Biology 1st Paper (Botany) · Classes 11-12 · Chapter 1 · 1.1

Protoplast, Protoplasm and Non-living Cell Contents.

Is everything inside the cell wall alive? No. Some of it is living, and some is only stored or dumped there. This note teaches you to tell the two apart, and to see which box a familiar thing like chlorophyll falls into.

1. Protoplast and protoplasm

The cell wall is non-living. Everything the wall encloses, beneath it, is the protoplast. The protoplast has two parts: living protoplasm and non-living matter.

The transparent, sticky, jelly-like semifluid, colloidal living substance inside the cell is protoplasm. The scientist Purkinje first used the word in 1840. In Greek, proto means first and plasma means formation.

According to Huxley, protoplasm is the physical basis of life, because it carries out all the basic biological work of the cell.

2. What protoplasm is like

Physically, protoplasm holds 70%-90% water. It is a translucent, colourless, jelly-like semifluid sticky substance, granular and colloidal. It can change from jelly to fluid and back as its surroundings change. Its specific gravity is higher than that of water. Heat, acid and alcohol make it coagulate.

Chemically, among the organic compounds protein is the most abundant, followed by carbohydrate, lipid and vitamin. Among the inorganic compounds, water is the most abundant.

Biologically, protoplasm responds to stimuli. It does all the metabolic work: food making, intake, assimilation, respiration, growth and reproduction. It takes in and loses water by osmosis.

3. How protoplasm moves

The stream-like movement seen in the protoplasm of a walled cell is cyclosis, or streaming. It is of two kinds: unidirectional and multidirectional.

Inside the cell the protoplasm flows like a stream. The blue dots ride along in it. Run the two kinds of cell one after the other.

In rotation, the protoplasm circles in one direction along the wall around a single vacuole, as in the cells of Hydrilla (the leaf of the water weed). In circulation, it moves irregularly in various directions around several vacuoles, as in the cells of Tradescantia. Swapping the names and examples is the commonest slip, so match them below.

4. The tree of cell contents

Protoplasm has three main parts: the plasma membrane (cell membrane), the cytoplasm and the nucleus.

The other part of the protoplast holds the non-living products of cell metabolism (ergastic substances). They fall into three classes: reserve materials, secretory products and excretory products. Do not mix up protoplast, protoplasm and cytoplasm. Open the branches and see which sits inside which.

5. Three boxes for non-living matter

Reserve materials are carbohydrate, protein and fat. The soluble sugars are glucose, sugar and inulin. The insoluble ones are starch grains, cellulose and glycogen. Oils and fats lie as droplets.

Secretory products are pigments, enzymes, hormones and nectar. The notable pigments are chlorophyll, anthocyanin and carotenoids. So chlorophyll is secretory, not reserve.

Excretory products are resin, tannin, gum, latex, alkaloids, organic acids, volatile oils and mineral crystals. Plants have no separate system for getting rid of waste, so these pile up inside the cells.

The chief mineral crystal is calcium oxalate. The needle-shaped ones are raphides. Crystals of calcium carbonate shaped like a bunch of grapes are cystoliths. Now sort fourteen chips into the three boxes.

6. The cell is where the work happens

Glycolysis, respiration, photosynthesis, cell division, protein synthesis and enzyme making all take place in the cytoplasm or in the organelles. That is why the cell is called the base of all the activities of a living thing.

7. Check yourself

Three questions in the exam's style. Start with the first.

In the second, read the names carefully.

The last one is short, but it has a trap.

The whole note on seven cards.

Source: Biology 1st Paper (Botany), Classes 11-12 (NCTB), Chapter 1 “Cell and Its Structure”, section 1.1.