TB is caused by the bacterium Mycobacterium tuberculosis. It spreads through the air when people with active TB cough or sneeze, and infects the lungs. Each year 1.6 million people die from TB. Symptoms include fever, weight loss, persistent cough, and fatigue. While a healthy immune system may prevent the disease from spreading, untreated TB can damage the lungs and spread to other organs. Treatment requires taking multiple antibiotics for 6-9 months to kill all bacteria and prevent drug resistance.

1. TB summarised

3. Prokaryotic Cell Structure As you can see, the structure is very different from plant and animal cells that we have already learnt about. Capsule is a layer of mucilage which may unite bacteria into colonies. Pili are protein rods concerned with cell-cell attachment. The sex pilus is involved in DNA transfer Plasma membrane is a typical phospholipid bilayer. Plasmids are small pieces of circular DNA which replicate independently of the main genome. Cell wall has a rigid framework of murein , a polysaccharide cross-linked by peptide chains. Genetic material is composed of a circle of double-stranded DNA which is not enclosed within a nucleus. Ribosomes smaller than those in eukaryotes and not supported by an endoplasmic reticulum. Food stores are typically lipid droplets glycogen granules. Flagellum is responsible for motility of many bacteria.