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Questions and Answers
What is the main function of cholesterol molecules in the cell membrane?
What is the term for the movement of molecules down their concentration gradient?
What is the purpose of carbohydrates attached to lipids and proteins in the cell membrane?
What is the term for the arrangement of proteins and lipids in the cell membrane?
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What is the function of integral proteins in the cell membrane?
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What is the term for the movement of molecules against their concentration gradient?
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What is the characteristic of the cell membrane that allows certain molecules to pass through while restricting others?
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What is the function of peripheral proteins in the cell membrane?
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Study Notes
Structure and Composition
- Phospholipid bilayer: a double layer of lipids with hydrophilic heads and hydrophobic tails
- Embedded proteins: integral proteins (span the membrane) and peripheral proteins (attached to the surface)
- Cholesterol molecules: embedded between phospholipids, maintaining fluidity and structure
- Carbohydrates: attached to lipids and proteins, forming glycolipids and glycoproteins
Functions
- Barrier function: regulates what enters and leaves the cell
- Cell signaling: proteins and lipids participate in signal transduction pathways
- Cell adhesion: proteins and carbohydrates facilitate cell-cell interactions
- Transport: proteins facilitate movement of molecules across the membrane
- Cell recognition: carbohydrates and proteins help identify self and non-self
Fluid Mosaic Model
- Fluidity: phospholipid bilayer is dynamic and flexible, allowing for movement of proteins and lipids
- Mosaic: proteins and lipids are arranged in a mosaic pattern, with varying degrees of mobility
Types of Transport
- Passive transport: movement of molecules down their concentration gradient (diffusion, osmosis)
- Active transport: movement of molecules against their concentration gradient, requiring energy input
- Facilitated diffusion: assisted transport of molecules down their concentration gradient
- Receptor-mediated endocytosis: uptake of molecules into the cell through receptor-mediated vesicle formation
Membrane Permeability
- Semipermeable: allows certain molecules to pass through, while restricting others
- Selective permeability: specific molecules are allowed to pass through, while others are restricted
- Permeability coefficients: measure of a molecule's ability to pass through the membrane
Cell Membrane Structure
- Phospholipid bilayer consists of a double layer of lipids with hydrophilic heads and hydrophobic tails
- Integral proteins span the membrane, while peripheral proteins attach to the surface
- Cholesterol molecules are embedded between phospholipids, maintaining fluidity and structure
- Carbohydrates attach to lipids and proteins, forming glycolipids and glycoproteins
Cell Membrane Functions
- Regulates what enters and leaves the cell through barrier function
- Participates in signal transduction pathways through proteins and lipids
- Facilitates cell-cell interactions through proteins and carbohydrates
- Enables movement of molecules across the membrane through proteins
- Helps identify self and non-self through carbohydrates and proteins
Fluid Mosaic Model
- Phospholipid bilayer is dynamic and flexible, allowing for movement of proteins and lipids
- Proteins and lipids are arranged in a mosaic pattern, with varying degrees of mobility
Cell Transport
- Passive transport: movement of molecules down their concentration gradient through diffusion and osmosis
- Active transport: movement of molecules against their concentration gradient, requiring energy input
- Facilitated diffusion: assisted transport of molecules down their concentration gradient
- Receptor-mediated endocytosis: uptake of molecules into the cell through receptor-mediated vesicle formation
Membrane Properties
- Semipermeable: allows certain molecules to pass through, while restricting others
- Selective permeability: specific molecules are allowed to pass through, while others are restricted
- Permeability coefficients: measure of a molecule's ability to pass through the membrane
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Description
Quiz about the structure and composition of cell membranes, including phospholipid bilayer, embedded proteins, cholesterol, and carbohydrates. Learn about the functions of cell membranes, including barrier function and more.
