released into water so thy greinsulated fromOter*The melting points of a series of 18-carbon fatty acids are:stearic acid, 69.6°C; oleic acid, 13.4°C; linoleic acid, -5°C; andlinolenic acid, -11°℃.c)a)b)What structural aspect of these 18-carbon fatty acids can becorrelated with the melting point?Draw all the possible triacylglycerols that can beconstructed from glycerol, palmitic acid, and oleic acid.Rank them in order of increasing melting point.Branched-chain fatty acids are found in some bacterialmembrane lipids. Would their presence increase or decreasethe fluidity of the membranes (that is, give them a lower ohigher melting point)? Why?

Fatty acids are important micromolecules which combine together to form lipids in plants, animals and microorganisms. Fatty acid are composed of straight chain of an even number of carbon atoms, with hydrogen atoms along the chain and carboxyl group at the end. This carboxyl group make the molecule an acid. Based on the double bonds they are categorised as Saturated (all single bonds) and unsaturated (prescence of double or triple bond). These fatty acid exist along with glycerol in the form of triglyceride.Stearic acid: Stearic acid has an 18-carbon backbone and is a saturated long-chain fatty acid. Stearic acid can be found in a variety of animal and plant fats and is a key component of cocoa and shea butter. Pooint to remeember, stearic acid is saturated which means it has no double bonds, which also means the fatty acid is straight and no kinks are present. This makes stearic acid to stack together, due to which it exists as solid in room temperature. The melting point is 69.6o C. Oleic acid: Oleic acid has an 18-carbon backbone and with a double bond at carbon 9. It is classified chemically as a monounsaturated omega-9 fatty acid. It is an odourless and colourless oil. Oleic acid has double bond, this results in kink in the structure due to which, the molecules cannot stack together and hence exists as liquid in room temperature. Therefore, its melting temperature is less than stearic acid, i.e, 13.4o C. Linoleic acid: Linoleic acid has18 carbon backbone and it is di-unsaturated fatty acid. One double bond is located at Δ9 and other at Δ12. Both double bonds take up cis-configuration. Due to which it has double kinks in the structure and highly difficult to stack the molecules. Hence, linoleic acid is liquid in room temperature and its melting point is -50C. Linolenic acid: Linolenic acid has18 carbon backbone and it is tri-unsaturated fatty acid. One double bond is located at Δ9, Δ12 and Δ15 . All three double bonds take up cis-configuration. Due to which it has triple kinks in the structure and highly difficult to stack the molecules. Hence, linolenic acid is liquid in room temperature and its melting point is -110C. conclusion: Saturated fatty acid can stack together due to absence of double bonds and kinks and exist as solid in room temperature. Due to which they have high melting point. As the unsaturation of the fatty acid increases, the double bonds introduces kinks in the structure, due to which the molecules cannot stack effectively with each other and exists as liquid in room temperature and have low melting point point. More the kinks in the structure lower goes the melting point. 2) Triacylglycerol are composed of glycerol molecule, where each OH group is bound to fatty acid molecule. Such three fatty acid are attached to glycerol molecule forming triacylglycerol. The structutre of glycerol, palmitic acid and oleic acid is given below. Glycerol oleic acid palmitic acid Let me denote Glycerol as G, oleic acid as O and palmitic acid as P for convenience. Six different triacylglycerol can be constructed by using glycerol, palmitic acid and oleic acid. They are, OOO where oleic acid is bound to OH of first carbon, then OH of second carbon and OH of third carbon. Similarly, OOP where oleic acid is boound to OH of first carbon, Palmitic acid is bound to OH of second carbon and third carbon. The other posiibilities are OPO, PPO, POP and PPP. As we know, the saturated fatty acid have higher melting point than that of unsaturated fatty acid due to presence of doubl bonds in the unsaturated fatty acids. In this scenario, palmitic acid is saturated and oleic acid is unsaturated. Therefore the order of increasing melting point of these triacylglycerols is as follows: OOO<OOP ≈ OPO< OPO < PPO<PPP3)Branched-chain fatty acids are common components of bacterial and animal lipids. The fatty acyl chain is normally saturated, and the branch is a methyl-group, but unsaturated branched-chain fatty acids are found in marine animals, and branches other than methyl may be present in microbial lipids. Although mono-methyl-branched fatty acids are the most common, di- and poly-methyl-branched fatty acids are also known, and mycolic acids in particular are highly complex. As an alternative to unsaturated fatty acids, their primary function in membranes may be to increase the fluidity and lower the phase transition temperature of the lipid components. Hence, their presence increases the fluidity of membrane.