The Cell
You are made of trillions of cell.
As we study cells, remember this important truth:
If your cells aren’t happy, YOU aren’t going to be happy!
The cell is the basic unit of life.
Cells are classified into two main groups.
The first group are prokaryotic cells.
Prokaryotic cells do not have a nucleus. They have a nucleoid (resembles a nucleus).
They are very small and simple cells.
Prokaryotic cells are single-celled organisms.
Some examples of prokaryotic cells:
Bacteria (Kingdom Monera) Source: greenfacts.org
Prokaryotic cells resemble the earliest cells found on Earth. Source: Discover West Tours, Australia
The second group are eukaryotic cells.
Eukaryotic cells are very complex.
They are much larger than prokaryote cells.
Eukaryotes can be either single- or multi-celled.
They also have organelles (little organs).
Examples include: Plant cells Animal cells
How did we learn about the cell?
Robert Hooke discovers the cell in 1678 Robert Hooke(?) Source: University of St. Andrews
Anton van Leeuwenhoek Source: University of California Paleontology Museum
Anton van Leeuwenhoek Greatly improved the microscope (1680). Discovered microorganisms.
Matthias Schleiden Plants are made of cells (1838).
Theodor Schwann Animals are made of cells (1839).
Rudolph Virchow Cells can only come from other living cells.
Schleiden, Schwann, and Virchow’s work lead to the development of cell theory.
Cell Theory All living things are made of cells.
Cell Theory Cells are the basic unit of life.
Living cells can only come from other living cells.
Structure of the cell
A cell is made of organelles. (Organelle – “little organ.” )
Each organelle has a special function that keeps the cell running.
Nucleus The nucleus is the brain of the cell. It controls what everything that happens in a cell.
Cell Membrane It is the gateway of the cell. It controls what goes into and out of the cell.
Cell Membrane Controlling what goes in and out of the cell is called Selective Permeability.
Organelle responsible for digestion.
Lysosome Contains enzymes that help break down chemicals into forms that can be used by the cell.
Organelles that manufacture
Smooth ER (Endoplasmic Reticulum) Manufactures lipids (fats) and other products needed by the cell.
Golgi Body Manufactures lysosomes. Manufactures other complex molecules and packages them in vesicles.
Nucleolus Located in the nucleus. Responsible for the manufacture of ribosomes.
Ribosomes Manufacture proteins needs by the cell.
Organelles that provide power
Mitochondria Takes nutrients and provides energy for the cell.
Organelles that provide power and are found only in plant cells
Chloroplasts The food producer for the plant cell. Takes water, CO 2, and sunlight to produce sugar (food) and O 2 as a waste product.
Organelles that provide power support
Cell Membrane Surrounds the cell and helps maintain the shape of the cell.
Cytoplasm Helps the cell keep its shape and protects the cell. Cell organelles are found in the cytoplasm.
Cytoskeleton Provides physical structure to the cell.
Organelles that provide support and are found only in plant cells
Cell Wall Stiff outer wall that provides support, structure, and protection to the plant cell.
Central Vacuole A large vacuole in the plant cell. Provides extra support and structure to the cell.
Organelles that provide storage
Golgi Body Stores molecules necessary to make lysosomes and vesicles.
Lysosome Stores enzymes necessary to digest food, breakdown waste, and break down old organelles and dead cells.
Smooth ER Stores steroids and other chemicals the cell will need at a later time.
Vacuole Storage bubbles that can store food, chemicals, and water products.
Organelles that provide power transportation
Rough E.R. Transports ribosomes (attached to the rough E.R.) around the cell.
Organelles that provide waste removal
Lysosome Breaks down waste products. Called the “suicide organelle” because it destroys a dying cell.
And that’s cell basics.