50 terms

Photosynthesis

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Kreb's Cycle
in all plants and animals: a series of enzymatic reactions in mitochondria involving oxidative metabolism of acetyl compounds to produce high-energy phosphate compounds that are the source of cellular energy
Aerobic
process that requires oxygen
Anaerobic
process that does not require oxygen
Oxidative Phosphorylation
production of ATP using energy derived from the redox reactions of an electron transport chain; third major stage of cellular respiration
Alcohol Fermentation
glycolysis followed by the reduction of pyruvate to ethyl alcohol, regenerating NAD+ and releasing carbon dioxide
Acetyl CoA
the entry cmpound for the citric acid cycle in cellular respiration, formed from a fragment of pyruvate attached to a coenzyme
Cellular Respiration
catabolic pathways of aerobic and anaerobic respiration, which beaks down to organic molecules and us an electron transport chain for the production of ATP
Redox Reaction
chemical reaction involving the complete or partial transfer of one or more electons from one reactant to another
ATP Synthase
function in chemiosmosis with adjacent electron transport chains, using the energy of a proton concentration gradient to make ATP
Substrate-level Phosphorylation
enzyme-catalyzed formation of ATP by direct transfer of a phosphate group to ADP from an intermediate substrate in catabolism
Lactic Acid Fermentation
glycolysis followed by the reduction of pyruvate to lactate, regenerating NAD+ with no release of carbon dioxide
Oxidation
complete or partial loss of electrons from substance involved in a redox reaction
Glycolysis
series of reactions that splits glucose into pyruvate; starting point for fermentation and cellular respiration
Catabolism
breakdown of more complex substances into simpler ones with release of energy
Reduction
gain of electrons
Chemiosmosis
uses energy stored in the form of proton gradient across a membrane to drive synthesis of ATP
NAD+/NADH
an organic molecule that serves as an electron carrier by being oxidized (losing electrons) to NAD+ and reduced (gaining electrons) to NADH
Proton motive force
potential energy stored in the form of a proton electrochemical gradient, generated by the pumping of H+ ions across biological membrane during chemiosmosis
Proton gradient
used to create ATP. H+ in the thylakoid space can only diffuse down it gradient through an enzyme called ATPsynthase.
Photosynthesis
conversion of light energy to chemical energy stored in sugars or other organic compounds
Non-cyclic photophosphorylation
Photophosphorylation which generates both ATP and NADPH and uses both Photosystem II and Photosystem I.
Autotrophs
organism that obtains organic food molecules without eating other organisms or substances derived from other organisms
Cyclic electron flow
route of electron flow during the light reactions of photosynthesis that involves only photosystem I; produces ATP but not NADPH or oxygen
Heterotrophs
organism that obtains organic food molecules by eating other organisms or substances derived from them
Cyclic Phosphorylation
P700in photosystem 1 captures light and passes excited electrons down an electron transport chain to produce ATP, NADPH is not produced
Chlorophyll
green pigment located in membrane within chloroplasts of plants; participates directly in light reactions
Absorption spectrum
range of a pigment's ability to absorb various wavelengths of light
Mesophyll cells
leaf cells specialized for photosynthesis
Chlorophyll A
photosynthesis pigment that participates directly in light reactions
Rubisco (RUBP carboxylase)
enzyme that catalyzes the first step of Calvin Cycle
Stomata
microscopic pore surounded bu guard cells in epidermis of leaves and stems; allows gas exchange between environment and interior of plant
Action Spectrum
graph that profiles relatice effectiveness of different wavelengths of radiation in driving a particular process
C3 Plants
uses Calcin Cycle for initial steps that incorporate carbon dioxide into organic material, forming three-carbon compound as first stable intermediate
Stroma
fluid within chloroplast surrounding thylakoid membrane and containing ribosomes of DNA; involved in synthesis of organic molecules from carbon dioxide to water
Chlorophyll B
accessory photosynthesis pigment that transfers energy to chlorophyl A
Photorespiration
metabolic pathway that consumes oxygen and ATP, releases carbon dioxide, and decreases photosynthetic output
Light reactions
occur in thylakoid membranes of chloroplast; convert solar energy to chemical energy of ATP and NADPH, releasing oxygen; before Calvin Cycle
accessory pigments
Pigment that absorbs light at different wavelengths and then pass energy onto chlorophyll
C4 plants
Calcin cycle is preceded by reactions that incorporate carbon dioxide into a four-carbon compound, whose end product supplies carbon dioxide for Calvin Cycle
Calvin Cycle
involves fixation of atmospheric carbon dioxide and reduction of fixed carbon into carbohydrate; second part of photosynthesis, before light reactions
Bundle-sheath cells
in C4 plants, a type of photosynthesis cell arranged into tightly packed sheaths around veins of leaf
NADP+/NADPH
in photosynthesis, the major electron carrier involved in electron transport
Reaction Center chlorophyll
consists of a cluster of proteins plus a pair of chlorophyll molecules and some electron carriers
Photophosphorylation
process of generating ATP from ADP and phosphate by means of chemiosmosis, using a proton-motive force generated across membrane of thylakoid membrane
Carbon fixation
initial incorporation of carbon dioxide into an organic compound by an autotrophic organism
PEP carboxylase
An enzyme that adds CO2 to phosphoenolpyruvate (PEP) to form oxaloacetate in C4 plants. It acts prior to photosynthesis.
Photosystem I
light capturing unit in thylakoid membrane; has two molecules of P700 chlorophyll A at its reaction center; comes second
Photosystem II
light capturing unit in thylakoid membrane; has two molecules of P680 chlorophyll A at its reaction center; comes first
CAM plants
carbon dioxide enters open stomata during the night and is converted to organic acid, which leaves carbon dioxide for the Calvin Cycle during day (stomata closed)
Thylakoid membrane
inside chloroplast; often exist in stacks called grana; membranes contain molecular machinery used to convert light energy to chemical energy