What Is Cell Biology?

Cell biology is the subdiscipline of biology that studies the basic unit of life, the cell. 

It deals with all aspects of the cell including cell anatomy, cell division (mitosis and meiosis), and cell processes such as cell respiration, and cell death. 

Cell biology does not stand alone as a discipline but is closely related to other areas of biology such as genetics, molecular biology, and biochemistry.

Based on one of the basic principles of biology, the cell theory, the study of cells would not have been possible without the invention of the microscope. 

With the advanced microscopes of today such as the Scanning Electron Microscope and Transmission Electron Microscope, cell biologists are able to obtain detailed images of the smallest of cell structures.

Significant Events in Cell Biology

There have been several significant events throughout history that have led to the development of the field of cell biology as it exists today. Below are a few of these major events:

• 1655 - Robert Hooke gives first description of a cork tree cell.
• 1674 - Leeuwenhoek views protozoa.
• 1683 - Leeuwenhoek views bacteria.
• 1831 - Robert Brown was first to identify the nuleus as an important cell component.
• 1838 - Schleiden and Schwann introduce what would become the Cell Theory.
• 1857 - Kolliker describes mitochondria.
• 1869 - Miescher isolates DNA for the first time.
• 1882 - Kock identifies bacteria.
• 1898 - Golgi discovers the Golgi apparatus.
• 1931 - Ruska builds the first Transmission Electron Microscope.
• 1953 - Watson and Crick propose structure of DNA double-helix.
• 1965 - First commercial Scanning Electron Microscope produced.
• 1997 - First sheep cloned.
• 1998 - Mice cloned.
• 2003 - Human genome DNA sequence draft completed.

Careers in Cell Biology

Study in the field of cell biology can lead to various career paths. Many cell biologists are research scientists who work in industrial or academic laboratories. Other opportunities include:

• Cell Culture Specialist
• Clinical Quality Auditor
• Clinical Researcher
• Food & Drug Inspector
• Industrial Hygienist
• Medical Doctor
• Medical Illustrator
• Medical Writer
• Pathologist
• Pharmacologist
• Physiologist
• Professor
• Quality Control Specialist
• Technical Writer
• Veterinarian

More About Cell Biology

Cell Structure

Life is both wonderful and majestic. Yet for all of its majesty, all organisms are composed of the fundamental unit of life, the cell. The cell is the simplest unit of matter that is alive. 

From the unicellular bacteria to multicellular animals, the cell is one of the basic organizational principles of biology. 

Let's look at some of the components of this basic organizer of living organisms.

Eukaryotic Cells and Prokaryotic Cells

There are two primary types of cells: eukaryotic cells and prokaryotic cells. Eukaryotic cells are called so because they have a true nucleus. The nucleus, which houses DNA, is contained within a membrane and separated from other cellular structures. Prokaryotic cells however have no true nucleus. DNA in a prokaryotic cell is not separated from the rest of the cell but coiled up in a region called the nucleoid.

As organized in the Three Domain System, prokaryotes include archaeans and bacteria. Eukaryotes include animals, plants, fungi and protists. Typically, eukaryoitc cells are more complex and much larger than prokaryotic cells. On average, prokaryotic cells are about 10 times smaller in diameter than eukaryotic cells. 

Eukaryotes grow and reproduce through a process called mitosis. In organisms that also reproduce sexually, the reproductive cells are produced by a type of cell division called meiosis. Most prokaryotes reproduce through a process called binary fission. During binary fission, the single DNA molecule replicates and the original cell is divided into two identical daughter cells.

Both eukaryotic and prokaryotic organisms get the energy they need to grow and maintain normal cellular function through cellular respiration. Cellular respiration has three main stages: glycolysis, the citric acid cycle, and electron transport. In eukaryotes, most cellular respiration reactions take place within the mitochondria. In prokaryotes, they occur in the cytoplasm and/or within the cell membrane.

The Cell-Cell Structure

There are also many distinctions between eukaryotic and prokaryotic cell structure. The following table compares the cell structures found in a typical prokaryotic cell to those found in a typical animal eukaryotic cell.

Cell Structure Comparison

Eukaryotic and Prokaryotic Cell Structure
	Cell Structure	Prokaryotic Cell	Typical Animal Eukaryotic Cell
	Cell Membrane	Yes	Yes
	Cell Wall	Yes	No
	Centrioles	No	Yes
	Chromosomes	One long DNA strand	Many
	Cilia or Flagella	Yes, simple	Yes, complex
	Endoplasmic Reticulum	No	Yes (some exceptions)
	Golgi Complex	No	Yes
	Lysosomes	No	Common
	Mitochondria	No	Yes
	Nucleus	No	Yes
	Peroxisomes	No	Common
	Ribosomes	Yes	Yes

Robert Hooke was perhaps one of the most important scientists from the 17th century.   While his research and findings were often overshadowed by those of his rival Sir  Isaac Newton, one cannot argue their importance in the development of fields such as physics, astronomy, biology, and medicine, to name a few.

• One could say he was England's equivalent of 14th century genius Leonardo da Vinci, that he was a true renaissance man who was constantly seeking answers to questions, and inventing new and ingenious scientific instruments. 

•    Hooke's inventions include the spring control of the balance wheel in watches, and the first reflecting telescope.  Hooke also worked as an architect, although his dreams of redesigning London following the Great Fire of 1666 were brought down to smaller proportions.

One must realize that Robert Hooke's advances in the field of Microscopy and Astronomy opened doors which would one day lead to discoveries from scientists such as Dr. Edwin Hubble, and that some of his other inventions such as the universal joint, which is being used in the automobile industry, and his balanced springs, which are still part of some of the watches we wear.   Alas, for all the genius and for all his triumphs, Hooke was a sickly, bitter man who's work had oft been at the source of others' successes, a man who spent his entire life alone, orphaned at the age of 13 following his father's suicide. . To make matters worse, Hooke's one true love (Grace Hooke), also happened to be his niece, and the short while the two actually lived together at Hooke's home, there is no indication his love was reciprocated.    Hooke died alone, his estate being sold at auction to an illiterate woman by the name of Elizabeth Stevens Robert Hooke's remains were exhumed and reburied somewhere in North London in the 18th century, nut no one seems to know exactly where.  If the remains are found, Professor Michael Cooper of City University, London plans to utilize the forensic anthropology technique of facial reconstruction to give Robert Hooke a face, and perhaps more of the recognition he deserves.   The only likeness of Robert Hooke's that was available until now was the Hooke memorial window, St Helen's Bishopsgate, but it was destroyed during the IRA Bishopsgate bombing.

Anton Van Leeuwenhoek

The father of microscopy, Anton Van Leeuwenhoek of Holland (1632-1723), started as an apprentice in a dry goods store where magnifying glasses were used to count the threads in cloth. Anton van Leeuwenhoek was inspired by the glasses used by drapers to inspect the quality of cloth. He taught himself new methods for grinding and polishing tiny lenses of great curvature which gave magnifications up to 270x diameters, the finest known at that time.
These lenses led to the building of Anton Van Leeuwenhoek's microscopes considered the first practical microscopes, and the biological discoveries for which he is famous. Anton Van Leeuwenhoek was the first to see and describe bacteria (1674), yeast plants, the teeming life in a drop of water, and the circulation of blood corpuscles in capillaries. During a long life he used his lenses to make pioneer studies on an extraordinary variety of things, both living and non-living, and reported his findings in over a hundred letters to the Royal Society of England and the French Academy.