Virus

Definition

An infectious agent that can reproduce only inside living host cells.

Used by AQA, Edexcel and OCR

Specification 4.3.1.1, 4.3.1.2 · Paper 1

A disease-causing agent consisting of genetic material inside a protein coat; it can reproduce only inside living cells.
Viruses are much smaller than bacteria and cannot reproduce independently. A virus enters a living cell and uses the cell's machinery to make new virus particles. This disrupts the cell and may damage or destroy it.
Revise: Infectious Disease Spread
An infectious agent that reproduces only inside living host cells and may damage those cells.
Revise: Viral Diseases

1
Distinguish the mechanisms clearly: bacterial toxins damage tissues, whereas viruses reproduce inside cells and damage those cells.
2
Do not write that HIV and AIDS are the same thing. HIV is the virus; AIDS is the late stage of infection after severe damage to the immune system.
3
If asked to name the types of pathogen, give all four: viruses, bacteria, fungi and protists.

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Specification 5.4, 5.5, 5.7B · Paper 1

A very small, non-cellular particle that can reproduce only inside a living host cell.
For Edexcel GCSE Biology, you need to recognise four types of pathogen: viruses, bacteria, fungi and protists.
Revise: Pathogens
An infectious agent that can reproduce only inside a host cell.
Revise: Viral Infections: HIV and Ebola
A microscopic infectious particle that needs a living host cell to make new virus particles.
Revise: Lifecycle of a Virus

Specification B6.3f · Paper 2 (Foundation), Paper 4 (Higher)

A non-cellular infectious agent that replicates only inside a living host cell.
A virus is not a cell and can replicate only after entering a living host cell and using the cell's machinery.
Revise: Common infections

Paper 1 (Foundation), Paper 2 (Foundation), Paper 3 (Higher), Paper 4 (Higher)

The pathogen and the symptom are not the same thing: a virus, fungus or bacterium is a cause, whereas mottled leaves or swollen tissue are effects of infection.
Revise: Plant Diseases