Chapter 23: Problem 14
Draw the structure of the sphingomyelin that contains a myristic acid acyl group. Identify the hydrophilic head group and the hydrophobic tails in this molecule.
Short Answer
Expert verified
Sphingomyelin has a myristic acid tail and a phosphocholine head.
Step by step solution
01
Understand the Components of Sphingomyelin
Sphingomyelin is a type of sphingolipid found in cell membranes, particularly in the myelin sheath of nerve cells. It consists of three main components: a sphingosine backbone, a fatty acid attached through an amide bond forming ceramide, and a phosphocholine head group.
02
Identify the Sphingosine Backbone
The sphingosine backbone is an 18-carbon amino alcohol with trans-double bond at C4-C5. It forms the structural basis for sphingolipids, including sphingomyelin.
03
Add the Myristic Acid Acyl Group
Myristic acid, a 14-carbon saturated fatty acid (CH₃(CH₂)₁₂COOH), replaces the hydrogen on the amine group of the sphingosine to form an amide bond, creating a ceramide structure. This is done by attaching the carboxyl group (-COOH) of myristic acid to the amine (–NH₂) of sphingosine.
04
Attach the Phosphocholine Head Group
The phosphocholine group is connected to the primary alcohol group at the C1 position of the sphingosine backbone. It consists of a phosphate group linked to choline, creating the hydrophilic head of sphingomyelin.
05
Determine Hydrophilic and Hydrophobic Parts
The phosphocholine group forms the hydrophilic head, which is polar and water-attracting. The ceramide portion, including the sphingosine backbone and myristic acid tail, forms the hydrophobic tails, which are nonpolar and water-repelling.
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Key Concepts
These are the key concepts you need to understand to accurately answer the question.
Sphingosine
Sphingosine is a crucial molecule in the world of lipids and cell membranes. It acts as the backbone for a variety of sphingolipids, such as sphingomyelin, a key component of the myelin sheath in nerve cells.
This molecule is an 18-carbon amino alcohol. The presence of an amino group and a trans-double bond between the fourth and fifth carbon atoms gives it unique structural properties.
Its role goes beyond just being a structural scaffold. Sphingosine is involved in cellular signaling pathways. It influences processes like cell growth, differentiation, and apoptosis. Understanding sphingosine is key to grasping how cell membranes manage structure and function.
This molecule is an 18-carbon amino alcohol. The presence of an amino group and a trans-double bond between the fourth and fifth carbon atoms gives it unique structural properties.
Its role goes beyond just being a structural scaffold. Sphingosine is involved in cellular signaling pathways. It influences processes like cell growth, differentiation, and apoptosis. Understanding sphingosine is key to grasping how cell membranes manage structure and function.
Phosphocholine
Phosphocholine is an integral part of sphingomyelin's structure, providing the hydrophilic head in the molecule.
It comprises two main components: a phosphate group and choline. When linked together, these two create a polar, water-attracting head group that orients towards water-rich environments, such as the extracellular space and cytoplasm.
In biological membranes, the hydrophilic nature of phosphocholine helps in interactions with other molecules, aiding in the structural integrity and fluidity of the lipid bilayer.
It comprises two main components: a phosphate group and choline. When linked together, these two create a polar, water-attracting head group that orients towards water-rich environments, such as the extracellular space and cytoplasm.
In biological membranes, the hydrophilic nature of phosphocholine helps in interactions with other molecules, aiding in the structural integrity and fluidity of the lipid bilayer.
Myristic Acid
Myristic acid is a saturated fatty acid with 14 carbon atoms, denoted by the chemical formula CH₃(CH₂)₁₂COOH.
It plays a significant role in sphingomyelin when attached to the sphingosine backbone as an acyl group. This connection forms part of the ceramide structure in the molecule.
The presence of myristic acid contributes to the overall hydrophobic nature of sphingomyelin's structure. It influences how these molecules pack within cell membranes, impacting their stability and functionality.
It plays a significant role in sphingomyelin when attached to the sphingosine backbone as an acyl group. This connection forms part of the ceramide structure in the molecule.
The presence of myristic acid contributes to the overall hydrophobic nature of sphingomyelin's structure. It influences how these molecules pack within cell membranes, impacting their stability and functionality.
Ceramide
Ceramide is a lipid molecule comprised of sphingosine and a fatty acid, such as myristic acid, linked via an amide bond.
It forms the hydrophobic tail in sphingomyelin and is important for maintaining the structural integrity of cell membranes.
Ceramide molecules are essential in cellular signaling pathways. They play roles in regulating cell differentiation, proliferation, and apoptosis. Their properties significantly influence how cells respond to external stressors and stimuli.
It forms the hydrophobic tail in sphingomyelin and is important for maintaining the structural integrity of cell membranes.
Ceramide molecules are essential in cellular signaling pathways. They play roles in regulating cell differentiation, proliferation, and apoptosis. Their properties significantly influence how cells respond to external stressors and stimuli.
Hydrophilic Head
The hydrophilic head of sphingomyelin is primarily made up of the phosphocholine group.
This region is polar, meaning it is attracted to water and can interact with aqueous environments effectively. It faces outward in a biological membrane, towards the watery surroundings inside and outside cells.
The hydrophilic head plays a key role in the dynamic interactions between different molecules and ions, contributing to the formation and maintenance of the cell's lipid bilayer.
This region is polar, meaning it is attracted to water and can interact with aqueous environments effectively. It faces outward in a biological membrane, towards the watery surroundings inside and outside cells.
The hydrophilic head plays a key role in the dynamic interactions between different molecules and ions, contributing to the formation and maintenance of the cell's lipid bilayer.
Hydrophobic Tail
The hydrophobic tail of sphingomyelin consists of the ceramide structure, including the sphingosine and myristic acid components.
These tails are nonpolar and repel water, orienting themselves towards the inside of the membrane bilayer.
Their hydrophobic nature helps form the core of cell membranes, providing a barrier that protects cellular contents from the external environment. This structural arrangement is crucial for maintaining cellular homeostasis and the membrane's semi-permeable nature.
These tails are nonpolar and repel water, orienting themselves towards the inside of the membrane bilayer.
Their hydrophobic nature helps form the core of cell membranes, providing a barrier that protects cellular contents from the external environment. This structural arrangement is crucial for maintaining cellular homeostasis and the membrane's semi-permeable nature.
