Biology
Bacteria or prokaryotes are the most common living beings on Earth: one spoonful of soil can contain, for instance, up to 10,000 billion bacteria. They are unicellular organisms, i.e. they consist of one cell only. They are very small in size, since a large part of bacterial cells have a diameter of 1 to 10 microns (one micron equals one thousandth of a millimetre), so an orderly row of one thousand bacteria would be just one millimetre long. Bacterial cells, unlike the cells of superior organisms (eukaryotes), do not have organelles enwrapped in membranes (nucleus, Golgi apparatus…) or chromosomes. Chromosomes are structures made of DNA wrapped around proteins, called histones, and their purpose is to make the long DNA molecules contained in the nucleus more compact and orderly.
Chromosomes are essential since they arrange the large amount of genetic material contained in eukaryote cells: if, for instance, the DNA contained in just one human somatic cell were unwrapped, the resulting molecule would be approximately two metres long! In bacteria, instead, the DNA is not contained in a nucleus and is round in shape. Another specific feature of bacteria is their protective structure (the wall) that enwraps and encloses the whole cell. The cellular wall is composed of proteins and sugars and, as well as protecting the micro-organism, it puts the cell in contact with the external environment and the other bacterial cells.
Special reports
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24 November 2020
The glow of duck-billed platypuses
It's easy to answer "which is the strangest animal?". The answer: the platypus. These strange creatures live only in Australia…
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12 October 2020
Crispr-Cas9, the gene factory
Nobel 2020. The biochemists Emmanuelle Charpentier, French, and Jennifer A. Doudna, from the United States, were awarded the most important…
10 May 2020
A virus’s life
What are viruses Virus is a Latin word meaning poison. Viruses do not eat, breathe, move or reproduce on their…
29 February 2020
Let’s find out about viruses
Parasites at the edge of life Virus is a Latin word meaning poison. Viruses are pathogens (they make you ill)…
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31 October 2019
What language does science speak? 2nd part
There is an old proverb that says “the apple does not fall far from the tree ”. Apparently it seems…
1 September 2019
What language does science speak?
Do you remember the game called “Chinese whispers”? All the participants had to stand in line and the game started…
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24 November 2020
The glow of duck-billed platypuses
It's easy to answer "which is the strangest animal?". The answer: the platypus. These strange creatures live only in Australia…
12 October 2020
Crispr-Cas9, the gene factory
Nobel 2020. The biochemists Emmanuelle Charpentier, French, and Jennifer A. Doudna, from the United States, were awarded the most important…
-
10 May 2020
A virus’s life
What are viruses Virus is a Latin word meaning poison. Viruses do not eat, breathe, move or reproduce on their…
29 February 2020
Let’s find out about viruses
Parasites at the edge of life Virus is a Latin word meaning poison. Viruses are pathogens (they make you ill)…
-
24 November 2020
The glow of duck-billed platypuses
It's easy to answer "which is the strangest animal?". The answer: the platypus. These strange creatures live only in Australia…
From the Multimedia section
Facts
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Bio-luminescence
Many sea animals, including a lot of fish and molluscs that live in the dark in the ocean depths...
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Bacteria as Sherlock Holmes
A drop of blood, a fragment of skin or a hair found on the scene of a crime can supply…
Down-pouring bacteria
It sounds incredible, but recent researches have found that bacteria can cause some atmospheric phenomena...
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13 May 2011
Bio-luminescence
Many sea animals, including a lot of fish and molluscs that live in the dark in the ocean depths...
-
Bacteria as Sherlock Holmes
A drop of blood, a fragment of skin or a hair found on the scene of a crime can supply…
-
Down-pouring bacteria
It sounds incredible, but recent researches have found that bacteria can cause some atmospheric phenomena...
-
Bio-luminescence
Many sea animals, including a lot of fish and molluscs that live in the dark in the ocean depths...