What is a cell?

A cell is considered as the smallest unit of life without which life cannot be imagined.

"A cell is the building block of life as it can replicate itself and form a structure.

All living organisms are made up of cells. They may be unicellular (single cell) or multicellular (many cells). Cells are the basic blocks to building a body structure and converting food into energy and nutrient for the body.

Cells are of different shapes and sizes and have various components that perform multiple functions in an organism. Cells contain several organelles that perform various functions in the life process. The structure of an organelle is different from each other as it contains heredity material which is unique for every living organism.

A cell is studied under cell biology about cell structure and its function.

Cell biology is the detailed study of all the functional, structural and biological units of the cell organelle.

Discovery of cell

The discovery of cells has brought a remarkable change in medical science. It helped in defining how living organisms are made of. The word "cell" has taken from the Latin word "cella," which means "small room". A small consist of lots of working modules. Initially, Robert Hook saw the cell with the help of a microscope (a piece of cork was observed under a microscope) in 1665. Still, due to the limited magnification of his microscope, Robert Hooke couldn't see the detailed structure under a microscope, and he concluded them as non-living entities.

After that, another scientist named Anton van Leeuwenhoek's described a living cell with a movement observed by a highly magnified microscope. Therefore he stated that previous non-living entities were living entities named animalcules.

In the 1830s, two scientists (colleagues also) observed the cells deeply. Schneider observed plant cells, and Schwann observed animal cells and stated that all living organisms are made up of single or multiple cells, and the study of cell concept was named cell theory.

Later, a Scottish scientist (botanist) named Robert Brown displayed the internal structure of the cell. He stated that a nucleus is present in the cells of orchids.

Cell theory

The German scientist Rudolf Virchow, Theodor Schwann, and Matthias Schleiden had proposed cell theory that stated that a cell is the basic unit of life as all species on earth are composed of cells, and a cell can reproduce (arise of the new cell).

A new cell theory (modern) stated that cells provide energy to the body and all cells have the same chemical composition. A cell contains the genetic(hereditary) information of a living being.

The various characteristics of the cell are as follows:

• The cell provides a structure to the living organism's body.
• Every cell consists of a nucleus.
• A cell also has membrane-bound organelles in the cytoplasm.
• Each cell is divided into several cells to form a structure.
• The nucleus of every cell contains the hereditary information of a living organism necessary for reproduction and cell growth.
• Lysosomes digest unwanted materials in the cell.
• A plasma membrane surrounds each cell.
• Every cell contains chromosomes that contain DNA, known as genes of living organisms.
• The component of the cell has an organization.
• A cell can bring evolution.
• A cell can reproduce and respond.
• Cells can grow and develop.
• A cell can use the energy produced by itself by the food taken by a living organism.
• A cell can respond to stimuli.

What are the functions of the cell?

1. A cell provides structure and support.
2. A cell allows the transport of substances.
3. It facilitates growth mitosis.
4. Aids in production
5. A cell can produce energy.

There are two types of cells.

1. Prokaryotic cell
2. Eukaryotic cell

There are hundreds of different types of cells present in the human body, but we only consider some of them here.

1. Bone cell
   Bone cells primarily are of three types- Osteoclasts, Osteoblasts, and Osteocytes.
2. Stem cell
   Stem cells can be found in adult tissues and embryos, such as bone marrow.
3. Blood cells
   There are also three types - Red blood cells, white blood cells, and platelets.
4. Muscles cells
   Muscles cells are also known as myocytes and are long and tubular cells.
5. Sperm cell
   Only present in the male human body and the reason for reproducing a new life.
6. Fat cell
   Fat cell stores the fat in the body and are called adipocytes. Fat cells provide energy to the body as per requirement.
7. Female egg cell
   Only present in the female body combine with male sperm and produce an egg that results in the formation of a baby.
8. Nerve cell
   It has two major parts - the nerve process and the cell body. Nerve cells are part of the body's nervous system called neurons. They are the communication system of the body.

Components and structure of a cell

• Cell wall
• Cell membrane
• Cell organelles
  • Ribosomes
  • Vacuoles
  • Chloroplast
  • Nucleus
  • Nuclear membrane
  • Endoplasmic reticulum
  • Mitochondria
  • Golgi bodies