Arrange the following fatty acids from lowest à highest melting point: 18:1Δ 9 ; 18:0 ; 18:3Δ 9,12,15 ; 18:2Δ 9,12 a) 18:3 D 9,12,15 ; 18:2 D 9,12 ; 18:1 D 9 ; 18:0 b) 18:0 ; 18:3 D 9,12,15 ; 18:2 D 9,12 ; 18:1 D 9 c) 18:1 D 9 ; 18:0 ; 18:3 D 9,12,15 ; 18:2 D 9,12 d) 18:0 ; 18:1 D 9 ; 18:2 D 9,12 ; 18:3 D 9,12,15

Alright. So this practice problem wants us to arrange the following fatty acids that we see over here from the lowest melting point on the left to the highest melting point on the right. And so what we need to notice looking at these 4 fatty acids is that all 4 of them have a first number of 18, and this 18 is indicating the total number of carbon atoms in the fatty acid. So all 4 of these fatty acids have 18 carbon atoms and that means that they have the exact same length of their hydrocarbon chain and that means that we don't need to pay attention to the hydrocarbon chain length when we're trying to determine the melting points. And so, instead, what we're going to focus on is the degree of saturation or the number of double bonds that these fatty acids have. And so, notice that this fatty acid right here in the middle, 180, the 0 is indicating that there are 0 double bonds and so this is a saturated fatty acid since it has 0 double bonds. Whereas, the other ones that we see here and here and here are going to be unsaturated fatty acids because they do all have, double bonds 1, 2, and 3 double bonds respectively. And so what we need to recall from our previous lesson videos is that saturated fatty acids are going to have higher melting points and so that means that we expect 180 to have the highest melting point and so it should be furthest to the right, in comparison to the other fatty, acids. And so, when we consider this, we can clearly see that the only possible correct answer is gonna be option a since it's the only one that has 180 furthest to the right and all of the other ones don't have that. And so that's one quick and easy way to figure out that a is the correct answer. But if we didn't, if we weren't able to eliminate the other answer options just on that, how would we determine, the order of these other fatty acids? Well, we would have to take a look at the total number of double bonds and so recall that the more double bonds that there are, the lower the melting point is going to be And so that means that the one that has the highest amount of double bonds, which would be the 3 here, that's gonna have the lowest melting point and so that's gonna have to be the one furthest to the left. The one with 2 double bonds is gonna have the next lowest melting point and the one with only one double bond would have, the next, lowest melting point here. And so again, it's a here that is the correct answer to this practice problem and that concludes this practice. So I'll see you guys in our next video.

Arrange the following fatty acids from lowest à highest melting point: 18:1Δ 9 ; 18:0 ; 18:3Δ 9,12,15 ; 18:2Δ 9,12 a) 18:3 D 9,12,15 ; 18:2 D 9,12 ; 18:1 D 9 ; 18:0 b) 18:0 ; 18:3 D 9,12,15 ; 18:2 D 9,12 ; 18:1 D 9 c) 18:1 D 9 ; 18:0 ; 18:3 D 9,12,15 ; 18:2 D 9,12 d) 18:0 ; 18:1 D 9 ; 18:2 D 9,12 ; 18:3 D 9,12,15

18:0 ; 18:3Δ 9,12,15 ; 18:2Δ 9,12 ; 18:1Δ 9

18:1Δ 9 ; 18:0 ; 18:3Δ 9,12,15 ; 18:2Δ 9,12

18:0 ; 18:1Δ 9 ; 18:2Δ 9,12 ; 18:3Δ 9,12,15

Table of contents

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1. Introduction to Biochemistry4h 34m
2. Water3h 23m
3. Amino Acids8h 10m
4. Protein Structure10h 4m
5. Protein Techniques14h 5m
6. Enzymes and Enzyme Kinetics13h 38m
7. Enzyme Inhibition and Regulation 8h 42m
8. Protein Function 9h 41m
9. Carbohydrates7h 49m
10. Lipids5h 49m
11. Biological Membranes and Transport 6h 37m
12. Biosignaling9h 45m
Review 1: Nucleic Acids, Lipids, & Membranes2h 47m
Review 2: Biosignaling, Glycolysis, Gluconeogenesis, & PP-Pathway3h 12m
Review 3: Pyruvate & Fatty Acid Oxidation, Citric Acid Cycle, & Glycogen Metabolism2h 26m
Review 4: Amino Acid Oxidation, Oxidative Phosphorylation, & Photophosphorylation1h 48m

10. Lipids

Fatty Acid Nomenclature

Biochemistry

10. Lipids

Fatty Acid Nomenclature

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Multiple Choice

Arrange the following fatty acids from lowest à highest melting point: 18:1Δ⁹ ; 18:0 ; 18:3Δ^9,12,15 ; 18:2Δ^9,12

a) 18:3D^9,12,15; 18:2D^9,12 ; 18:1D⁹; 18:0
b) 18:0 ; 18:3D^9,12,15; 18:2D^9,12 ; 18:1D⁹
c) 18:1D⁹; 18:0 ; 18:3D^9,12,15; 18:2D^9,12
d) 18:0 ; 18:1D⁹; 18:2D^9,12; 18:3D^9,12,15

18:3Δ^9,12,15 ; 18:2Δ^9,12 ; 18:1Δ⁹ ; 18:0

18:0 ; 18:3Δ^9,12,15 ; 18:2Δ^9,12 ; 18:1Δ⁹

18:1Δ⁹ ; 18:0 ; 18:3Δ^9,12,15; 18:2Δ^9,12

18:0 ; 18:1Δ⁹ ; 18:2Δ^9,12; 18:3Δ^9,12,15

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Verified step by step guidance

Understand that the melting point of fatty acids is influenced by the degree of saturation and the length of the carbon chain. Saturated fatty acids have higher melting points than unsaturated ones due to tighter packing.

Identify the degree of unsaturation in each fatty acid: 18:0 is saturated, 18:1Δ9 has one double bond, 18:2Δ9,12 has two double bonds, and 18:3Δ9,12,15 has three double bonds.

Recognize that more double bonds (higher unsaturation) lead to lower melting points because they introduce kinks in the fatty acid chain, preventing tight packing.

Arrange the fatty acids from lowest to highest melting point based on the number of double bonds: 18:3Δ9,12,15 (three double bonds), 18:2Δ9,12 (two double bonds), 18:1Δ9 (one double bond), and 18:0 (no double bonds).

Select the correct option that matches the order: 18:3Δ9,12,15 ; 18:2Δ9,12 ; 18:1Δ9 ; 18:0.