Last seen: Jan 25, 2021
In the absence of Golgi apparatus, the following problems will arise: The secretory activities. of the cell will cease to occur. The broken membr...
The plasma membrane acts as a mechanical barrier to the protoplasm which regulates transport of materials into and out of cell maintaining the identit...
The ribosomes attached to the endoplasmic reticulum as well as present freely in the cytoplasm of all active cells are the site for the synthesis of p...
Lysosomes contain digestive enzymes that are capable of digesting the whole cell. During breakdown of cell structure, when the cell gets damaged, lyso...
If the organisation of a cell gets destroyed due to any reason then lysis of the whole cell will occur due to the enzymes released by lysosomes.
Mitochondrion Plastid
The differences between prokaryotic cell and eukaryotic cell are as follows: Prokaryotic cell 1. Size: generally small (1-10 μm). 2. Nuclear reg...
Plasma membrane permits the entry and exit of only selected materials in the cell. It also prevents movement of selected materials. Therefore, the pla...
CO2 moves in and out of the cells by the process of diffusion which involves movement of molecules from higher concentration to lower concentration ac...
All living organisms are made up of cells. Thus, cell is the structural unit of life. Each cell acquires distinct structure and function due to the or...
Robert Hooke discovered the cell in 1665. He examined a thin slice of cork through a self designed primitive microscope and saw that the cork resemble...
(a) The atomic number is 5. The mass number is 11. The valency is 3. (b) The element 'X’ is boron. (c) Aryan’s friend showed the value of helpin...
Atomic number - Gives the number of protons (Z) Mass number - Gives the number of protons and neutrons (A) Isotopes - When atoms of same element...
Rutherford’s α-particle scattering experiment: Fast moving α-particles were made to fall on a thin gold foil. Particles have +2 charge and 4u mass, ...
Atoms of same element with same atomic number but different mass number are isotopes. Characteristics: (1) Physical properties of the isotopes ar...
To understand the implications of Rutherford’s a-particle scattering experiment: Activity: Let a child stand in front of a wall with his eyes closed...
Bohr’s model of an atom is the best model and is correct because it gives the explanation of nucleons (protons and neutrons) in the centre and how ele...
Protons are heavy with mass 1 unit and hence are concentrated in the centre of the atom. The mass of electrons is negligible i.e.1/1800 times less tha...
Activity Take a scale, rub it on hair, try to attract a small bit of paper. Now divide the bit of paper further into smaller pieces. Again bring...
The combining capacity of an atom is called its valency. There are 2 types of valencies. Covalency: When an atom share electrons have combining c...