What is Facilitated Diffusion _ It’s Meaning and Definition Transport of substances across
What is Facilitated Diffusion _ It’s Meaning and Definition Transport of substances across.
Contents [hide]
- 1 Facilitated Diffusion: Meaning and Definition
- 2 Key Features of Facilitated Diffusion:
- 3 Examples of Facilitated Diffusion:
- 4 Difference Between Simple and Facilitated Diffusion
- 5 Conclusion
- 6
What is Facilitated Diffusion? – Meaning, Definition & Process
- 7
Meaning:
- 8
Definition:
- 9
Key Characteristics:
- 10
How It Works:
- 11
Examples:
- 12
Why is Facilitated Diffusion Important?
- 13
Comparison with Simple Diffusion:
- 14 What is Facilitated Diffusion _ It’s Meaning and Definition Transport of substances across
Facilitated Diffusion: Meaning and Definition
Meaning of Facilitated Diffusion
Facilitated diffusion is a passive transport process in which substances move across a cell membrane with the help of transport proteins. Unlike simple diffusion, it requires specific carrier or channel proteins to allow molecules to pass through the lipid bilayer of the membrane.
Definition of Facilitated Diffusion
Facilitated diffusion is the passive movement of molecules across a cell membrane via specific transport proteins, without the use of cellular energy (ATP), following the concentration gradient (from high to low concentration).
Key Features of Facilitated Diffusion:
Passive Transport → No ATP required.
Uses Transport Proteins → Carrier or channel proteins assist movement.
Moves Down the Concentration Gradient → From high to low concentration.
Specificity → Only certain molecules are transported.
Examples of Facilitated Diffusion:
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Glucose Transport → Glucose enters cells through GLUT (Glucose Transporter) proteins.
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Ion Channels → Sodium (Na⁺), Potassium (K⁺), and Calcium (Ca²⁺) move via ion channels.
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Aquaporins → Special channels for water molecules.
Difference Between Simple and Facilitated Diffusion
Feature | Simple Diffusion | Facilitated Diffusion |
---|---|---|
Energy Required? | No | No |
Transport Proteins? | No | Yes (Carrier/Channel Proteins) |
Speed | Slow | Faster |
Example | Oxygen, CO₂ | Glucose, Ions |
Conclusion
Facilitated diffusion is essential for transporting large, polar, or charged molecules that cannot pass through the cell membrane by simple diffusion. It plays a vital role in cellular homeostasis and nutrient absorption.
What is Facilitated Diffusion? – Meaning, Definition & Process
Meaning:
Facilitated diffusion is a type of passive transport where substances move across a cell membrane with the help of special proteins, but without using energy (ATP).
Definition:
Facilitated diffusion is the process of passive movement of molecules across the cell membrane through transport proteins, without the use of energy, along the concentration gradient (from high to low concentration).
Key Characteristics:
Feature | Facilitated Diffusion |
---|---|
Type of transport | Passive (no energy needed) |
Direction | High → Low concentration |
Requires membrane protein | Yes (channel or carrier proteins) |
Examples of substances | Glucose, amino acids, ions like Na⁺, K⁺ |
How It Works:
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A molecule (like glucose) is too large or charged to pass directly through the lipid bilayer.
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Transport proteins (either channel or carrier) in the membrane help the molecule pass through.
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The movement is still passive — it happens along the concentration gradient (from more to less).
Examples:
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Glucose transport into muscle and fat cells via GLUT proteins.
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Ion channels allow Na⁺, K⁺, and Cl⁻ to move across the membrane in neurons.
Why is Facilitated Diffusion Important?
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Allows large or polar molecules to enter or exit cells.
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Helps maintain homeostasis.
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Essential for cell signaling, muscle function, and nutrient absorption.
Comparison with Simple Diffusion:
Feature | Simple Diffusion | Facilitated Diffusion |
---|---|---|
Uses proteins? | ||
Energy used? | ||
Type of substances | Small, non-polar (O₂, CO₂) | Larger, polar (Glucose, Ions) |
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