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Biology – Cells, Tissues, Organs, Organisms; Kingdoms of Archaea, Protista, Fungi, Plants, and Animals

© Donald Reinhardt,2010
Atoms and compounds are the building blocks of cells which gives rise to more complex structures and the kingdoms of life. 
Prokaryotic Cell Compared to Eukaryotic Cell
Biology is the study and science of life. Biologists study life from the tiny viruses and bacteria, to the largest mammals of the sea – whales – and Homo sapiens, the human species, and the land-dwelling mammal that dominates the planet — for better, or worse.  

Prokaryote Cells, Bacteria , Archaea and Eubacteria

The smallest and simplest living cells are prokaryotes, commonly called bacteria. Bacteria are small, microscopic, simple cells. Bacteria may be as small as 0.2 micrometers (um = millionth of a meter; m= 39.37 inches). Bacteria have a simple, nucleus or nucleoid of DNA with no surrounding nuclear membrane. All prokaryotes have ribosomes and enzymes, and they divide by simple binary fission (splitting in two). 

Most bacteria are helpful and, depending on the bacterial species, each type can do such things as: fix nitrogen, digest waste, recycle dead animal and plant matter, and even inhibit and kill other microorganisms. Some bacteria arepathogens of plants and animals – they cause damage to cells and tissues of the host that they infect, and they may even cause death of the host. Examples of pathogenic bacteria include staphylococci and streptococci.

 Eukaryote Cells, Protists, Fungi, Plants and Animals 

Eukaryotes are larger than prokaryotic cells, Typical eukaryotic cells are about 1 to 10 micrometers or larger in diameter. Eukaryotes include fungi (molds and yeast cells), plant, and animal cells. All fungi, plants and animals have: a membrane-bound nucleus with distinct chromosomes of DNA that undergo classic mitotic division, a cytoplasm with large ribosomes ( size of 80 S, compared to prokaryote 70 S), and mitochondria. Plants also contain chloroplasts which enable photosynthesis.

Chemistry is and Important Part of the World of Biology

The biological world and its kingdoms cannot really be understood and appreciated without a reasonable background in basic chemistry at the inorganic and organic levels. Chemistry is not difficult if studied one step at a time, thoughtfully and carefully. All living things are composed of chemicals, and these chemicals form the fabric of cells and organisms, which all interact with the chemical environments that surrounds them. Early basic chemistry will include some useful chemical definitions of matter, elements, and atoms, followed by a brief study of water and pH.

Simple Mouth Tissue Experiment Reveals Pro- and Eu- karyotic Cells

Anyone can see both eukaryotic and prokaryote cells easily with a simple slide, toothpick, methylene blue and microscope. The toothpick is scraped on the inside of the cheek. The scraping is smeared onto the slide's surface and air-dried. Usually, a small amount of heat is applied by a flame or hot plate. Then a drop of methylene blue is added to cover the smeared cells on the slide and permitted to stain for a minute. The slide's surface is rinsed with gently running water in the sink, blotted dry with a paper towel, and then observed at total magnifications of 100x, 450x and, if possible, 1000x. Cocci and bacilli of the bacteria (or prokaryotes = prokaryotic cells) are seen, often attached to squamous epithelial cells (eukaryotic cells) of the human mouth. Two different kingdoms on one slide. Sometimes a thrid kingdom of cells might also be seen on the same slide – the kingdom of fungi or Mycota manifest by the presence of distinct budding, eukaryotic yeast cells which are larger than bacteria.

All the Written Material within Site is Copyrighted 2010 and Owned by Dr. Donald Reinhardt, and this original material is protected legally by this copyright notice and by theDigital Millennium Act. None of this original material may be copied or reproduced without the expressed written consent of the author. 

Donald Reinhardt is a Consultant in Medical and Industrial Microbiology and a Freelance Science writer. He is available for specific assignments for those who are interested – by contacting Other questions related to this teaching site should be directed to