🦠 Structure of Prokaryotic Cells and of Viruses


Prokaryotic cells

Viruses


 

 

Prokaryotic cells

 

Prokaryotes do not have a nucleus like eukaryotes do. Their DNA is not membrane-bound, just free in the cytoplasm. The extra features of prokaryotic cells vs. eukaryotic cells you must learn are:

 

-the cytoplasm overall does not contain membrane-bound organelles such as mitochondria and endoplasmic reticulum

-prokaryotic ribosomes are smaller than their eukaryotic counterparts

-as previously covered, and their primary defining element, they lack a nucleus; instead, their DNA is a single circular molecule freely present in the cytoplasm and not associated with any proteins such as histones in eukaryotes

-they have a cell wall which contains a special glycoprotein called murein (also known as peptidoglycan)

 

 

Some prokaryotes also go further to have some specialised parts, some seen in the diagram:

-one or more plasmids which are also circular DNA loops but much smaller; these can be exchanged between cells or even between different species as they can carry genes for antibiotic resistance

-a capsule made of polysaccharides as their outermost layer (on top of the cell wall on top of the plasma membrane)

-one or more flagella which aid in locomotion…