Waxes - Online Tutor, Practice Problems & Exam Prep

Waxes are simple lipids formed by an ester bond between a long chain fatty acid and a long chain alcohol. This structure gives waxes their unique properties, including water repellency, making them essential for protective coatings on bird feathers and plant leaves. Understanding waxes as a specific classification of fatty acids enhances comprehension of lipid diversity and functionality in biological systems.

Waxes Concept 1

In this video, let's talk about waxes. Now waxes are simple lipids composed of a long chain alcohol and a long chain fatty acid. The fatty acid and the alcohol are attached by an ester bond. If we take a look here, this part is our ester bond, where we have our carbonyl connected to an oxygen, and then here we have our long chain alcohol. And then over here on this side, we have our fatty acid. Remember that we have our lipids, which are broken down into our fatty acids and steroids. Underneath fatty acids when we break it down further, we have our waxes. We also have these three other classifications that lie below fatty acids, but we're not concerned with them for now. For right now, we're looking at waxes themselves, which again, we have an ester bond connecting together our fatty acid and our long chain alcohol. Now, here we're going to say that waxes possess repellent properties. And we're going to say they form protective coatings on feathers of birds and leaves of plants. So, just remember when it comes to waxes, they are a further classification, a more specific classification of fatty acids themselves. And when we talk about them, we're looking at an ester bond connecting a fatty acid and a long chain alcohol.

Waxes Example 1

For this example, it says, provide a structure of beeswax. It contains myricyl alcohol and palmitic acid. So step 1 says, draw the structure of the alcohol in its condensed form, as well as the fatty acid. We're going to place an OH from the alcohol next to the carboxyl group of the fatty acid. Now, let's just do that first. The alcohol is CH₃, and we're going to say here that it has 29 of these CH₂ groups. We're going to do 28 of them together. The 29th one, we're going to have it branch off, and then it's connected to the OH group.

Now we need to draw the fatty acid, which is palmitic acid. Palmitic acid represents a saturated fatty acid. And if we recall our memory tool 1, it is that Lori's Mystic Palace Stores Art. Here, the mnemonic PALIS stands for palmitic acid. This mnemonic starts at 12 carbons and goes up to 20. And we have carbons 14, 16, 18. So, palmitic acid is a fatty acid that's saturated and it has a total of 16 carbons. The first carbon is part of the carboxylic acid, so that's 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16. Okay. So that's 16. So we've done that part.

Now instead of OH on alcohol, we're just gonna draw an O; this is going to help later on when we connect these two together, and we're going to say, do not draw OH on fatty acid. So let's remove this OH. We have these two fragments.

Step 2 is we're going to form the Ester Bond. So we're going to draw a bond between the oxygen of the alcohol and the carbonyl carbon of the fatty acid. Connect these two together, this oxygen with this carbonyl carbon here, and we'll have our beeswax. So let's write this out.

We have CH₃ connected to 20 of these CH₂s, connected to 1 more CH₂, then O, which is going to be connected to the carbonyl carbon. So remember it's 16 carbons, so 2, 4, 6, 8, 10, 12, 14, 16. So that's 16. So this would represent our beeswax. We've combined the alcohol with our saturated fatty acid in order to make this particular type of wax. They're connected together through an ester bond.

Here’s what students ask on this topic:

What are waxes composed of in terms of their chemical structure?

Waxes are simple lipids composed of a long chain fatty acid and a long chain alcohol. These two components are connected by an ester bond. The ester bond is formed between the carbonyl group (C=O) of the fatty acid and the hydroxyl group (OH) of the alcohol. This unique structure gives waxes their characteristic properties, such as water repellency. Understanding this composition is crucial for comprehending the role of waxes in biological systems, such as their function in forming protective coatings on bird feathers and plant leaves.

What properties do waxes possess due to their chemical structure?

Due to their chemical structure, waxes possess water-repellent properties. This is primarily because the ester bond between the long chain fatty acid and the long chain alcohol creates a hydrophobic (water-repelling) molecule. These properties make waxes essential for forming protective coatings on bird feathers and plant leaves, helping to prevent water loss and providing a barrier against environmental elements. This functionality is crucial for the survival of many organisms in various ecosystems.

How do waxes differ from other types of lipids?

Waxes differ from other types of lipids primarily in their structure and function. While all lipids are hydrophobic, waxes are specifically composed of a long chain fatty acid and a long chain alcohol connected by an ester bond. This structure gives them unique properties, such as water repellency. In contrast, other lipids like triglycerides are composed of glycerol and three fatty acids, and phospholipids contain a phosphate group. These structural differences result in varied functions, with waxes being used for protective coatings, while other lipids play roles in energy storage and cell membrane structure.

What role do waxes play in biological systems?

In biological systems, waxes play a crucial role in providing protective coatings. For example, they form a waterproof layer on the feathers of birds, which helps in keeping them dry and buoyant. Similarly, waxes coat the leaves of plants, reducing water loss through evaporation and protecting against environmental stressors like pathogens and UV radiation. These protective functions are vital for the survival and efficiency of various organisms, highlighting the importance of waxes in nature.

What is the significance of the ester bond in waxes?

The ester bond in waxes is significant because it connects the long chain fatty acid to the long chain alcohol, forming the wax molecule. This bond is crucial for the hydrophobic properties of waxes, making them water-repellent. The ester bond is formed through a condensation reaction, where a molecule of water is released. This bond not only defines the structure of waxes but also contributes to their stability and functionality in biological systems, such as forming protective coatings on bird feathers and plant leaves.