DP Biology (first assessment 2025)

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Question EXEX.1B.HL.TZ0.1c

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Date Example questions Example questions Marks available [Maximum mark: 4] Reference code EXEX.1B.HL.TZ0.1c
Level HL Paper 1B Time zone TZ0
Command term Discuss Question number c Adapted from N/A
c.
[Maximum mark: 4]
EXEX.1B.HL.TZ0.1c
(c)

Discuss the evidence provided by viral structure and function that suggests they evolved from living organisms.   

[4]

Markscheme
  1. complexity in structure/ big size of some viruses evidence evolution from bacteria that lost cell components/functions;
  2. e.g. they might have evolved from a kind of parasitic bacteria that can only replicate inside a host;
  3. retroviruses/ some viruses and some eukaryotic cells have similar mechanisms for the synthesis of DNA from RNA/ contain reverse transcriptases;
  4. suggesting genetic material moved out of cells and evolved into viruses;
  5. they are obligate parasites/, so they could not exist before living cells;
  6. all living organisms share same genetic material from universal common ancestor/LUCA, so viruses having similar genetic material must have evolved from cells;

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