Contributed by Javid Naseem
The diagram below shows the electromicrograph of a cell from an unknown organism.
(i) Name the organelles A to D.
(ii) This cell is thought to be the cell of a bacterium. Do you agree? Explain why.
(iii) Explain how D helps in the absorption of digested food from the ileum.
(iv) Explain why structures A and B are usually situated closely to each other in the cells.
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Answer: (i) A – (rough) endoplasmic reticulum; B – golgi body; C – ribosome; D – mitochondrion
Deduct 1 mark for each incorrect answer; reject answers with wrong spelling
(ii) No. The cell above has a nucleus surrounded by a nuclear membrane which is absent in bacteria [1]. The cell above also lacks a cell wall [1] which is characteristic of bacterium.
(iii) Food substances/glucose in the cells of ileum oxidised to release (NOT produce/manufacture) energy during aerobic respiration [1]. This energy is used by the cells in the ileum to transport food substances/AW
(iv) ER is where lipids and proteins (made in ribosomes) are synthesised [1]. These synthesised macromolecules are sent as vesicles to Golgi Apparatus to be stored [1], processed and packaged for secretory outside the cell [1].
