Hsc 265 Essay

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Causes and spread of infection HSC unit 265 Outcome 1 – Understand the causes of infection. Viruses Viruses are microscopic pathogens that infect living cells and tissues. They are the smallest kind of microbe, with the size ranging from around 20-200 nanometers, around 35 times smaller than a human red blood cell and around 100th the size of a regular bacteria. Viruses are not living things. They are complex molecules of proteins and genetic material but they do not have their own cell structure. Viruses cannot replicate without infecting a living cell. Unlike bacteria that has everything it needs to reproduce, viruses need to use a living cell's organelles (cell parts that are it's organs) in order to replicate. Viruses infect all living things, including fungi and even bacteria. Bacteria Bacteria are larger than viruses. They come in a variety of shapes, typically spheres and rods. They are living things, complete with organelles and a 'skin' called cell membrane. Some bacteria are capable of movement through tail like structures called flagella. Bacteria usually reproduce via binary fission, a form of asexual reproduction where the bacteria replicates its DNA then divides itself into two identical cells. Unlike viruses, bacteria do not need a host cell (although they still need nutrients) to reproduce. Harmful bacteria are referred to as pathogens. These pathogens cause disease that usually start in a specific location but when left untreated, can cause septiceamia (the blood becomes infected and unusable by the body) which leads to shock and ultimately death. Most bacterial infections produce pus, a substance containing dead white blood cells. White blood cells, or leukocytes are our body's response to the bacterial infection. They engulf the bacteria and produce chemicals that kill any other bacteria

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