What is the difference between chlorophyll and xanthophyll

This is also a difference between carotene and xanthophyll. Carotene is one of the two types of carotenoids that mainly occur in plant parts including fruits and vegetables. It is responsible for giving an orange color to the plant. Additionally, it does not contain any oxygen atoms in its structure. In contrast, xanthophyll is the other type of carotenoid responsible for giving a yellow color to the plant.

Significantly, it contains a single oxygen atom in its structure. Both carotene and xanthophyll serve as accessory pigments which capture and pass sunlight to chlorophyll a. However, the main difference between carotene and xanthophyll is the color they give to the plant. Szalay, Jessie. View all posts. Leave a Reply Cancel reply. Because they contain a special primitive form of DNA, and have a double outer membrane the outer one would be from the host cell, while the inner one is structurally similar to that of a bacterial cell membrane , we think they were derived from photosynthetic bacteria billions of years ago.

They are also approximately the same size as a bacterium. Carotenoids are an ancient class of pigments, thought to have evolved perhaps 3 billion years ago. Figure 3. Spectral absorbance curve for chlorophyll and carotenoids.

Image courtesy of D. Reed, TAMU. One function of carotenoids is to absorb light in wavelengths that chlorophyll is inefficient at absorbing, such as the blue-green to green wavelengths. Figure 3 shows the absorption spectrum for chlorophyll and carotenoids.

Along the horizontal line is the range of wavelengths that correspond to visible light, and which is nearly the same as that used by plants for photosynthesis. Notice that short wavelengths correspond to the blue portion of the spectrum, while longer wavelengths encompass the red portion.

You can easily see that chlorophyll preferentially absorbs the blue and red wavelengths, and does poorly in the green range. That is why leaves appear green, because light reflected from leaf to your eye is enriched in the green wavelengths relative to the blue or red. Figure 4. Chlorophyll antennae and associated pigments molecules carotenoids. Meanwhile, the carotenoids are absorbing maximally at those wavelengths where chlorophyll does poorly light blue to green.

Once that light energy is absorbed, the carotenoids pass that energy on to a neighboring chlorophyll molecule. In the leaf, chlorophyll molecules and carotenoids are situated near each other in clusters, somewhat analogous to a dish antenna see Figure 4. This physical arrangement maximizes the capture of a photon a packet of light energy, a concept courtesy of quantum physics , because if chlorophyll molecules were just individually arraigned throughout the chloroplast, most photons would miss them and the potential to harness their energy would be wasted.

Because carotenoids assist in absorbing photons for photosynthesis, they have been called accessory pigments. But over the past 30 years, it has become apparent that they have a second function, no less important than the first. And that is to divert excess energy away from the chlorophyll molecules. This is exactly opposite of its functioning as I have just described it, which may seem confusing.

But in fact, it makes great sense. When too much light strikes a leaf, that energy has to be dissipated. When just enough light reaches a leaf, it is used to move electrons and protons so the leaf can make sugars during photosynthesis.

But if too much energy comes in, the electron transport chain ETC , which is responsible for moving the electrons, gets overloaded. A note here: the ETC is not really a chain in the literal sense. Rather, it is a series of molecules that alternately accept or donate electrons, all the while moving them in a single direction. Think of it as a bucket brigade at a fire, where each person transfers a bucket of water to the next person, except that instead of moving water, the molecules move electrons.

When the ETC gets overloaded, bad things can happen. In one case, electrons that are energized when light strikes the chlorophyll molecule can be dumped onto oxygen molecules, creating a type of new type of oxygen known as superoxide O2-, essentially oxygen with an extra negative charge. This is a very dangerous molecule, because it can react with membranes and proteins in the chloroplast, causing severe damage and eventual death.

Flora oder Allgemeine Botanische Zeitung , 4 , Procedures for the extraction, separation and estimation of the major fat-soluble pigments of hay. Journal of the Science of Food and Agriculture , 5 1 , Spruit-van Der Burg. Emission spectra of luminous bacteria.

Biochimica et Biophysica Acta , 5 , Blaauw-Jansen , J. Komen , J. Thomas , A. Kluyver , J. On the relation between the formation of assimilatory pigments and the rate of photosynthesis in etiolated oat seedlings. Therefore, they are not soluble in water.

Instead, they are soluble in fat. Also, in photosynthetic organisms, carotenoids play a role of accessory pigments. Though carotenoids are unable to transfer absorbed light into the photosynthetic pathway directly, they can transfer their light to chlorophylls and assist the photosynthesis. Hence, they are present within the chloroplasts and even in cyanobacteria, as well.

Moreover, carotenoids are popular as important antioxidants as well. They are capable of deactivating free radicals; hence, provide health benefits.

Furthermore, they have an anticancer property. Also, some carotenoids can convert into vitamin A, which is vital for the good vision and growth and development. Not only that, carotenoids are popular as anti-inflammatory compounds that prevent inflammatory conditions. Besides, carotenoids provide immune benefits as well.

Chlorophylls are green colour plant pigments while the carotenoids are yellow to red colour plant pigments. Therefore, this is the key difference between chlorophyll and carotenoids. Furthermore, there are several types of chlorophylls; chlorophyll a, b, c and d while there are only two types of carotenoids.

They are the carotenes and xanthophylls.