Cell
(i) within the living organisms, Cells are basic structural units.
(ii) Cells is also compared to bricks. Bricks are assembled to create a building. Similarly, cells are assembled to create the body of each organism.
(iii) it's the fundamental structural and functional unit of life. All organisms are made from cells
(iv) Sub cellular structures of cell include organelles, the cell wall, and, if present, the nucleus.
(v) Size of the cell is 1 to 100 micrometer.
(vi) Cells are produced by the division of pre existing cell. Each cell contains genetic material that's passed down during reproduction process.
(v) Cells within the living organisms are complex living structures unlike non-living bricks.
(vi) All basic chemical and physiological functions like repairing, growth, excretion movement, immunity, communication, and digestion - are happen inside cells.

Discovery of the Cell:
(i) In 1665, English people scientist scientist observed slices of cork which is a component of bark of the tress, under a straightforward magnifying device. He noticed partitioned boxes or compartments within the cork slice.
(ii) These boxes gave the look of a honeycomb. He also noticed that these boxes were separated from the opposite by a wall or partition. Hooke named them ‘cell’ for every box. Hooke observed as boxes or cells within the cork were actually dead cells. These boxes gave the impression of a honeycomb.Types of cell:
1. Prokaryotic Cells:
The cells having nuclear material without nuclear membrane are termed prokaryotic cells. The organisms with these styles of cells are called prokaryotes (pro: primitive; karyon: nucleus). Examples: bacteria and blue chlorophyte.

2. Eukaryotic cells:
The cells having well organised nucleus with a nuclear membrane are designated as eukaryotic cells. All organisms apart from bacteria and blue chlorophyte are called Eukaryotes. (Eu : true; karyon: nucleus).

Organisms Show Variety in Cell Number, Shape and Size:
Millions of living organisms have cells with different shapes and sizes. Their organs also vary in shape, size and number of cells.
(i) shape has trillions of cells which vary in several size and shapes. Different groups of cells perform a range of functions. Organisms fabricated from quite one cell are called multicellular organisms. An organism with billions of cells Starts life as one beast cell. The fertilised ovum multiplies by dividing process and also the number of cells increases for development.
(ii) The single-celled organisms are made from single cell called unicellular organisms. one celled organism performs all the required functions that multicellular organisms perform
(iii) A single-celled organism, like amoeba, captures and digests food, respires, excretes, grows and reproduces. Similar functions in multi-cellular organisms are administrated by groups of specialized cells forming different tissues. Tissues, in turn, form organs.

1. Shape of Cells:
(i) Generally, cell’s shapes are rounding, spherical or elongated. Some sorts of cells are long and pointed at both ends. They exhibit spindle shape. Some sorts of cells are branched just like the somatic cell or a neuron, which receives and transfers messages for helping to manage and coordinate the working of various parts of the body.(ii) Components of the cell are enclosed during a membrane. This membrane provides shape to the cells of plants and animals. semipermeable membrane is a further covering over the cell wall in plant cells. It gives shape and rigidity to those cells.

2. Size of Cells:
(i) The cell’s size in living organisms could also be as small as a millionth of a metre (micrometre or micron) or could also be as large as some centimetres.
(ii) Most of the cells are microscopic in size and aren't visible to the eye. they have to be enlarged or magnified by a microscope for seeing.
(iii) the tiniest cell is 0.1 to 0.5 micrometre in bacteria. the most important cell measuring 170 mm ×130 mm, which is that the egg of an ostrich.
(iv) the dimensions of the cells has no relation with the dimensions of the body of the animal or plant.



Cell Structure and Function:
(i) Each organ within the living organisms performs different functions like digestion, assimilation and absorption. Similarly, different organs of a plant perform particular/ specialized functions. Example: roots help within the absorption of water and minerals.
(ii) Each organ is further made from smaller parts called tissues. A tissue may be a group of comparable type cells performing a selected function.

Parts of the Cell:
The basic components of a cell are cell wall, cytoplasm and nucleus
3. Nucleus:
(i) it's vital component of the living cell. it's generally dense and spherical organelle and located within the centre of the cell. It is seen easily with the assistance of a microscope. Nucleus is separated from the cytoplasm by a membrane called the nuclear membrane. This membrane is additionally porous and allows the movement of materials between the cytoplasm and therefore the inside the nucleus.
(ii) it's incorporates nucleolus, thread-like structures called chromosomes. These carry genes and help in inheritance or transfer of characters from the fogeys to the offspring. The chromosomes is seen only if the cell divides.
(iii) Genes contains genetic codes which are liable for the unique physical character of an animal or a plant.
(iv) Nucleus acts as control centre of the activities of the cell. the whole content of a living cell is understood as protoplasm. It includes the cytoplasm and therefore the nucleus. It controls all the metabolic activities of cell.
(v) Nucleus is that the storehouse of genes. Without nucleus, cell can neither survive nor shows specialized activities.