Text Chapter 4: Photosynthesis Flashcards
Light-Dependent “Photo” Reactions
energy from light is used to form ATP (energy carrier) and NADPH (electron carrier), occur in photosystems located in thylakoid membranes
Light-Independent “Synthesis” Reactions
produce glucose using as a CO2 as a carbon source, occur in stroma of chloroplast, use ATP and NADPH from light-dependent reactions, six turns of the cycle produce one glucose molecule
Mesophyll Cells
contain chloroplasts for photosynthesis
Bundle Sheath Cells
a layer of cells that form a sheath surrounding the vascular bundles
C3 Pathway
CO2 enters the Calvin Cycle to produce glucose
C4 Pathway
difference in location) CO2 is incorporated into a 4-Carbon compound in mesophyll cells and released into more interior bundle sheath cells for the Calvin Cycle
CAM Pathway
(difference in timing): CO2 incorporated into 4-Carbon compound stored in vacuoles at night and released for Calvin Cycle during the day
Thylakoid
location of “photo” reactions, where light is converted into chemical energy
Stroma
location of “synthesis” reactions, where chemical energy from the “photo” reactions is used to synthesize sugars
Chlorophyll a and b
major photosynthetic pigments, absorb violet, blue, and red wavelengths, reflect green
Carotenoids
absorb blue and green wavelengths, reflect red, yellow, and orange
ATP
energy carrier
NADPH
electron carrier
Rubisco
most abundant enzyme on earth- plucks carbon atoms from CO2 molecules in the air (during fixation)
ATP Synthase
transfers hydrogen ions from the thylakoid back into the stroma as ATP
Photosystem
a biochemical mechanism in plants by which chlorophyll absorbs light energy for photosynthesis
Light-Harvesting Complex
water is split to supply new electrons, light energy boosts an electron into the reaction center for transport into the electron transport chain
Primary Electron Acceptor
first molecule in the electron transport chain to accept the electron and pass it along
Electron Transport Chain
series of compounds that transfer electrons from electron donors to electron acceptors via redox reactions, and couples this electron transfer with the transfer of protons (H+ ions) across a membrane.
Carbon Fixation
the enzyme Rubisco plucks Carbon atoms from CO2 molecules in the air. The carbon atoms are attached to an organic molecule
Sugar Creation
modifying the organic molecule into a 3-carbon sugar
Regeneration
some molecules of G3P are used to regenerate the original organic molecule, using original energy for ATP
Water-Splitting Photosystem
light energy is used to transfer electrons to primary electron acceptor and go down the electron transport chain. Electrons donated by water. ATP is built by the release of hydrogen ions in the thylakoid
NADPH-Producing Photosystem
identical to water-splitting photosystem, except that electrons are donated by the electron transport chain. High-energy electrons are passed to NADP+, creating NADPH
Importance of Pigments and Photosystems in Photosynthesis
light-dependent (“photo”) reactions occur in photosystems located in thylakoid membranes. Organized array of pigment molecules, each photosystem contains a light-harvesting complex with a reaction center and an electron transport system ——-pigments capture light of a certain wavelength
Chemiosmosis in Chloroplasts
diffusion of protons through channel in ATP synthase gives energy for ATP synthesis
Significance of C3 or Carbon-Fixing Reactions
make carbohydrates, energy efficient
Cellular Respiration v. Photosynthesis
Cellular respiration starts with glucose and ends with CO2 and water, occurs in the inner membrane of the mitochondria
Photosynthesis starts with CO2, ends with glucose, occurs in chloroplast
Based on the Lab, Factors that can increase the Rate of Photosynthesis
light, CO2
Reactions that use Water
light-dependent reactions AND light-independent reactions
Reactions that Release Oxygen
light-dependent “photo” reactions
Reactions that use Energy from ATP
light-independent “synthesis” reactions
