2.1.2 Structure of prokaryotic cells and of viruses

What are distinguishing features of prokaryotic cells?

• cytoplasm lacking membrane-bound organelles

• so genetic material not enclosed in a nucleus

Describe the general structure of prokaryotic cells

Compare and contrast the structure of eukaryotic and prokaryotic cells

Explain why viruses are described as acellular and non-living

• acellular - not made of cells, no cell membrane / cytoplasm / organelles 

• non-living - have no metabolism, cannot independently move / respire / replicate / excrete 

Describe the general structure of a virus particle

1. Nucleic acids (RNA or DNA) surrounded by capsid (protein coat protects genetic material)

2. attachment proteins allow attachment to specific host cells

3. no cytoplasm, ribosomes, cell wall, cell-surface membrane etc

4. some also surrounded by a lipid envelope e.g. HIV