Lipid: Difference between revisions
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A lipid is a "water-insoluble biomolecule that is highly soluble in organic solvents" by definition <ref>Berg, JM. (2006) "Biochemistry" 6th Ed. p329, New York, W.H. Freeman and company</ref>. The lipid's we come across most often are those which play the most important role in forming the [[Lipid bilayer|lipid bilayer]] membranes around cells, these are [[Phospholipid|phospholipids]]. They (like all lipids) contain a [[Hydrophobic|hydrophobic]], long hydrocarbon chain 'tail', they also contain a 'head'. In phospholipids the main component of this 'head' is a phosphate, it is also formed from an alcohol and a platform bonded to the phosphate creating the [[Hydrophilic|hydrophilic]] part of the lipid. Lipids are [[Amphiphatic|amphiphatic]], they have both a hydrophilic and a hydrophobic part. | A lipid is a "water-insoluble biomolecule that is highly soluble in organic solvents" by definition <ref>Berg, JM. (2006) "Biochemistry" 6th Ed. p329, New York, W.H. Freeman and company</ref>. The lipid's we come across most often are those which play the most important role in forming the [[Lipid bilayer|lipid bilayer]] membranes around cells, these are [[Phospholipid|phospholipids]]. They (like all lipids) contain a [[Hydrophobic|hydrophobic]], long hydrocarbon chain 'tail', they also contain a 'head'. In phospholipids the main component of this 'head' is a phosphate, it is also formed from an alcohol and a platform bonded to the phosphate creating the [[Hydrophilic|hydrophilic]] part of the lipid. Lipids are [[Amphiphatic|amphiphatic]], they have both a hydrophilic and a hydrophobic part. | ||
The role of phospholipid bilayer is to allow the conditions inside the cell to be different to those outside and to control the movement of substances into and out of the cell. It is the phospholipids in the membrane that control the movement of the substances into and out of the cell. As only lipid-soluble molecules to pass through them therefore entering and leaving the cell and water-soluble molecules cannot pass throught therefore are prevented from entering and leaving the cell. | The role of phospholipid bilayer is to allow the conditions inside the cell to be different to those outside and to control the movement of substances into and out of the cell. It is the phospholipids in the membrane that control the movement of the substances into and out of the cell. As only lipid-soluble molecules to pass through them therefore entering and leaving the cell and water-soluble molecules cannot pass throught therefore are prevented from entering and leaving the cell <ref>AQA As level biology text book, page 52</ref>. | ||
=== References | === References<br> === | ||
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Revision as of 00:03, 11 November 2013
A lipid is a "water-insoluble biomolecule that is highly soluble in organic solvents" by definition [1]. The lipid's we come across most often are those which play the most important role in forming the lipid bilayer membranes around cells, these are phospholipids. They (like all lipids) contain a hydrophobic, long hydrocarbon chain 'tail', they also contain a 'head'. In phospholipids the main component of this 'head' is a phosphate, it is also formed from an alcohol and a platform bonded to the phosphate creating the hydrophilic part of the lipid. Lipids are amphiphatic, they have both a hydrophilic and a hydrophobic part.
The role of phospholipid bilayer is to allow the conditions inside the cell to be different to those outside and to control the movement of substances into and out of the cell. It is the phospholipids in the membrane that control the movement of the substances into and out of the cell. As only lipid-soluble molecules to pass through them therefore entering and leaving the cell and water-soluble molecules cannot pass throught therefore are prevented from entering and leaving the cell [2].