Viruses (HL IB Biology)

It suggests that viruses arose from genetic material capable of moving between cells.

It suggests that viruses predate cellular life and represent an early step in the evolution of life.

It proposes that viruses are remnants of cellular organisms that became parasites.

It states that viruses evolved simultaneously alongside their hosts through coevolution.

Antigenic drift involves rapid, unpredictable genetic changes, while antigenic shift involves slow, gradual accumulation of mutations.

Antigenic drift occurs when two viruses combine their genetic material in a single host cell, while antigenic shift results from small mutations over time.

Antigenic drift involves the gradual accumulation of small genetic changes, while antigenic shift occurs when two or more viruses combine their genetic material, leading to a major change.

Antigenic drift leads to new virus types unrecognisable to the immune system, while antigenic shift creates only minor changes in viral surface proteins.

The viral DNA produces proteins that suppress the immune response, resulting in persistent virion production.

A repressor protein coded by the viral DNA prevents transcription and translation.

The host cell lacks the necessary enzymes for viral replication, forcing the virus to remain dormant until external factors activate its DNA.

Viral nucleic acid disrupts host cell reproduction, preventing cell division until lytic triggers occur.