- Books Name
- CBSE Class 7 Science Book
- Publication
- Param Publication
- Course
- CBSE Class 7
- Subject
- Science
Photosynthesis
The process by which green plant prepare their food in the presence of sunlight, (Carbondioxide)CO2 , water, chlorophyll.
There are four requirement for photosynthesis.
(A) Sunlight:- It comes from sun & provide energy for photosynthesis.
(B) Carbon dioxide (CO2):- It is obtained from air and taken through tiny pores called stomata present on the under surface of leaves.
(C) Chlorophyll:- The chlorophyll is present in the chloroplast. Chloroplast regarded as Kitchen of cell and present in Green leaves.
• Besides chlorophyll cetain other pigments are also present in plants like :
(a) Carotenes : Organe in colour e.g. Carrot.
(b) Xanthophylls : Orange yellow in colour e.g. Maize.
(c) Phycobilins : Different colours like red, violet e.g., Blue-green algae, brown algae etc.
(D) Water (H2O):- They are obtained from the soil by the roots of plants and are transported to the leaves.
Plants have Vascular tissues called Xylem & Phloem.
(i) Xylem transport water and minerals to the leaves.
(ii) Phloem transport food (Sucrose) to various part of plant.