IB Biology HL 2.2.5 Prokaryote Cell Structure

Practise IB Biology HL 2.2.5 by analysing bacterial ultrastructure, chromosome organisation, cell walls and prokaryote–eukaryote differences.

Exam points

Compare prokaryote and eukaryote chromosomes using DNA shape, histones, number and location.
Describe bacterial ultrastructure and distinguish Gram-positive from Gram-negative cell walls.
Explain how naked DNA, plasmids and 70S ribosomes distinguish prokaryotic organisation.

[Maximum number: 4]

Draw a labelled diagram of a prokaryotic cell.

Award [1] for each structure clearly drawn and correctly labelled, up to [4 max].
cell wall - a uniformly thick wall;
pili - hair-like structures connected to cell wall / flagellum - at least length of the cell;
plasma/cell membrane $\left.-\quad \begin{array}{l}\text { represented by a continuous single } \\ \text { line; }\end{array}\right\} \begin{aligned} & \text { (may be labelled } \\ & \text { as the innermost } \\ & \text { wall line) }\end{aligned}$
ribosomes (70S) - drawn as small discrete dots;
naked DNA/nucleoid - region with DNA not enclosed in membrane;
plasmid - circular ring of DNA;
cytoplasm - the non-structural material within the cell;
[4 max]
Award [2 max] if any eukaryotic structure is shown.

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A2.2.5—Prokaryote cell structure question 1