Practice question · Sort into groups
Sort each protein by how it associates with the membrane.
Groups: Integral protein · Peripheral protein
- Requires detergent to extract
- Sits on one surface only
- Held by a hydrophobic belt of amino acids
- Can be removed by changing salt concentration
- Spans the entire bilayer
Hints
- The dividing question is whether the protein penetrates the hydrophobic core.
- Anything crossing the core needs a hydrophobic region and detergent to remove.
Show the answer
Integral protein: Spans the entire bilayer, Held by a hydrophobic belt of amino acids, Requires detergent to extract
Peripheral protein: Sits on one surface only, Can be removed by changing salt concentration
Why
Integral proteins penetrate the hydrophobic core and need detergent to extract; peripheral ones are held by weaker surface interactions and come away with a salt change. The extraction method is how the two are distinguished experimentally.
Practise Cell Membranes
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