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QLDBiologyQuick questions
Unit 2: Maintaining the internal environment
Quick questions on Pathogens and modes of disease transmission (QCE Biology Unit 2)
8short Q&A pairs drawn directly from our worked dot-point answer. For full context and worked exam questions, read the parent dot-point page.
What is bacteria?Show answer
Prokaryotic, single-celled organisms with circular DNA, 70S ribosomes and (in most species) a peptidoglycan cell wall. Reproduce by binary fission. Cause disease either by damaging tissues directly or by producing toxins.
What are viruses?Show answer
Non-cellular: nucleic acid (DNA or RNA) inside a protein capsid, sometimes with a lipid envelope studded with glycoproteins. Cannot reproduce on their own; they hijack host cell machinery to replicate.
What is fungi?Show answer
Eukaryotic; chitin cell walls. Mostly multicellular networks of hyphae; some are single-celled yeasts. Cause disease through tissue invasion, allergic reactions or mycotoxins.
What are protists?Show answer
Eukaryotic, mostly unicellular. Varied structures including flagella, cilia or pseudopodia. Many have complex life cycles involving vectors.
What are prions?Show answer
Misfolded versions of a normal cellular protein (PrP). They convert correctly folded copies into the misfolded form, producing aggregates that damage neurons. No nucleic acid is involved.
What is q1?Show answer
Compare bacteria and viruses as pathogens, identifying two structural differences and one consequence for antibiotic treatment. [3 marks]
What is q2?Show answer
A reef diver returns from the Great Barrier Reef with a fungal skin infection (_Tinea_) and reports a fellow diver had the same condition. Identify the mode of transmission and explain why fungal infections are often persistent. [3 marks]
What is q3?Show answer
Refer to malaria caused by _Plasmodium falciparum_. (a) Classify the pathogen and identify the vector. (b) Describe the lifecycle stages in mosquito and human.