outline key structural features of a prokaryotic cell as found in a typical bacterium, including: • unicellular • generally 1–5 μm diameter • peptidoglycan cell walls • circular DNA • 70S ribosomes • absence of organelles surrounded by double membranes

state the name and type of pathogen that causes each of the following diseases: • cholera – caused by the bacterium Vibrio cholerae • malaria – caused by the protocitists Plasmodium falciparum, Plasmodium malariae, Plasmodium ovale and Plasmodium vivax • tuberculosis (TB) – caused by the bacteria Mycobacterium tuberculosis and Mycobacterium bovis • HIV/AIDS – caused by the human immunodeficiency virus (HIV)