Structure of Bacteria

At about 3.5 billion years old, bacteria are one of the oldest living organisms on earth. They are responsible for a range of diseases including cholera, tuberculosis and the plague amongst many others. But they aren’t all bad; there are trillions of good bacteria living in your gut that are essential to your health. They can produce vitamins, prevent tumour formation, help the immune system fight pathogens and protect against carcinogens, amongst other benefits. Bacteria cells are very small; much smaller than plant and animal cells. They are found practically everywhere on Earth and live in some of the most unusual and seemingly inhospitable places. Bacteria are unicellular prokaryotes. They come in lots of different shapes and sizes, but contain the same elements. As they are prokaryotes, they do not have a membrane bound nucleus. The DNA is in the cytoplasm, in the area known as the nucleoid. Bacteria have a flexible cell wall that protects them from physical damage and is exposed to the external surroundings. A flagellum that helps the bacteria to move. Bacteria have two types of DNA; plasmid DNA and chromosomal DNA. The chromosomal DNA carries most of the genetic information. The plasmid DNA forms small loops and carries extra information such as resistance to antibiotics, production of toxins and tolerance to toxic environments. The ribosome is involved in protein synthesis. The pili enable the bacteria to attach to hosts and surfaces like teeth, intestines and rocks. They are also involved in DNA exchange between bacteria, in bacterial conjugation.