Study the following comprehension and answer the questions that follow.
It has been found that the chloroplasts is a membranous structure, consisting of 3
membranes. The third layer forms stacked sack like structures called as grana. It is believed
to be a site for trapping of solar energy. Substances found in chloroplast which capture
sunlight are called photosynthetic pigments. There are several types of photosynthetic
in the process to produce organic molecules like glucose in
pigments involved
plants.
Where is chlorophyll and other pigments present in the plant ?
i.
Name some parts where you think photosynthesis occurs.
ii. Do you think new reddish leaves of plants also carry out photosynthesis ? What could be role
of their colour ?
What makes chloroplast appear completely different from other cell organelles ?
Answers
Answer:
i. The chlorophyll and other pigments are located in special structures of chloroplasts.
ii. Photosynthesis occurs in two phases - light reaction and dark reaction. The dark reaction occurs in the stroma of the chloroplasts. The light reaction takes place in the thylakoids of the chloroplasts.
iii. Yes, they carry out photosynthesis as they contain chlorophyll but the colour is masked due to accessory pigments such as carotene. The role of the colour could be that it serves as a attractive pigment.
iv. 1) Chloroplasts are considered to be the food factories of the plant.
2) They contain a green coloured photosynthetic pigment called chlorophyll.
3) Chlorophyll traps the solar energy and reduce the carbondioxide to glucose.
4) The presence of photosynthetic pigments (chlorophyll) or light harvesting structures make the chloroplast appear completely different from other organelles.