From the last chapter, we recall that all living organisms are made of cells. In unicellular organisms, a single cell performs all basic functions. For example, in Amoeba, a single cell carries out movement, intake of food and respiratory gases, respiration and excretion. But in multi-cellular organisms there are millions of cells.
Let us compare their structure and functions.
Do plants and animals have the same
structure? Do they both perform similar
There are noticeable differences between the two. Plants are stationary or fixed – they don't move. Most of the tissues they have are supportive, which provides them with structural strength. Most of these tissues are dead, since dead cells can provide mechanical strength as easily as live ones, and need less maintenance.
6.2.1 MERISTEMATIC TISSUE
1. Take two glass jars and fill them with water.
2. Now, take two onion bulbs and place one on each jar, as shown in Fig. 6.1.
When we breathe we can actually feel the movement of our chest. How do these body parts move? For this we have specialised cells called muscle cells (Fig. 6.8). The contraction and relaxation of these cells result in movement.