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Cellular life is life with cellular structure. The usual meaning of life as we know it assumes that an organism have either unicellular or multicellular structure. However, implied by the modifier "cellular" is the existence of earth-based life that is non-cellular. This point of view usually includes the classification of viruses as life-forms.
In discussing the domains of life, the term Cytota is occasionally used as a kingdom, domain, or empire name to distinguish cell-based life from the non-cellular life (labelled Acytota). Both would be the only two subdivisions of earthly life -- also known as terrestrial organisms, Biota, Naturae, or Vitae.
The issue of life being both cellular and non-cellular has recently come to the fore due to the 2003 discovery that the Mimivirus is very large, had genes for hundreds of proteins and can make some proteins that are involved in the synthesis of other proteins. This finding has suggested to some virologists and bacteriologists that there should be a fourth -- that is, viral -- domain of life, in addition to the cellular domains of Prokaryota (Archaea and Bacteria), and Eukaryota.
To get a further understanding of cellular life, we must be clear on the make up of a cell. There are so many unique cells with different functions, yet most contain similar makeup. Most cells have an outer surface called plasma membrane which can filter contents from coming in and out of the cell. Cells also contain the main central “brain” or control center called a nucleus. Each little part of a cell organizes the structures and depicts what the cell is to do. Each piece takes care of its own job that allows complete function of a cell and its growth.
Animal Cells – Contain a plasma membrane and contains multi organelles needed to provide nutrients to the cell. Contains nucleus, golgi apparatus, endoplasmic reticulum, ribosomes, lysosomes, vacules, mitochondria, chromatin (the dna makeup of cell).
Bacteria - There are both good and bad bacteria and can be found living in the most versatile areas.
Plant Cells – Has a structure somewhat like an animal cell but it is missing many components of a cell. Plant cells can use different sources of nutrients such as water and sunlight.
Virus Structure - Viruses are not living, but reproduce and are parasitic to living organisms. Some viruses come in different forms and stronger strands are harder to fight.
We also need to understand the life cycle of cell. There are stages that a cell goes through to multiply. These stages include from early interphase, prophase, metaphase, anaphase, telophase, and cytokinesis. What is amazing and ironic about cellular life is that is goes through on a timed schedule. One major debate is should scientists and doctors alter the creation of cells; in other words clone cells and organisms.
Copyright © 1998-1999, All Rights Reserved, Anthony Carpi Cell photographs courtesy of The Cell web site Cell diagram courtesy of Dr. G. Weaver, Colorado University at Denver
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http://www.ncbi.nlm.nih.gov/books/bv.fcgi?rid=mcb.section.213 © 2000 by W. H. Freeman and Company.
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