Pathogens and Viruses

IGCSE Edexcel Biology
1.4 Pathogens and Viruses
Key Concept: Pathogens are disease-causing organisms. Viruses are not living but reproduce inside host cells.

Section A: Pathogens

1. Define the term pathogen. [2]
2. Name four groups of pathogens. [4]

Section B: Viruses

3. State three reasons why viruses are not considered living organisms. [3]
4. Label the virus diagram with: protein coat (capsid) and genetic material (DNA or RNA). [2]
[Virus diagram]
5. Give three diseases caused by viruses. [3]
6. Describe how viruses reproduce inside a host cell. [3]
Total marks: 17

Mark Scheme

1. A disease-causing organism or agent [2]
2. Any four: bacteria, fungi, protoctists, viruses [4]
3. Any three: not made of cells, no metabolism, do not grow, reproduce only inside host cells [3]
4. Protein coat (capsid) and genetic material correctly labelled [2]
5. Any three: influenza, HIV, tobacco mosaic virus, measles (any three) [3]
6. Virus attaches to host cell, injects genetic material, uses host machinery to make new viruses, cell bursts or releases new viruses [3]