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37 terms

AP Biology Chapter 8

AP Biology Chapter 8 Photosynthesis, energy from sunlight
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Photosynthesis
synthesis of compounds with the aid of radiant energy (especially in plants)
Light reactions
reactions of photosynthesis that use energy from light to produce ATP and NADPH
Light-independent reactions
phase of photosynthesis where energy form light dependent reactions is used to produced glucose and additional ATP molecules
Electromagnetic radiation
radiation consisting of waves of energy associated with electric and magnetic fields resulting from the acceleration of an electric charge
Photons
light quanta
Wavelength
the distance (measured in the direction of propagation) between two points in the same phase in consecutive cycles of a wave
Absorption
the mental state of being preoccupied by something
Ground state
(physics) the lowest energy state of an atom or other particle
Excited state
a state in which an atom has a higher potential energy than it has in its ground state
Pigments
molecules that absorb specific wavelengths of sunlight
Absorption spectrum
The range of a pigment's ability to absorb various wavelengths of light.
Action spectrum
the efficiency with which electromagnetic radiation produces a photochemical reaction plotted as a function of the wavelength of the radiation
Chlorophylls
the most common and important photosynthetic pigments in plants and algae
Accessory pigments
Pigment that absorbs light at different wavelengths and then pass energy onto chlorophyll
Carotenoids
An accessory pigment, either yellow or orange, in the chloroplasts of plants. By absorbing wavelengths of light that chlorophyll cannot, carotenoids broaden the spectrum of colors that can drive photosynthesis.
Phycobillins
good at absorbing blue light
Antenna systems
light harvesting complexes; absorbs energy and forms part of a photosystem
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.
NADP+
Nicotinamide adenine dinucleotide phosphate, an acceptor that temporarily stores energized electrons produced during the light reactions.
Non electron transport
the linear flow of electrons through photosystems I and II; results in the formation of ATP (by chemiosmosis), NADPH, and O2
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
Z scheme
a model depicting the series of energy changes of an electron during the light reactions of photosynthesis. The electron absorbs light energy twice, resulting in an energy curve with a zigzag shape
Ferredoxin
an iron sulfur protein that acts as another mobile electron carrier of the pathway; then transfers to the NADP+ reductase
Cyclic electron transport
In photosynthesis, the cyclic flow of electrons through Photosystem I; ATP is formed by chemiosmosis, but no photolysis of water occurs, and O2 and NADPH are not produced.
Plastoquinone
Transports the protons to the lumen of the thylakoid discs ,while the electrons continue through the chain into the cytochrome bf6 protein complex
Plastocyanin
acts as an electron carrier between the cytochrome b6f and photosystem 1 (PS1) complexes in the photosynthetic electron-transfer chain.
Calvin cycle
The second of two major stages in photosynthesis (following the light reactions), involving atmospheric CO2 fixation and reduction of the fixed carbon into carbohydrate.
Ribulose 1,5-bisphosphate
the final phase of the calvin cycle is the regeneration of _____ ____
Ribulose bisphosphate carboxylase/oxygenase
Rubisco.
Oxygenase
an oxidoreductase that catalyzes the incorporation of molecular oxygen
Carboxylase
This enzyme catalyzes the addition of a -COO-, or the addition of an acid group.
Photorespiration
A metabolic pathway that consumes oxygen, releases carbon dioxide, generates no ATP, and decreases photosynthetic output; generally occurs on hot, dry, bright days, when stomata close and the oxygen concentration in the leaf exceeds that of carbon dioxide.
Mesophyll
The ground tissue of a leaf, sandwiched between the upper and lower epidermis and specialized for photosynthesis.
Phosphoenolpyruvate
The last reaction of glycolysis produces more ATP by transferring the phosphate group PEP to ADP., second energy rich compound in glycolysis; its dephosphorylation can be coupled to ATP production
PEP carboxylase
An enzyme that adds CO2 to phosphoenolpyruvate (PEP) to form oxaloacetate in C4 plants. It acts prior to photosynthesis.
Bundle sheath cells
A type of photosynthetic cell arranged into tightly packed sheaths around the veins of a leaf.
Crassulacean acid metabolism
An adaptation for photosynthesis in arid conditions, first discovered in the family Crassulaceae. In this process, a plant takes up CO2 and incorporates it into a variety of organic acids at night; during the day, CO2 is released from organic acids for use in the Calvin cycle.