Studied by 1 person
Based on the 3rd edition biology textbook written by C.J. Clegg, Andrew Davis, Christopher Talbot
photosynthesis
the production of glucose from carbon dioxide and water, in the presence of chlorophyll and enzymes, using light energy, producing oxygen as a waste product
chlorophyll
the main photosynthetic pigments of green plants, occurring in the grana membranes (thylakoid membranes) of the chloroplasts; also found in cyanobacteria and in the chloroplasts of algae
pigment
coloured compounds produced by metabolism
accessory pigments
light-absorbing compounds that trap light energy and channel it to chlorophyll a, the primary pigment, which initiates the reactions of photosynthesis
photolysis
the splitting of water molecules using light energy
chromatography
the technique used to separate components of a mixture involves letting soluble substances spread across filter paper (or through a powder)
chromatogram
the pattern formed on an adsorbent medium showing the result of separating the components of a mixture by chromatography
R(f) value
a constant distance that a particular substance moves up a chromatogram relative to its solvent front; the R(f) value of the compound is equal to the distance travelled by the compound divided by the distance travelled by the solvent front (both distances measured from the origin)
absorption spectrum
a graph showing the relative absorbance of different wavelengths of light by a pigment
action spectrum
range of wavelengths of light within which a process like photosynthesis takes place
light-dependent reactions
part of photosynthesis occurs in. the grana of chloroplasts and requires light, water is split, and ATP and NADPH are generated
photophosphorylation
the formation of ATP using light energy (in the light-dependent step of photosynthesis)
light-independent reactions
part of photosynthesis occurring in the stroma of chloroplasts; it uses the products of the light-dependent step to reduce (or fix) carbon dioxide to glucose
photosystems
molecular arrays of chlorophyll, accessory pigments and proteins (light-harvesting complexes) with a special chlorophyll as the reaction centre from which an excited electron is emitted
light-harvesting complex (LHC)
an array of protein and chlorophyll molecules embedded in the thylakoid membrane of plants =, algae, and cyanobacteria, which transfer light energy to one chlorophyll a molecule at the reaction centre of a photosystem
photosystem 1
a chlorophyll-protein complex that uses light energy to release excited electrons, replacing each lost electron with one in the ground state (electrons are received from photosystem 2); it is activated by the light wavelength 700nm
photosystem 2
a membrane super-complex of proteins and several hundred chlorophyll molecules, plus accessory pigments, that carries out the initial reaction of photosynthesis; light from the Sun excites electrons, which pass down an electron transport chain: these electrons are replaced by splitting water to release protons and electrons; it is activated by the light wavelength 680nm
ground-state electrons
the energy level normally occupied by an electron; the state of lowest energy for an electron
high-energy (excited) electrons
chlorophyll in photosystems 1 and 2 absorbs light energy (photons), which increases the energy level of electrons
non-cyclic photophosphorylation
process used to produce NADPH in addition yo ATP; requires presence of water
cyclic photophosphorylation
process that produces a steady supply of ATP in the presence of sunlight
Calvin cycle
a cycle of reactions in the stroma of the chloroplast, also known as the light-independent reactions, in which carbon dioxide is converted to carbohydrate
rubisco (RuBisCo)
ribulose-1,5-bisphosphate carboxylase is an enzyme involved in the first major step of carbon fixation; it is the central enzyme of photosynthesis
fixation
carbon dioxide combines with ribulose biphosphate, forming an unstable 6-carbon sugar that splits immediately to form two molecules of glycerate 3-phosphate
reduction
glycerate 3-phosphate combines with H from NADPH using energy from ATP (both taken from light-dependent stage) and forms water and triose phosphate
regeneration
triose phosphate is used directly to convert to RuBP, the acceptor molecule, using ATP energy to reorganize back to the correct shape
product synthesis
triose phosphate is used directly in respiration or converted to glucose using ATP energy to organize carbons taken from carbon dioxide
