Structure of chloroplast:

These are green plastids that consist of the chlorophyll pigment. Chloroplasts are flat disc shaped structures. It is a double membraned structure. Chloroplast consists of the membranous system consisting of grana, the stroma lamellae, and the matrix stroma. The stacked portion of membrane-bounded, flattened discs of the chloroplasts is known as grana. Each disc-like structure of grana is known as a thylakoid. Grana are made up of disc-like structures known as thylakoids. Stack of thylakoids are placed on each other to form a stack-like structure called Granum. Light reaction takes place in the granum of the chloroplast.. The dark reaction takes place in the stroma of the chloroplast. The colourless fluid of the chloroplast is known as stroma. Stroma lamellae are membranous structure the interconnects the two thylakoids. Photosynthetic pigments: Photosynthetic pigments are substances that have an ability to absorb light, at specific wavelengths. The chromatographic separation of the leaf pigments revealed that four major pigments contribute to the colour of the leaves: Chlorophyll a (bright or blue green) Chlorophyll b (yellow green) Xanthophylls (yellow) Carotenoids (yellow to yellow-orange) Most of the photosynthesis takes place in the blue and the red region of the visible spectrum (VIBGYOR), but some photosynthesis also does take place at the other wavelengths of the visible spectrum. Though chlorophyll a is the major pigment responsible for trapping light, other thylakoid pigments like chlorophyll b, xanthophylls and carotenoids, which are called accessory pigments, also absorb light and transfer the energy to chlorophyll a