Viruses

Question 1

define viruses

Answer 1

tiny particles of nucleic acid

Question 2

describe the structure of a virus

Answer 2

• have attachment proteins
• attachment proteins
• a capsid
• have no ribosomes, cytoplasm and cell membrane

Question 3

How do viruses infect a cell?

Answer 3

1. the attachment proteins on the capsid attach to complementary receptor proteins on the surface of host cells
2. the virus enters the host cell = injects the nucleic acid, so hijacks the cell’s machinery
3. the cell copies the viruses nucleic acids and forms new protein coats and viruses

Question 4

how do viruses behave outside the host cell and what do they not have?

Answer 4

they’re inert, so can’t replicate and they have no metabolism of their own