Viruses
Viruses come in many shapes and structures.
Each virus has a core of genetic material — either RNA or DNA — surrounded by a protein coat.
They do not have:
Nucleus
Cytoplasm
Cell organelles
Cell membrane (though some may have an extra outer membrane)
Virus particles are not cells.
They cannot feed, respire, excrete, or grow.
It is debated whether viruses are truly living organisms.
Viruses can reproduce only inside living cells, using the host cell’s materials to make more viruses.
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