Chapter 15: Problem 57
What is the function of the lipid bilayer in a cell membrane?
Short Answer
Expert verified
The lipid bilayer acts as a selective barrier and provides fluidity and flexibility to the cell membrane.
Step by step solution
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Key Concepts
These are the key concepts you need to understand to accurately answer the question.
Cell Membrane
The cell membrane, also known as the plasma membrane, is a vital component of all living cells. It serves as a protective barrier that separates the cell's interior from the external environment.
This boundary is essential for maintaining the cell's integrity and functions.
The cell membrane is notably made up of a lipid bilayer, which forms its basic foundation and decides its properties.
This membrane controls the movement of substances in and out of the cell, ensuring that the internal environment remains stable and balanced.
This boundary is essential for maintaining the cell's integrity and functions.
The cell membrane is notably made up of a lipid bilayer, which forms its basic foundation and decides its properties.
This membrane controls the movement of substances in and out of the cell, ensuring that the internal environment remains stable and balanced.
Phospholipids
Phospholipids are the key building blocks of the lipid bilayer in cell membranes. Each phospholipid molecule consists of a hydrophilic (water-loving) head and two hydrophobic (water-fearing) tails.
The hydrophilic heads face the watery environments inside and outside the cell, while the hydrophobic tails point inward, away from water, forming a double-layered structure.
This arrangement creates a semi-permeable membrane that regulates what can enter and exit the cell.
Phospholipids make the membrane flexible and self-sealing, allowing it to accommodate growth and cellular processes.
The hydrophilic heads face the watery environments inside and outside the cell, while the hydrophobic tails point inward, away from water, forming a double-layered structure.
This arrangement creates a semi-permeable membrane that regulates what can enter and exit the cell.
Phospholipids make the membrane flexible and self-sealing, allowing it to accommodate growth and cellular processes.
Selective Permeability
Selective permeability is a crucial feature of the cell membrane's lipid bilayer. It means that the membrane allows some substances to pass through while blocking others.
Small nonpolar molecules, like oxygen and carbon dioxide, move in and out freely through simple diffusion.
However, larger or charged molecules cannot easily cross the lipid bilayer. These molecules need help from specialized transport proteins.
This selective permeability is vital for maintaining the cell's internal environment and regulating the intake of nutrients and the expulsion of waste products.
Small nonpolar molecules, like oxygen and carbon dioxide, move in and out freely through simple diffusion.
However, larger or charged molecules cannot easily cross the lipid bilayer. These molecules need help from specialized transport proteins.
This selective permeability is vital for maintaining the cell's internal environment and regulating the intake of nutrients and the expulsion of waste products.
Membrane Proteins
Membrane proteins are integral to the functioning of the cell membrane. They are either embedded within or attached to the lipid bilayer.
These proteins perform various essential roles, such as transporting molecules across the membrane, acting as receptors for signal transduction, and aiding in cell recognition.
Transport proteins facilitate the movement of substances that cannot diffuse freely, ensuring vital nutrients enter and waste products leave the cell.
Receptor proteins detect extracellular signals and initiate intracellular responses, crucial for processes like cell signaling.
These proteins perform various essential roles, such as transporting molecules across the membrane, acting as receptors for signal transduction, and aiding in cell recognition.
Transport proteins facilitate the movement of substances that cannot diffuse freely, ensuring vital nutrients enter and waste products leave the cell.
Receptor proteins detect extracellular signals and initiate intracellular responses, crucial for processes like cell signaling.
Cell Signaling
Cell signaling is the process by which cells communicate with each other. This communication is essential for coordinating various cellular activities.
The cell membrane plays a vital role in cell signaling through its membrane proteins, which act as receptors for signaling molecules.
When a signaling molecule binds to a receptor protein, it triggers a change in the protein's shape, initiating a signal transduction pathway.
This pathway relays the signal into the cell, resulting in a specific response, such as changes in gene expression, cell movement, or metabolism.
The cell membrane plays a vital role in cell signaling through its membrane proteins, which act as receptors for signaling molecules.
When a signaling molecule binds to a receptor protein, it triggers a change in the protein's shape, initiating a signal transduction pathway.
This pathway relays the signal into the cell, resulting in a specific response, such as changes in gene expression, cell movement, or metabolism.
