Description: The article below is mainly designed to talk about the what is active transport. In this article, the author offers you a lecture on the types of active and passive transport. The lecture is clear because of the examples and diagram so it is useful for you to learn knowledge.
Welcome back. Today’s topic is cellular transport. We will be specifically talking about the two kinds of cell transport and comparing them as well as introducing you to how they work. Passive and active transport are the two ways that a cell moves things across a membrane. This is important for the cell because this is the way that the cell maintains balance, otherwise, known as homeostasis.
Active and passive transport. The two ways are different in one critical way. Active transport requires energy. We see the word active and energy. Passive transport requires no energy. Passive transport happens on its own and does not require any extra energy from the cell. You need to be familiar with the examples of active transport and passive transport.
Passive transport happens in two ways. Simple diffusion means molecules move from an area of high concentration to a low concentration. You can recall from diffusion and osmosis. It does not require energy. Diffusion can happen across the cell membrane through the lipid bilayer without anything else.
Involved passive transport also can occur through protein channels which allow mall certain molecules water for instance to move through. When the cell allows water to move through itself, we would call that osmosis because osmosis is the movement of water. Active transport involves protein pumps as well which are integrated into the protein. In this case they’re active and protein pumps require energy to work.
Endocytosis and Eexocytosis. Those are our types of active and passive transport. Now, I’m going to show you how each of these works. Passive transport. Diffusion and osmosis. Look at the diagram. The first thing you need to notice is the molecules that are moving here and you need to notice where the concentration is.
There’s a high concentration and there’s a low concentration. Molecules that are small and uncharged can simply move through the lipid bilayer. If you remember from what you learned about the cell membrane, you will know that these molecules can simply pass through from an area of high concentration to low concentration.
Large and charged molecules move through a special channel protein which is integrated or embedded in that lipid bilayer. They allow large molecules to pass through the cell membrane. Molecules that normally would be too large to pass through the lipid bilayer on their own. This is passive transport because they are moving from a high to a low. No energy is required for that to occur.
Sometimes passive transport involves a protein that is designed to carry a specific molecule. In this case, you’ll notice that this molecule fits in this protein that is embedded. The molecule is moving from high concentration to low concentration. It does not require energy even though the carrier protein is changing shape and moving.
Active transport. We’re going to begin by talking about exocytosis and endocytosis. In this case, you need to note where the interior of the cell is. This is done with a vesicle. this is a vesicle. A vesicle is a small package of material surrounded by a lipid bilayer. It’s like a mini cell within the cell. This vesicle moves up and fuses with the cell wall here and then opens up, allowing the molecules to exit the cell.
We have the cell interior and we have the exterior. Cells use this to move any molecule that they make on the inside to the outside. This is particularly important in your brain. Your brain is often moving signaling proteins from one nerve cell in your brain to another. It allows the nerve cells to communicate with each other.
Endocytosis is the opposite. The way that I remember this is endo. Endocytosis is moving endo the cell. I don’t know if it works. If it works for you, use it. Exocytosis out of the cell, endocytosis endo the cell or into the cell. We have the cell interior.
In this case, the molecules here are engulfed by the cell and brought into the inside of the cell forming a vesicle. Here is our vesicle. Both of these are active transport because it requires the cell to use energy to engulf the molecules or to push the molecules outside of itself to move that vesicle around to fuse it with the cell membrane.
Can you distinguish between the two? Which one is endocytosis? Which one is exocytosis? This one is endocytosis movement into the cell and this one is EXO cytosis movement of molecules out of the cell.
The last type of active transport is one that involves protein pumps. If you look at this diagram here, you will see our phospholipid bilayer with our heads and our tails. We have a protein that is integrated into it here.
In this case, the protein is a type of pumps called a proton pump. It’s pumping hydrogen ions. and you’ll also notice this word ATP. If you recall, ATP is the energy source of the cell. In this case, the ATP is being added to the protein pump.
The other thing I want you to notice is that the high concentration is here and the low concentration is here. In this case, if we have our hill, things are moving from low to high. If you roll a rock up a hill, it requires energy. Remember active transport is a type of transport that requires energy. Proton pumps are used to move molecules from an area of low concentration to high concentration.
That is the end of this mini lesson. On the types of cell transport, you need to be familiar with the differences between active and passive transport and the kinds of active and passive transports. By looking at a diagram, you’re going to be able to identify the five main kinds of passive and active transports.