Year 9 Science · Unit 1 · Lesson 2
Challenge Worksheet
Learning Goals
Find the mistake
A student wrote this answer
"Viruses are the smallest living things on Earth, they are just tiny bacteria. Both bacteria and viruses are single-celled microorganisms that reproduce on their own by splitting in two. Because they are both living cells, antibiotics can kill both bacteria and viruses. The difference is that viruses are smaller and harder to treat, but they are essentially the same type of pathogen."
1. Identify all the scientific mistakes in the student's answer. List each one separately.
2. Rewrite the student's answer correctly in three to four sentences. Use the correct scientific terminology for virus structure (capsid, genetic material) and replication (host cell hijacking, lysis).
3. Viruses are debated among scientists as being "on the boundary of life." List two characteristics that viruses share with living things and two characteristics that suggest they are not truly alive. Based on this, do you think viruses should be classified as living organisms? Justify your answer.
1. HIV destroys T-helper cells (a type of white blood cell) rather than directly damaging other organs. Using your understanding of how viruses replicate, hijacking host cell machinery and lysing the cell, explain why HIV infections are so difficult to treat compared with bacterial infections, and predict what would happen to a person's ability to fight other infections as their T-helper cell count drops over time.
2. A new pathogen is discovered that is eukaryotic, has a cell wall, reproduces by budding, and causes a skin infection that responds to fluconazole treatment. Identify the pathogen type and explain your reasoning by referring to at least three pieces of evidence from the description.
Wrap Up
In one sentence, what was the main idea of this lesson?