A LevelBiologyAQARevision NotesCell StructureCell StructureViruses

Viruses (AQA A Level Biology): Revision Note

Exam code: 7402

Lára Marie McIvor

Written by: Lára Marie McIvor

Reviewed by: Ruth Brindle

Updated on

The structure of viruses

  • Viruses are non-living because they:

    • are non-cellular

    • cannot reproduce independently (they require a host)

    • do not grow or respond to stimuli

    • do not carry out protein synthesis (they use the protein-building machinery in host cells)

    • They have no metabolic activity

  • All viruses are parasitic

  • They are much smaller than prokaryotic and eukaryotic cells

  • Structurally they have:

    • Genetic material: either DNA or RNA, and can be single or double-stranded

    • A capsid: a protein coat surrounding genetic material and containing attachment proteins

    • Attachment proteins: these bind to receptors on host cells during invasion

Diagram of a virus showing a capsid, protein molecules, and DNA or RNA genetic code, with labelled parts in a circular and helical structure.
A viral particle

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Author
Reviewer
Lára Marie McIvor

Author: Lára Marie McIvor

Expertise: Biology, Psychology & Sociology Subject Lead

Lára graduated from Oxford University in Biological Sciences and has now been a science tutor working in the UK for several years. Lára has a particular interest in the area of infectious disease and epidemiology, and enjoys creating original educational materials that develop confidence and facilitate learning.

Ruth Brindle

Reviewer: Ruth Brindle

Expertise: Biology Content Creator

Ruth graduated from Sheffield University with a degree in Biology and went on to teach Science in London whilst also completing an MA in innovation in Education. With 10 years of teaching experience across the 3 key science disciplines, Ruth decided to set up a tutoring business to support students in her local area. Ruth has worked with several exam boards and loves to use her experience to produce educational materials which make the mark schemes accessible to all students.

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