Description: The article is mainly designed to talk about what is active transport. The author introduces passive transport and active transport with many vivid examples to you. The introduction is in detail so it is easy to understand.
Hi, it’s Mrs. Young here. Welcome to my podcast today on passive transport VS active transport. This is what we already know. We know that all cells are surrounded by a selectively permeable cell membrane.
You need to remember that selectively permeable means that the cell membrane let something in and something out but not everything can go freely. How do certain things such as water, carbon dioxide and oxygen get in and out of the cell? There’s a couple of different ways.
The first one we’re going to talk about is passive transport. This is the movement of materials through a cell membrane without the use of cellular energy. The cells don’t have to use up any of their precious energy to move things in and out. Some examples are diffusion and osmosis.
These are types of passive transport that we’ll talk about a little bit more. You can think about passive transport. It is like riding a bike downhill. If you ride a bike downhill, you’re moving and the bike is moving. You don’t have to do anything. You don’t have to exert any energy or pedal or do any of that to move. You sit back and enjoy the ride.
Let’s talk about diffusion. Diffusion is a form of passive transport. This is the movement of molecules from a area of higher concentration to an area of lower concentration. You can see here. You have a bunch of molecules up in the corner. They’re slowly diffusing until they’re all equally spaced.
Diffusion happens because you have a bunch of molecules concentrating into one small space. They’re going to start bouncing off each other. Molecules are always moving and when there’s a bunch of them all together, they’re going to collide and they’re going to keep colliding. As they hit each other, they’re going to start spreading out. That’s how diffusion works.
An example is that if you are at the front of a room and you spray some air freshener, the people in the back will eventually smell the air freshener that you sprayed. It may take a while but they will eventually be able to smell it because those particles have diffused through the air.
The other type of passive transport is osmosis. Osmosis is when is the diffusion of water across a selectively permeable membrane. osmosis only deals with water. That’s the important part here. You can see we have the selectively permeable membrane. That’s dashed line. On one side, we have the pink water molecules and on the other side, we have the big purple sucrose molecules. With osmosis, those water molecules are going to diffuse across that membrane to try and balance out those sucrose molecules. Now the water is equal on both sides.
Next, we have active transport. so active transport is the movement of materials across the cell membrane using cellular energy. You can think of this as riding a bike uphill. If you’re going uphill, you have to pedal and exert energy to try and overcome that gravity and get up the hill. That’s exactly what active transport is.
You would use active transport when you were trying to move particles that are in a lower concentration to a higher concentration. If you were in a high concentration, Those particles would want to move across to the lower. However, sometimes you have to get stuff from the lower end to the higher end so you’re going to have to exert some energy. That’s when you would use active transport.
Here’s a question. We’ve all seen the little cartoon of Garfield that says learning by osmosis based on what you’ve learned in this podcast, what makes this cartoon incorrect? You can pause if you need to think about it.
Dwight from the Office says learning through osmosis is false because osmosis is diffusion that applies specifically to water. Are you correct? In this poster, you need to say learning through diffusion. I hope that this will be helpful. Thank you for reading. Have a great day.