Plant Pigments Flashcards
what are pigments? what does there presence allow?
pigment are organic molecules that have colour
-their presence allows organisms to be colourful
what are the two possibilities that a flower may appear purple? how can we distinguish between them?
- the petals produce a purple pigment
- the petal produces both a red pigment and a blue pigment, which when combined appear purple
-if we can separate the mixture of pigments into their individual components –> ie. Chromatography
what was the technique used to separate pigments in this experiment? how does it separate pigments?
thin layer chromatography - TLC
-separates pigments based on their level of polarity
what are polar molecules, what kinds of bonds can they make? non-polar molecules, what kinds of bonds can they make?
polar molecules are molecules made up of atoms of differing electronegativity, meaning they share their electrons unequally causing a slight charge –> meaning these molecules can form hydrogen bonds
-non-polar molecules are molecules made up of atoms of the same electronegativity, meaning they share their electrons equally and do not carry a charge –> meaning these molecules do not form hydrogen bonds
what is the property of adhesion? which molecules have this property? what is adsorption?
- meaning they will stick to other molecules
- occurs in polar molecules –> ie will stick to other polar molecules
- adsorption is the tendency of a substance to stick to a surface
how does thin layer chromatography work?
a mixture of molecules are applied to one spot on a solid support (the slide) which is coated with a thin polar surface layer
- then the slide is placed in a non-polar solvent which will move by capillary action up the slide
- the molecules mixture will dissolve in the solvent and as it moves upwards, it will pull pigments with it
what is the thin polar layer used in this experiment? why does it work?
silica
-it works because is has hydroxyl groups (which are polar) and can form hydrogen bonds with polar regions on other molecules
what is the solvent called that the polar slide is placed into?
-the developing solvent
which pigments move the most? the least?
nonpolar pigments easily dissolve in the nonpolar solvent and are carried up the slide
-polar pigments stick to the silica and either move slowly or don’t move at all
- the more non-polar a pigment is, the farther it moves up slide (ie. no polar groups)
- the more polar a a pigment is, the more likely it is not to move (ie. has the most polar groups)
what are the 2 major polar groups that we are looking for in the pigments in this experiment? which is more polar
- hydroxyl group (-OH) - more polar
2. carbonyl group (C=O)
what is silica in this experiment? what is the developing solvent?
silica –> stationary phase (does not move)
developing solvent –> mobile phase (moves)
where are pigments in leaves/petals located? what is their function?
in thykaloid membranes of chloroplasts
-function in the light reactions of photosynthesis
what is the primary pigment molecule in light reactions? where is it located? what are accessory pigments? where are they located? what do accessory pigments do?
- chlorophyll a, located in reaction center of PSI and PSII
- chlorophyll b, carotenes, and xanthophylls, located outside of reaction centers
- accessory pigments absorb additional wavelengths of lights and transfer this energy to chlorophyll a –> increase efficiency of photosynthesis and make it possible to use a greater range of wavelengths
what do non-photosynthetic pigments contribute? what are they, where are they located? what are examples of these?
- contribute to colours of flowers/fruits/leaves/stems/roots
- they are water soluble compounds –> located dissolved in the fluid of vacuoles
- anthocyanins, anthoxanthins
what needed to be added to the plants ass they were being crushed? why?
- an extracting solvent
- it dissolved the pigments when they were extracted from the leaves