1 THE WORLD OF MICROBES Good guys or Bad guys? Which of these microbes do you think are Good guys and which ones are Bad guys? In groups, discuss the reasons for your choices. MICROBES GOOD BAD GUY GUY Clostridium Botulinum (in food) Escherichia coli (in the intestine) Helicobacter pylori Lactobacillus bifidus Penicillium notatum Saccharomyces cerevisiae Salmonella typhi MICROBES: THE FACTORY OF EVERYTHING 1 4.1 Use the words in the box to complete the following passage; then listen to the recording and check if you have completed it correctly. atmosphere biomass biotechnology bodies creatures food chain fermented foods genes genomes groups habitats human life immune system intestines life nitrogen oxygen pollution control sea springs Microbes, or microorganisms, are tiny (1) ............................... that individually are too small to be seen by the naked eye. They are the oldest form of (2) ............................... on Earth and, in weight, represent 60% of the (3) ............................... of all life on Earth. They live everywhere: in the soil, water and air, in animal (4) ..............................., and in extreme settings such as rocks, glaciers, hot (5) .............................., and deep (6) ................................ The wide variety of microbial (7) ............................... reflects an enormous diversity of biochemical and metabolic traits. The majority of microbes contribute to the quality of (8) .............................. ................................ They make about half the (9) ............................... we breath. Staphylococcus aureus They are the foundation of the (10) ............................... Streptococcus lactis to make (11) ............................... Streptococcus pneumoniae ............................... that feeds all life on earth. They have been used for thousands of years ..............................., such as bread, cheese and yoghurt. Some soil microbes release (12) ............................... that plants need for growth and emit gases that maintain the precarious composition of the Earth s (13) ................................ They are also at work in agriculture, industry, (14) ............................... ............................... and medicine. In our (15) ..............................., different microbes help to digest food, ward off invasive organisms and engage in battles with the human (16) ............................... ................................ Microbes are a source of new (17) ............................... and organisms of to feed: to give food to naked eye: without using a microscope setting: location tiny: extremely small to ward off: to defend against 142 Module 4 ELEMENTS value in (18) ............................... and energy production. Microbial (19) ............................... are relatively easy to study, so understanding their genomes helps understand how more complex genomes developed. There are five basic (20) ............................... of microbes: bacteria, fungi (yeasts and moulds), protozoa, microalgae and viruses.