There are two kinds of forces, or attractions, that operate in a molecule— intramolecular and intermolecular . Let's try to understand this difference through the following example. Figure of towels sewn and Velcroed representing bonds between hydrogen and chlorine atoms We have six towels—three are purple in color, labeled hydrogen and three are pink in color, labeled chlorine . We are given a sewing needle and black thread to sew one hydrogen towel to one chlorine towel. After sewing, we now have three pairs of towels: hydrogen sewed to chlorine. The next step is to attach these three pairs of towels to each other. For this we use Velcro as shown above. So, the result of this exercise is that we have six towels attached to each other through thread and Velcro. Now if I ask you to pull this assembly from both ends, what do you think will happen? The Velcro junctions will fall apart while the sewed junctions will stay as is. The attachment created by Velcro...
PLANT TISSUES I. Meristematic tissue: Characteristics: 1. Cells are small. 2. Cell walls thin. 3. Nuclei large and conspicuous. 4. Cells are without vacuoles. 5. Cells actively dividing. Location: 1. Tip of roots, tips of stem and branches. 2. Between bark and wood of the tree and is responsible for increase in the diameter of the stem. II. Permanent Tissues: A. Simple Permanent Tissues: (i ) Protective Tissue: Characteristic: Cell wall thick. Location: Surface of roots, stems, leaves Function: Provide protection Example: Epidermis of leaves, which secretes a waxy water-proof substance. (ii) Supporting Tissue: Parenchyma Collenchyma Sclerenchyma 1. Characteristics a. Spherical. b. Cell wall thin. c. Large intercellular spaces present between the cells. d. Consists of living cells at maturity. a. Elongated cel...
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