Term
| what are 3 areas of photobiology? |
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Definition
1. photosynthesis
2. photomorphogenesis
3.photoperiodism |
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Term
| what is photomorphogenesis? |
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Definition
| light regulated plant development |
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Term
| what area of photobiology does the study of phytochrome fit under? |
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Definition
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Term
| what wavelength of light is 'far red'? |
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Definition
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Term
| what wavelenght of light is visible? |
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Definition
|
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Term
| what end of the spectrum carries more energy? |
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Definition
| violet end (400nm) - smaller wavelength |
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Term
| what is an absorption spectrum? |
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Definition
| graph of a compounds absrbance vs. wavelength |
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Term
| what is an action spectrum? |
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Definition
| graph of effectiveness of light in a process vs. wavelength |
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Term
| what is the main difference between the action spectrum and absorption spectrum of light in chlorophyll? |
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Definition
| green light not absorbed but relatively high action |
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Term
| how does green light result in high action but low absorption? |
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Definition
| green light is used over and over again in chlorplasts b/c it isn't absorbed and bounces around inside. |
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Term
| what did Engleman's experiment show? |
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Definition
| that the absorption spectrum of chlorphyll coincided witht he action spectrum of photosynthesis |
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Term
| how did Engleman determine the action spectrum of photosynthesis? |
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Definition
| by comparing oxygen production of Spirogyra in diff. wavelengths |
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Term
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Definition
| a pigment that absorbs light for the eventual use in a physiological process |
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Term
| what are 7 types of photoreceptors found in plants? |
|
Definition
1.chlorophylls
2.carotenoids
3.phycobillins
4.flavonoids
5.betacyanins
6.cryptochrome
7.UV-B receptors |
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Term
| what are the two main structures of a chlorophyll molecule? |
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Definition
| porphyrin head and hydrocarbon tail |
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Term
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Definition
| a cyclic tetrapyrole surrounding magnesium |
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Term
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Definition
| 4 nitrogen containing pyrole rings bonded together |
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Term
| what 2 important biological molecules contain tetrapyroles? |
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Definition
| chlorophyll and hemoglobin |
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Term
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Definition
| chlorophyll that has lost its magnesium |
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Term
| what color is pheophytin? |
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Definition
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Term
| what is the name of the hydrocarbon tail in chlorophyll? |
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Definition
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Term
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Definition
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Term
| what organisms rely mainly on chlopophyll a? |
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Definition
| higher plants, algae, cyanobacteria |
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Term
| what distinguishes chlorophyll a? |
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Definition
| a methyl (CH3) group on ring II |
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Term
| what color is chlorophyll a? |
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Definition
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Term
| what organisms have chlorophyll b? |
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Definition
| higher plants and green algae |
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Term
| what color is chlorophyll b? |
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Definition
|
|
Term
| what distinguishes chlorophyll b? |
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Definition
| formyl group (CHO) on ring II |
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Term
| which is more polat, chlorophyll a or b? why? |
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Definition
| b is more polar becasue of Oxygen in formyl group. oxygen is fairly electronegative |
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Term
| what organisms is chlorophyll c associated with? |
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Definition
| diatoms, dinoflagellates, and brown algae |
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Term
| what distinguishes chlorophyll c? |
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Definition
| methyl group (CH3) on ring II (like chlorophyll a) but no phytol tail |
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Term
| what organism is associated with chlorphyll d? |
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Definition
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|
Term
| what distinguishes chlorophyll d? |
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Definition
| same as chlorophyll a (methyl on ring II) but has substitution on ring I |
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|
Term
| what is protochlorophyll a? |
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Definition
| the immediate precursor to chlorophyll a |
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Term
| where is protochlorophyll a found? |
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Definition
| in dark-grown angiosperm seedlings |
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Term
| what accounts for the yellow color in a dark grown angiosperm seedling? |
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Definition
| carotenoids and protochlorphyll a |
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Term
| what is the structure of a carotenoid? |
