TOPIC : ANIMAL CELL

INTRODUCTIONAll function of the bodies of living organisms are

performed by various system. These systems are groups of organs performing one principal junction. Each organ is made up of tissues and each tissue is made up of cells. The cell is the basic structure and functional unit of life. Cells are also known as the building blocks of life. They are of two types : 1) Animal cell

2)Plant cell Animal cells are eukaryotic cells, or cells with a

membrane bound nucleus. It consists of:

NUCLEUSIt is a spherical body

containing many organelles, including the nucleolus . The nucleus controls many of the functions of the cell & contains DNA. The nucleus is surrounded by the nuclear membrane.

RIBOSOMESSmall organelles

composed of RNA- rich cytoplasmic granules that are sites of protien synthesis.

MITOCHONDRIA

It is a spherical to rod shaped organelles with a double membrane. The mitochondria converts the energy stored in glucose into ATP for the cell.

LYSOSOMEThese are the round organelles surrounded by a membrane and containing digestive enzymes. This is where the digestion of cell nutrients takes place.

Golgi bodiesIt is flattened,

layered, sac like organelle that look like a stack of pancakes and is located near the nucleus. It produces the membrane that surrounds the lysosomes.

Endoplasmic reticulumThey are of two types : 1) Rough

endoplasmic reticulum: transports materials through the cell & produces protiens in sacs called cristinae.

2) smooth endoplasmic reticulum:

it contains enzymes and produces and digests fats.

Plasma cell membraneIt is the thin layer of protien and fat that surrounds the cell. The cell membrane is semi permeable, allowing some substances to pass into the cell and blocking others.

conclusionCell is the structural & functional unit of life.

Structurally the cell is formed of three major parts: plasma membrane , cytoplasm & its contents and nucleus. In animal cell, cell wall is absent. Vacuoles may present or absent. Animal cell possess both centrioles and centrosomes. In animal cell , food is present in the form of glycogen , which is a polysacchride.