1. Characteristics of life &viruses
Classification
Characteristics of life &viruses

2. Objectives Identify the characteristics of living organisms
Differentiate between viruses and living organisms
Explain the structure of viruses
Explain the function of viruses

3. Living or non-living?

4. Living or non-living?

5. Living or non-living?

6. Living or non-living?

7. Living or non-living?

8. Pull out your “characteristics of life” list from Monday
What were some of the characteristics your group came up with?

9. When is an organisms living?
For something to be described as living, that something must display all seven characteristics of life.
Although many different people have many different opinions about what "living" means, the following characteristics were designated "characteristics of living things" with the consensus of the scientific community.

10. When is an organisms living?
Living things are:
Made up of cells
Respond to environment
/Maintain Homeostasis
Use energy
Grow and develop
Reproduce

11. Are Viruses Living?
Virus- An infectious particle that cannot grow or reproduce apart from a living cell.

12. Are viruses living?
This is a very interesting question which has instigated many heated debates in scientific circles.
Why are viruses such a big deal? Well, viruses are interesting because they are neither inanimate nor living; a virus is "midway between brute matter and living organism" (Wolfhard Weidel).

13. Are viruses living? Living characteristics
“Not living” characteristics
Respond to environment
Not composed of cells
Evolve
Do not use energy (on their own)
Reproduce
Do not reproduce (on their own)
Contain proteins and nucleic acids
Can form crystals and remain dormant for long periods of time
So are viruses living?
NO!

14. Virus structure Parts: Nucleic acid- DNA or RNA
Caspid- protein shell surrounding a virus; proteins determine shape of virus
Viral envelope- protective coating formed from host cell membrane
Spikes- used to recognize and attach to the cell it attacks

15. Viruses come in many shapes

16. Viruses come in many shapes

17. How do viruses reproduce?
Viral Replication:
Attaches to a healthy cell
Injects its DNA or RNA into the cell
Viral DNA is added to host DNA
Viral DNA is copied with the host DNA every time the cell divides
Now viral DNA is passed on to every new daughter cell!

18. Function of viruses A virus that causes little or no harm to the host
Benign viruses
Virulent viruses
A virus that causes little or no harm to the host
Cause disease
Difficult to cure:
Replicate quickly
Undergo frequent mutations
Medicines made to destroy viruses often attack and harm healthy cells

19. Viruses Video!! Be sure to answer the 10 questions!