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Definition
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Term
| where in a cells structure are carotenoids found? |
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Definition
| membranes of chloroplasts and chromoplasts |
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Term
| what are the 2 main types of carotenoids? |
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Definition
| carotenes and xanthophylls |
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Term
| what type of carotenoid is lycopene? |
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Definition
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Term
| what is the major carotene found in higher plants? |
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Definition
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Term
| what color are carotenes? |
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Definition
|
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Term
| what color are xanthophylls? |
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Definition
|
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Term
| which is the more polar carotenoid? why? |
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Definition
| xanthophylls b/c of hydroxyl groups at either ends |
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Term
| what are 2 types of xanthophylls? |
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Definition
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|
Term
| what is a hydroxylated alpha-carotene called? what is a hydroxylated beta-carotene called? |
|
Definition
alpha - lutein
beta - zeaxanthin |
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|
Term
| what is the difference between carotenes and xanthophylls? |
|
Definition
| xanthophylls are hydroxylated (OH groups on the ends) |
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Term
|
Definition
| breakdown of chlorophyll caused by excess blue light |
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|
Term
| how does beta-carotene function in chloroplasts? |
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Definition
|
|
Term
| what are the effects of beta-carotene absorbing blue light in the chloroplasts? |
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Definition
1. collects Energy to be passed to chlorophyll
2. reduces risk of photo-oxidation |
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Term
| what organisms use phycobillins? |
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Definition
| red-algae, blue-green bacteria, green plants |
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Term
| what is the role of phycobillins in red-algae and blue-green bacteria? |
|
Definition
| accessory light-harvesting pigments |
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|
Term
| what is the role of phycobillins in green plants? |
|
Definition
| critical regulatory system |
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|
Term
| what is the structure of a phycobillin? |
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Definition
| a straight chain tetrapyrole covalently linked to a protein |
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|
Term
| what is a phycobiliprotein? |
|
Definition
| another name for the structure of a phycobillin |
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|
Term
| what type of pigments are 'bilins' or 'bile pigments'? |
|
Definition
|
|
Term
|
Definition
| tetrapyrole chromophore bonded with apoprotein (a phycobillin) |
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Term
| what phycobillins found in higher plants? |
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Definition
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Term
| what phycobillins found in blue green bacteria and red algae? |
|
Definition
1.phycoerythrin
2.phycocyanin
3.allophycocyanin |
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Term
| what part of the spectrum is absorbed by phycobillins found in blue-green bacteria and red algae? |
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Definition
|
|
Term
| what are the 2 types of phytochrome? |
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Definition
|
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Term
| what is the structure of flavonoids? |
|
Definition
| phenyl propand derivatives (C6 ring - C3 chain - C6ring) |
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Term
| what are the 3 types of flavonoids? |
|
Definition
1.flavones
2.flavonols
3.anthocyanidines |
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Term
| what flavonoids associated with pink, purple, blue color in fruits and flowers? |
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Definition
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|
Term
| what flavonnoids associated with yellow color in some flowers? |
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Definition
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|
Term
| what flavonoids associated with the white color of some floweres? |
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Definition
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|
Term
| what compounds make up the structure of an anthocyanin? |
|
Definition
| an aglycone and a glycoside (sugar) |
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Term
| what type of flavonoid consists of a solitary aglycone? |
|
Definition
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|
Term
| how many diff. types of aglycones are there? |
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Definition
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|
Term
| what color are anthocyanins at low pH, netural,high? |
|
Definition
low- red
neutral - violet
high-blue |
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|
Term
| what specifically causes 'blueness' in anthocyanins? |
|
Definition
| hydroxylation (addition of OH groups) |
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|
Term
| what specifically causes 'redness' in anthocyanins? |
|
Definition
| methoxylation (addition of OCH3 groups) |
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|
Term
| what are the 2 main roles of anthocyanins? |
|
Definition
1.attract pollinators
2.absorb UV light |
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|
Term
| what prompts the synthesis of anthocyanins? |
|
Definition
|
|
Term
| what plant family tends to have betacyanins? |
|
Definition
|
|
Term
| what 2 characteristics about betacyanin mentioned in class? |
|
Definition
1. contain Nitrogen
2. not pH sensitive |
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|
Term
| what newly discovered photoreceptor has a blue light action spectrum? |
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Definition
|
|
Term
| what plant responses associated with blue + UV light? |
|
Definition
| phototropism, hypocotyl elongation |
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|
Term
| what plant was cryptochrome finally identified? |
|
Definition
|
|
Term
|
Definition
| cryptochrome I - protein that mediates hypocotyl elongation |
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|
Term
| what range do UV-B receptors absorb? |
|
Definition
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