In 1665, Robert Hook discovered cell, which is comes from latin word and it means a little room.He discovered dead cells. Nucleus is the brain of the cell because it control all the activities of cells. The largest cell which we can see in our naked eye is ostrich egg.In cell, Lysosome is known as suicidal bag.It is found only in animal cell, absent in plant cell.Ribosomes helps in protein synthesis. Cell wall is the non living part of the cell, which is only found in plant cell.Cell wall is the outermost layer of the plant cell.Living cells were discovered by Leeuwenhoek in 1674, in pond water for the first time.The hydrolytic enzymes present in the Lysosomes are synthesized in rough endoplasmic reticulum.Chromosome are made up of DNA and protein.The undefined nuclear region of prokaryotes is also known as Nucleoid.Silver nitrate solution is used to study golgi apparatus.In biology, the cell is the basic structure of organisms. All cells are made by other cells. The environment outside the cell is separated from the inside of the cell by the cell membrane. Inside some cells, parts of the cell stay separate from other parts by plasma membranes.All living things are made up of cells.

• Cells are made up of proteins and organelles.
• Groups of cells form tissues and systems.
• The main purpose of a cell is to organize. Cells hold a variety of pieces and each cell has a different set of functions. Some cells move throughout the body, like blood cells. Others are attached to one another like muscle cells, and they stay in one place. Some cells, like skin cells, divide and reproduce quickly. Nerve cells, do not divide or reproduce except under usual circumstances.
• The longest cells in the human body are the motor neurons. They can be up to 4.5 feet (1.37 meters) long and run from the lower spinal cord to the big toe.
• Red blood cells carry oxygen around the body. They are created inside the bone marrow of your bones.The largest cell, a fertilized egg, is too small to be seen with the naked eye.
• Human cells have a membrane that holds the contents together. However, this membrane is not just a sac. It has receptors that identify the cell to other cells.
• Within the cell membrane are two major compartments, the cytoplasm and the nucleus. The cytoplasm contains structures that consume and transform energy and perform the cell’s functions. The nucleus contains the cell’s genetic material and the structures that control cell division and reproduction.
• Although there are different types of cells, most cells have the same components. A cell consists of a nucleus and cytoplasm which is contained within the cell membrane. The cell membrane regulates what passes in and out of the cell. Inside every cell are mitochondria. Mitochondria are tiny structures that provide the cell with energy.
• Cells are specialised to their function. This is known as specialised cells. Each group of specialised cells organises to form what is known as a tissue. For example, the heart muscular cells which organise with each other to form the muscular tissue of the heart wall.