absorption spectrum
the variation in the amount of light absorbed at different wavelengths
action spectrum
the variation in how effective light is at driving photosynthesis at different wavelengths
visible light
the range of electromagnetic radiation that is visible to human eye
photon
the basic unit of light; contains energy utilized in photosynthesis
spectrophotometer
measures wavelengths of length
photosystem
protein complex containing light-absorbing pigments where photosynthesis takes place
photosystem I (PS I)
a protein complex that uses light energy to synthesize NADPH; contains an antenna complex and a reaction center
photosystem II (PS II)
a protein complex that uses light energy to synthesize ATP; contains an antenna complex and a reaction center
light-harvesting complex (antenna complex)
part of the photosystem; contains chlorophyll and carotenoid pigments
reaction center
contains two chlorophyll a molecules that absorb light
chlorophyll a
a photosynthetic pigment that serves as a primary electron donor in the electron transport chain
chlorophyll b
– a photosynthetic pigment found only in plants and green algae
light reaction
the first step in photosynthesis where light energy is converted to chemical energy; takes place on the thylakoid membrane
electron transport chain
facilities the conversion of light energy (sunlight) into chemical energy in photosynthesis by transferring electrons from a donor to an acceptor and generating ATP
NADP+
the last molecule in the electron transport chain of the light reactions; used to create a proton gradient in chloroplasts
primary electron acceptor
accepts the electron from chlorophyll and donates it to the electron transport chain
photophosphorylation
the synthesis of ATP using light energy transported through the electron transport chain
cyclic electron flow
an electron transport pathway that produces ATP without NADPH; associated with photosystem I
noncyclic electron flow
an electron pathway where electrons travel one-way from H2O to NADP+
ATP synthase
a membrane-spanning protein complex that uses the transport of protons across the membrane to produce ATP
proton gradient
a difference in potential on either side of the plasma membrane created by the active transport of protons through proton pumps
potential energy
energy stored in matter as a result of its position or configuration; can be used to do work
Calvin Cycle (light-independent reaction)
the second step of photosynthesis where electrons are used to convert inorganic CO2 into organic CO2
carbon fixation
the transformation of inorganic atmospheric CO2 into organic molecules (e.g.: glucose)
glyceraldehyde-3-phosphate (G3P)
produced during the Calvin cycle from two molecules of GP (which were produced in the first step of the light-independent reactions)
photorespiration
metabolic process where RuBP has O2 added instead of CO2
RUBISCO
enzyme that catalyzes reaction of RuBP with either O2 or CO2 in the first step of carbon fixation
CAM plant
uses the crassulacean acid metabolism (CAM) pathway to produce CO2 for the Calvin cycle; both processes occur in the mesophyll, but at a different time of day; adapted to surviving in dry, hot conditions
C3 plant
depends on the light-independent reactions of photosynthesis (Calvin cycle); cannot grown in hot areas
C4 plant
uses a C4 pathway to fix CO2 into oxaloacetate and produce CO2 for the Calvin cycle
