3.2.1 Cell structure (viruses)

Question 1

Why are viruses referred to as ‘particles’ instead of cells

Answer 1

Acellular and non-living: no cytoplasm, cannot self reproduce, no metabolism

Question 2

Describe the structure of a viral particle

Answer 2

Linear genetic material (DNA or RNA)
Surrounded by capsid (protein coat)
Attachment proteins

Question 3

State the role of the capsid on viral particles

Answer 3

Protect nucleic acid from degradation by restriction endonucleases
Surface sites enable viral particle to bind to and enter host cells or inject their genetic material

Question 4

State the role of attachment proteins on viral proteins

Answer 4

Enable viral particle to bind to complementary sites on host cell: entry via endosymbiosis