Virus

Viruses are simple structures composed of nucleic acid within a protein shell, sometimes with an outer membrane. There is debate about whether they are living organisms, as they have genes and evolve but cannot survive outside living cells and lack cellular structure and metabolism.

What is the basic structure of a virus?

• A cell with a nucleus

• A single strand of DNA

• A packet of nucleic acid in a protein shell

• A complex cell with organelles

What additional component might some viruses have?

• A cell wall

• A nucleus

• An outer phospholipid membrane

• Mitochondria

Why is there debate about whether viruses are living organisms?

• They have a complex metabolism

• They have genes and evolve but lack cellular structure

• They can reproduce independently

• They can survive in any environment

What is one reason viruses are not considered living organisms?

• They have their own metabolism

• They can survive outside living cells

• They lack their own cellular structure

• They do not evolve

What do viruses lack that prevents them from being considered fully living?

• The ability to evolve

• A protective protein shell

• Genes

• Their own metabolism