Biology 9700 · AS & A Level · Fluid mosaic membranes

Fluid mosaic membranes — practice question

The fatty acids elaidic acid and oleic acid have identical structural formulae, each containing one double bond in the chain. Even so, the chain shapes are not the same, as the diagram shows. Which row indicates the effect of these fatty acids on the structure and behaviour of a cell surface membrane?

  • Aelaidic acid does not fit closely with other fatty acids so that the membrane is less fluid at high temperatures; oleic acid fits closely with other fatty acids so that the membrane is less fluid at low temperatures
  • Belaidic acid does not fit closely with other fatty acids so that the membrane is more fluid at low temperatures; oleic acid fits closely with other fatty acids so that the membrane is less fluid at low temperatures
  • Celaidic acid fits closely with other fatty acids so that the membrane is less fluid at high temperatures; oleic acid does not fit closely with other fatty acids so that the membrane is more fluid at low temperatures
  • Delaidic acid fits closely with other fatty acids so that the membrane is more fluid at low temperatures; oleic acid does not fit closely with other fatty acids so that the membrane is more fluid at high temperatures

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