Passive Transport | Definition, Procedure & Examples

By | October 23, 2019

Passive Transport

Passive Transport Definition:

What is Passive transport: It is a process in which a molecule or ion passes through a cell membrane via a concentration gradient. It is also known as passive diffusion, which forms a region of high concentration to the region of low concentration.

It is totally opposite to active transport. As active transport needs energy in physical activity, while passive transports require no energy at all.

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Active Vs Passive Transport

Difference between Active transport and passive transport is described below in the given table :

Active Transport Passive Transport
Active transport pumps molecules through the cell membrane against the concentration gradient.Passive transport allows molecules to pass the cell membrane through a concentration gradient.
Utilize cellular energy in the form of ATPDoes not require cellular energy.
Endocytosis, exocytosis, secretion of substances into bloodstream and sodium/potassium pump are types of active transport.Diffusion, facilitated diffusion and osmosis are the types of passive transport
Allows molecules to pass the cell membrane, disrupting the equilibrium established by the diffusion
A dynamic equilibrium of water, nutrients, gasses, and wastes are maintained between cytosol and extracellular environment
Ions, large proteins, complex sugars, and cells are transportedWater soluble molecules like small monosaccharides,lipids, carbon dioxide, oxygen, and water are transported.
Required for the entrance of large, insoluble molecules into the cellAllows the maintenance of a delicate homeostasis between the cytosol and extracellular fluid

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Examples of Passive Transport:

Passive transport has four forms:

  • Simple diffusion
  • Facilitated diffusion
  • Filtration
  • Osmosis
  1. BAC Goin’ Up:

Once the ethanol like the ‘alcohol’ ingredient in wine, beer, and spirits enter the human body, then it hits the bloodstream at slow speed. Due to this reason, people can have BAC without feeling drunk, and because of this people become intoxicated with minutes of taking a shot.

This is due to molecules of ethanol enact simple diffusion with ease expert. Their ultra-microscopic size permits them to pass through cell and tissue membranes easily and affect the body without consuming energy.

      2. Neurotransmission Impossible:

The brain cells or ‘neurons’ rely on passive transport to communicate with each other easily. The spindly web of synapses in the human’s head relies on two ions, potassium (K+) and sodium (Na+) that works along with a gradient.

The sodium (Na+) and potassium (K+) ions move from the high concentration region toward the lower concentration region, such as the ethanol molecules. These neurons require help to do their works because they need little assistance. Instead of simple diffusion, they perform facilitated diffusion.

(Not) a Pile of Waste:

The intestine in human bodies does a lot more than push excrement from the bodies. The main job of intestine is extracting nutrients from the food. The human body extracts vitamins, nutrients, and minerals, etc. from the body using a form of passive transport.

The process of filtration occurs when we separate solids from the liquids or separate liquids from the gasses by a membrane. As it is, the nutrients (liquid) separate from the wastes (solid) of the body by passing through the intestine and into the bloodstream.

Fresh Veggies:

The “re-juicing” soaking raisins constitutes is also use a form of passive transport, this is osmosis.

There are different forms of passive transport that seek the equilibrium rather than the simple movement across the concentration gradient. The water passes by the raisin’s membrane not just to reach the less concentration region, but also to made grape equal to its outside environment.