Viruses are infectious agents that are not classified as living organisms.
State two life processes that viruses cannot carry out independently (when outside a host cell).
Name one disease in humans that is caused by a protoctist pathogen.
Prions are infectious pathogens composed entirely of protein material folded into an abnormal, disease-causing shape. Prions do not contain any nucleic acids.
Suggest two structural or functional differences between prions and typical viruses.
7 exam-style questions on Edexcel IGCSE Biology Characteristics of living organisms. Each one has a worked solution and a mark scheme showing where the marks go.