Pathogens • Aims: • Must be able to define the term pathogen and state the different forms. • Should be able to describe the main features of the different forms of pathogen. • Could be able to give examples of each pathogen form and outline how they affect humans.
Pathogens • Pathogens are microbes that cause diseases when they live in other organisms. • Pathogens can cause the following effects: • Destroy cells • Produce toxins (poisons) • Interfere with normal function • Excessive immune response • There are several main forms of pathogen:
Prion • Tiny protein particles. • No nucleic acids.
virus • Sub-microscopic molecules. • Have protein coats surrounding an RNA or DNA core . • Only capable of growth and replication inside cells.
Bacteria • Microscopic unicellular organisms.
Fungi • Single or multicellular organisms. • Produce spores and obtain food directly by absorption. • Sometimes classified as plants without chlorophyll.
Viroid • Plant pathogens. • Consist of short strands of circular RNA. • No protein coat.
protozoa • Single-celled parasites that resemble animals and may form large colonies.
Activity • Complete the disease sheet using information in chapter 7.