Chlorophyll and carotenoids relationship poems

Leaf Chromatography | Science project |

The biochemical and cytological mechanisms responsible for the differences in red color quality of apples (Malus domestics Borkh.) were investigated. During most of the growing season, leaves contain more chlorophyll than any other and the orange pigments are called carotenoids (carotenoids are easy to . Chlorophyll is the molecule that absorbs sunlight and uses its energy to take in one form of power, light; and produce another power, chemical difference." the green colour fades and is replaced by the oranges and reds of carotenoids.

Cut out strip of coffee filter paper about 6 inches long and 1 inch wide.


Attach the strip to the pencil with a piece of tape. Make sure the bottom of the strip hangs straight. Adjust the length of the filter paper strip so that the bottom just touches the green liquid in the cup. Checking every couple minutes, wait for the band of solvent to migrate to the top of the filter paper. Different colored bands should become evident along the strip.

Study your strip, and try to identify the pigments. Results Your results will vary depending on the types of leaves that you chose and how careful your leaf chromatography technique was.


You might not see all the pigments. An orange-colored band is likely to be near the top. Below that, you should see a yellowish band, a blue-green band, and a greenish-yellowish band, respectively.

When you ground up your leaves, the pulp was probably green because of the overwhelming amount of chlorophyll. You were instructed not to use water as a solvent because the pigments in leaves are not very soluble in it: The orange colored band, made of the pigment called carotenoids.

The relationship between chlorophyll and the carotenoids in the algal flagellate, Euglena.

The yellow xanthophylls are the next most soluble, followed by the blue-green chlorophyll A. The least soluble pigment is the yellow green chlorophyll B. Jean Senebier, a swiss pastor, found that "fixed air" CO2 was taken up during photosynthesis, and Theodore de Saussure discovered that the other reactant necessary was water. The final contribution to the story came from a German surgeon, Julius Robert Mayer rightwho recognised that plants convert solar energy into chemical energy.

The plants take in one form of power, light; and produce another power, chemical difference. The glucose sugar is either directly used as an energy source by the plant for metabolism or growth, or is polymerised to form starch, so it can be stored until needed. The waste oxygen is excreted into the atmosphere, where it is made use of by plants and animals for respiration.

Chlorophyll as a Photoreceptor Chlorophyll is the molecule that traps this 'most elusive of all powers' - and is called a photoreceptor. It is found in the chloroplasts of green plants, and is what makes green plants, green. The basic structure of a chlorophyll molecule is a porphyrin ringco-ordinated to a central atom.

This is very similar in structure to the heme group found in hemoglobin, except that in heme the central atom is iron, whereas in chlorophyll it is magnesium. Click for 3D structure file There are actually 2 main types of chlorophyll, named a and b. Both of these two chlorophylls are very effective photoreceptors because they contain a network of alternating single and double bonds, and the orbitals can delocalise stabilising the structure. Such delocalised polyenes have very strong absorption bands in the visible regions of the spectrum, allowing the plant to absorb the energy from sunlight.

The different sidegroups in the 2 chlorophylls 'tune' the absorption spectrum to slightly different wavelengths, so that light that is not significantly absorbed by chlorophyll a, at, say, nm, will instead be captured by chlorophyll b, which absorbs strongly at that wavelength.

Thus these two kinds of chlorophyll complement each other in absorbing sunlight. Plants can obtain all their energy requirements from the blue and red parts of the spectrum, however, there is still a large spectral region, between nm, where very little light is absorbed.

This light is in the green region of the spectrum, and since it is reflected, this is the reason plants appear green. Chlorophyll absorbs so strongly that it can mask other less intense colours.

Some of these more delicate colours from molecules such as carotene and quercetin are revealed when the chlorophyll molecule decays in the Autumn, and the woodlands turn red, orange, and golden brown.