Bacterial cell structure & function: Nucleoid

Fun Facts

-Bacteria have flourished on earth for over three billion years!

-Bacteria adapt properties allowing them to present a wide array of coloring.

-A genophore of a true organism can be as small as 580,073 base pairs (Mycoplasma genitalium).

-Ribosome comes from ribonucleic acid and "Greek: soma (meaning body)".

-There are an estimated 75 to 100 trillion cells in the human body. It is believed by scientists that there are more bacteria in your body than the number of cells in your body.

-Scientists estimate that the total mass of the Earth's bacteria out weighs allof the plants and animals and all other living things combined.

-Soap and water are more effective at killing germs than antibacterial hand sanitizers.

-A single pancreas cell can synthesize 5 million molecules of protein per minute.

-If a nuclear war wiped out civilization most of the Earth's bacteria wouldn't be affected.

-Ribosomes that are from bacteria, archaea and eukaryotes have significantly different in its structure and it’s RNA.

-Nearly a third of all bottled drinking water purchased in the US is contaminated with bacteria.

Friday, July 31, 2009

Nucleoid

Written By: Doraline
MB0902
092472X

The nucleoid is an irregularly-shaped region within the cell of prokaryotes which has nuclear material without a nuclear membrane and where the genetic material is localized. The genome of prokaryotic organisms generally is a circular, double-stranded piece of DNA, of which multiple copies may exist at any time. The length of a genome widely varies, but generally is at least a few million base pairs. Storage of the genome within a nucleoid can be contrasted against that within eukaryotes, where the genome is packed into chromatin and sequestered within a membrane-enclosed organelle called the nucleus.

Source from: http://en.wikipedia.org/wiki/File:Celltypes.png

A genophore is the DNA of a prokaryote, commonly referred to as a prokaryotic chromosome. The term chromosome is misleading for a genophore because the genophore lacks chromatin. The genophore is compacted through a mechanism known as supercoiling, where a chromosome is compacted via chromatin. The genophore is circular in most prokaryotes, and linear in very few. The circular nature of the genophore allows replication to occur without telomeres. Genophores are generally of a much smaller size than Eukaryotic chromosomes. Many eukaryotes carry genophores in organelles such as mitochondria and chloroplasts. These organelles are very similar to true prokaryotes.

The nucleoid can be clearly visualized on an electron micrograph at high magnification, although its appearance may differ, it is clearly visible against the cytosol. Sometimes even strands of what is thought to be DNA are visible. By staining with the Feulgen stain, which specifically stains DNA, the nucleoid can also be seen under a light microscope.

source from:http://biology.kenyon.edu/courses/biol114/Chap01/chrom_struct.html