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Cell and Cell Structure Introduction
Did You Know? - The cells that make up our body are so small that you would fit over 200 of them on the full stop at the end of this sentence. The word cell is derived from the Latin word cellula which means a little room. It was the British botanist Robert Hooke who, in 1664, w..
Cell wall
The cell wall is present only in plant cells. It is made up of a complex polysaccharide carbohydrate called cellulose. Its function is to give strength and rigidity to the cell. It is non-living..
9. Somatic mutation theory
According to this theory genetic mutations occur and accumulate with increasing age, causing cells to deteriorate and malfuncti..
Electrochemical Cells
The fact that chemical reactions produce electrical effects was discovered accidentally in 1791 by Luigi Galwani, professor of anatomy at the University of Bologna, Italy. He found that an electric current flowed across two dissimilar metals between which was a moist substance. In his case, the moi..
Theory of Continuity of Germplasm
This was proposed by Weismann who did not agree with Lamarck's theory of inheritance of acquired characters. To prove his point, he cut off the tails of many successive generations of mice. This resulted in forced disuse of the tail. According to the theory of use and disuse, t..
Cell Wall
The cell wall is present only in plant cells. It is made up of a complex polysaccharide (carbohydrate) called cellulose. Its function is to give strength and rigidity to the cell. It is non-living...
The cell wall is present only in plant cells. It is made up of a complex polysaccharide (carbohydrate) called cellulose. Its function is to give strength and rigidity to the cell. It is non-living...Cell Organelles
The word organelles (Latin: organas=instrument) is used to describe the living structures inside the cytoplasm, having definite shape, structure and functions. The various cell organelles in a cell can be broadly classified into the following two categories i. Membrano..
7. Wear and tear theory
According to this theory, cells and tissues have vital parts that wear out resulting in ageing. DNA undergoes continual damage throughout life, due to various reasons. DNA damage leads to malfunctioning of genes, proteins, cells and deterioration of tissues and organs...
6. Cross linking theory
According to this theory, the accumulation of cross linked proteins damages cells and tissues and slows down bodily processes resulting in ageing. In a process called non-enzymatic glycosylation, glucose molecules attach themselves to proteins resulting in a chain of chemical re..
Ion exchange theory
Both cations and anions have a tendency to get adsorbed on the surfaces of the cell walls, and exchange with ions present in the soil solution. This process of exchange between the adsorbed ions and ions in solution is known as ion exchange. Mineral elements can be absorbed in the form of..
Both cations and anions have a tendency to get adsorbed on the surfaces of the cell walls, and exchange with ions present in the soil solution. This process of exchange between the adsorbed ions and ions in solution is known as ion exchange. Mineral elements can be absorbed in the form of..See what our Users say :
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