Difference Between Active Transport and Passive Transport

The key difference between active transport and passive transport is that the active transport moves molecules from low concentration to high concentration against the concentration gradient via a semi-permeable membrane while passive transport moves molecules along the concentration gradient from high concentration to low concentration. Furthermore, Active transport requires energy for molecular movements in contrast to passive transport, which does not require energy.

Active transport and passive transport are two processes that describe the movements of molecules from one region to another region as a result of a concentration gradient. The concentration gradient is a gradual change in concentration of particles in a solution between two regions and gradient results when there is an unequal distribution of ions across the cell membrane. So when movements of particles are against the concentration gradient, it is active transport, and if it’s towards the concentration gradient, it is a passive transport.

CONTENTS

1. Overview and Key Difference
2. What is Active Transport 
3. What is Passive Transport
4. Similarities Between Active Transport and Passive Transport
5. Side by Side Comparison – Active Transport vs Passive Transport in Tabular Form
6. Summary

What is Active Transport?

Active transport is the movement of ions or molecules from a region of low concentration to a region of high concentration via a semi-permeable membrane. It occurs against the concentration gradient. Hence it requires energy in the form of ATP. It is a vital process for a cell because important molecules such as glucose, ions, etc., accumulate inside the cell due to this process.

It’s a unidirectional process affected by metabolic inhibitors and temperature. Carrier proteins are involved in this process. Active transport occurs in two ways: primary active transport and secondary active transport.

What is Passive Transport?

Passive transport refers to the process which moves molecules from a region of high concentration region to a region of low concentration along the concentration gradient. Since it occurs towards the concentration gradient, it does not require energy.

Moreover, temperature and metabolic inhibitors do not affect this process. It is bidirectional. However passive transport does not allow the accumulation of molecules inside the cell. In contrast to active transport, passive transport is slow and less selective.

What are the Similarities Between Active Transport and Passive Transport?

• Active transport and passive transport involve in molecule movements.
• These processes use ion channels.
• Both are important for maintaining the homeostasis of the cells.

What is the Difference Between Active Transport and Passive Transport?

Active transport is the movement of molecules from a region of low concentration to a region of high concentration via a semi-permeable membrane against the concentration gradient. In contrast, passive transport is the movement of molecules from a region of high concentration to a region of low concentration along the concentration gradient. This is the difference between active transport and passive transport. Furthermore, the active transport requires energy in the form of ATP while the passive transport does not require energy.

Another difference between active transport and passive transport is that the active transport is a highly selective process. It is also a rapid, unidirectional process that allows accumulating of substances in the cell. This transport is affected by temperature as well as metabolic inhibitors. Passive transport, on the other hand, is a less selective process. Moreover, it is a slow, bidirectional process that does not allow the accumulation of substances in the cell. It is also not affected by temperature or metabolic inhibitors. In addition, Carrier proteins are involved in active transport, but not in passive transport.

The below infographic presents a more detailed analysis of the difference between active transport and passive transport.

Summary – Active Transport vs Passive Transport

Active transport and passive transport are two ways of molecular movements. Active transport moves molecules against the concentration gradient while passive transport moves molecules along the concentration gradient. Moreover, active transport uses energy, unlike passive transport, which does not need energy. Furthermore, active transport allows molecules to accumulate inside the cells while passive transport does not. This is the difference between active transport and passive transport.

Reference:

1. “Active Transport.” Khan Academy, Available here.

Image Courtesy:

1. “Scheme sodium-potassium pump-en” By LadyofHats Mariana Ruiz Villarreal – Own work. (Public Domain) via Commons Wikimedia
2. “Active-passive transport” By Lizanne Koch – own work with ChemBioDraw (Public Domain) via Commons Wikimedia