3.6 - Prokaryotic cells and viruses

• prokaryotic cells are smaller than eukaryotic cells and have no nucleus or nuclear envelope
• plasmids are used in genetic engineering as vectors
• bacterial cells contain 70s ribosomes, which are smaller than the 80s ribosomes found in eukaryotic cells, but can synthesise proteins
• viruses and bacteria are types of prokaryotic cells
• viruses are acellular, non living particles. they are smaller than bacteria (20-300 nm)
• viruses contain nucleic acids but rely on host cells to replicate. their nucleic acids are enclosed within a protein coat called a capsid, which has attachment proteins on it, allowing the virus to identify and attach to a host cell