Draw an 18-carbon unsaturated fatty acid that contains two carbon–carbon double bonds, one on carbon 6 and one on carbon 9 (count starting with the carboxyl carbon). Is this a “straight-chain” molecule or a “bent” molecule?

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Welcome back, everyone draw the structure of an unsaturated fatty acid with 20 carbons and two double bonds located at carbons five and 10 is this molecule linear or bent. So first of all, if we're drawing the structure of a E asset, we have to begin by drawing carboxyl and that carbonyl we o bonded to carbonyl carbon. Then we understand that this acid has 20 carbons and it has two double bonds and those double bonds are located at carbons five and 10. So we have our first carbon coming from carboxy followed by the second one, the third one, the fourth one and then the fifth one. This is where the double bond starts. And essentially we have to recall that double bonds generally have cis configuration right in those fatty assets. So we want to draw a double bond starting at carbon number 51234 and five in extending towards carbon number six. And since it is AIS configuration, the two implicit hydrogens must be on the same side of the double bond. We can see that they are both above the double bond. And now we have carbon number six followed by carbon number seven, number eight, number nine. And then since we have arrived at carbon number 10, this is where the double bond is going to begin extending towards carbon number 11, right? So 56789 and 10 all by carbon 11. And we need to make sure that we have 20 total. So 10 and this is where we want this configuration again. This is the general configuration. So 1011, 12, 1314, 15, 16, 1718, 19 and 20. So let's check the final fragment. 1011, 1213, 1415, 1617, 1819 20. So indeed, we have 20 carbons, the double bonds start at carbons five and some. And that's it. We have the required structure and as we can see it's on B, right? And the reason why it's banned is due to the presence of those cis configurations at the double bonds. Now, if there were no double bonds, we would say that the fatty acid has a linear or straight chain due to the absence of double bonds, but the presence of double bonds causes kings, right? And we can consider the overall structure bent due to the ability to attain this configuration. Thank you for watching.

Draw an 18-carbon unsaturated fatty acid that contains two carbon–carbon double bonds, one on carbon 6 and one on carbon 9 (count starting with the carboxyl carbon). Is this a “straight-chain” molecule or a “bent” molecule?

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Key Concepts

Fatty Acid Structure

Unsaturation and Double Bonds

Molecular Geometry