Biodiversity and Classification of Microorganisms is one of 10 topics in the Grade 11 Life Sciences CAPS syllabus, covered across 3 lessons on Study Vault. Below are real practice questions from this topic with full worked answers.
Sample practice questions
Easy
1. Why are viruses considered to exist at the boundary between living and non-living matter?
They have no cell structure and cannot carry out life processes independently, but can reproduce inside a host cell
They are fully living organisms identical to bacteria in every way
They have cells but no genetic material at all
They can carry out metabolism completely independently of any host
Answer: They have no cell structure and cannot carry out life processes independently, but can reproduce inside a host cell — Viruses lack cell structure and independent metabolism, so they cannot carry out life processes on their own, yet they carry genetic material and can reproduce once inside a living host cell, placing them at the boundary of what is considered "alive".
Easy
2. What is the protective protein coat surrounding a virus's genetic material called?
The capsid
The cell wall
The nucleoid
The mycelium
Answer: The capsid — The capsid is the protein coat that surrounds and protects the viral genetic material (DNA or RNA).
Medium
3. Why are viruses described as "obligate intracellular parasites"?
They can only replicate by hijacking the machinery of a living host cell
They can replicate independently outside any host cell
They only infect plant cells, never animal cells
They contain both DNA and RNA in every particle
Answer: They can only replicate by hijacking the machinery of a living host cell — Because viruses lack ribosomes, metabolic enzymes, and any means of independent reproduction, they must take over a host cell's own machinery to replicate, making them obligate intracellular parasites.
