Question

An example for a saturated fatty acid, present in nature is (a) oleic acid (b) linoleic acid (c) linolenic acid (d) palmitic acid

Short answer

The example of a saturated fatty acid is palmitic acid (d).

Step-by-step solution

Defining Saturated and Unsaturated Fatty Acids

Saturated fatty acids are types of fatty acids that lack double bonds between the individual carbon atoms. This means that each carbon atom is fully "saturated" with hydrogen atoms. Unsaturated fatty acids, in contrast, have one or more double bonds.

Analyzing Given Options

Let's review the options provided: - Oleic acid is a monounsaturated fatty acid, which means it has one double bond. - Linoleic and linolenic acids are polyunsaturated fatty acids, having multiple double bonds. - Palmitic acid is a saturated fatty acid, meaning it has no double bonds between carbons.

Identifying the Correct Answer

From the analysis in Step 2, we see that only palmitic acid fits the definition of a saturated fatty acid because it lacks double bonds between carbon atoms.

Key concepts

Saturated vs Unsaturated Fatty Acids

Fatty acids are a vital component of lipids, which are essential for our health. They are classified into two main types: saturated and unsaturated fatty acids. Understanding the difference between these two types is crucial to grasp their roles in the body and their health implications.

Saturated fatty acids are characterized by the absence of double bonds between the carbon atoms in their hydrocarbon chain. This means each carbon atom is bonded to the maximum possible number of hydrogen atoms, making them "saturated" with hydrogens. An easy way to think about it is that these fatty acids have straight chains which allow them to pack tightly together. This structural layout contributes to their solid state at room temperature, like butter and lard.

Unsaturated fatty acids, on the other hand, have one or more double bonds in their carbon chain. These double bonds introduce kinks in the chain, preventing tight packing and thus, keeping them in a liquid state at room temperature. Examples include oils like olive oil and canola oil. There are two sub-categories of unsaturated fatty acids: monounsaturated fatty acids, which have one double bond, and polyunsaturated fatty acids, which have two or more double bonds.

Palmitic Acid

Palmitic acid is one of the most common saturated fatty acids found in animals and plants. This specific type of fatty acid is crucial for numerous biological functions. While palmitic acid is naturally found in palm oil, it also occurs in butter, cheese, milk, and meat. It has the chemical formula \( C_{16}H_{32}O_{2} \,\), indicating that it contains 16 carbon atoms and 32 hydrogen atoms.

As a saturated fatty acid, palmitic acid plays several roles in the body, such as energy storage and provision. These fatty acids impact cholesterol levels, where excessive intake may elevate LDL cholesterol, the so-called "bad" cholesterol, potentially increasing heart disease risk. Hence, it is essential to moderate the consumption of foods rich in palmitic acid.

• Found in: Palm oil, dairy products, meat.
• Function: Energy storage, influencing cholesterol levels.

Double Bonds in Fatty Acids

Double bonds in fatty acids play a significant role in defining their physical and chemical properties. Such bonds occur when two carbon atoms share two pairs of electrons, creating a tighter bond compared to single bonds. This configuration is key in differentiating saturated from unsaturated fatty acids.

When a fatty acid has one double bond, it is termed monounsaturated. Oleic acid is a classic example of this type. If there are multiple double bonds, the fatty acid is polyunsaturated – as seen in linoleic and linolenic acids. The presence of double bonds imparts fluidity to these molecules, affecting how they interact with biological membranes and influence health outcomes.

The cis and trans configurations of double bonds further affect the structure and functionality of fatty acids. In a cis configuration, the hydrogen atoms are on the same side of the double bond, causing a bend in the chain. This bend prevents the fatty acids from packing closely together, resulting in a liquid state at room temperature. Contrastingly, the trans configuration aligns the hydrogens on opposite sides, leading to a straighter chain.

• Monounsaturated: One double bond (e.g., oleic acid).
• Polyunsaturated: Multiple double bonds (e.g., linoleic acid).
• Cis vs. Trans: Influences melting point and health effects.