Types of Micro-organisms (WJEC GCSE Biology): Revision Note

Types of Micro-organisms

• Micro-organisms are living organisms which are too small to be seen by the naked eye

• Most microorganisms are not harmful and contribute positively to ecosystems and human life

  • Many play a key role in essential processes like nutrient recycling, decomposition, and symbiotic relationships

• Beneficial micro-organisms are found in nature, agriculture, medicine, and industry

  • Examples of beneficial microorganisms include those used in

    • food fermentation

    • genetic engineering

    • antibiotic production

• Micro-organisms that do cause harm are called pathogens

  • Pathogens are microorganisms which cause disease

  • They are capable of infecting plants, animals, and humans, leading to illnesses and sometimes severe health complications

  • Examples of pathogens include

    • bacteria

    • viruses

    • fungi

    • protists

• The balance between beneficial and harmful microorganisms is important

  • Proper hygiene, sanitation, and disease control measures take into account this balance in maintaining public health and environmental stability.