Viruses: Practice Quiz for High School Biology

📚 Topic Summary

Viruses are tiny infectious agents that can only replicate inside the living cells of an organism. They're not considered living because they lack the ability to reproduce independently. Instead, they invade host cells and use the host's cellular machinery to produce more virus particles. These particles then infect new cells, continuing the cycle. Understanding viruses is crucial in biology, especially when studying diseases and developing treatments.

🧪 Part A: Vocabulary

Match the following terms with their correct definitions:

1. Virus
2. Capsid
3. Host Cell
4. Bacteriophage
5. Retrovirus

Definitions:

1. A virus that infects bacteria.
2. The protein shell of a virus.
3. A microscopic infectious agent that replicates inside a living cell.
4. A cell that is infected by a virus.
5. A virus that uses RNA as its genetic material and employs reverse transcriptase to produce DNA.

🧬 Part B: Fill in the Blanks

Complete the following paragraph with the correct terms:

Viruses are composed of genetic material, either DNA or ____(1)____, surrounded by a protein coat called a ____(2)____. They infect ____(3)____ cells by attaching to the cell surface and injecting their genetic material. Some viruses, like ____(4)____, can integrate their genetic material into the host cell's DNA. Viral replication leads to the production of new virus particles, which are then released to infect other cells. This process can cause disease in the ____(5)____.

Answers:

1. RNA
2. Capsid
3. Host
4. Retroviruses
5. Host

🤔 Part C: Critical Thinking

Explain why viruses are not considered living organisms. Provide at least three reasons.

Answer:

Viruses are not considered living organisms for several key reasons:

• 🦠 They cannot reproduce on their own. They require a host cell to replicate.
• ⚡ They lack cellular machinery, such as ribosomes, necessary for protein synthesis. They rely on the host cell's machinery.
• 🧫 They do not carry out metabolic processes independently. They do not have their own energy production systems.