The Basic Features of The Cell

Despite the diversity among cells, three basic features are common to all cell types. All cells have an outer boundary, an interior substance, and a control region. Organelle are parts of cell which can performs special function.

Plasma Membrane

The cell’s outer boundary, called the plasma membrane (or the cell membrane), covers a cell’s surface and acts as a barrier between the inside and the outside of a cell. All materials enter or exit through the plasma membrane.

Cytoplasm

The region of the cell that is within the plasma membrane and that includes the fluid, the cytoskeleton, and all of the organelles except the nucleus is called the cytoplasm. The part of the cytoplasm that includes molecules and small particles, such as ribosomes, but not membrane-bound organelles is the cytosol.

Control Center

Cells carry coded information in the form of DNA for regulating their functions and reproducing themselves. The DNA in some types of cells floats freely inside the cell, it’s called as nucleoid. Other cells have a membrane-bound organelle that contains a cell’s DNA. This membrane-bound structure is called the nucleus.

Organelle

Organelle is any of several part of cell, or membrane-bound structures with specialized functions, suspended in the cytosol of cells or extended outer the cell membrane.

Separation of cell functions into distinct compartments—the organelles—benefits the eukaryotic cell. One benefit is that chemical reactions that would normally not occur in the same area of the cell can now be carried out at the same time.

Comparing the Two Basic Cell Types 

With the development of better microscopes, scientists observed that all cells contain small, specialized structures called organelles. Many, but not all, organelles are surrounded by membranes. Each organelle has a specific function in the cell.

Cells can be divided into two broad groups: those that contain membrane-bound organelles and those that do not.

Prokaryotes

Prokaryotic cells are organisms that lack a membrane-bound nucleus and membrane-bound organelles. Although prokaryotic cells lack a nucleus, their genetic information—in the form of DNA—is often concentrated in a part of the cell called the nucleoid. Prokaryotes are divided into two domains: Bacteria and Archaebacteria. The domain Bacteria includes organisms that are similar to the first cellular life-forms. The domain Archaebacteria includes organisms that are thought to be more closely related to eukaryotic cells found in all other kingdoms of life.

Prokaryotic Cell and Eukaryotic Cell Comparison

Eukaryotes

Cells of the other type, those containing membrane-bound organelles, are called eukaryotic cells. Most of the multicellular organisms we know are made up of eukaryotic cells and are therefore called eukaryotes. It is important to note, however, that some eukaryotes, such as amoebas, or some algae and yeast, are unicellular organisms.

Compare the prokaryotic and eukaryotic cells in the figure above. Separation of cell functions into distinct compartments—the organelles—benefits the eukaryotic cell. One benefit is that chemical reactions that would normally not occur in the same area of the cell can now be carried out at the same time.

Robert Brown, a Scottish scientist, observed that eukaryotic cells contain a prominent structure, which Rudolf Virchow later concluded was the structure responsible for cell division. We now know this structure as the nucleus, the central membrane-bound organelle that manages or controls cellular functions.