Prokaryotes and Viruses

Bacterial Cell: Diagram

Capsule

Layer of polysaccharides (sometimes proteins), protects the bacterial cell and its often associated with pathogenic bacteria because it serves as a barrier from phagocytosis

Mesosome

Tightly folded region of the cell membrane containing all the membrane bound proteins required for respiration

Pilli

Little hairs to allow the bacteria to stick together

Plasmid

Small circular piece of DNA

Cell Wall

• 10-80nm thick

• Made of murein

Similarities and Differences between Eukaryotic and Prokaryotic cells

Virus (HIV) Diagram

 

Virus

• Acellular

• Non-living particles

• Smaller than Bacteria ranging from 20-399nm

• Contains nucleic acid either as DNA or RNA

• Can only replicate inside host cells

• Nucleic acid is enclosed inside a protein coat called a capsid

• Some viruses have a lipid envelope

• Some viruses have attachment protiens on their envelope which allow the virus to attach to a host cell

Name the 2 Virus replication cycles

• Lytic cycle

• Lysogenic cycle

Lytic Cycle

• The virus attaches to the host cell, where it binds to the receptor

• The virus can inject either its DNA or RNA, depending on what kind of genetic material it has, into the cell

• Some types of viruses are actually taken inside the cell themselves

• It takes the genetic material from the virus and it starts following the instructions which tell the cell to make copies of the virus

• Cell makes multiple copies of the virus causing the cell membrane to burst - the cell can’t survive without the cell membrane

• The viral copies get out of the cell and infect other cells

• Viruses assemble

Lysogenic Cycle

• Viruses inject their genetic material but it stays hidden in the host’s genetic material

• When the host makes new cells, it replicates both its own genetic material and the viral genetic material

• May trigger the Lytic cycle

Matrix

Fluid containing enzymes to help the virus survive

Protein Capsid

Encloses the nucleic acid

Lipid envelope

Protects Virus

Attachment Proteins

Helps virus bind to host cell